| Message ID | 20230117204439.76841-2-nick.hawkins@hpe.com |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | ARM: Add GXP I2C Support | expand |
On Wed, 18 Jan 2023 at 00:52, <nick.hawkins@hpe.com> wrote: > > From: Nick Hawkins <nick.hawkins@hpe.com> > > The GXP SoC supports 10 I2C engines. Each I2C engine is completely > independent and can function both as an I2C master and I2C slave. The > I2C master can operate in a multi master environment. The engines support > a scalable speed from 8kHZ to 1.5 Mhz. > > Signed-off-by: Nick Hawkins <nick.hawkins@hpe.com> Looks pretty good to me. I have some minor review comments below. Reviewed-by: Joel Stanley <joel@jms.id.au> > > --- > > v2: > *Removed rogue tab in structure > *Removed use of __iomem base local variables as it was unnecessary > *Switched #if IS_ENABLED() -> if (IS_ENABLED()) inside functions > *Removed use of pr_* functions > *Removed informational prints in register and unregister functions > *Removed print from interrupt handler > *No informational prints in probe function > *Switched dev_err for dev_err_probe in probe function > *Use respective helper for mapping the resource to __iomem > --- > drivers/i2c/busses/Kconfig | 7 + > drivers/i2c/busses/Makefile | 1 + > drivers/i2c/busses/i2c-gxp.c | 609 +++++++++++++++++++++++++++++++++++ > 3 files changed, 617 insertions(+) > create mode 100644 drivers/i2c/busses/i2c-gxp.c > > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig > index e50f9603d189..8b3951e0ca5c 100644 > --- a/drivers/i2c/busses/Kconfig > +++ b/drivers/i2c/busses/Kconfig > @@ -1457,4 +1457,11 @@ config I2C_VIRTIO > This driver can also be built as a module. If so, the module > will be called i2c-virtio. > > +config I2C_GXP > + tristate "GXP I2C Interface" > + depends on ARCH_HPE_GXP || COMPILE_TEST > + help > + This enables support for GXP I2C interface. The I2C engines can be > + either I2C master or I2C slaves. > + > endmenu > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile > index e73cdb1d2b5a..dcc96eab6d68 100644 > --- a/drivers/i2c/busses/Makefile > +++ b/drivers/i2c/busses/Makefile > @@ -127,6 +127,7 @@ obj-$(CONFIG_I2C_THUNDERX) += i2c-thunderx.o > obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o > obj-$(CONFIG_I2C_XLP9XX) += i2c-xlp9xx.o > obj-$(CONFIG_I2C_RCAR) += i2c-rcar.o > +obj-$(CONFIG_I2C_GXP) += i2c-gxp.o > > # External I2C/SMBus adapter drivers > obj-$(CONFIG_I2C_DIOLAN_U2C) += i2c-diolan-u2c.o > diff --git a/drivers/i2c/busses/i2c-gxp.c b/drivers/i2c/busses/i2c-gxp.c > new file mode 100644 > index 000000000000..bd41858a3149 > --- /dev/null > +++ b/drivers/i2c/busses/i2c-gxp.c > @@ -0,0 +1,609 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */ > + > +#include <linux/err.h> > +#include <linux/io.h> > +#include <linux/i2c.h> > +#include <linux/module.h> > +#include <linux/of_device.h> > +#include <linux/regmap.h> > +#include <linux/mfd/syscon.h> > + > +#define GXP_MAX_I2C_ENGINE 10 > +static const char * const gxp_i2c_name[] = { > + "gxp-i2c0", "gxp-i2c1", "gxp-i2c2", "gxp-i2c3", > + "gxp-i2c4", "gxp-i2c5", "gxp-i2c6", "gxp-i2c7", > + "gxp-i2c8", "gxp-i2c9" }; > + > +/* Default value */ > +#define GXP_I2C_BIT_RATE 100000 /* 100kHz */ > + > +/* GXP I2C Global interrupt status/enable register*/ > +#define GXP_I2CINTSTAT 0x00 > +#define GXP_I2CINTEN 0x04 > + > +/* GXP I2C registers */ > +#define GXP_I2CSTAT 0x00 > +#define MASK_STOP_EVENT 0x20 > +#define MASK_ACK 0x08 > +#define MASK_RW 0x04 > +#define GXP_I2CEVTERR 0x01 > +#define MASK_SLAVE_CMD_EVENT 0x01 > +#define MASK_SLAVE_DATA_EVENT 0x02 > +#define MASK_MASTER_EVENT 0x10 > +#define GXP_I2CSNPDAT 0x02 > +#define GXP_I2CMCMD 0x04 > +#define GXP_I2CSCMD 0x06 > +#define GXP_I2CSNPAA 0x09 > +#define GXP_I2CADVFEAT 0x0A > +#define GXP_I2COWNADR 0x0B > +#define GXP_I2CFREQDIV 0x0C > +#define GXP_I2CFLTFAIR 0x0D > +#define GXP_I2CTMOEDG 0x0E > +#define GXP_I2CCYCTIM 0x0F > + > +static bool i2c_global_init_done; > + > +enum { > + GXP_I2C_IDLE = 0, > + GXP_I2C_ADDR_PHASE, > + GXP_I2C_RDATA_PHASE, > + GXP_I2C_WDATA_PHASE, > + GXP_I2C_ADDR_NACK, > + GXP_I2C_DATA_NACK, > + GXP_I2C_ERROR, > + GXP_I2C_COMP > +}; > + > +struct gxp_i2c_drvdata { > + struct device *dev; > + void __iomem *base; > + u32 bus_frequency; > + int engine; > + int irq; > + struct completion completion; > + struct i2c_adapter adapter; > + struct i2c_msg *curr_msg; > + int msgs_remaining; > + int msgs_num; > + u8 *buf; > + size_t buf_remaining; > + unsigned char