| Message ID | 1427477624-23127-4-git-send-email-p.marczak@samsung.com |
|---|---|
| State | Superseded |
| Delegated to: | Simon Glass |
| Headers | show |
Hi Przemyslaw, On 27 March 2015 at 11:33, Przemyslaw Marczak <p.marczak@samsung.com> wrote: > This commit adds driver model support to software emulated i2c bus driver. > The device-tree node is compatible with the kernel i2c-gpio driver. It means, > that boards device-tree "i2c-gpio" node, should be the same as in the kernel. > For operating, it requires proper compatible and gpio pins dts description. > Added: > - Config: CONFIG_DM_I2C_GPIO > - File: drivers/i2c/i2c-gpio.c > - File: doc/device-tree-bindings/i2c/i2c-gpio.txt > > Driver base code is taken from: drivers/i2c/soft-i2c.c, changes: > - update comments style, > - move preprocesor macros into functions, > - add device-tree support, > - add driver model i2c support. > - add Kconfig entry > > Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com> > CC: Masahiro Yamada <yamada.masahiro@socionext.com> > Cc: Lukasz Majewski <l.majewski@samsung.com> > Cc: Mike Frysinger <vapier@gentoo.org> > Cc: Simon Glass <sjg@chromium.org> > Cc: Heiko Schocher <hs@denx.de> > > Changes V2: > - new file for software i2c driver: i2c-gpio.c > - update driver naming: use of "i2c-gpio" > - add full compatibility with the kernels device-tree "i2c-gpio" node > - fix Kconfig entry Sorry I still have a few more comments. > --- > doc/device-tree-bindings/i2c/i2c-gpio.txt | 37 ++++ > drivers/i2c/Kconfig | 9 + > drivers/i2c/Makefile | 1 + > drivers/i2c/i2c-gpio.c | 353 ++++++++++++++++++++++++++++++ > 4 files changed, 400 insertions(+) > create mode 100644 doc/device-tree-bindings/i2c/i2c-gpio.txt > create mode 100644 drivers/i2c/i2c-gpio.c > > diff --git a/doc/device-tree-bindings/i2c/i2c-gpio.txt b/doc/device-tree-bindings/i2c/i2c-gpio.txt > new file mode 100644 > index 0000000..3978381 > --- /dev/null > +++ b/doc/device-tree-bindings/i2c/i2c-gpio.txt > @@ -0,0 +1,37 @@ > +I2C gpio device binding > +======================= > + > +Driver: > +- drivers/i2c/i2c-gpio.c > + > +Software i2c device-tree node properties: > +Required: > +* #address-cells = <1>; > +* #size-cells = <0>; > +* compatible = "i2c-gpio"; > +* gpios = <sda ...>, <scl ...>; > + > +Optional: > +* i2c-gpio,delay-us = <5>; > + The resulting transfer speed can be adjusted by setting the delay[us] > + between gpio-toggle operations. Speed [Hz] = 1us / 4 * udelay, > + It not defined, then default is 5us (~50KHz). > + > +Example: > + > +i2c-gpio@1 { > + #address-cells = <1>; > + #size-cells = <0>; > + > + compatible = "i2c-gpio"; > + gpios = <&gpd1 0 GPIO_ACTIVE_HIGH>, /* SDA */ > + <&gpd1 1 GPIO_ACTIVE_HIGH>; /* CLK */ > + > + i2c-gpio,delay-us = <5>; > + > + some_device@5 { > + compatible = "some_device"; > + reg = <0x5>; > + ... > + }; > +}; > diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig > index 979522f..22e4a7c 100644 > --- a/drivers/i2c/Kconfig > +++ b/drivers/i2c/Kconfig > @@ -19,6 +19,15 @@ config DM_I2C_COMPAT > to convert all code for a board in a single commit. It should not > be enabled for any board in an official release. > > +config DM_I2C_GPIO > + bool "Enable Driver Model for software emulated I2C bus driver" > + depends on DM_I2C && DM_GPIO > + help > + Enable the i2c bus driver emulation by using the GPIO. by using GPIOs. > + The bus gpio configuration is given by the device-tree. GPIO device tree (no hypen) > + Kernel style device-tree node for i2c-gpio is supported. Kernel-style device tree bindings are supported > + Binding info: doc/device-tree-bindings/i2c/i2c-gpio.txt > + > config SYS_I2C_UNIPHIER > bool "UniPhier I2C driver" > depends on ARCH_UNIPHIER && DM_I2C > diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile > index 774bc94..d9e9f3a 100644 > --- a/drivers/i2c/Makefile > +++ b/drivers/i2c/Makefile > @@ -6,6 +6,7 @@ > # > obj-$(CONFIG_DM_I2C) += i2c-uclass.o > obj-$(CONFIG_DM_I2C_COMPAT) += i2c-uclass-compat.o > +obj-$(CONFIG_DM_I2C_GPIO) += i2c-gpio.o > > obj-$(CONFIG_SYS_I2C_ADI) += adi_i2c.o > obj-$(CONFIG_I2C_MV) += mv_i2c.o > diff --git a/drivers/i2c/i2c-gpio.c b/drivers/i2c/i2c-gpio.c > new file mode 100644 > index 0000000..8e9ed6b > --- /dev/null > +++ b/drivers/i2c/i2c-gpio.c > @@ -0,0 +1,353 @@ > +/* > + * (C) Copyright 2015, Samsung Electronics > + * Przemyslaw Marczak <p.marczak@samsung.com> > + * Add driver-model support as a separated driver file > + * > + * (C) Copyright 2009 > + * Heiko Schocher, DENX Software Engineering, hs@denx.de. > + * Changes for multibus/multiadapter I2C support. > + * > + * (C) Copyright 2001, 2002 > + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. > + * > + * SPDX-License-Identifier: GPL-2.0+ > + * > + * This has been changed substantially by Gerald Van Baren, Custom IDEAS, > + * vanbaren@cideas.com. It was heavily influenced by LiMon, written by > + * Neil Russell. > + */ > +#include <common.h> > +#include <errno.h> > +#include <dm.h> > +#include <i2c.h> > +#include <div64.h> > +#include <asm/gpio.h> > + > +#define DEFAULT_UDELAY 5 > +#define RETRIES 0 > +#define I2C_ACK 0 > +#define I2C_NOACK 1 > + > +#ifdef