Message ID | 1411983159-4692-1-git-send-email-anders.berg@avagotech.com |
---|---|
State | Superseded, archived |
Headers | show |
On 09/29/2014 03:02 PM, Anders Berg wrote: > Add I2C bus driver for the controller found in the LSI Axxia family SoCs. The > driver implements 10-bit addressing and SMBus transfer modes via emulation > (including SMBus block data read). > > Signed-off-by: Anders Berg <anders.berg@avagotech.com> > --- > > Changelog > > v2: > - Document the len <= 255 limitation > - return IRQ_HANDLED on unexpected IRQs > - fixed a number of style issues > - handle zero-length messages > - use reinit_completion() where appropriate > - enable for COMPILE_TEST > > .../devicetree/bindings/i2c/i2c-axxia.txt | 30 ++ > drivers/i2c/busses/Kconfig | 11 + > drivers/i2c/busses/Makefile | 1 + > drivers/i2c/busses/i2c-axxia.c | 561 +++++++++++++++++++++ > 4 files changed, 603 insertions(+) > create mode 100644 Documentation/devicetree/bindings/i2c/i2c-axxia.txt > create mode 100644 drivers/i2c/busses/i2c-axxia.c > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-axxia.txt b/Documentation/devicetree/bindings/i2c/i2c-axxia.txt > new file mode 100644 > index 0000000..2296d78 > --- /dev/null > +++ b/Documentation/devicetree/bindings/i2c/i2c-axxia.txt > @@ -0,0 +1,30 @@ > +LSI Axxia I2C > + > +Required properties : > +- compatible : Must be "lsi,api2c" > +- reg : Offset and length of the register set for the device > +- interrupts : the interrupt specifier > +- #address-cells : Must be <1>; > +- #size-cells : Must be <0>; > +- clock-names : Must contain "i2c". > +- clocks: Must contain an entry for each name in clock-names. See the common > + clock bindings. > + > +Optional properties : > +- clock-frequency : Desired I2C bus clock frequency in Hz. If not specified, > + the default 100 kHz frequency will be used. As only Normal and Fast modes > + are supported, possible values are 100000 and 400000. > + > +Example : > + > +i2c@02010084000 { > + compatible = "lsi,api2c"; > + device_type = "i2c"; > + #address-cells = <1>; > + #size-cells = <0>; > + reg = <0x20 0x10084000 0x00 0x1000>; > + interrupts = <0 19 4>; > + clocks = <&clk_per>; > + clock-names = "i2c"; > + clock-frequency = <400000>; > +}; > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig > index 2ac87fa..8983474 100644 > --- a/drivers/i2c/busses/Kconfig > +++ b/drivers/i2c/busses/Kconfig > @@ -77,6 +77,17 @@ config I2C_AMD8111 > This driver can also be built as a module. If so, the module > will be called i2c-amd8111. > > +config I2C_AXXIA > + tristate "Axxia I2C controller" > + depends on ARCH_AXXIA || COMPILE_TEST > + default ARCH_AXXIA > + help > + Say yes if you want to support the I2C bus on Axxia platforms. > + > + Please note that this controller is limited to transfers of maximum > + 255 bytes in length. Any attempt to to a larger transfer will return > + an error. > + > config I2C_I801 > tristate "Intel 82801 (ICH/PCH)" > depends on PCI > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile > index 49bf07e..5899edb 100644 > --- a/drivers/i2c/busses/Makefile > +++ b/drivers/i2c/busses/Makefile > @@ -12,6 +12,7 @@ obj-$(CONFIG_I2C_ALI15X3) += i2c-ali15x3.o > obj-$(CONFIG_I2C_AMD756) += i2c-amd756.o > obj-$(CONFIG_I2C_AMD756_S4882) += i2c-amd756-s4882.o > obj-$(CONFIG_I2C_AMD8111) += i2c-amd8111.o > +obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o > obj-$(CONFIG_I2C_I801) += i2c-i801.o > obj-$(CONFIG_I2C_ISCH) += i2c-isch.o > obj-$(CONFIG_I2C_ISMT) += i2c-ismt.o > diff --git a/drivers/i2c/busses/i2c-axxia.c b/drivers/i2c/busses/i2c-axxia.c > new file mode 100644 > index 0000000..c6faca1 > --- /dev/null > +++ b/drivers/i2c/busses/i2c-axxia.c > @@ -0,0 +1,561 @@ > +/* > + * This driver implements I2C master functionality using the LSI API2C > + * controller. > + * > + * NOTE: The controller has a limitation in that it can only do transfers of > + * maximum 255 bytes at a time. If a larger transfer is attempted, error code > + * (-EINVAL) is returned. > + * > + * This software is licensed under the terms of the GNU General Public > + * License version 2, as published by the Free Software Foundation, and > + * may be copied, distributed, and modified under those terms. > + */ > +#include <linux/clk.h> > +#include <linux/clkdev.h> > +#include <linux/err.h> > +#include <linux/i2c.h> > +#include <linux/init.h> > +#include <linux/interrupt.h> > +#include <linux/module.h> > +#include <linux/io.h> > +#include <linux/kernel.h> > +#include <linux/platform_device.h> > + > +#define SCL_WAIT_TIMEOUT_NS 25000000 > +#define I2C_XFER_TIMEOUT (msecs_to_jiffies(250)) > +#define I2C_STOP_TIMEOUT (msecs_to_jiffies(100)) > +#define FIFO_SIZE 8 > + > +#define GLOBAL_CONTROL 0x00 > +#define GLOBAL_MST_EN BIT(0) > +#define GLOBAL_SLV_EN BIT(1) > +#define GLOBAL_IBML_EN BIT(2) > +#define INTERRUPT_STATUS 0x04 > +#define INTERRUPT_ENABLE 0x08 > +#define INT_SLV BIT(1) > +#define INT_MST BIT(0) > +#define WAIT_TIMER_CONTROL 0x0c > +#define WT_EN BIT(15) > +#define WT_VALUE(_x) ((_x) & 0x7fff) > +#define IBML_TIMEOUT 0x10 > +#define IBML_LOW_MEXT 0x14 > +#define IBML_LOW_SEXT 0x18 > +#define TIMER_CLOCK_DIV 0x1c > +#define I2C_BUS_MONITOR 0x20 > +#define SOFT_RESET 0x24 > +#define MST_COMMAND 0x28 > +#define CMD_BUSY (1<<3) > +#define CMD_MANUAL (0x00 | CMD_BUSY) > +#define CMD_AUTO (0x01 | CMD_BUSY) > +#define MST_RX_XFER 0x2c > +#define MST_TX_XFER 0x30 > +#define MST_ADDR_1 0x34 > +#define MST_ADDR_2 0x38 > +#define MST_DATA 0x3c > +#define MST_TX_FIFO 0x40 > +#define MST_RX_FIFO 0x44 > +#define MST_INT_ENABLE 0x48 > +#define MST_INT_STATUS 0x4c > +#define MST_STATUS_RFL (1 << 13) /* RX FIFO serivce */ > +#define MST_STATUS_TFL (1 << 12) /* TX FIFO service */ > +#define MST_STATUS_SNS (1 << 11) /* Manual mode done */ > +#define MST_STATUS_SS (1 << 10) /* Automatic mode done */ > +#define MST_STATUS_SCC (1 << 9) /* Stop complete */ > +#define MST_STATUS_IP (1 << 8) /* Invalid parameter */ > +#define MST_STATUS_TSS (1 << 7) /* Timeout */ > +#define MST_STATUS_AL (1 << 6) /* Arbitration lost */ > +#define MST_STATUS_ND (1 << 5) /* NAK on data phase */ > +#define MST_STATUS_NA (1 << 4) /* NAK on address phase */ > +#define MST_STATUS_NAK (MST_STATUS_NA | \ > + MST_STATUS_ND) > +#define MST_STATUS_ERR (MST_STATUS_NAK | \ > + MST_STATUS_AL | \ > + MST_STATUS_IP | \ > + MST_STATUS_TSS) > +#define MST_TX_BYTES_XFRD 0x50 > +#define MST_RX_BYTES_XFRD 0x54 > +#define SCL_HIGH_PERIOD 0x80 > +#define SCL_LOW_PERIOD 0x84 > +#define SPIKE_FLTR_LEN 0x88 > +#define SDA_SETUP_TIME 0x8c > +#define SDA_HOLD_TIME 0x90 > + > +/** > + * axxia_i2c_dev - I2C device context > + * @base: pointer to register struct > + * @msg: pointer to current message > + * @msg_xfrd: number of bytes transferred in msg > + * @msg_err: error code for completed message > + * @msg_complete: xfer completion object > + * @dev: device reference > + * @adapter: core i2c abstraction > + * @i2c_clk: clock reference for i2c input clock > + * @bus_clk_rate: current i2c bus clock rate > + */ > +struct axxia_i2c_dev { > + void __iomem *base; > + struct i2c_msg *msg; > + size_t msg_xfrd; > + int msg_err; > + struct completion msg_complete; > + struct device *dev; > + struct i2c_adapter adapter; > + struct clk *i2c_clk; > + u32 bus_clk_rate; > +}; > + > +static void i2c_int_disable(struct axxia_i2c_dev *idev, u32 mask) > +{ > + u32 int_en; > + > + int_en = readl(idev->base + MST_INT_ENABLE); > + writel(int_en & ~mask, idev->base + MST_INT_ENABLE); > +} > + > +static void i2c_int_enable(struct axxia_i2c_dev *idev, u32 mask) > +{ > + u32 int_en; > + > + int_en = readl(idev->base + MST_INT_ENABLE); > + writel(int_en | mask, idev->base + MST_INT_ENABLE); > +} > + > +/** > + * ns_to_clk - Convert time (ns) to clock cycles for the given clock frequency. > + */ > +static u32 ns_to_clk(u64 ns, u32 clk_mhz) > +{ > + return div_u64(ns * clk_mhz, 1000); > +} > + > +static int axxia_i2c_init(struct axxia_i2c_dev *idev) > +{ > + u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate; > + u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000; > + u32 t_setup; > + u32 t_high, t_low; > + u32 tmo_clk; > + u32 prescale; > + unsigned long timeout; > + > + dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n", > + idev->bus_clk_rate, clk_mhz, divisor); > + > + /* Reset controller */ > + writel(0x01, idev->base + SOFT_RESET); > + timeout = jiffies + msecs_to_jiffies(100); > + while (readl(idev->base + SOFT_RESET) & 1) { > + if (time_after(jiffies, timeout)) { > + dev_warn(idev->dev, "Soft reset failed\n"); > + break; > + } > + } > + > + /* Enable Master Mode */ > + writel(0x1, idev->base + GLOBAL_CONTROL); > + > + if (idev->bus_clk_rate <= 100000) { > + /* Standard mode SCL 50/50, tSU:DAT = 250 ns */ > + t_high = divisor * 1 / 2; > + t_low = divisor * 1 / 2; > + t_setup = ns_to_clk(250, clk_mhz); > + } else { > + /* Fast mode SCL 33/66, tSU:DAT = 100 ns */ > + t_high = divisor * 1 / 3; > + t_low = divisor * 2 / 3; > + t_setup = ns_to_clk(100, clk_mhz); > + } > + > + /* SCL High Time */ > + writel(t_high, idev->base + SCL_HIGH_PERIOD); > + /* SCL Low Time */ > + writel(t_low, idev->base + SCL_LOW_PERIOD); > + /* SDA Setup Time */ > + writel(t_setup, idev->base + SDA_SETUP_TIME); > + /* SDA Hold Time, 300ns */ > + writel(ns_to_clk(300, clk_mhz), idev->base + SDA_HOLD_TIME); > + /* Filter <50ns spikes */ > + writel(ns_to_clk(50, clk_mhz), idev->base + SPIKE_FLTR_LEN); > + > + /* Configure Time-Out Registers */ > + tmo_clk = ns_to_clk(SCL_WAIT_TIMEOUT_NS, clk_mhz); > + > + /* Find prescaler value that makes tmo_clk fit in 15-bits counter. */ > + for (prescale = 0; prescale < 15; ++prescale) { > + if (tmo_clk <= 0x7fff) > + break; > + tmo_clk >>= 1; > + } > + if (tmo_clk > 0x7fff) > + tmo_clk = 0x7fff; > + > + /* Prescale divider (log2) */ > + writel(prescale, idev->base + TIMER_CLOCK_DIV); > + /* Timeout in divided clocks */ > + writel(WT_EN | WT_VALUE(tmo_clk), idev->base + WAIT_TIMER_CONTROL); > + > + /* Mask all master interrupt bits */ > + i2c_int_disable(idev, ~0); > + > + /* Interrupt enable */ > + writel(0x01, idev->base + INTERRUPT_ENABLE); > + > + return 0; > +} > + > +static int i2c_m_rd(const struct i2c_msg *msg) > +{ > + return (msg->flags & I2C_M_RD) != 0; > +} > + > +static int i2c_m_ten(const struct i2c_msg *msg) > +{ > + return (msg->flags & I2C_M_TEN) != 0; > +} > + > +static int i2c_m_recv_len(const struct i2c_msg *msg) > +{ > + return (msg->flags & I2C_M_RECV_LEN) != 0; > +} > + > +/** > + * axxia_i2c_empty_rx_fifo - Fetch data from RX FIFO and update SMBus block > + * transfer length if this is the first byte of such a transfer. > + */ > +static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev) > +{ > + struct i2c_msg *msg = idev->msg; > + size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO); > + int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd); > + > + while (bytes_to_transfer-- > 0) { > + int c = readl(idev->base + MST_DATA); > + > + if (idev->msg_xfrd == 0 && i2c_m_recv_len(msg)) { > + /* > + * Check length byte for SMBus block read > + */ > + if (c <= 0 || c > I2C_SMBUS_BLOCK_MAX) { > + idev->msg_err = -EPROTO; > + i2c_int_disable(idev, ~0); > + complete(&idev->msg_complete); > + break; > + } > + msg->len = 1 + c; > + writel(msg->len, idev->base + MST_RX_XFER); > + } > + msg->buf[idev->msg_xfrd++] = c; > + } > + > + return 0; > +} > + > +/** > + * axxia_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer. > + * @return: Number of bytes left to transfer. > + */ > +static int axxia_i2c_fill_tx_fifo(struct axxia_i2c_dev *idev) > +{ > + struct i2c_msg *msg = idev->msg; > + size_t tx_fifo_avail = FIFO_SIZE - readl(idev->base + MST_TX_FIFO); > + int bytes_to_transfer = min(tx_fifo_avail, msg->len - idev->msg_xfrd); > + int ret = msg->len - idev->msg_xfrd - bytes_to_transfer; > + > + while (bytes_to_transfer-- > 0) > + writel(msg->buf[idev->msg_xfrd++], idev->base + MST_DATA); > + > + return ret; > +} > + > +static irqreturn_t axxia_i2c_isr(int irq, void *_dev) > +{ > + struct axxia_i2c_dev *idev = _dev; > + u32 status; > + > + if (!