state; > + struct i2c_client *slave; > + unsigned char stopped; > +}; > + > +static struct regmap *i2cg_map; > + > +static void gxp_i2c_start(struct gxp_i2c_drvdata *drvdata) > +{ > + u16 value; > + > + drvdata->buf = drvdata->curr_msg->buf; > + drvdata->buf_remaining = drvdata->curr_msg->len; > + > + /* Note: Address in struct i2c_msg is 7 bits */ > + value = drvdata->curr_msg->addr << 9; > + > + if (drvdata->curr_msg->flags & I2C_M_RD) { > + /* Read */ > + value |= 0x05; > + } else { > + /* Write */ > + value |= 0x01; > + } > + > + drvdata->state = GXP_I2C_ADDR_PHASE; > + writew(value, drvdata->base + GXP_I2CMCMD); > +} > + > +static int gxp_i2c_master_xfer(struct i2c_adapter *adapter, > + struct i2c_msg *msgs, int num) > +{ > + int ret; > + struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(adapter); > + unsigned long time_left; > + > + drvdata->msgs_remaining = num; > + drvdata->curr_msg = msgs; > + drvdata->msgs_num = num; > + reinit_completion(&drvdata->completion); > + > + gxp_i2c_start(drvdata); > + > + time_left = wait_for_completion_timeout(&drvdata->completion, > + adapter->timeout); > + ret = num - drvdata->msgs_remaining; > + if (time_left == 0) { > + switch (drvdata->state) { > + case GXP_I2C_WDATA_PHASE: > + dev_err(drvdata->dev, > + "gxp_i2c_start:write Data phase timeout at msg[%d]\n", > + ret); > + break; > + case GXP_I2C_RDATA_PHASE: > + dev_err(drvdata->dev, > + "gxp_i2c_start:read Data phase timeout at msg[%d]\n", > + ret); > + break; > + case GXP_I2C_ADDR_PHASE: > + dev_err(drvdata->dev, > + "gxp_i2c_start:Addr phase timeout\n"); > + break; > + default: > + dev_err(drvdata->dev, > + "gxp_i2c_start:i2c transfer timeout state=%d\n", > + drvdata->state); > + break; > + } > + return -ETIMEDOUT; > + } > + > + if (drvdata->state == GXP_I2C_ADDR_NACK) { > + dev_err(drvdata->dev, > + "gxp_i2c_start:No ACK for address phase\n"); > + return -EIO; > + } else if (drvdata->state == GXP_I2C_DATA_NACK) { > + dev_err(drvdata->dev, "gxp_i2c_start:No ACK for data phase\n"); > + return -EIO; > + } > + > + return ret; > +} > + > +static u32 gxp_i2c_func(struct i2c_adapter *adap) > +{ > + if (IS_ENABLED(CONFIG_I2C_SLAVE)) > + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SLAVE; > + > + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; > +} > + > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > +static int gxp_i2c_reg_slave(struct i2c_client *slave) > +{ > + struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(slave->adapter); > + > + if (drvdata->slave) > + return -EBUSY; > + > + if (slave->flags & I2C_CLIENT_TEN) > + return -EAFNOSUPPORT; > + > + drvdata->slave = slave; > + > + writeb(slave->addr << 1, drvdata->base + GXP_I2COWNADR); > + writeb(0x69, drvdata->base + GXP_I2CSCMD); > + > + return 0; > +} > + > +static int gxp_i2c_unreg_slave(struct i2c_client *slave) > +{ > + struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(slave->adapter); > + > + WARN_ON(!drvdata->slave); > + > + writeb(0x00, drvdata->base + GXP_I2COWNADR); > + writeb(0xF0, drvdata->base + GXP_I2CSCMD); > + > + drvdata->slave = NULL; > + > + return 0; > +} > +#endif > + > +static const struct i2c_algorithm gxp_i2c_algo = { > + .master_xfer = gxp_i2c_master_xfer, > + .functionality = gxp_i2c_func, > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > + .reg_slave = gxp_i2c_reg_slave, > + .unreg_slave = gxp_i2c_unreg_slave, > +#endif > +}; > + > +static void gxp_i2c_stop(struct gxp_i2c_drvdata *drvdata) > +{ > + /* Clear event and send stop */ > + writeb(0x82, drvdata->base + GXP_I2CMCMD); > + > + complete(&drvdata->completion); > +} > + > +static void gxp_i2c_restart(struct gxp_i2c_drvdata *drvdata) > +{ > + u16 value; > + > + drvdata->buf = drvdata->curr_msg->buf; > + drvdata->buf_remaining = drvdata->curr_msg->len; > + > + value = drvdata->curr_msg->addr << 9; > + > + if (drvdata->curr_msg->flags & I2C_M_RD) { > + /* Read and clear master event */ > + value |= 0x85; > + } else { > + /* Write and clear master event */ > + value |= 0x81; > + } > + > + drvdata->state = GXP_I2C_ADDR_PHASE; > + > + writew(value, drvdata->base + GXP_I2CMCMD); > +} > + > +static void gxp_i2c_chk_addr_ack(struct gxp_i2c_drvdata *drvdata) > +{ > + u16 value; > + > + value = readb(drvdata->base + GXP_I2CSTAT); > + if (!