DEBUG_I2C > +#define PRINTD(fmt, args...) do { \ > + printf (fmt, ##args); \ > + } while (0) > +#else > +#define PRINTD(fmt, args...) > +#endif I don't see any point in this - how about just using debug() instead? > + > +DECLARE_GLOBAL_DATA_PTR; > + > +enum { > + PIN_SDA = 0, > + PIN_SCL, PIN_COUNT > +}; > + Document these members - speed is in HzHz, udelay is the delay for what? > +struct i2c_gpio_bus { > + unsigned int speed; > + unsigned long udelay; > + struct gpio_desc gpios[2]; /* sda, scl */ gpios[PIN_COUNT] > +}; > + > +/* Local functions */ > +static void send_reset(struct gpio_desc *, struct gpio_desc *, int); > +static void send_start(struct gpio_desc *, struct gpio_desc *, int); > +static void send_stop(struct gpio_desc *, struct gpio_desc *, int); > +static void send_ack(struct gpio_desc *, struct gpio_desc *, int, int); > +static int write_byte(struct gpio_desc *, struct gpio_desc *, int, uchar); > +static uchar read_byte(struct gpio_desc *, struct gpio_desc *, int, int); If you move send_reset() down a bit can you drop these declarations? > + > +static int I2C_READ(struct gpio_desc *sda) Lower case - how about gpio_i2c_read()? Same for others. > +{ > + return dm_gpio_get_value(sda); > +} > + > +static void I2C_SDA(struct gpio_desc *sda, int bit) > +{ > + if (bit) { > + dm_gpio_set_dir_flags(sda, GPIOD_IS_IN); I assume the polarity is never set, so this should be OK. > + } else { > + dm_gpio_set_dir_flags(sda, GPIOD_IS_OUT); > + dm_gpio_set_value(sda, 0); > + } > +} > + > +static void I2C_SCL(struct gpio_desc *scl, int bit) > +{ > + dm_gpio_set_dir_flags(scl, GPIOD_IS_OUT); > + dm_gpio_set_value(scl, bit); > +} > + > +static void I2C_DELAY(unsigned long us) > +{ > + udelay(us); /* 1/4 I2C clock duration */ > +} > + > +/** > + * Send a reset sequence consisting of 9 clocks with the data signal high > + * to clock any confused device back into an idle state. Also send a > + * <stop> at the end of the sequence for belts & suspenders. > + */ > +static void send_reset(struct gpio_desc *scl, struct gpio_desc *sda, int delay) > +{ > + int j; > + > + I2C_SCL(scl, 1); > + I2C_SDA(sda, 1); > + > + for (j = 0; j < 9; j++) { > + I2C_SCL(scl, 0); > + I2C_DELAY(delay); > + I2C_DELAY(delay); > + I2C_SCL(scl, 1); > + I2C_DELAY(delay); > + I2C_DELAY(delay); I wonder why we don't do one call with delay * 2? > + } > + send_stop(scl, sda, delay); > +} > + > +/* START: High -> Low on SDA while SCL is High */ > +static void send_start(struct gpio_desc *scl, struct gpio_desc *sda, int delay) > +{ > + I2C_DELAY(delay); > + I2C_SDA(sda, 1); > + I2C_DELAY(delay); > + I2C_SCL(scl, 1); > + I2C_DELAY(delay); > + I2C_SDA(sda, 0); > + I2C_DELAY(delay); > +} > + > +/* STOP: Low -> High on SDA while SCL is High */ > +static void send_stop(struct gpio_desc *scl, struct gpio_desc *sda, int delay) > +{ > + I2C_SCL(scl, 0); > + I2C_DELAY(delay); > + I2C_SDA(sda, 0); > + I2C_DELAY(delay); > + I2C_SCL(scl, 1); > + I2C_DELAY(delay); > + I2C_SDA(sda, 1); > + I2C_DELAY(delay); > +} > + > +/* ack should be I2C_ACK or I2C_NOACK */ > +static void send_ack(struct gpio_desc *scl, struct gpio_desc *sda, > + int delay, int ack) > +{ > + I2C_SCL(scl, 0); > + I2C_DELAY(delay); > + I2C_SDA(sda, ack); > + I2C_DELAY(delay); > + I2C_SCL(scl, 1); > + I2C_DELAY(delay); > + I2C_DELAY(delay); > + I2C_SCL(scl, 0); > + I2C_DELAY(delay); > +} > + > +/* Send 8 bits and look for an acknowledgement */ > +static int write_byte(struct gpio_desc *scl, struct gpio_desc *sda, > + int delay, uchar data) > +{ > + int j; > + int nack; > + > + for (j = 0; j < 8; j++) { > + I2C_SCL(scl, 0); > + I2C_DELAY(delay); > + I2C_SDA(sda, data & 0x80); > + I2C_DELAY(delay); > + I2C_SCL(scl, 1); > + I2C_DELAY(delay); > + I2C_DELAY(delay); This sequence of 7 calls appears a lot in this code. Could it go in a function and be called from various places? > + > + data <<= 1; > + } > + > + /* Look for an <ACK>(negative logic) and return it */ > + I2C_SCL(scl, 0); > + I2C_DELAY(delay); > + I2C_SDA(sda, 1); > + I2C_DELAY(delay); > + I2C_SCL(scl, 1); > + I2C_DELAY(delay); > + I2C_DELAY(delay); > + nack = I2C_READ(sda); > + I2C_SCL(scl, 0); > + I2C_DELAY(delay); > + > + return nack; /* not a nack is an ack */ > +} > + > +/** > + * if ack == I2C_ACK, ACK the byte so can continue reading, else > + * send I2C_NOACK to end the read. > + */ > +static uchar read_byte(struct gpio_desc *scl, struct gpio_desc *sda, > + int delay, int ack) > +{ > + int data; > + int j; > + > + /* Read 8 bits, MSB first */ > + I2C_SDA(sda, 1); > + data = 0; > + for (j = 0; j < 8; j++) { > + I2C_SCL(scl, 0); > + I2C_DELAY(delay); > + I2C_SCL(scl, 1); > + I2C_DELAY(delay); > + data <<= 1; > + data |= I2C_READ(sda); > + I2C_DELAY(delay); > + } > + send_ack(scl, sda, delay, ack); > + > + return data; > +} > + > +static int i2c_write_data(struct i2c_gpio_bus *bus, uchar chip, > + uchar *buffer, int len, bool end_with_repeated_start) > +{ > + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; > + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; > + unsigned int delay = bus->udelay; > + int failures = 0; > + > + PRINTD("%s: chip %x buffer %p len %d\n", __func__, chip, buffer, len); > + > + send_start(scl, sda, delay); > + if (write_byte(scl, sda, delay, chip << 1)) { > + send_stop(scl, sda, delay); > + PRINTD("i2c_write, no chip responded %02X\n", chip); > + return -EIO; > + } > + > + while (len-- > 0) { > + if (write_byte(scl, sda, delay, *buffer++)) > + failures++; > + } > + > + send_stop(scl, sda, delay); > + > + return failures; > +} > + > +static int i2c_read_data(struct i2c_gpio_bus *bus, uchar chip, > + uchar *buffer, int len) > +{ > + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; > + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; > + unsigned int delay = bus->udelay; > + > + PRINTD("%s: chip %x buffer: %x len %d\n", __func__, chip, buffer, len); > + > + send_start(scl, sda, delay); > + write_byte(scl, sda, delay, (chip << 1) | 1); /* read cycle */ > + > + while (len-- > 0) > + *buffer++ = read_byte(scl, sda, delay, len == 0); > + > + send_stop(scl, sda, delay); > + > + return 0; > +} > + > +static int i2c_gpio_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs) > +{ > + struct i2c_gpio_bus *bus = dev_get_priv(dev); > + int ret; > + > + for (; nmsgs > 0; nmsgs--, msg++) { > + bool next_is_read = nmsgs > 1 && (msg[1].flags & I2C_M_RD); > + if (msg->flags & I2C_M_RD) > + ret = i2c_read_data(bus, msg->addr, msg->buf, msg->len); > + else > + ret = i2c_write_data(bus, msg->addr, msg->buf, msg->len, > + next_is_read); > + > + if (ret) > + return -EREMOTEIO; > + } > + > + return 0; > +} > + > +static int i2c_gpio_probe(struct udevice *dev, uint chip, uint chip_flags) > +{ > + struct i2c_gpio_bus *bus = dev_get_priv(dev); > + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; > + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; > + unsigned int delay = bus->udelay; > + int ret; > + > + send_start(scl, sda, delay); > + ret = write_byte(scl, sda, delay, (chip << 1) | 0); > + send_stop(scl, sda, delay); > + > + PRINTD("%s: bus: %d (%s) chip: %x flags: %x ret: %d\n", > + __func__, dev->seq, dev->name, chip, chip_flags, ret); > + > + return ret; > +} > + > +static int i2c_gpio_set_bus_speed(struct udevice *dev, unsigned int speed) > +{ > + struct i2c_gpio_bus *bus = dev_get_priv(dev); > + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; > + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; > + > + bus->speed = speed; > + bus->udelay = lldiv(1000000, speed << 2); Why lldiv() if the value can never be >100,000? Can we just use normal division? > + > + send_reset(scl, sda, bus->udelay); > + > + PRINTD("%s: bus: %d (%s) speed: %u Hz (1/4 of period: %lu us)\n", > + __func__, dev->seq, dev->name, speed, bus->udelay); > + > + return 0; > +} > + > +static int i2c_gpio_ofdata_to_platdata(struct udevice *dev) > +{ > + struct i2c_gpio_bus *bus = dev_get_priv(dev); > + const void *blob = gd->fdt_blob; > + int node = dev->of_offset; > + int ret; > + > + ret = gpio_request_list_by_name(dev, "gpios", bus->gpios, > + ARRAY_SIZE(bus->gpios), 0); > + if (ret < 0) > + goto error; > + > + bus->udelay = fdtdec_get_int(blob, node, "i2c-gpio,delay-us", > + DEFAULT_UDELAY); > + > + PRINTD("%s: bus: %d (%s) fdt node ok\n", __func__, dev->seq, dev->name); > + > + return 0; > +error: > + error("Can't get %s gpios! Error: %d", dev->name, ret); > + return ret; > +} > + > +static const struct dm_i2c_ops i2c_gpio_ops = { > + .xfer = i2c_gpio_xfer, > + .probe_chip = i2c_gpio_probe, > + .set_bus_speed = i2c_gpio_set_bus_speed, > +}; > + > +static const struct udevice_id i2c_gpio_ids[] = { > + { .compatible = "i2c-gpio" }, > + { } > +}; > + > +U_BOOT_DRIVER(i2c_gpio) = { > + .name = "i2c-gpio", > + .id = UCLASS_I2C, > + .of_match = i2c_gpio_ids, > + .ofdata_to_platdata = i2c_gpio_ofdata_to_platdata, > + .priv_auto_alloc_size = sizeof(struct i2c_gpio_bus), > + .ops = &i2c_gpio_ops, > +}; > -- > 1.9.1 > Regards, Simon
Hello Simon, On 03/28/2015 04:08 PM, Simon Glass wrote: > Hi Przemyslaw, > > On 27 March 2015 at 11:33, Przemyslaw Marczak <p.marczak@samsung.com> wrote: >> This commit adds driver model support to software emulated i2c bus driver. >> The device-tree node is compatible with the kernel i2c-gpio driver. It means, >> that boards device-tree "i2c-gpio" node, should be the same as in the kernel. >> For operating, it requires proper compatible and gpio pins dts description. >> Added: >> - Config: CONFIG_DM_I2C_GPIO >> - File: drivers/i2c/i2c-gpio.c >> - File: doc/device-tree-bindings/i2c/i2c-gpio.txt >> >> Driver base code is taken from: drivers/i2c/soft-i2c.c, changes: >> - update comments style, >> - move preprocesor macros into functions, >> - add device-tree support, >> - add driver model i2c support. >> - add Kconfig entry >> >> Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com> >> CC: Masahiro Yamada <yamada.masahiro@socionext.com> >> Cc: Lukasz Majewski <l.majewski@samsung.com> >> Cc: Mike Frysinger <vapier@gentoo.org> >> Cc: Simon Glass <sjg@chromium.org> >> Cc: Heiko Schocher <hs@denx.de> >> >> Changes V2: >> - new file for software i2c driver: i2c-gpio.c >> - update driver naming: use of "i2c-gpio" >> - add full compatibility with the kernels device-tree "i2c-gpio" node >> - fix Kconfig entry > > Sorry I still have a few more comments. > OK, this is the purpose of this list:) >> --- >> doc/device-tree-bindings/i2c/i2c-gpio.txt | 37 ++++ >> drivers/i2c/Kconfig | 9 + >> drivers/i2c/Makefile | 1 + >> drivers/i2c/i2c-gpio.c | 353 ++++++++++++++++++++++++++++++ >> 4 files changed, 400 insertions(+) >> create mode 100644 doc/device-tree-bindings/i2c/i2c-gpio.txt >> create mode 100644 drivers/i2c/i2c-gpio.c >> >> diff --git a/doc/device-tree-bindings/i2c/i2c-gpio.txt b/doc/device-tree-bindings/i2c/i2c-gpio.txt >> new file mode 100644 >> index 0000000..3978381 >> --- /dev/null >> +++ b/doc/device-tree-bindings/i2c/i2c-gpio.txt >> @@ -0,0 +1,37 @@ >> +I2C gpio device binding >> +======================= >> + >> +Driver: >> +- drivers/i2c/i2c-gpio.c >> + >> +Software i2c device-tree node properties: >> +Required: >> +* #address-cells = <1>; >> +* #size-cells = <0>; >> +* compatible = "i2c-gpio"; >> +* gpios = <sda ...>, <scl ...>; >> + >> +Optional: >> +* i2c-gpio,delay-us = <5>; >> + The resulting transfer speed can be adjusted by setting the delay[us] >> + between gpio-toggle operations. Speed [Hz] = 1us / 4 * udelay, >> + It not defined, then default is 5us (~50KHz). >> + >> +Example: >> + >> +i2c-gpio@1 { >> + #address-cells = <1>; >> + #size-cells = <0>; >> + >> + compatible = "i2c-gpio"; >> + gpios = <&gpd1 0 GPIO_ACTIVE_HIGH>, /* SDA */ >> + <&gpd1 1 GPIO_ACTIVE_HIGH>; /* CLK */ >> + >> + i2c-gpio,delay-us = <5>; >> + >> + some_device@5 { >> + compatible = "some_device"; >> + reg = <0x5>; >> + ... >> + }; >> +}; >> diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig >> index 979522f..22e4a7c 100644 >> --- a/drivers/i2c/Kconfig >> +++ b/drivers/i2c/Kconfig >> @@ -19,6 +19,15 @@ config DM_I2C_COMPAT >> to convert all code for a board in a single commit. It should not >> be enabled for any board in an official release. >> >> +config DM_I2C_GPIO >> + bool "Enable Driver Model for software emulated I2C bus driver" >> + depends on DM_I2C && DM_GPIO >> + help >> + Enable the i2c bus driver emulation by using the GPIO. > > by using GPIOs. > >> + The bus gpio configuration is given by the device-tree. > > GPIO > > device tree > (no hypen) > >> + Kernel style device-tree node for i2c-gpio is supported. > > Kernel-style device tree bindings are supported > Thanks, will fix the all above. >> + Binding info: doc/device-tree-bindings/i2c/i2c-gpio.txt >> + >> config SYS_I2C_UNIPHIER >> bool "UniPhier I2C driver" >> depends on ARCH_UNIPHIER && DM_I2C >> diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile >> index 774bc94..d9e9f3a 100644 >> --- a/drivers/i2c/Makefile >> +++ b/drivers/i2c/Makefile >> @@ -6,6 +6,7 @@ >> # >> obj-$(CONFIG_DM_I2C) += i2c-uclass.o >> obj-$(CONFIG_DM_I2C_COMPAT) += i2c-uclass-compat.o >> +obj-$(CONFIG_DM_I2C_GPIO) += i2c-gpio.o >> >> obj-$(CONFIG_SYS_I2C_ADI) += adi_i2c.o >> obj-$(CONFIG_I2C_MV) += mv_i2c.o >> diff --git a/drivers/i2c/i2c-gpio.c b/drivers/i2c/i2c-gpio.c >> new file mode 100644 >> index 0000000..8e9ed6b >> --- /dev/null >> +++ b/drivers/i2c/i2c-gpio.c >> @@ -0,0 +1,353 @@ >> +/* >> + * (C) Copyright 2015, Samsung Electronics >> + * Przemyslaw Marczak <p.marczak@samsung.com> >> + * Add driver-model support as a separated driver file >> + * >> + * (C) Copyright 2009 >> + * Heiko Schocher, DENX Software Engineering, hs@denx.de. >> + * Changes for multibus/multiadapter I2C support. >> + * >> + * (C) Copyright 2001, 2002 >> + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. >> + * >> + * SPDX-License-Identifier: GPL-2.0+ >> + * >> + * This has been changed substantially by Gerald Van Baren, Custom IDEAS, >> + * vanbaren@cideas.com. It was heavily influenced by LiMon, written by >> + * Neil Russell. >> + */ >> +#include <common.h> >> +#include <errno.h> >> +#include <dm.h> >> +#include <i2c.h> >> +#include <div64.h> >> +#include <asm/gpio.h> >> + >> +#define DEFAULT_UDELAY 5 >> +#define RETRIES 0 >> +#define I2C_ACK 0 >> +#define I2C_NOACK 1 >> + >> +#ifdef DEBUG_I2C >> +#define PRINTD(fmt, args...) do { \ >> + printf (fmt, ##args); \ >> + } while (0) >> +#else >> +#define PRINTD(fmt, args...) >> +#endif > > I don't see any point in this - how about just using debug() instead? > Right, will change to debug(). >> + >> +DECLARE_GLOBAL_DATA_PTR; >> + >> +enum { >> + PIN_SDA = 0, >> + PIN_SCL, > > PIN_COUNT > Ok >> +}; >> + > > Document these members - speed is in HzHz, udelay is the delay for what? > The delay was described in the binding file, I will also add the description beside the structure. And I will remove the speed, since uclass keeps an info about this. >> +struct i2c_gpio_bus { >> + unsigned int speed; >> + unsigned long udelay; >> + struct gpio_desc gpios[2]; /* sda, scl */ > > gpios[PIN_COUNT] > Ok. >> +}; >> + >> +/* Local functions */ >> +static void send_reset(struct gpio_desc *, struct gpio_desc *, int); >> +static void send_start(struct gpio_desc *, struct gpio_desc *, int); >> +static void send_stop(struct gpio_desc *, struct gpio_desc *, int); >> +static void send_ack(struct gpio_desc *, struct gpio_desc *, int, int); >> +static int write_byte(struct gpio_desc *, struct gpio_desc *, int, uchar); >> +static uchar read_byte(struct gpio_desc *, struct gpio_desc *, int, int); > > If you move send_reset() down a bit can you drop these declarations? > >> + >> +static int I2C_READ(struct gpio_desc *sda) > > Lower case - how about gpio_i2c_read()? Same for others. > Ok, will clean this functions. >> +{ >> + return dm_gpio_get_value(sda); >> +} >> + >> +static void I2C_SDA(struct gpio_desc *sda, int bit) >> +{ >> + if (bit) { >> + dm_gpio_set_dir_flags(sda, GPIOD_IS_IN); > > I assume the polarity is never set, so this should be OK. > Yes, this works fine. >> + } else { >> + dm_gpio_set_dir_flags(sda, GPIOD_IS_OUT); >> + dm_gpio_set_value(sda, 0); >> + } >> +} >> + >> +static void I2C_SCL(struct gpio_desc *scl, int bit) >> +{ >> + dm_gpio_set_dir_flags(scl, GPIOD_IS_OUT); >> + dm_gpio_set_value(scl, bit); >> +} >> + >> +static void I2C_DELAY(unsigned long us) >> +{ >> + udelay(us); /* 1/4 I2C clock duration */ >> +} >> + >> +/** >> + * Send a reset sequence consisting of 9 clocks with the data signal high >> + * to clock any confused device back into an idle state. Also send a >> + * <stop> at the end of the sequence for belts & suspenders. >> + */ >> +static void send_reset(struct gpio_desc *scl, struct gpio_desc *sda, int delay) >> +{ >> + int j; >> + >> + I2C_SCL(scl, 1); >> + I2C_SDA(sda, 1); >> + >> + for (j = 0; j < 9; j++) { >> + I2C_SCL(scl, 0); >> + I2C_DELAY(delay); >> + I2C_DELAY(delay); >> + I2C_SCL(scl, 1); >> + I2C_DELAY(delay); >> + I2C_DELAY(delay); > > I wonder why we don't do one call with delay * 2? > Right. >> + } >> + send_stop(scl, sda, delay); >> +} >> + >> +/* START: High -> Low on SDA while SCL is High */ >> +static void send_start(struct gpio_desc *scl, struct gpio_desc *sda, int delay) >> +{ >> + I2C_DELAY(delay); >> + I2C_SDA(sda, 1); >> + I2C_DELAY(delay); >> + I2C_SCL(scl, 1); >> + I2C_DELAY(delay); >> + I2C_SDA(sda, 0); >> + I2C_DELAY(delay); >> +} >> + >> +/* STOP: Low -> High on SDA while SCL is High */ >> +static void send_stop(struct gpio_desc *scl, struct gpio_desc *sda, int delay) >> +{ >> + I2C_SCL(scl, 0); >> + I2C_DELAY(delay); >> + I2C_SDA(sda, 0); >> + I2C_DELAY(delay); >> + I2C_SCL(scl, 1); >> + I2C_DELAY(delay); >> + I2C_SDA(sda, 1); >> + I2C_DELAY(delay); >> +} >> + >> +/* ack should be I2C_ACK or I2C_NOACK */ >> +static void send_ack(struct gpio_desc *scl, struct gpio_desc *sda, >> + int delay, int ack) >> +{ >> + I2C_SCL(scl, 0); >> + I2C_DELAY(delay); >> + I2C_SDA(sda, ack); >> + I2C_DELAY(delay); >> + I2C_SCL(scl, 1); >> + I2C_DELAY(delay); >> + I2C_DELAY(delay); >> + I2C_SCL(scl, 0); >> + I2C_DELAY(delay); >> +} >> + >> +/* Send 8 bits and look for an acknowledgement */ >> +static int write_byte(struct gpio_desc *scl, struct gpio_desc *sda, >> + int delay, uchar data) >> +{ >> + int j; >> + int nack; >> + >> + for (j = 0; j < 8; j++) { >> + I2C_SCL(scl, 0); >> + I2C_DELAY(delay); >> + I2C_SDA(sda, data & 0x80); >> + I2C_DELAY(delay); >> + I2C_SCL(scl, 1); >> + I2C_DELAY(delay); >> + I2C_DELAY(delay); > > This sequence of 7 calls appears a lot in this code. Could it go in a > function and be called from various places? > Ok, I will clean this. >> + >> + data <<= 1; >> + } >> + >> + /* Look for an <ACK>(negative logic) and return it */ >> + I2C_SCL(scl, 0); >> + I2C_DELAY(delay); >> + I2C_SDA(sda, 1); >> + I2C_DELAY(delay); >> + I2C_SCL(scl, 1); >> + I2C_DELAY(delay); >> + I2C_DELAY(delay); >> + nack = I2C_READ(sda); >> + I2C_SCL(scl, 0); >> + I2C_DELAY(delay); >> + >> + return nack; /* not a nack is an ack */ >> +} >> + >> +/** >> + * if ack == I2C_ACK, ACK the byte so can continue reading, else >> + * send I2C_NOACK to end the read. >> + */ >> +static uchar read_byte(struct gpio_desc *scl, struct gpio_desc *sda, >> + int delay, int ack) >> +{ >> + int data; >> + int j; >> + >> + /* Read 8 bits, MSB first */ >> + I2C_SDA(sda, 1); >> + data = 0; >> + for (j = 0; j < 8; j++) { >> + I2C_SCL(scl, 0); >> + I2C_DELAY(delay); >> + I2C_SCL(scl, 1); >> + I2C_DELAY(delay); >> + data <<= 1; >> + data |= I2C_READ(sda); >> + I2C_DELAY(delay); >> + } >> + send_ack(scl, sda, delay, ack); >> + >> + return data; >> +} >> + >> +static int i2c_write_data(struct i2c_gpio_bus *bus, uchar chip, >> + uchar *buffer, int len, bool end_with_repeated_start) >> +{ >> + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; >> + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; >> + unsigned int delay = bus->udelay; >> + int failures = 0; >> + >> + PRINTD("%s: chip %x buffer %p len %d\n", __func__, chip, buffer, len); >> + >> + send_start(scl, sda, delay); >> + if (write_byte(scl, sda, delay, chip << 1)) { >> + send_stop(scl, sda, delay); >> + PRINTD("i2c_write, no chip responded %02X\n", chip); >> + return -EIO; >> + } >> + >> + while (len-- > 0) { >> + if (write_byte(scl, sda, delay, *buffer++)) >> + failures++; >> + } >> + >> + send_stop(scl, sda, delay); >> + >> + return failures; >> +} >> + >> +static int i2c_read_data(struct i2c_gpio_bus *bus, uchar chip, >> + uchar *buffer, int len) >> +{ >> + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; >> + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; >> + unsigned