(readl(idev->base + INTERRUPT_STATUS) & INT_MST)) > + return IRQ_NONE; > + > + /* Read interrupt status bits */ > + status = readl(idev->base + MST_INT_STATUS); > + > + if (!idev->msg) { > + dev_warn(idev->dev, "unexpected interrupt"); Missed terminating new line '\n' > + goto out; > + } > + > + /* RX FIFO needs service? */ > + if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL)) > + axxia_i2c_empty_rx_fifo(idev); > + > + /* TX FIFO needs service? */ > + if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) { > + if (axxia_i2c_fill_tx_fifo(idev) == 0) > + i2c_int_disable(idev, MST_STATUS_TFL); > + } > + > + if (status & MST_STATUS_SCC) { > + /* Stop completed */ > + i2c_int_disable(idev, ~0); > + complete(&idev->msg_complete); > + } else if (status & MST_STATUS_SNS) { > + /* Transfer done */ > + i2c_int_disable(idev, ~0); > + if (i2c_m_rd(idev->msg) && idev->msg_xfrd < idev->msg->len) > + axxia_i2c_empty_rx_fifo(idev); > + complete(&idev->msg_complete); > + } else if (unlikely(status & MST_STATUS_ERR)) { > + /* Transfer error */ > + i2c_int_disable(idev, ~0); > + if (status & MST_STATUS_AL) > + idev->msg_err = -EAGAIN; > + else if (status & MST_STATUS_NAK) > + idev->msg_err = -ENXIO; > + else > + idev->msg_err = -EIO; > + dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u tx=%u/%u\n", > + status, > + idev->msg->addr, > + readl(idev->base + MST_RX_BYTES_XFRD), > + readl(idev->base + MST_RX_XFER), > + readl(idev->base + MST_TX_BYTES_XFRD), > + readl(idev->base + MST_TX_XFER)); > + complete(&idev->msg_complete); > + } > + > +out: > + /* Clear interrupt */ > + writel(INT_MST, idev->base + INTERRUPT_STATUS); > + > + return IRQ_HANDLED; > +} > + Its looks good if we move the entire ISR above probe/remove functionalities... > +static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg) > +{ > + u32 int_mask = MST_STATUS_ERR | MST_STATUS_SNS; > + u32 rx_xfer, tx_xfer; > + u32 addr_1, addr_2; > + int ret; > + > + if (msg->len > 255) { > + dev_warn(idev->dev, "unsupported length %u\n", msg->len); > + return -EINVAL; > + } > + > + idev->msg = msg; > + idev->msg_xfrd = 0; > + idev->msg_err = 0; > + reinit_completion(&idev->msg_complete); > + > + if (i2c_m_ten(msg)) { > + /* 10-bit address > + * addr_1: 5'b11110 | addr[9:8] | (R/nW) > + * addr_2: addr[7:0] > + */ > + addr_1 = 0xF0 | ((msg->addr >> 7) & 0x06); > + addr_2 = msg->addr & 0xFF; > + } else { > + /* 7-bit address > + * addr_1: addr[6:0] | (R/nW) > + * addr_2: dont care > + */ > + addr_1 = (msg->addr << 1) & 0xFF; > + addr_2 = 0; > + } > + > + if (i2c_m_rd(msg)) { > + /* I2C read transfer */ > + rx_xfer = i2c_m_recv_len(msg) ? I2C_SMBUS_BLOCK_MAX : msg->len; > + tx_xfer = 0; > + addr_1 |= 1; /* Set the R/nW bit of the address */ > + } else { > + /* I2C write transfer */ > + rx_xfer = 0; > + tx_xfer = msg->len; > + } > + > + writel(rx_xfer, idev->base + MST_RX_XFER); > + writel(tx_xfer, idev->base + MST_TX_XFER); > + writel(addr_1, idev->base + MST_ADDR_1); > + writel(addr_2, idev->base + MST_ADDR_2); > + > + if (i2c_m_rd(msg)) > + int_mask |= MST_STATUS_RFL; > + else if (axxia_i2c_fill_tx_fifo(idev) != 0) > + int_mask |= MST_STATUS_TFL; > + > + /* Start manual mode */ > + writel(CMD_MANUAL, idev->base + MST_COMMAND); > + > + i2c_int_enable(idev, int_mask); > + > + ret = wait_for_completion_timeout(&idev->msg_complete, > + I2C_XFER_TIMEOUT); > + > + i2c_int_disable(idev, int_mask); > + > + if (readl(idev->base + MST_COMMAND) & CMD_BUSY) > + dev_warn(idev->dev, "busy after xfer"); '\n' > + > + if (ret == 0) > + idev->msg_err = -ETIMEDOUT; > + > + if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO) > + axxia_i2c_init(idev); > + > + return idev->msg_err; > +} > + > +static int axxia_i2c_stop(struct axxia_i2c_dev *idev) > +{ > + u32 int_mask = MST_STATUS_ERR | MST_STATUS_SCC; > + int ret; > + > + reinit_completion(&idev->msg_complete); > + > + /* Issue stop */ > + writel(0xb, idev->base + MST_COMMAND); > + i2c_int_enable(idev, int_mask); > + ret = wait_for_completion_timeout(&idev->msg_complete, > + I2C_STOP_TIMEOUT); > + i2c_int_disable(idev, int_mask); > + if (ret == 0) > + return -ETIMEDOUT; > + > + if (readl(idev->base + MST_COMMAND) & CMD_BUSY) > + dev_warn(idev->dev, "busy after stop"); '\n' > + > + return 0; > +} > + > +static int > +axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) > +{ > + struct axxia_i2c_dev *idev = i2c_get_adapdata(adap); > + int i; > + int ret = 0; > + > + for (i = 0; ret == 0 && i < num; ++i) > + ret = axxia_i2c_xfer_msg(idev, &msgs[i]); > + > + axxia_i2c_stop(idev); > + > + return ret ? : i; > +} > + > +static u32 axxia_i2c_func(struct i2c_adapter *adap) > +{ > + u32 caps = (I2C_FUNC_I2C | > + I2C_FUNC_10BIT_ADDR | > + I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA); > + return caps; return (I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA); > +} > + > +static const struct i2c_algorithm axxia_i2c_algo = { > + .master_xfer = axxia_i2c_xfer, > + .functionality = axxia_i2c_func, > +}; > + > +static int axxia_i2c_probe(struct platform_device *pdev) > +{ > + struct device_node *np = pdev->dev.of_node; > + struct axxia_i2c_dev *idev = NULL; > + struct resource *res; > + void __iomem *base; > + int irq; > + int ret = 0; > + > + idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL); > + if (!idev) > + return -ENOMEM; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); Error checking on *res*...? We should *return* on platform_get_resource() failure.. > + base = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(base)) > + return PTR_ERR(base); > + > + irq = platform_get_irq(pdev, 0); > + if (irq < 0) { > + dev_err(&pdev->dev, "missing interrupt resource\n"); > + return irq; > + } > + > + idev->i2c_clk = devm_clk_get(&pdev->dev, "i2c"); > + if (IS_ERR(idev->i2c_clk)) { > + dev_err(&pdev->dev, "missing clock"); Missed terminating new line '\n' > + return PTR_ERR(idev->i2c_clk); > + } > + > + idev->base = base; > + idev->dev = &pdev->dev; > + init_completion(&idev->msg_complete); > + > + of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate); > + if (idev->bus_clk_rate == 0) > + idev->bus_clk_rate = 100000; /* default clock rate */ > + > + ret = axxia_i2c_init(idev); > + if (ret) { > + dev_err(&pdev->dev, "failed to initialize"); Missed terminating new line '\n' > + return ret; > + } > + > + ret = devm_request_irq(&pdev->dev, irq, axxia_i2c_isr, 0, > + pdev->name, idev); > + if (ret) { > + dev_err(&pdev->dev, "failed to claim IRQ%d\n", irq); > + return ret; > + } > + > + clk_prepare_enable(idev->i2c_clk); > + > + i2c_set_adapdata(&idev->adapter, idev); > + strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name)); > + idev->adapter.owner = THIS_MODULE; > + idev->adapter.class = I2C_CLASS_HWMON; > + idev->adapter.algo = &axxia_i2c_algo; > + idev->adapter.dev.parent = &pdev->dev; > + idev->adapter.dev.of_node = pdev->dev.of_node; > + > + platform_set_drvdata(pdev, idev); > + > + ret = i2c_add_adapter(&idev->adapter); > + if (ret) { > + dev_err(&pdev->dev, "failed to add adapter\n"); > + return ret; > + } > + > + return 0; > +} > + > +static int axxia_i2c_remove(struct platform_device *pdev) > +{ > + struct axxia_i2c_dev *idev = platform_get_drvdata(pdev); > + > + clk_disable_unprepare(idev->i2c_clk); > + i2c_del_adapter(&idev->adapter); > + > + return 0; > +} > + > +/* Match table for of_platform binding */ > +static const struct of_device_id axxia_i2c_of_match[] = { > + { .compatible = "lsi,api2c", }, > + {}, > +}; > + > +MODULE_DEVICE_TABLE(of, axxia_i2c_of_match); > + > +static struct platform_driver axxia_i2c_driver = { > + .probe = axxia_i2c_probe, > + .remove = axxia_i2c_remove, > + .driver = { > + .name = "axxia-i2c", > + .of_match_table = axxia_i2c_of_match, > + }, > +}; > + > +module_platform_driver(axxia_i2c_driver); > + > +MODULE_DESCRIPTION("Axxia I2C Bus driver"); > +MODULE_AUTHOR("Anders Berg <anders.berg@lsi.com>"); > +MODULE_LICENSE("GPL v2");
On 09/29/2014 03:43 PM, Wolfram Sang wrote: >>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> Error checking on *res*...? >> >> We should *return* on platform_get_resource() failure.. >> >>> + base = devm_ioremap_resource(&pdev->dev, res); > Nope. devm_ioremap_resource does that. > Yes it will [1]. Thanks for the clarification. [1]:http://lxr.free-electrons.com/source/lib/devres.c#L117
> >+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > Error checking on *res*...? > > We should *return* on platform_get_resource() failure.. > > >+ base = devm_ioremap_resource(&pdev->dev, res); Nope. devm_ioremap_resource does that.
On Mon, Sep 29, 2014 at 12:07 PM, Varka Bhadram <varkabhadram@gmail.com> wrote: > On 09/29/2014 03:02 PM, Anders Berg wrote: >> >> Add I2C bus driver for the controller found in the LSI Axxia family SoCs. >> The >> driver implements 10-bit addressing and SMBus transfer modes via emulation >> (including SMBus block data read). >> >> Signed-off-by: Anders Berg <anders.berg@avagotech.com> >> --- >> (...) >> + >> + if (!idev->msg) { >> + dev_warn(idev->dev, "unexpected interrupt"); > > > Missed terminating new line '\n' > Right, I'll fix that (all occurrences) > >> + goto out; >> + } >> + >> + /* RX FIFO needs service? */ >> + if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL)) >> + axxia_i2c_empty_rx_fifo(idev); >> + >> + /* TX FIFO needs service? */ >> + if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) { >> + if (axxia_i2c_fill_tx_fifo(idev) == 0) >> + i2c_int_disable(idev, MST_STATUS_TFL); >> + } >> + >> + if (status & MST_STATUS_SCC) { >> + /* Stop completed */ >> + i2c_int_disable(idev, ~0); >> + complete(&idev->msg_complete); >> + } else if (status & MST_STATUS_SNS) { >> + /* Transfer done */ >> + i2c_int_disable(idev, ~0); >> + if (i2c_m_rd(idev->msg) && idev->msg_xfrd < >> idev->msg->len) >> + axxia_i2c_empty_rx_fifo(idev); >> + complete(&idev->msg_complete); >> + } else if (unlikely(status & MST_STATUS_ERR)) { >> + /* Transfer error */ >> + i2c_int_disable(idev, ~0); >> + if (status & MST_STATUS_AL) >> + idev->msg_err = -EAGAIN; >> + else if (status & MST_STATUS_NAK) >> + idev->msg_err = -ENXIO; >> + else >> + idev->msg_err = -EIO; >> + dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u >> tx=%u/%u\n", >> + status, >> + idev->msg->addr, >> + readl(idev->base + MST_RX_BYTES_XFRD), >> + readl(idev->base + MST_RX_XFER), >> + readl(idev->base + MST_TX_BYTES_XFRD), >> + readl(idev->base + MST_TX_XFER)); >> + complete(&idev->msg_complete); >> + } >> + >> +out: >> + /* Clear interrupt */ >> + writel(INT_MST, idev->base + INTERRUPT_STATUS); >> + >> + return IRQ_HANDLED; >> +} >> + > > > Its looks good if we move the entire ISR above probe/remove > functionalities... > Not sure what you mean here... The ISR _is_ above probe/remove. /Anders -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/29/2014 04:43 PM, Anders Berg wrote: > On Mon, Sep 29, 2014 at 12:07 PM, Varka Bhadram <varkabhadram@gmail.com> wrote: >> On 09/29/2014 03:02 PM, Anders Berg wrote: >>> Add I2C bus driver for the controller found in the LSI Axxia family SoCs. >>> The >>> driver implements 10-bit addressing and SMBus transfer