(value & MASK_ACK)) { > + /* Got no ack, stop */ > + drvdata->state = GXP_I2C_ADDR_NACK; > + gxp_i2c_stop(drvdata); > + return; > + } > + > + if (drvdata->curr_msg->flags & I2C_M_RD) { > + /* Start to read data from slave */ > + if (drvdata->buf_remaining == 0) { > + /* No more data to read, stop */ > + drvdata->msgs_remaining--; > + drvdata->state = GXP_I2C_COMP; > + gxp_i2c_stop(drvdata); > + return; > + } > + drvdata->state = GXP_I2C_RDATA_PHASE; > + > + if (drvdata->buf_remaining == 1) { > + /* The last data, do not ack */ > + writeb(0x84, drvdata->base + GXP_I2CMCMD); > + } else { > + /* Read data and ack it */ > + writeb(0x8C, drvdata->base + GXP_I2CMCMD); > + } > + } else { > + /* Start to write first data to slave */ > + if (drvdata->buf_remaining == 0) { > + /* No more data to write, stop */ > + drvdata->msgs_remaining--; > + drvdata->state = GXP_I2C_COMP; > + gxp_i2c_stop(drvdata); > + return; > + } > + value = *drvdata->buf; > + value = value << 8; > + /* Clear master event */ > + value |= 0x80; > + drvdata->buf++; > + drvdata->buf_remaining--; > + drvdata->state = GXP_I2C_WDATA_PHASE; > + writew(value, drvdata->base + GXP_I2CMCMD); > + } > +} > + > +static void gxp_i2c_ack_data(struct gxp_i2c_drvdata *drvdata) > +{ > + u8 value; > + > + /* Store the data returned */ > + value = readb(drvdata->base + GXP_I2CSNPDAT); > + *drvdata->buf = value; > + drvdata->buf++; > + drvdata->buf_remaining--; > + > + if (drvdata->buf_remaining == 0) { > + /* No more data, this message is completed. */ > + drvdata->msgs_remaining--; > + > + if (drvdata->msgs_remaining == 0) { > + /* No more messages, stop */ > + drvdata->state = GXP_I2C_COMP; > + gxp_i2c_stop(drvdata); > + return; > + } > + /* Move to next message and start transfer */ > + drvdata->curr_msg++; > + gxp_i2c_restart(drvdata); > + return; > + } > + > + /* Ack the slave to make it send next byte */ > + drvdata->state = GXP_I2C_RDATA_PHASE; > + if (drvdata->buf_remaining == 1) { > + /* The last data, do not ack */ > + writeb(0x84, drvdata->base + GXP_I2CMCMD); > + } else { > + /* Read data and ack it */ > + writeb(0x8C, drvdata->base + GXP_I2CMCMD); > + } > +} > + > +static void gxp_i2c_chk_data_ack(struct gxp_i2c_drvdata *drvdata) > +{ > + u16 value; > + > + value = readb(drvdata->base + GXP_I2CSTAT); > + if (!(value & MASK_ACK)) { > + /* Received No ack, stop */ > + drvdata->state = GXP_I2C_DATA_NACK; > + gxp_i2c_stop(drvdata); > + return; > + } > + > + /* Got ack, check if there is more data to write */ > + if (drvdata->buf_remaining == 0) { > + /* No more data, this message is completed */ > + drvdata->msgs_remaining--; > + > + if (drvdata->msgs_remaining == 0) { > + /* No more messages, stop */ > + drvdata->state = GXP_I2C_COMP; > + gxp_i2c_stop(drvdata); > + return; > + } > + /* Move to next message and start transfer */ > + drvdata->curr_msg++; > + gxp_i2c_restart(drvdata); > + return; > + } > + > + /* Write data to slave */ > + value = *drvdata->buf; > + value = value << 8; > + > + /* Clear master event */ > + value |= 0x80; > + drvdata->buf++; > + drvdata->buf_remaining--; > + drvdata->state = GXP_I2C_WDATA_PHASE; > + writew(value, drvdata->base + GXP_I2CMCMD); > +} > + > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > +static bool gxp_i2c_slave_irq_handler(struct gxp_i2c_drvdata *drvdata) > +{ > + u16 value; > + u8 buf; > + int ret; > + > + value = readb(drvdata->base + GXP_I2CEVTERR); If you're reading value with readb, it could be a u8 too? > + > + /* Received start or stop event */ > + if (value & MASK_SLAVE_CMD_EVENT) { > + value = readb(drvdata->base + GXP_I2CSTAT); > + /* Master sent stop */ > + if (value & MASK_STOP_EVENT) { > + if (drvdata->stopped == 0) > + i2c_slave_event(drvdata->slave, I2C_SLAVE_STOP, &buf); > + writeb(0x69, drvdata->base + GXP_I2CSCMD); > + drvdata->stopped = 1; > + } else { > + /* Master sent start and wants to read */ > + drvdata->stopped = 0; > + if (value & MASK_RW) { > + i2c_slave_event(drvdata->slave, > + I2C_SLAVE_READ_REQUESTED, &buf); > + value = buf << 8 | 0x61; > + writew(value, drvdata->base + GXP_I2CSCMD); > + } else { > + /* Master wants to write to us */ > + ret = i2c_slave_event(drvdata->slave, > + I2C_SLAVE_WRITE_REQUESTED, &buf); > + if (!ret) { > + /* Ack next byte from master */ > + writeb(0x69, drvdata->base + GXP_I2CSCMD); > + } else { > + /* Nack next byte from master */ > + writeb(0x61, drvdata->base + GXP_I2CSCMD); > + } > + } > + } > + } else if (value & MASK_SLAVE_DATA_EVENT) { > + value = readb(drvdata->base + GXP_I2CSTAT); > + /* Master wants to read */ > + if (value & MASK_RW) { > + /* Master wants another byte */ > + if (value & MASK_ACK) { > + i2c_slave_event(drvdata->slave, > + I2C_SLAVE_READ_PROCESSED, &buf); > + value = buf << 8 | 0x61; > + writew(value, drvdata->base + GXP_I2CSCMD); > + } else { > + /* No more bytes needed */ > + writew(0x69, drvdata->base + GXP_I2CSCMD); > + } > + } else { > + /* Master wants to write to us */ > + value = readb(drvdata->base + GXP_I2CSNPDAT); > + buf = (uint8_t)value; > + ret = i2c_slave_event(drvdata->slave, > + I2C_SLAVE_WRITE_RECEIVED, &buf); > + if (!ret) { > + /* Ack next byte from master */ > + writeb(0x69, drvdata->base + GXP_I2CSCMD); > + } else { > + /* Nack next byte from master */ > + writeb(0x61, drvdata->base + GXP_I2CSCMD); > + } > + } > + } else { > + return false; > + } > + > + return true; > +} > +#endif > + > +static irqreturn_t gxp_i2c_irq_handler(int irq, void *_drvdata) > +{ > + struct gxp_i2c_drvdata *drvdata = (struct gxp_i2c_drvdata *)_drvdata; > + u32 value; > + > + regmap_read(i2cg_map, GXP_I2CINTSTAT, &value); > + if (!(value & (1 << drvdata->engine))) 1U, or BIT(drvdata->engine). This is checking that the interrupt is for an engine that is enabled (or that is present)? > + return IRQ_NONE; > + > + value = readb(drvdata->base + GXP_I2CEVTERR); > + > + /* Error */ > + if (value & ~(MASK_MASTER_EVENT | MASK_SLAVE_CMD_EVENT | > + MASK_SLAVE_DATA_EVENT)) { > + /* Clear all events */ > + writeb(0x00, drvdata->base + GXP_I2CEVTERR); > + drvdata->state = GXP_I2C_ERROR; > + gxp_i2c_stop(drvdata); > + return IRQ_HANDLED; > + } > + > + if (IS_ENABLED(CONFIG_I2C_SLAVE)) { > + /* Slave mode */ > + if (value & (MASK_SLAVE_CMD_EVENT | MASK_SLAVE_DATA_EVENT)) { > + if (gxp_i2c_slave_irq_handler(drvdata)) > + return IRQ_HANDLED; > + return IRQ_NONE; > + } > + } > + > + /* Master mode */ > + switch (drvdata->state) { > + case GXP_I2C_ADDR_PHASE: > + gxp_i2c_chk_addr_ack(drvdata); > + break; > + > + case GXP_I2C_RDATA_PHASE: > + gxp_i2c_ack_data(drvdata); > + break; > + > + case GXP_I2C_WDATA_PHASE: > + gxp_i2c_chk_data_ack(drvdata); > + break; > + } > + > + return IRQ_HANDLED; > +} > + > +static void gxp_i2c_init(struct gxp_i2c_drvdata *drvdata) > +{ > + drvdata->state = GXP_I2C_IDLE; > + writeb(2000000 / drvdata->bus_frequency, > + drvdata->base + GXP_I2CFREQDIV); > + writeb(0x32, drvdata->base + GXP_I2CFLTFAIR); > + writeb(0x0a, drvdata->base + GXP_I2CTMOEDG); > + writeb(0x00, drvdata->base + GXP_I2CCYCTIM); > + writeb(0x00, drvdata->base + GXP_I2CSNPAA); > + writeb(0x00, drvdata->base + GXP_I2CADVFEAT); > + writeb(0xF0, drvdata->base + GXP_I2CSCMD); > + writeb(0x80, drvdata->base + GXP_I2CMCMD); > + writeb(0x00, drvdata->base + GXP_I2CEVTERR); > + writeb(0x00, drvdata->base + GXP_I2COWNADR); > +} > + > +static int gxp_i2c_probe(struct platform_device *pdev) > +{ > + struct gxp_i2c_drvdata *drvdata; > + int rc; > + struct resource *res; > + struct i2c_adapter *adapter; > + > + if (!i2c_global_init_done) { > + i2cg_map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, > + "hpe,sysreg"); > + if (IS_ERR(i2cg_map)) { > + return dev_err_probe(&pdev->dev, IS_ERR(i2cg_map), > + "failed to map i2cg_handle\n"); > + } > + > + /* Disable interrupt */ > + regmap_update_bits(i2cg_map, GXP_I2CINTEN, 0x00000FFF, 0); > + i2c_global_init_done = true; > + } > + > + drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), > + GFP_KERNEL); > + if (!drvdata) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, drvdata); > + drvdata->dev = &pdev->dev; > + init_completion(&drvdata->completion); > + > + drvdata->base = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(drvdata->base)) > + return PTR_ERR(drvdata->base); > + > + /* Use physical memory address to determine which I2C engine this is. */ > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + drvdata->engine = (res->start & 0xf00) >> 8; As I understand it res->start will correspond to drvdata->base, so you can use that instead? > + > + if (drvdata->engine >= GXP_MAX_I2C_ENGINE) { > + return dev_err_probe(&pdev->dev, -EINVAL, "i2c engine% is unsupported\n", > + drvdata->engine); > + } > + > + rc = platform_get_irq(pdev, 0); > + if (rc < 0) > + return dev_err_probe(&pdev->dev, rc, "unable to obtain IRQ number\n"); platform_get_irq does dev_err_probe for you, just return rc. > + > + drvdata->irq = rc; > + rc = devm_request_irq(&pdev->dev, drvdata->irq, gxp_i2c_irq_handler, > + IRQF_SHARED, gxp_i2c_name[drvdata->engine], drvdata); > + if (rc < 0) > + return dev_err_probe(&pdev->dev, rc, "irq request failed\n"); > + > + rc = of_property_read_u32(pdev->dev.of_node, > + "clock-frequency", &drvdata->bus_frequency); The