int delay = bus->udelay; >> + >> + PRINTD("%s: chip %x buffer: %x len %d\n", __func__, chip, buffer, len); >> + >> + send_start(scl, sda, delay); >> + write_byte(scl, sda, delay, (chip << 1) | 1); /* read cycle */ >> + >> + while (len-- > 0) >> + *buffer++ = read_byte(scl, sda, delay, len == 0); >> + >> + send_stop(scl, sda, delay); >> + >> + return 0; >> +} >> + >> +static int i2c_gpio_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs) >> +{ >> + struct i2c_gpio_bus *bus = dev_get_priv(dev); >> + int ret; >> + >> + for (; nmsgs > 0; nmsgs--, msg++) { >> + bool next_is_read = nmsgs > 1 && (msg[1].flags & I2C_M_RD); >> + if (msg->flags & I2C_M_RD) >> + ret = i2c_read_data(bus, msg->addr, msg->buf, msg->len); >> + else >> + ret = i2c_write_data(bus, msg->addr, msg->buf, msg->len, >> + next_is_read); >> + >> + if (ret) >> + return -EREMOTEIO; >> + } >> + >> + return 0; >> +} >> + >> +static int i2c_gpio_probe(struct udevice *dev, uint chip, uint chip_flags) >> +{ >> + struct i2c_gpio_bus *bus = dev_get_priv(dev); >> + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; >> + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; >> + unsigned int delay = bus->udelay; >> + int ret; >> + >> + send_start(scl, sda, delay); >> + ret = write_byte(scl, sda, delay, (chip << 1) | 0); >> + send_stop(scl, sda, delay); >> + >> + PRINTD("%s: bus: %d (%s) chip: %x flags: %x ret: %d\n", >> + __func__, dev->seq, dev->name, chip, chip_flags, ret); >> + >> + return ret; >> +} >> + >> +static int i2c_gpio_set_bus_speed(struct udevice *dev, unsigned int speed) >> +{ >> + struct i2c_gpio_bus *bus = dev_get_priv(dev); >> + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; >> + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; >> + >> + bus->speed = speed; >> + bus->udelay = lldiv(1000000, speed << 2); > > Why lldiv() if the value can never be >100,000? Can we just use normal division? > ok, will change this. And I will remove the speed, since it's the same value as uclass provides in struct dm_i2c_bus. >> + >> + send_reset(scl, sda, bus->udelay); >> + >> + PRINTD("%s: bus: %d (%s) speed: %u Hz (1/4 of period: %lu us)\n", >> + __func__, dev->seq, dev->name, speed, bus->udelay); >> + >> + return 0; >> +} >> + >> +static int i2c_gpio_ofdata_to_platdata(struct udevice *dev) >> +{ >> + struct i2c_gpio_bus *bus = dev_get_priv(dev); >> + const void *blob = gd->fdt_blob; >> + int node = dev->of_offset; >> + int ret; >> + >> + ret = gpio_request_list_by_name(dev, "gpios", bus->gpios, >> + ARRAY_SIZE(bus->gpios), 0); >> + if (ret < 0) >> + goto error; >> + >> + bus->udelay = fdtdec_get_int(blob, node, "i2c-gpio,delay-us", >> + DEFAULT_UDELAY); >> + >> + PRINTD("%s: bus: %d (%s) fdt node ok\n", __func__, dev->seq, dev->name); >> + >> + return 0; >> +error: >> + error("Can't get %s gpios! Error: %d", dev->name, ret); >> + return ret; >> +} >> + >> +static const struct dm_i2c_ops i2c_gpio_ops = { >> + .xfer = i2c_gpio_xfer, >> + .probe_chip = i2c_gpio_probe, >> + .set_bus_speed = i2c_gpio_set_bus_speed, >> +}; >> + >> +static const struct udevice_id i2c_gpio_ids[] = { >> + { .compatible = "i2c-gpio" }, >> + { } >> +}; >> + >> +U_BOOT_DRIVER(i2c_gpio) = { >> + .name = "i2c-gpio", >> + .id = UCLASS_I2C, >> + .of_match = i2c_gpio_ids, >> + .ofdata_to_platdata = i2c_gpio_ofdata_to_platdata, >> + .priv_auto_alloc_size = sizeof(struct i2c_gpio_bus), >> + .ops = &i2c_gpio_ops, >> +}; >> -- >> 1.9.1 >> > > Regards, > Simon > Thank you for the review. Best regards,
diff --git a/doc/device-tree-bindings/i2c/i2c-gpio.txt b/doc/device-tree-bindings/i2c/i2c-gpio.txt new file mode 100644 index 0000000..3978381 --- /dev/null +++ b/doc/device-tree-bindings/i2c/i2c-gpio.txt @@ -0,0 +1,37 @@ +I2C gpio device binding +======================= + +Driver: +- drivers/i2c/i2c-gpio.c + +Software i2c device-tree node properties: +Required: +* #address-cells = <1>; +* #size-cells = <0>; +* compatible = "i2c-gpio"; +* gpios = <sda ...>, <scl ...>; + +Optional: +* i2c-gpio,delay-us = <5>; + The resulting transfer speed can be adjusted by setting the delay[us] + between gpio-toggle operations. Speed [Hz] = 1us / 4 * udelay, + It not defined, then default is 5us (~50KHz). + +Example: + +i2c-gpio@1 { + #address-cells = <1>; + #size-cells = <0>; + + compatible = "i2c-gpio"; + gpios = <&gpd1 0 GPIO_ACTIVE_HIGH>, /* SDA */ + <&gpd1 1 GPIO_ACTIVE_HIGH>; /* CLK */ + + i2c-gpio,delay-us = <5>; + + some_device@5 { + compatible = "some_device"; + reg = <0x5>; + ... + }; +}; diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig index 979522f..22e4a7c 100644 --- a/drivers/i2c/Kconfig +++ b/drivers/i2c/Kconfig @@ -19,6 +19,15 @@ config DM_I2C_COMPAT to convert all code for a board in a single commit. It should not be enabled for any board in an official release. +config DM_I2C_GPIO + bool "Enable Driver Model for software emulated I2C bus driver" + depends on DM_I2C && DM_GPIO + help + Enable the i2c bus driver emulation by using the GPIO. + The bus gpio configuration is given by the device-tree. + Kernel style device-tree node for i2c-gpio is supported. + Binding info: doc/device-tree-bindings/i2c/i2c-gpio.txt + config SYS_I2C_UNIPHIER bool "UniPhier I2C driver" depends on ARCH_UNIPHIER && DM_I2C diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile index 774bc94..d9e9f3a 100644 --- a/drivers/i2c/Makefile +++ b/drivers/i2c/Makefile @@ -6,6 +6,7 @@ # obj-$(CONFIG_DM_I2C) += i2c-uclass.o obj-$(CONFIG_DM_I2C_COMPAT) += i2c-uclass-compat.o +obj-$(CONFIG_DM_I2C_GPIO) += i2c-gpio.o obj-$(CONFIG_SYS_I2C_ADI) += adi_i2c.o obj-$(CONFIG_I2C_MV) += mv_i2c.o diff --git a/drivers/i2c/i2c-gpio.c b/drivers/i2c/i2c-gpio.c new file mode 100644 index 0000000..8e9ed6b --- /dev/null +++ b/drivers/i2c/i2c-gpio.c @@ -0,0 +1,353 @@ +/* + * (C) Copyright 2015, Samsung Electronics + * Przemyslaw Marczak <p.marczak@samsung.com> + * Add driver-model support as a separated driver file + * + * (C) Copyright 2009 + * Heiko Schocher, DENX Software Engineering, hs@denx.de. + * Changes for multibus/multiadapter I2C support. + * + * (C) Copyright 2001, 2002 + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. + * + * SPDX-License-Identifier: GPL-2.0+ + * + * This has been changed substantially by Gerald Van Baren, Custom IDEAS, + * vanbaren@cideas.com. It was heavily influenced by LiMon, written by + * Neil Russell. + */ +#include <common.h> +#include <errno.h> +#include <dm.h> +#include <i2c.h> +#include <div64.h> +#include <asm/gpio.h> + +#define DEFAULT_UDELAY 5 +#define RETRIES 0 +#define I2C_ACK 0 +#define I2C_NOACK 1 + +#ifdef DEBUG_I2C +#define PRINTD(fmt, args...) do { \ + printf (fmt, ##args); \ + } while (0) +#else +#define PRINTD(fmt, args...) +#endif + +DECLARE_GLOBAL_DATA_PTR; + +enum { + PIN_SDA = 0, + PIN_SCL, +}; + +struct i2c_gpio_bus { + unsigned int speed; + unsigned long udelay; + struct gpio_desc gpios[2]; /* sda, scl */ +}; + +/* Local functions */ +static void send_reset(struct gpio_desc *, struct gpio_desc *, int); +static void send_start(struct gpio_desc *, struct gpio_desc *, int); +static void send_stop(struct gpio_desc *, struct gpio_desc *, int); +static void send_ack(struct gpio_desc *, struct gpio_desc *, int, int); +static int write_byte(struct gpio_desc *, struct gpio_desc *, int, uchar); +static uchar read_byte(struct gpio_desc *, struct gpio_desc *, int, int); + +static int I2C_READ(struct gpio_desc *sda) +{ + return dm_gpio_get_value(sda); +} + +static void I2C_SDA(struct gpio_desc *sda, int bit) +{ + if (bit) { + dm_gpio_set_dir_flags(sda, GPIOD_IS_IN); + } else { + dm_gpio_set_dir_flags(sda, GPIOD_IS_OUT); + dm_gpio_set_value(sda, 0); + } +} + +static void I2C_SCL(struct gpio_desc *scl, int bit) +{ + dm_gpio_set_dir_flags(scl, GPIOD_IS_OUT); + dm_gpio_set_value(scl, bit); +} + +static void I2C_DELAY(unsigned long us) +{ + udelay(us); /* 1/4 I2C clock duration */ +} + +/** + * Send a reset sequence consisting of 9 clocks with the data signal high + * to clock any confused device back into an idle state. Also send a + * <stop> at the end of the sequence for belts & suspenders. + */ +static void send_reset(struct gpio_desc *scl, struct gpio_desc *sda, int delay) +{ + int j; + + I2C_SCL(scl, 1); + I2C_SDA(sda, 1); + + for (j = 0; j < 9; j++) { + I2C_SCL(scl, 0); + I2C_DELAY(delay); + I2C_DELAY(delay); + I2C_SCL(scl, 1); + I2C_DELAY(delay); + I2C_DELAY(delay); + } + send_stop(scl, sda, delay); +} + +/* START: High -> Low on SDA while SCL is High */ +static void send_start(struct gpio_desc *scl, struct gpio_desc *sda, int delay) +{ + I2C_DELAY(delay); + I2C_SDA(sda, 1); + I2C_DELAY(delay); + I2C_SCL(scl, 1); + I2C_DELAY(delay); + I2C_SDA(sda, 0); + I2C_DELAY(delay); +} + +/* STOP: Low -> High on SDA while SCL is High */ +static void send_stop(struct gpio_desc *scl, struct gpio_desc *sda, int delay) +{ + I2C_SCL(scl, 0); + I2C_DELAY(delay); + I2C_SDA(sda, 0); + I2C_DELAY(delay); + I2C_SCL(scl, 1); + I2C_DELAY(delay); + I2C_SDA(sda, 1); + I2C_DELAY(delay); +} + +/* ack should be I2C_ACK or I2C_NOACK */ +static void send_ack(struct gpio_desc *scl, struct gpio_desc *sda, + int delay, int ack) +{ + I2C_SCL(scl, 0); + I2C_DELAY(delay); + I2C_SDA(sda, ack); + I2C_DELAY(delay); + I2C_SCL(scl, 1); + I2C_DELAY(delay); + I2C_DELAY(delay); + I2C_SCL(scl, 0); + I2C_DELAY(delay); +} + +/* Send 8 bits and look for an acknowledgement */ +static int write_byte(struct gpio_desc *scl, struct gpio_desc *sda, + int delay, uchar data) +{ + int j; + int nack; + + for (j = 0; j < 8; j++) { + I2C_SCL(scl, 0); + I2C_DELAY(delay); + I2C_SDA(sda, data & 0x80); + I2C_DELAY(delay); + I2C_SCL(scl, 1); + I2C_DELAY(delay); + I2C_DELAY(delay); + + data <<= 1; + } + + /* Look for an <ACK>(negative logic) and return it */ + I2C_SCL(scl, 0); + I2C_DELAY(delay); + I2C_SDA(sda, 1); + I2C_DELAY(delay); + I2C_SCL(scl, 1); + I2C_DELAY(delay); + I2C_DELAY(delay); + nack = I2C_READ(sda); + I2C_SCL(scl, 0); + I2C_DELAY(delay); + + return nack; /* not a nack is an ack */ +} + +/** + * if ack == I2C_ACK, ACK the byte so can continue reading, else + * send I2C_NOACK to end the read. + */ +static uchar read_byte(struct gpio_desc *scl, struct gpio_desc *sda, + int delay, int ack) +{ + int data; + int j; + + /* Read 8 bits, MSB first */ + I2C_SDA(sda, 1); + data = 0; + for (j = 0; j < 8; j++) { + I2C_SCL(scl, 