modes via emulation >>> (including SMBus block data read). >>> >>> Signed-off-by: Anders Berg <anders.berg@avagotech.com> >>> --- >>> > (...) >>> + >>> + if (!idev->msg) { >>> + dev_warn(idev->dev, "unexpected interrupt"); >> >> Missed terminating new line '\n' >> > Right, I'll fix that (all occurrences) > >>> + goto out; >>> + } >>> + >>> + /* RX FIFO needs service? */ >>> + if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL)) >>> + axxia_i2c_empty_rx_fifo(idev); >>> + >>> + /* TX FIFO needs service? */ >>> + if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) { >>> + if (axxia_i2c_fill_tx_fifo(idev) == 0) >>> + i2c_int_disable(idev, MST_STATUS_TFL); >>> + } >>> + >>> + if (status & MST_STATUS_SCC) { >>> + /* Stop completed */ >>> + i2c_int_disable(idev, ~0); >>> + complete(&idev->msg_complete); >>> + } else if (status & MST_STATUS_SNS) { >>> + /* Transfer done */ >>> + i2c_int_disable(idev, ~0); >>> + if (i2c_m_rd(idev->msg) && idev->msg_xfrd < >>> idev->msg->len) >>> + axxia_i2c_empty_rx_fifo(idev); >>> + complete(&idev->msg_complete); >>> + } else if (unlikely(status & MST_STATUS_ERR)) { >>> + /* Transfer error */ >>> + i2c_int_disable(idev, ~0); >>> + if (status & MST_STATUS_AL) >>> + idev->msg_err = -EAGAIN; >>> + else if (status & MST_STATUS_NAK) >>> + idev->msg_err = -ENXIO; >>> + else >>> + idev->msg_err = -EIO; >>> + dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u >>> tx=%u/%u\n", >>> + status, >>> + idev->msg->addr, >>> + readl(idev->base + MST_RX_BYTES_XFRD), >>> + readl(idev->base + MST_RX_XFER), >>> + readl(idev->base + MST_TX_BYTES_XFRD), >>> + readl(idev->base + MST_TX_XFER)); >>> + complete(&idev->msg_complete); >>> + } >>> + >>> +out: >>> + /* Clear interrupt */ >>> + writel(INT_MST, idev->base + INTERRUPT_STATUS); >>> + >>> + return IRQ_HANDLED; >>> +} >>> + >> >> Its looks good if we move the entire ISR above probe/remove >> functionalities... >> > Not sure what you mean here... The ISR _is_ above probe/remove. I mean ISR should immediately above probe functionality. So that we can see devm_request_irq(..,isr_name,..) ISR directly with isr name..
> >>Its looks good if we move the entire ISR above probe/remove > >>functionalities... > >> > >Not sure what you mean here... The ISR _is_ above probe/remove. > > I mean ISR should immediately above probe functionality. So that we can see > devm_request_irq(..,isr_name,..) ISR directly with isr name.. Not so important to me, '*' in vim does that whereever the function is. Still, thanks for the review!
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig > index 2ac87fa..8983474 100644 > --- a/drivers/i2c/busses/Kconfig > +++ b/drivers/i2c/busses/Kconfig > @@ -77,6 +77,17 @@ config I2C_AMD8111 > This driver can also be built as a module. If so, the module > will be called i2c-amd8111. > > +config I2C_AXXIA > + tristate "Axxia I2C controller" > + depends on ARCH_AXXIA || COMPILE_TEST > + default ARCH_AXXIA > + help > + Say yes if you want to support the I2C bus on Axxia platforms. > + > + Please note that this controller is limited to transfers of maximum > + 255 bytes in length. Any attempt to to a larger transfer will return > + an error. > + > config I2C_I801 > tristate "Intel 82801 (ICH/PCH)" > depends on PCI > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile > index 49bf07e..5899edb 100644 > --- a/drivers/i2c/busses/Makefile > +++ b/drivers/i2c/busses/Makefile > @@ -12,6 +12,7 @@ obj-$(CONFIG_I2C_ALI15X3) += i2c-ali15x3.o > obj-$(CONFIG_I2C_AMD756) += i2c-amd756.o > obj-$(CONFIG_I2C_AMD756_S4882) += i2c-amd756-s4882.o > obj-$(CONFIG_I2C_AMD8111) += i2c-amd8111.o > +obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o > obj-$(CONFIG_I2C_I801) += i2c-i801.o > obj-$(CONFIG_I2C_ISCH) += i2c-isch.o > obj-$(CONFIG_I2C_ISMT) += i2c-ismt.o Please put it to the embedded section. ... > + idev->adapter.class = I2C_CLASS_HWMON; Being a DT driver, you most probably don't need this.
On Fri, Oct 3, 2014 at 12:36 PM, Wolfram Sang <wsa@the-dreams.de> wrote: >> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig >> index 2ac87fa..8983474 100644 >> --- a/drivers/i2c/busses/Kconfig >> +++ b/drivers/i2c/busses/Kconfig >> @@ -77,6 +77,17 @@ config I2C_AMD8111 >> This driver can also be built as a module. If so, the module >> will be called i2c-amd8111. >> >> +config I2C_AXXIA >> + tristate "Axxia I2C controller" >> + depends on ARCH_AXXIA || COMPILE_TEST >> + default ARCH_AXXIA >> + help >> + Say yes if you want to support the I2C bus on Axxia platforms. >> + >> + Please note that this controller is limited to transfers of maximum >> + 255 bytes in length. Any attempt to to a larger transfer will return >> + an error. >> + >> config I2C_I801 >> tristate "Intel 82801 (ICH/PCH)" >> depends on PCI >> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile >> index 49bf07e..5899edb 100644 >> --- a/drivers/i2c/busses/Makefile >> +++ b/drivers/i2c/busses/Makefile >> @@ -12,6 +12,7 @@ obj-$(CONFIG_I2C_ALI15X3) += i2c-ali15x3.o >> obj-$(CONFIG_I2C_AMD756) += i2c-amd756.o >> obj-$(CONFIG_I2C_AMD756_S4882) += i2c-amd756-s4882.o >> obj-$(CONFIG_I2C_AMD8111) += i2c-amd8111.o >> +obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o >> obj-$(CONFIG_I2C_I801) += i2c-i801.o >> obj-$(CONFIG_I2C_ISCH) += i2c-isch.o >> obj-$(CONFIG_I2C_ISMT) += i2c-ismt.o > > Please put it to the embedded section. > OK. > ... > >> + idev->adapter.class = I2C_CLASS_HWMON; > > Being a DT driver, you most probably don't need this. > Right, thanks. I'll fix up these and submit a v3. /Anders -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/devicetree/bindings/i2c/i2c-axxia.txt b/Documentation/devicetree/bindings/i2c/i2c-axxia.txt new file mode 100644 index 0000000..2296d78 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-axxia.txt @@ -0,0 +1,30 @@ +LSI Axxia I2C + +Required properties : +- compatible : Must be "lsi,api2c" +- reg : Offset and length of the register set for the device +- interrupts : the interrupt specifier +- #address-cells : Must be <1>; +- #size-cells : Must be <0>; +- clock-names : Must contain "i2c". +- clocks: Must contain an entry for each name in clock-names. See the common + clock bindings. + +Optional properties : +- clock-frequency : Desired I2C bus clock frequency in Hz. If not specified, + the default 100 kHz frequency will be used. As only Normal and Fast modes + are supported, possible values are 100000 and 400000. + +Example : + +i2c@02010084000 { + compatible = "lsi,api2c"; + device_type = "i2c"; + #address-cells = <1>; + #size-cells = <0>; + reg = <0x20 0x10084000 0x00 0x1000>; + interrupts = <0 19 4>; + clocks = <&clk_per>; + clock-names = "i2c"; + clock-frequency = <400000>; +}; diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 2ac87fa..8983474 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -77,6 +77,17 @@ config I2C_AMD8111 This driver can also be built as a module. If so, the module will be called i2c-amd8111. +config I2C_AXXIA + tristate "Axxia I2C controller" + depends on ARCH_AXXIA || COMPILE_TEST + default ARCH_AXXIA + help + Say yes if you want to support the I2C bus on Axxia platforms. + + Please note that this controller is limited to transfers of maximum + 255 bytes in length. Any attempt to to a larger transfer will return + an error. + config I2C_I801 tristate "Intel 82801 (ICH/PCH)" depends on PCI diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 49bf07e..5899edb 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -12,6 +12,7 @@ obj-$(CONFIG_I2C_ALI15X3) += i2c-ali15x3.o obj-$(CONFIG_I2C_AMD756) += i2c-amd756.o obj-$(CONFIG_I2C_AMD756_S4882) += i2c-amd756-s4882.o obj-$(CONFIG_I2C_AMD8111) += i2c-amd8111.o +obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o obj-$(CONFIG_I2C_I801) += i2c-i801.o obj-$(CONFIG_I2C_ISCH) += i2c-isch.o obj-$(CONFIG_I2C_ISMT) += i2c-ismt.o diff --git a/drivers/i2c/busses/i2c-axxia.c b/drivers/i2c/busses/i2c-axxia.c new file mode 100644 index 0000000..c6faca1 --- /dev/null +++ b/drivers/i2c/busses/i2c-axxia.c @@ -0,0 +1,561 @@ +/* + * This driver implements I2C master functionality using the LSI API2C + * controller. + * + * NOTE: The controller has a limitation in that it can only do transfers of + * maximum 255 bytes at a time. If a larger transfer is attempted, error code + * (-EINVAL) is returned. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + */ +#include <linux/clk.h> +#include <linux/clkdev.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> + +#define SCL_WAIT_TIMEOUT_NS 25000000 +#define I2C_XFER_TIMEOUT (msecs_to_jiffies(250)) +#define I2C_STOP_TIMEOUT (msecs_to_jiffies(100)) +#define FIFO_SIZE 8 + +#define GLOBAL_CONTROL 0x00 +#define GLOBAL_MST_EN BIT(0) +#define GLOBAL_SLV_EN BIT(1) +#define GLOBAL_IBML_EN BIT(2) +#define INTERRUPT_STATUS 0x04 +#define INTERRUPT_ENABLE 0x08 +#define INT_SLV BIT(1) +#define INT_MST BIT(0) +#define WAIT_TIMER_CONTROL 0x0c +#define WT_EN BIT(15) +#define WT_VALUE(_x) ((_x) & 0x7fff) +#define IBML_TIMEOUT 0x10 +#define IBML_LOW_MEXT 0x14 +#define IBML_LOW_SEXT 0x18 +#define TIMER_CLOCK_DIV 0x1c +#define I2C_BUS_MONITOR 0x20 +#define SOFT_RESET 0x24 +#define MST_COMMAND 0x28 +#define CMD_BUSY (1<<3) +#define CMD_MANUAL (0x00 | CMD_BUSY) +#define CMD_AUTO (0x01 | CMD_BUSY) +#define MST_RX_XFER 0x2c +#define MST_TX_XFER 0x30 +#define MST_ADDR_1 0x34 +#define MST_ADDR_2 0x38 +#define MST_DATA 0x3c +#define MST_TX_FIFO 0x40 +#define MST_RX_FIFO 0x44 +#define MST_INT_ENABLE 0x48 +#define MST_INT_STATUS 0x4c +#define MST_STATUS_RFL (1 << 13) /* RX FIFO serivce */ +#define MST_STATUS_TFL (1 << 12) /* TX FIFO service */ +#define MST_STATUS_SNS (1 << 11) /* Manual mode done */ +#define MST_STATUS_SS (1 << 10) /* Automatic mode done */ +#define MST_STATUS_SCC (1 << 9) /* Stop complete */ +#define MST_STATUS_IP (1 << 8) /* Invalid parameter */ +#define MST_STATUS_TSS (1 << 7) /* Timeout */ +#define MST_STATUS_AL (1 << 6) /* Arbitration lost */ +#define MST_STATUS_ND (1 << 5) /* NAK on data phase */ +#define MST_STATUS_NA (1 << 4) /* NAK on address phase */ +#define MST_STATUS_NAK (MST_STATUS_NA | \ + MST_STATUS_ND) +#define MST_STATUS_ERR (MST_STATUS_NAK | \ + MST_STATUS_AL | \ + MST_STATUS_IP | \ + MST_STATUS_TSS) +#define MST_TX_BYTES_XFRD 0x50 +#define MST_RX_BYTES_XFRD 0x54 +#define SCL_HIGH_PERIOD 0x80 +#define SCL_LOW_PERIOD 0x84 +#define SPIKE_FLTR_LEN 0x88 +#define SDA_SETUP_TIME 0x8c +#define SDA_HOLD_TIME 0x90 + +/** + * axxia_i2c_dev - I2C device context + * @base: pointer to register struct + * @msg: pointer to current message + * @msg_xfrd: number of bytes transferred in msg + * @msg_err: error code for completed message + * @msg_complete: xfer completion object + * @dev: device reference + * @adapter: core i2c abstraction + * @i2c_clk: clock reference for i2c input clock + * @bus_clk_rate: current i2c bus clock rate + */ +struct axxia_i2c_dev { + void __iomem *base; + struct i2c_msg *msg; + size_t msg_xfrd; + int msg_err; + struct completion msg_complete; + struct device *dev; + struct i2c_adapter adapter; + struct clk *i2c_clk; + u32 bus_clk_rate; +}; + +static void i2c_int_disable(struct axxia_i2c_dev *idev, u32 mask) +{ + u32 int_en; + + int_en = readl(idev->base + MST_INT_ENABLE); + writel(int_en & ~mask, idev->base + MST_INT_ENABLE); +} + +static void i2c_int_enable(struct axxia_i2c_dev *idev, u32 mask) +{ + u32 int_en; + + int_en = readl(idev->base + MST_INT_ENABLE); + writel(int_en | mask, idev->base + MST_INT_ENABLE); +} + +/** + * ns_to_clk - Convert time (ns) to clock cycles for the given clock frequency. + */ +static u32 ns_to_clk(u64 ns, u32 clk_mhz) +{ + return