i2c core has helpers here, see if i2c_parse_fw_timings does what you want. > + if (rc < 0) > + drvdata->bus_frequency = GXP_I2C_BIT_RATE; > + > + gxp_i2c_init(drvdata); > + > + /* Enable interrupt */ > + regmap_update_bits(i2cg_map, GXP_I2CINTEN, BIT(drvdata->engine), > + BIT(drvdata->engine)); > + > + adapter = &drvdata->adapter; > + i2c_set_adapdata(adapter, drvdata); > + > + adapter->owner = THIS_MODULE; > + adapter->class = I2C_CLASS_DEPRECATED; I don't think this is needed for new drivers? > + strscpy(adapter->name, "HPE GXP I2C adapter", sizeof(adapter->name)); > + adapter->algo = &gxp_i2c_algo; > + adapter->dev.parent = &pdev->dev; > + adapter->dev.of_node = pdev->dev.of_node; > + > + rc = i2c_add_adapter(adapter); > + if (rc) > + return dev_err_probe(&pdev->dev, rc, "i2c add adapter failed\n"); > + > + return 0; > +} > + > +static int gxp_i2c_remove(struct platform_device *pdev) > +{ > + struct gxp_i2c_drvdata *drvdata = platform_get_drvdata(pdev); > + Do you want to disable the IRQs here? > + i2c_del_adapter(&drvdata->adapter); > + > + return 0; > +} > + > +static const struct of_device_id gxp_i2c_of_match[] = { > + { .compatible = "hpe,gxp-i2c" }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, gxp_i2c_of_match); > + > +static struct platform_driver gxp_i2c_driver = { > + .probe = gxp_i2c_probe, > + .remove = gxp_i2c_remove, > + .driver = { > + .name = "gxp-i2c", > + .of_match_table = gxp_i2c_of_match, > + }, > +}; > +module_platform_driver(gxp_i2c_driver); > + > +MODULE_AUTHOR("Nick Hawkins <nick.hawkins@hpe.com>"); > +MODULE_DESCRIPTION("HPE GXP I2C bus driver"); > +MODULE_LICENSE("GPL"); > -- > 2.17.1 >
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index e50f9603d189..8b3951e0ca5c 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -1457,4 +1457,11 @@ config I2C_VIRTIO This driver can also be built as a module. If so, the module will be called i2c-virtio. +config I2C_GXP + tristate "GXP I2C Interface" + depends on ARCH_HPE_GXP || COMPILE_TEST + help + This enables support for GXP I2C interface. The I2C engines can be + either I2C master or I2C slaves. + endmenu diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index e73cdb1d2b5a..dcc96eab6d68 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -127,6 +127,7 @@ obj-$(CONFIG_I2C_THUNDERX) += i2c-thunderx.o obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o obj-$(CONFIG_I2C_XLP9XX) += i2c-xlp9xx.o obj-$(CONFIG_I2C_RCAR) += i2c-rcar.o +obj-$(CONFIG_I2C_GXP) += i2c-gxp.o # External I2C/SMBus adapter drivers obj-$(CONFIG_I2C_DIOLAN_U2C) += i2c-diolan-u2c.o diff --git a/drivers/i2c/busses/i2c-gxp.c b/drivers/i2c/busses/i2c-gxp.c new file mode 100644 index 000000000000..bd41858a3149 --- /dev/null +++ b/drivers/i2c/busses/i2c-gxp.c @@ -0,0 +1,609 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */ + +#include <linux/err.h> +#include <linux/io.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/regmap.h> +#include <linux/mfd/syscon.h> + +#define GXP_MAX_I2C_ENGINE 10 +static const char * const gxp_i2c_name[] = { + "gxp-i2c0", "gxp-i2c1", "gxp-i2c2", "gxp-i2c3", + "gxp-i2c4", "gxp-i2c5", "gxp-i2c6", "gxp-i2c7", + "gxp-i2c8", "gxp-i2c9" }; + +/* Default value */ +#define GXP_I2C_BIT_RATE 100000 /* 100kHz */ + +/* GXP I2C Global interrupt status/enable register*/ +#define GXP_I2CINTSTAT 0x00 +#define GXP_I2CINTEN 0x04 + +/* GXP I2C registers */ +#define GXP_I2CSTAT 0x00 +#define MASK_STOP_EVENT 0x20 +#define MASK_ACK 0x08 +#define MASK_RW 0x04 +#define GXP_I2CEVTERR 0x01 +#define MASK_SLAVE_CMD_EVENT 0x01 +#define MASK_SLAVE_DATA_EVENT 0x02 +#define MASK_MASTER_EVENT 0x10 +#define GXP_I2CSNPDAT 0x02 +#define GXP_I2CMCMD 0x04 +#define GXP_I2CSCMD 0x06 +#define GXP_I2CSNPAA 0x09 +#define GXP_I2CADVFEAT 0x0A +#define GXP_I2COWNADR 0x0B +#define GXP_I2CFREQDIV 0x0C +#define GXP_I2CFLTFAIR 0x0D +#define GXP_I2CTMOEDG 0x0E +#define GXP_I2CCYCTIM 0x0F + +static bool i2c_global_init_done; + +enum { + GXP_I2C_IDLE = 0, + GXP_I2C_ADDR_PHASE, + GXP_I2C_RDATA_PHASE, + GXP_I2C_WDATA_PHASE, + GXP_I2C_ADDR_NACK, + GXP_I2C_DATA_NACK, + GXP_I2C_ERROR, + GXP_I2C_COMP +}; + +struct gxp_i2c_drvdata { + struct device *dev; + void __iomem *base; + u32 bus_frequency; + int engine; + int irq; + struct completion completion; + struct i2c_adapter adapter; + struct i2c_msg *curr_msg; + int msgs_remaining; + int msgs_num; + u8 *buf; + size_t buf_remaining; + unsigned char state; + struct i2c_client *slave; + unsigned char stopped; +}; + +static struct regmap *i2cg_map; + +static void gxp_i2c_start(struct gxp_i2c_drvdata *drvdata) +{ + u16 value; + + drvdata->buf = drvdata->curr_msg->buf; + drvdata->buf_remaining = drvdata->curr_msg->len; + + /* Note: Address in struct i2c_msg is 7 bits */ + value = drvdata->curr_msg->addr << 9; + + if (drvdata->curr_msg->flags & I2C_M_RD) { + /* Read */ + value |= 0x05; + } else { + /* Write */ + value |= 0x01; + } + + drvdata->state = GXP_I2C_ADDR_PHASE; + writew(value, drvdata->base + GXP_I2CMCMD); +} + +static int gxp_i2c_master_xfer(struct i2c_adapter *adapter, + struct i2c_msg *msgs, int num) +{ + int ret; + struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(adapter); + unsigned long time_left; + + drvdata->msgs_remaining = num; + drvdata->curr_msg = msgs; + drvdata->msgs_num = num; + reinit_completion(&drvdata->completion); + + gxp_i2c_start(drvdata); + + time_left = wait_for_completion_timeout(&drvdata->completion, + adapter->timeout); + ret = num - drvdata->msgs_remaining; + if (time_left == 0) { + switch (drvdata->state) { + case GXP_I2C_WDATA_PHASE: + dev_err(drvdata->dev, + "gxp_i2c_start:write Data phase timeout at msg[%d]\n", + ret); + break; + case GXP_I2C_RDATA_PHASE: + dev_err(drvdata->dev, + "gxp_i2c_start:read Data phase timeout at msg[%d]\n", + ret); + break; + case GXP_I2C_ADDR_PHASE: + dev_err(drvdata->dev, + "gxp_i2c_start:Addr phase timeout\n"); + break; + default: + dev_err(drvdata->dev, + "gxp_i2c_start:i2c transfer timeout state=%d\n", + drvdata->state); + break; + } + return -ETIMEDOUT; + } + + if (drvdata->state == GXP_I2C_ADDR_NACK) { + dev_err(drvdata->dev, + "gxp_i2c_start:No ACK for address phase\n"); + return -EIO; + } else if (drvdata->state == GXP_I2C_DATA_NACK) { + dev_err(drvdata->dev, "gxp_i2c_start:No ACK for data phase\n"); + return -EIO; + } + + return ret; +} + +static u32 gxp_i2c_func(struct i2c_adapter *adap) +{ + if (IS_ENABLED(CONFIG_I2C_SLAVE)) + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SLAVE; + + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +static int gxp_i2c_reg_slave(struct i2c_client *slave) +{ + struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(slave->adapter); + + if (drvdata->slave) + return -EBUSY; + + if (slave->flags & I2C_CLIENT_TEN) + return -EAFNOSUPPORT; + + drvdata->slave = slave; + + writeb(slave->addr << 1, drvdata->base + GXP_I2COWNADR); + writeb(0x69, drvdata->base + GXP_I2CSCMD); + + return 0; +} + +static int gxp_i2c_unreg_slave(struct i2c_client *slave) +{ + struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(slave->adapter); + + WARN_ON(!drvdata->slave); + + writeb(0x00, drvdata->base + GXP_I2COWNADR); + writeb(0xF0, drvdata->base + GXP_I2CSCMD); + + drvdata->slave = NULL; + + return 0; +} +#endif + +static const struct i2c_algorithm gxp_i2c_algo = { + .master_xfer = gxp_i2c_master_xfer, + .functionality = gxp_i2c_func, +#if IS_ENABLED(CONFIG_I2C_SLAVE) + .reg_slave = gxp_i2c_reg_slave, + .unreg_slave = gxp_i2c_unreg_slave, +#endif +}; + +static void gxp_i2c_stop(struct gxp_i2c_drvdata *drvdata) +{ + /* Clear event and send stop */ + writeb(0x82, drvdata->base + GXP_I2CMCMD); + + complete(&drvdata->completion); +} + +static void gxp_i2c_restart(struct gxp_i2c_drvdata *drvdata) +{ + u16 value; + + drvdata->buf = drvdata->curr_msg->buf; + drvdata->buf_remaining = drvdata->curr_msg->len; + + value = drvdata->curr_msg->addr << 9; + + if (drvdata->curr_msg->flags & I2C_M_RD) { + /* Read and clear master event */ + value |= 0x85; + } else { + /* Write and clear master event */ + value |= 0x81; + } + + drvdata->state = GXP_I2C_ADDR_PHASE; + + writew(value, drvdata->base + GXP_I2CMCMD); +} + +static void gxp_i2c_chk_addr_ack(struct gxp_i2c_drvdata *drvdata) +{ + u16 value; + + value = readb(drvdata->base + GXP_I2CSTAT); + if (!