0); + I2C_DELAY(delay); + I2C_SCL(scl, 1); + I2C_DELAY(delay); + data <<= 1; + data |= I2C_READ(sda); + I2C_DELAY(delay); + } + send_ack(scl, sda, delay, ack); + + return data; +} + +static int i2c_write_data(struct i2c_gpio_bus *bus, uchar chip, + uchar *buffer, int len, bool end_with_repeated_start) +{ + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; + unsigned int delay = bus->udelay; + int failures = 0; + + PRINTD("%s: chip %x buffer %p len %d\n", __func__, chip, buffer, len); + + send_start(scl, sda, delay); + if (write_byte(scl, sda, delay, chip << 1)) { + send_stop(scl, sda, delay); + PRINTD("i2c_write, no chip responded %02X\n", chip); + return -EIO; + } + + while (len-- > 0) { + if (write_byte(scl, sda, delay, *buffer++)) + failures++; + } + + send_stop(scl, sda, delay); + + return failures; +} + +static int i2c_read_data(struct i2c_gpio_bus *bus, uchar chip, + uchar *buffer, int len) +{ + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; + unsigned int delay = bus->udelay; + + PRINTD("%s: chip %x buffer: %x len %d\n", __func__, chip, buffer, len); + + send_start(scl, sda, delay); + write_byte(scl, sda, delay, (chip << 1) | 1); /* read cycle */ + + while (len-- > 0) + *buffer++ = read_byte(scl, sda, delay, len == 0); + + send_stop(scl, sda, delay); + + return 0; +} + +static int i2c_gpio_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs) +{ + struct i2c_gpio_bus *bus = dev_get_priv(dev); + int ret; + + for (; nmsgs > 0; nmsgs--, msg++) { + bool next_is_read = nmsgs > 1 && (msg[1].flags & I2C_M_RD); + if (msg->flags & I2C_M_RD) + ret = i2c_read_data(bus, msg->addr, msg->buf, msg->len); + else + ret = i2c_write_data(bus, msg->addr, msg->buf, msg->len, + next_is_read); + + if (ret) + return -EREMOTEIO; + } + + return 0; +} + +static int i2c_gpio_probe(struct udevice *dev, uint chip, uint chip_flags) +{ + struct i2c_gpio_bus *bus = dev_get_priv(dev); + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; + unsigned int delay = bus->udelay; + int ret; + + send_start(scl, sda, delay); + ret = write_byte(scl, sda, delay, (chip << 1) | 0); + send_stop(scl, sda, delay); + + PRINTD("%s: bus: %d (%s) chip: %x flags: %x ret: %d\n", + __func__, dev->seq, dev->name, chip, chip_flags, ret); + + return ret; +} + +static int i2c_gpio_set_bus_speed(struct udevice *dev, unsigned int speed) +{ + struct i2c_gpio_bus *bus = dev_get_priv(dev); + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; + + bus->speed = speed; + bus->udelay = lldiv(1000000, speed << 2); + + send_reset(scl, sda, bus->udelay); + + PRINTD("%s: bus: %d (%s) speed: %u Hz (1/4 of period: %lu us)\n", + __func__, dev->seq, dev->name, speed, bus->udelay); + + return 0; +} + +static int i2c_gpio_ofdata_to_platdata(struct udevice *dev) +{ + struct i2c_gpio_bus *bus = dev_get_priv(dev); + const void *blob = gd->fdt_blob; + int node = dev->of_offset; + int ret; + + ret = gpio_request_list_by_name(dev, "gpios", bus->gpios, + ARRAY_SIZE(bus->gpios), 0); + if (ret < 0) + goto error; + + bus->udelay = fdtdec_get_int(blob, node, "i2c-gpio,delay-us", + DEFAULT_UDELAY); + + PRINTD("%s: bus: %d (%s) fdt node ok\n", __func__, dev->seq, dev->name); + + return 0; +error: + error("Can't get %s gpios! Error: %d", dev->name, ret); + return ret; +} + +static const struct dm_i2c_ops i2c_gpio_ops = { + .xfer = i2c_gpio_xfer, + .probe_chip = i2c_gpio_probe, + .set_bus_speed = i2c_gpio_set_bus_speed, +}; + +static const struct udevice_id i2c_gpio_ids[] = { + { .compatible = "i2c-gpio" }, + { } +}; + +U_BOOT_DRIVER(i2c_gpio) = { + .name = "i2c-gpio", + .id = UCLASS_I2C, + .of_match = i2c_gpio_ids, + .ofdata_to_platdata = i2c_gpio_ofdata_to_platdata, + .priv_auto_alloc_size = sizeof(struct i2c_gpio_bus), + .ops = &i2c_gpio_ops, +};
This commit adds driver model support to software emulated i2c bus driver. The device-tree node is compatible with the kernel i2c-gpio driver. It means, that boards device-tree "i2c-gpio" node, should be the same as in the kernel. For operating, it requires proper compatible and gpio pins dts description. Added: - Config: CONFIG_DM_I2C_GPIO - File: drivers/i2c/i2c-gpio.c - File: doc/device-tree-bindings/i2c/i2c-gpio.txt Driver base code is taken from: drivers/i2c/soft-i2c.c, changes: - update comments style, - move preprocesor macros into functions, - add device-tree support, - add driver model i2c support. - add Kconfig entry Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com> CC: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Lukasz Majewski <l.majewski@samsung.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Simon Glass <sjg@chromium.org> Cc: Heiko Schocher <hs@denx.de> Changes V2: - new file for software i2c driver: i2c-gpio.c - update driver naming: use of "i2c-gpio" - add full compatibility with the kernels device-tree "i2c-gpio" node - fix Kconfig entry --- doc/device-tree-bindings/i2c/i2c-gpio.txt | 37 ++++ drivers/i2c/Kconfig | 9 + drivers/i2c/Makefile | 1 + drivers/i2c/i2c-gpio.c | 353 ++++++++++++++++++++++++++++++ 4 files changed, 400 insertions(+) create mode 100644 doc/device-tree-bindings/i2c/i2c-gpio.txt create mode 100644 drivers/i2c/i2c-gpio.c