div_u64(ns * clk_mhz, 1000); +} + +static int axxia_i2c_init(struct axxia_i2c_dev *idev) +{ + u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate; + u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000; + u32 t_setup; + u32 t_high, t_low; + u32 tmo_clk; + u32 prescale; + unsigned long timeout; + + dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n", + idev->bus_clk_rate, clk_mhz, divisor); + + /* Reset controller */ + writel(0x01, idev->base + SOFT_RESET); + timeout = jiffies + msecs_to_jiffies(100); + while (readl(idev->base + SOFT_RESET) & 1) { + if (time_after(jiffies, timeout)) { + dev_warn(idev->dev, "Soft reset failed\n"); + break; + } + } + + /* Enable Master Mode */ + writel(0x1, idev->base + GLOBAL_CONTROL); + + if (idev->bus_clk_rate <= 100000) { + /* Standard mode SCL 50/50, tSU:DAT = 250 ns */ + t_high = divisor * 1 / 2; + t_low = divisor * 1 / 2; + t_setup = ns_to_clk(250, clk_mhz); + } else { + /* Fast mode SCL 33/66, tSU:DAT = 100 ns */ + t_high = divisor * 1 / 3; + t_low = divisor * 2 / 3; + t_setup = ns_to_clk(100, clk_mhz); + } + + /* SCL High Time */ + writel(t_high, idev->base + SCL_HIGH_PERIOD); + /* SCL Low Time */ + writel(t_low, idev->base + SCL_LOW_PERIOD); + /* SDA Setup Time */ + writel(t_setup, idev->base + SDA_SETUP_TIME); + /* SDA Hold Time, 300ns */ + writel(ns_to_clk(300, clk_mhz), idev->base + SDA_HOLD_TIME); + /* Filter <50ns spikes */ + writel(ns_to_clk(50, clk_mhz), idev->base + SPIKE_FLTR_LEN); + + /* Configure Time-Out Registers */ + tmo_clk = ns_to_clk(SCL_WAIT_TIMEOUT_NS, clk_mhz); + + /* Find prescaler value that makes tmo_clk fit in 15-bits counter. */ + for (prescale = 0; prescale < 15; ++prescale) { + if (tmo_clk <= 0x7fff) + break; + tmo_clk >>= 1; + } + if (tmo_clk > 0x7fff) + tmo_clk = 0x7fff; + + /* Prescale divider (log2) */ + writel(prescale, idev->base + TIMER_CLOCK_DIV); + /* Timeout in divided clocks */ + writel(WT_EN | WT_VALUE(tmo_clk), idev->base + WAIT_TIMER_CONTROL); + + /* Mask all master interrupt bits */ + i2c_int_disable(idev, ~0); + + /* Interrupt enable */ + writel(0x01, idev->base + INTERRUPT_ENABLE); + + return 0; +} + +static int i2c_m_rd(const struct i2c_msg *msg) +{ + return (msg->flags & I2C_M_RD) != 0; +} + +static int i2c_m_ten(const struct i2c_msg *msg) +{ + return (msg->flags & I2C_M_TEN) != 0; +} + +static int i2c_m_recv_len(const struct i2c_msg *msg) +{ + return (msg->flags & I2C_M_RECV_LEN) != 0; +} + +/** + * axxia_i2c_empty_rx_fifo - Fetch data from RX FIFO and update SMBus block + * transfer length if this is the first byte of such a transfer. + */ +static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev) +{ + struct i2c_msg *msg = idev->msg; + size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO); + int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd); + + while (bytes_to_transfer-- > 0) { + int c = readl(idev->base + MST_DATA); + + if (idev->msg_xfrd == 0 && i2c_m_recv_len(msg)) { + /* + * Check length byte for SMBus block read + */ + if (c <= 0 || c > I2C_SMBUS_BLOCK_MAX) { + idev->msg_err = -EPROTO; + i2c_int_disable(idev, ~0); + complete(&idev->msg_complete); + break; + } + msg->len = 1 + c; + writel(msg->len, idev->base + MST_RX_XFER); + } + msg->buf[idev->msg_xfrd++] = c; + } + + return 0; +} + +/** + * axxia_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer. + * @return: Number of bytes left to transfer. + */ +static int axxia_i2c_fill_tx_fifo(struct axxia_i2c_dev *idev) +{ + struct i2c_msg *msg = idev->msg; + size_t tx_fifo_avail = FIFO_SIZE - readl(idev->base + MST_TX_FIFO); + int bytes_to_transfer = min(tx_fifo_avail, msg->len - idev->msg_xfrd); + int ret = msg->len - idev->msg_xfrd - bytes_to_transfer; + + while (bytes_to_transfer-- > 0) + writel(msg->buf[idev->msg_xfrd++], idev->base + MST_DATA); + + return ret; +} + +static irqreturn_t axxia_i2c_isr(int irq, void *_dev) +{ + struct axxia_i2c_dev *idev = _dev; + u32 status; + + if (!(readl(idev->base + INTERRUPT_STATUS) & INT_MST)) + return IRQ_NONE; + + /* Read interrupt status bits */ + status = readl(idev->base + MST_INT_STATUS); + + if (!idev->msg) { + dev_warn(idev->dev, "unexpected interrupt"); + goto out; + } + + /* RX FIFO needs service? */ + if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL)) + axxia_i2c_empty_rx_fifo(idev); + + /* TX FIFO needs service? */ + if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) { + if (axxia_i2c_fill_tx_fifo(idev) == 0) + i2c_int_disable(idev, MST_STATUS_TFL); + } + + if (status & MST_STATUS_SCC) { + /* Stop completed */ + i2c_int_disable(idev, ~0); + complete(&idev->msg_complete); + } else if (status & MST_STATUS_SNS) { + /* Transfer done */ + i2c_int_disable(idev, ~0); + if (i2c_m_rd(idev->msg) && idev->msg_xfrd < idev->msg->len) + axxia_i2c_empty_rx_fifo(idev); + complete(&idev->msg_complete); + } else if (unlikely(status & MST_STATUS_ERR)) { + /* Transfer error */ + i2c_int_disable(idev, ~0); + if (status & MST_STATUS_AL) + idev->msg_err = -EAGAIN; + else if (status & MST_STATUS_NAK) + idev->msg_err = -ENXIO; + else + idev->msg_err = -EIO; + dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u tx=%u/%u\n", + status, + idev->msg->addr, + readl(idev->base + MST_RX_BYTES_XFRD), + readl(idev->base + MST_RX_XFER), + readl(idev->base + MST_TX_BYTES_XFRD), + readl(idev->base + MST_TX_XFER)); + complete(&idev->msg_complete); + } + +out: + /* Clear interrupt */ + writel(INT_MST, idev->base + INTERRUPT_STATUS); + + return IRQ_HANDLED; +} + +static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg) +{ + u32 int_mask = MST_STATUS_ERR | MST_STATUS_SNS; + u32 rx_xfer, tx_xfer; + u32 addr_1, addr_2; + int ret; + + if (msg->len > 255) { + dev_warn(idev->dev, "unsupported length %u\n", msg->len); + return -EINVAL; + } + + idev->msg = msg; + idev->msg_xfrd = 0; + idev->msg_err = 0; + reinit_completion(&idev->msg_complete); + + if (i2c_m_ten(msg)) { + /* 10-bit address + * addr_1: 5'b11110 | addr[9:8] | (R/nW) + * addr_2: addr[7:0] + */ + addr_1 = 0xF0 | ((msg->addr >> 7) & 0x06); + addr_2 = msg->addr & 0xFF; + } else { + /* 7-bit address + * addr_1: addr[6:0] | (R/nW) + * addr_2: dont care + */ + addr_1 = (msg->addr << 1) & 0xFF; + addr_2 = 0; + } + + if (i2c_m_rd(msg)) { + /* I2C read transfer */ + rx_xfer = i2c_m_recv_len(msg) ? I2C_SMBUS_BLOCK_MAX : msg->len; + tx_xfer = 0; + addr_1 |= 1; /* Set the R/nW bit of the address */ + } else { + /* I2C write transfer */ + rx_xfer = 0; + tx_xfer = msg->len; + } + + writel(rx_xfer, idev->base + MST_RX_XFER); + writel(tx_xfer, idev->base + MST_TX_XFER); + writel(addr_1, idev->base + MST_ADDR_1); + writel(addr_2, idev->base + MST_ADDR_2); + + if (i2c_m_rd(msg)) + int_mask |= MST_STATUS_RFL; + else if (axxia_i2c_fill_tx_fifo(idev) != 0) + int_mask |= MST_STATUS_TFL; + + /* Start manual mode */ + writel(CMD_MANUAL, idev->base + MST_COMMAND); + + i2c_int_enable(idev, int_mask); + + ret = wait_for_completion_timeout(&idev->msg_complete, + I2C_XFER_TIMEOUT); + + i2c_int_disable(idev, int_mask); + + if (readl(idev->base + MST_COMMAND) & CMD_BUSY) + dev_warn(idev->dev, "busy after xfer"); + + if (ret == 0) + idev->msg_err = -ETIMEDOUT; + + if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO) + axxia_i2c_init(idev); + + return idev->msg_err; +} + +static int axxia_i2c_stop(struct axxia_i2c_dev *idev) +{ + u32 int_mask = MST_STATUS_ERR | MST_STATUS_SCC; + int ret; + + reinit_completion(&idev->msg_complete); + + /* Issue stop */ + writel(0xb, idev->base + MST_COMMAND); + i2c_int_enable(idev, int_mask); + ret = wait_for_completion_timeout(&idev->msg_complete, + I2C_STOP_TIMEOUT); + i2c_int_disable(idev, int_mask); + if (ret == 0) + return -ETIMEDOUT; + + if (readl(idev->base + MST_COMMAND) & CMD_BUSY) + dev_warn(idev->dev, "busy after stop"); + + return 0; +} + +static int +axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) +{ + struct axxia_i2c_dev *idev = i2c_get_adapdata(adap); + int i; + int ret = 0; + + for (i = 0; ret == 0 && i < num; ++i) + ret = axxia_i2c_xfer_msg(idev, &msgs[i]); + + axxia_i2c_stop(idev); + + return ret ? : i; +} + +static u32 axxia_i2c_func(struct i2c_adapter *adap) +{ + u32 caps = (I2C_FUNC_I2C | + I2C_FUNC_10BIT_ADDR | + I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA); + return caps; +} + +static const struct i2c_algorithm axxia_i2c_algo = { + .master_xfer = axxia_i2c_xfer, + .functionality = axxia_i2c_func, +}; + +static int axxia_i2c_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct axxia_i2c_dev *idev = NULL; + struct resource *res; + void __iomem *base; + int irq; + int ret = 0; + + idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL); + if (!idev) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(base)) + return PTR_ERR(base); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(&pdev->dev, "missing interrupt resource\n"); + return irq; + } + + idev->i2c_clk = devm_clk_get(&pdev->dev, "i2c"); + if (IS_ERR(idev->i2c_clk)) { + dev_err(&pdev->dev, "missing clock"); + return PTR_ERR(idev->i2c_clk); + } + + idev->base = base; + idev->dev = &pdev->dev; + init_completion(&idev->msg_complete); + + of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate); + if (idev->bus_clk_rate == 0) + idev->bus_clk_rate = 100000; /* default clock rate */ + + ret = axxia_i2c_init(idev); + if (ret) { + dev_err(&pdev->dev, "failed to initialize"); + return ret; + } + + ret = devm_request_irq(&pdev->dev, irq, axxia_i2c_isr, 0, + pdev->name, idev); + if (ret) { + dev_err(&pdev->dev, "failed to claim IRQ%d\n", irq); + return ret; + } + + clk_prepare_enable(idev->i2c_clk); + + i2c_set_adapdata(&idev->adapter, idev); + strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name)); + idev->adapter.owner = THIS_MODULE; + idev->adapter.class = I2C_CLASS_HWMON; + idev->adapter.algo = &axxia_i2c_algo; + idev->adapter.dev.parent = &pdev->dev; + idev->adapter.dev.of_node = pdev->dev.of_node; + + platform_set_drvdata(pdev, idev); + + ret = i2c_add_adapter(&idev->adapter); + if (ret) { + dev_err(&pdev->dev, "failed to add adapter\n"); + return ret; + } + + return 0; +} + +static int axxia_i2c_remove(struct platform_device *pdev) +{ + struct axxia_i2c_dev *idev = platform_get_drvdata(pdev); + + clk_disable_unprepare(idev->i2c_clk); + i2c_del_adapter(&idev->adapter); + + return 0; +} + +/* Match table for of_platform binding */ +static const struct of_device_id axxia_i2c_of_match[] = { + { .compatible = "lsi,api2c", }, + {}, +}; + +MODULE_DEVICE_TABLE(of, axxia_i2c_of_match); + +static struct platform_driver axxia_i2c_driver = { + .probe = axxia_i2c_probe, + .remove = axxia_i2c_remove, + .driver = { + .name = "axxia-i2c", + .of_match_table = axxia_i2c_of_match, + }, +}; + +module_platform_driver(axxia_i2c_driver); + +MODULE_DESCRIPTION("Axxia I2C Bus driver"); +MODULE_AUTHOR("Anders Berg <anders.berg@lsi.com>"); +MODULE_LICENSE("GPL v2");
Add I2C bus driver for the controller found in the LSI Axxia family SoCs. The driver implements 10-bit addressing and SMBus transfer modes via emulation (including SMBus block data read). Signed-off-by: Anders Berg <anders.berg@avagotech.com> --- Changelog v2: - Document the len <= 255 limitation - return IRQ_HANDLED on unexpected IRQs - fixed a number of style issues - handle zero-length messages - use reinit_completion() where appropriate - enable for COMPILE_TEST .../devicetree/bindings/i2c/i2c-axxia.txt | 30 ++ drivers/i2c/busses/Kconfig | 11 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-axxia.c | 561 +++++++++++++++++++++ 4 files changed, 603 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-axxia.txt create mode 100644 drivers/i2c/busses/i2c-axxia.c