(value & MASK_ACK)) { + /* Got no ack, stop */ + drvdata->state = GXP_I2C_ADDR_NACK; + gxp_i2c_stop(drvdata); + return; + } + + if (drvdata->curr_msg->flags & I2C_M_RD) { + /* Start to read data from slave */ + if (drvdata->buf_remaining == 0) { + /* No more data to read, stop */ + drvdata->msgs_remaining--; + drvdata->state = GXP_I2C_COMP; + gxp_i2c_stop(drvdata); + return; + } + drvdata->state = GXP_I2C_RDATA_PHASE; + + if (drvdata->buf_remaining == 1) { + /* The last data, do not ack */ + writeb(0x84, drvdata->base + GXP_I2CMCMD); + } else { + /* Read data and ack it */ + writeb(0x8C, drvdata->base + GXP_I2CMCMD); + } + } else { + /* Start to write first data to slave */ + if (drvdata->buf_remaining == 0) { + /* No more data to write, stop */ + drvdata->msgs_remaining--; + drvdata->state = GXP_I2C_COMP; + gxp_i2c_stop(drvdata); + return; + } + value = *drvdata->buf; + value = value << 8; + /* Clear master event */ + value |= 0x80; + drvdata->buf++; + drvdata->buf_remaining--; + drvdata->state = GXP_I2C_WDATA_PHASE; + writew(value, drvdata->base + GXP_I2CMCMD); + } +} + +static void gxp_i2c_ack_data(struct gxp_i2c_drvdata *drvdata) +{ + u8 value; + + /* Store the data returned */ + value = readb(drvdata->base + GXP_I2CSNPDAT); + *drvdata->buf = value; + drvdata->buf++; + drvdata->buf_remaining--; + + if (drvdata->buf_remaining == 0) { + /* No more data, this message is completed. */ + drvdata->msgs_remaining--; + + if (drvdata->msgs_remaining == 0) { + /* No more messages, stop */ + drvdata->state = GXP_I2C_COMP; + gxp_i2c_stop(drvdata); + return; + } + /* Move to next message and start transfer */ + drvdata->curr_msg++; + gxp_i2c_restart(drvdata); + return; + } + + /* Ack the slave to make it send next byte */ + drvdata->state = GXP_I2C_RDATA_PHASE; + if (drvdata->buf_remaining == 1) { + /* The last data, do not ack */ + writeb(0x84, drvdata->base + GXP_I2CMCMD); + } else { + /* Read data and ack it */ + writeb(0x8C, drvdata->base + GXP_I2CMCMD); + } +} + +static void gxp_i2c_chk_data_ack(struct gxp_i2c_drvdata *drvdata) +{ + u16 value; + + value = readb(drvdata->base + GXP_I2CSTAT); + if (!(value & MASK_ACK)) { + /* Received No ack, stop */ + drvdata->state = GXP_I2C_DATA_NACK; + gxp_i2c_stop(drvdata); + return; + } + + /* Got ack, check if there is more data to write */ + if (drvdata->buf_remaining == 0) { + /* No more data, this message is completed */ + drvdata->msgs_remaining--; + + if (drvdata->msgs_remaining == 0) { + /* No more messages, stop */ + drvdata->state = GXP_I2C_COMP; + gxp_i2c_stop(drvdata); + return; + } + /* Move to next message and start transfer */ + drvdata->curr_msg++; + gxp_i2c_restart(drvdata); + return; + } + + /* Write data to slave */ + value = *drvdata->buf; + value = value << 8; + + /* Clear master event */ + value |= 0x80; + drvdata->buf++; + drvdata->buf_remaining--; + drvdata->state = GXP_I2C_WDATA_PHASE; + writew(value, drvdata->base + GXP_I2CMCMD); +} + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +static bool gxp_i2c_slave_irq_handler(struct gxp_i2c_drvdata *drvdata) +{ + u16 value; + u8 buf; + int ret; + + value = readb(drvdata->base + GXP_I2CEVTERR); + + /* Received start or stop event */ + if (value & MASK_SLAVE_CMD_EVENT) { + value = readb(drvdata->base + GXP_I2CSTAT); + /* Master sent stop */ + if (value & MASK_STOP_EVENT) { + if (drvdata->stopped == 0) + i2c_slave_event(drvdata->slave, I2C_SLAVE_STOP, &buf); + writeb(0x69, drvdata->base + GXP_I2CSCMD); + drvdata->stopped = 1; + } else { + /* Master sent start and wants to read */ + drvdata->stopped = 0; + if (value & MASK_RW) { + i2c_slave_event(drvdata->slave, + I2C_SLAVE_READ_REQUESTED, &buf); + value = buf << 8 | 0x61; + writew(value, drvdata->base + GXP_I2CSCMD); + } else { + /* Master wants to write to us */ + ret = i2c_slave_event(drvdata->slave, + I2C_SLAVE_WRITE_REQUESTED, &buf); + if (!ret) { + /* Ack next byte from master */ + writeb(0x69, drvdata->base + GXP_I2CSCMD); + } else { + /* Nack next byte from master */ + writeb(0x61, drvdata->base + GXP_I2CSCMD); + } + } + } + } else if (value & MASK_SLAVE_DATA_EVENT) { + value = readb(drvdata->base + GXP_I2CSTAT); + /* Master wants to read */ + if (value & MASK_RW) { + /* Master wants another byte */ + if (value & MASK_ACK) { + i2c_slave_event(drvdata->slave, + I2C_SLAVE_READ_PROCESSED, &buf); + value = buf << 8 | 0x61; + writew(value, drvdata->base + GXP_I2CSCMD); + } else { + /* No more bytes needed */ + writew(0x69, drvdata->base + GXP_I2CSCMD); + } + } else { + /* Master wants to write to us */ + value = readb(drvdata->base + GXP_I2CSNPDAT); + buf = (uint8_t)value; + ret = i2c_slave_event(drvdata->slave, + I2C_SLAVE_WRITE_RECEIVED, &buf); + if (!ret) { + /* Ack next byte from master */ + writeb(0x69, drvdata->base + GXP_I2CSCMD); + } else { + /* Nack next byte from master */ + writeb(0x61, drvdata->base + GXP_I2CSCMD); + } + } + } else { + return false; + } + + return true; +} +#endif + +static irqreturn_t gxp_i2c_irq_handler(int irq, void *_drvdata) +{ + struct gxp_i2c_drvdata *drvdata = (struct gxp_i2c_drvdata *)_drvdata; + u32 value; + + regmap_read(i2cg_map, GXP_I2CINTSTAT, &value); + if (!(value & (1 << drvdata->engine))) + return IRQ_NONE; + + value = readb(drvdata->base + GXP_I2CEVTERR); + + /* Error */ + if (value & ~(MASK_MASTER_EVENT | MASK_SLAVE_CMD_EVENT | + MASK_SLAVE_DATA_EVENT)) { + /* Clear all events */ + writeb(0x00, drvdata->base + GXP_I2CEVTERR); + drvdata->state = GXP_I2C_ERROR; + gxp_i2c_stop(drvdata); + return IRQ_HANDLED; + } + + if (IS_ENABLED(CONFIG_I2C_SLAVE)) { + /* Slave mode */ + if (value & (MASK_SLAVE_CMD_EVENT | MASK_SLAVE_DATA_EVENT)) { + if (gxp_i2c_slave_irq_handler(drvdata)) + return IRQ_HANDLED; + return IRQ_NONE; + } + } + + /* Master mode */ + switch (drvdata->state) { + case GXP_I2C_ADDR_PHASE: + gxp_i2c_chk_addr_ack(drvdata); + break; + + case GXP_I2C_RDATA_PHASE: + gxp_i2c_ack_data(drvdata); + break; + + case GXP_I2C_WDATA_PHASE: + gxp_i2c_chk_data_ack(drvdata); + break; + } + + return IRQ_HANDLED; +} + +static void gxp_i2c_init(struct gxp_i2c_drvdata *drvdata) +{ + drvdata->state = GXP_I2C_IDLE; + writeb(2000000 / drvdata->bus_frequency, + drvdata->base + GXP_I2CFREQDIV); + writeb(0x32, drvdata->base + GXP_I2CFLTFAIR); + writeb(0x0a, drvdata->base + GXP_I2CTMOEDG); + writeb(0x00, drvdata->base + GXP_I2CCYCTIM); + writeb(0x00, drvdata->base + GXP_I2CSNPAA); + writeb(0x00, drvdata->base + GXP_I2CADVFEAT); + writeb(0xF0, drvdata->base + GXP_I2CSCMD); + writeb(0x80, drvdata->base + GXP_I2CMCMD); + writeb(0x00, drvdata->base + GXP_I2CEVTERR); + writeb(0x00, drvdata->base + GXP_I2COWNADR); +} + +static int gxp_i2c_probe(struct platform_device *pdev) +{ + struct gxp_i2c_drvdata *drvdata; + int rc; + struct resource *res; + struct i2c_adapter *adapter; + + if (!i2c_global_init_done) { + i2cg_map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, + "hpe,sysreg"); + if (IS_ERR(i2cg_map)) { + return dev_err_probe(&pdev->dev, IS_ERR(i2cg_map), + "failed to map i2cg_handle\n"); + } + + /* Disable interrupt */ + regmap_update_bits(i2cg_map, GXP_I2CINTEN, 0x00000FFF, 0); + i2c_global_init_done = true; + } + + drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), + GFP_KERNEL); + if (!drvdata) + return -ENOMEM; + + platform_set_drvdata(pdev, drvdata); + drvdata->dev = &pdev->dev; + init_completion(&drvdata->completion); + + drvdata->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(drvdata->base)) + return PTR_ERR(drvdata->base); + + /* Use physical memory address to determine which I2C engine this is. */ + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + drvdata->engine = (res->start & 0xf00) >> 8; + + if (drvdata->engine >= GXP_MAX_I2C_ENGINE) { + return dev_err_probe(&pdev->dev, -EINVAL, "i2c engine% is unsupported\n", + drvdata->engine); + } + + rc = platform_get_irq(pdev, 0); + if (rc < 0) + return dev_err_probe(&pdev->dev, rc, "unable to obtain IRQ number\n"); + + drvdata->irq = rc; + rc = devm_request_irq(&pdev->dev, drvdata->irq, gxp_i2c_irq_handler, + IRQF_SHARED, gxp_i2c_name[drvdata->engine], drvdata); + if (rc < 0) + return dev_err_probe(&pdev->dev, rc, "irq request failed\n"); + + rc = of_property_read_u32(pdev->dev.of_node, + "clock-frequency", &drvdata->bus_frequency); + if (rc < 0) + drvdata->bus_frequency = GXP_I2C_BIT_RATE; + + gxp_i2c_init(drvdata); + + /* Enable interrupt */ + regmap_update_bits(i2cg_map, GXP_I2CINTEN, BIT(drvdata->engine), + BIT(drvdata->engine)); + + adapter = &drvdata->adapter; + i2c_set_adapdata(adapter, drvdata); + + adapter->owner = THIS_MODULE; + adapter->class = I2C_CLASS_DEPRECATED; + strscpy(adapter->name, "HPE GXP I2C adapter", sizeof(adapter->name)); + adapter->algo = &gxp_i2c_algo; + adapter->dev.parent = &pdev->dev; + adapter->dev.of_node = pdev->dev.of_node; + + rc = i2c_add_adapter(adapter); + if (rc) + return dev_err_probe(&pdev->dev, rc, "i2c add adapter failed\n"); + + return 0; +} + +static int gxp_i2c_remove(struct platform_device *pdev) +{ + struct gxp_i2c_drvdata *drvdata = platform_get_drvdata(pdev); + + i2c_del_adapter(&drvdata->adapter); + + return 0; +} + +static const struct of_device_id gxp_i2c_of_match[] = { + { .compatible = "hpe,gxp-i2c" }, + {}, +}; +MODULE_DEVICE_TABLE(of, gxp_i2c_of_match); + +static struct platform_driver gxp_i2c_driver = { + .probe = gxp_i2c_probe, + .remove = gxp_i2c_remove, + .driver = { + .name = "gxp-i2c", + .of_match_table = gxp_i2c_of_match, + }, +}; +module_platform_driver(gxp_i2c_driver); + +MODULE_AUTHOR("Nick Hawkins <nick.hawkins@hpe.com>"); +MODULE_DESCRIPTION("HPE GXP I2C bus driver"); +MODULE_LICENSE("GPL");