Hi Przemyslaw,
> This change adds driver model support to software emulated
> i2c bus driver. To bind the driver, proper device-tree node
> must be defined, with the following attributes:
> - alias: to keep proper bus order
> - compatible: 'soft-i2c'
> - clock-frequency [Hz]
> - clock-pin, data-pin: gpio phandles
>
> /* Define the alias number to keep bus numbering order */
> aliases {
> [...]
> i2c5 = "/i2c@13500000";
> i2c6 = "/soft-i2c@1";
> [...]
> };
>
> /* Define the basic bus attributes */
> soft-i2c@1 {
> #address-cells = <1>;
> #size-cells = <0>;
> compatible = "soft-i2c";
> clock-frequency = <50000>;
>
> /* Define the proper GPIO pins */
> clock-pin = <&gpa0 0 GPIO_ACTIVE_HIGH>;
> data-pin = <&gpa0 1 GPIO_ACTIVE_HIGH>;
>
> /* Optionally, define some driver node (bus child) */
> somedev@0x44 {
> compatible = "somedev";
> reg = <0x44>;
> [...]
> };
> };
>
> The device can be accessed by the i2c command:
> i2c dev 8 (bus number set by alias)
> i2c probe <0x44> (address is optionally)
> i2c md 0x44 0x0 (dump dev registers at address 0x0)
> Valid chip addresses: 0x44 (success!)
> ...
>
> The previous driver functionality stays unchanged. Driving the bus
> lines is done by dm gpio calls in the preprocessor macros. Each, can
> be redefined by the user as previous.
>
> Tested on Trats2 and Odroid U3.
>
> Signed-off-by: Przemyslaw Marczak <p.marc...@samsung.com>
> Cc: Masahiro Yamada <yamad...@jp.panasonic.com>
> Cc: Mike Frysinger <vap...@gentoo.org>
> Cc: Simon Glass <s...@chromium.org>
> Cc: Heiko Schocher <h...@denx.de>
> ---
> drivers/i2c/Makefile | 1 +
> drivers/i2c/soft_i2c.c | 410
> +++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed,
> 400 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
> index 774bc94..7039b6d 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-$(CONFIG_DM_I2C_SOFT) += soft_i2c.o
>
> obj-$(CONFIG_SYS_I2C_ADI) += adi_i2c.o
> obj-$(CONFIG_I2C_MV) += mv_i2c.o
> diff --git a/drivers/i2c/soft_i2c.c b/drivers/i2c/soft_i2c.c
> index db9b402..7afae0b 100644
> --- a/drivers/i2c/soft_i2c.c
> +++ b/drivers/i2c/soft_i2c.c
> @@ -1,4 +1,7 @@
> /*
> + * (C) Copyright 2015, Samsung Electronics
> + * Przemyslaw Marczak <p.marc...@samsung.com>
> + *
> * (C) Copyright 2009
> * Heiko Schocher, DENX Software Engineering, h...@denx.de.
> * Changes for multibus/multiadapter I2C support.
> @@ -14,6 +17,11 @@
> */
>
> #include <common.h>
> +#include <errno.h>
> +#include <dm.h>
> +#include <i2c.h>
> +#include <div64.h>
> +#include <asm/gpio.h>
> #ifdef CONFIG_MPC8260 /* only valid
> for MPC8260 */ #include <ioports.h>
> #include <asm/io.h>
> @@ -32,11 +40,9 @@
> #if defined(CONFIG_MPC852T) || defined(CONFIG_MPC866)
> #include <asm/io.h>
> #endif
> -#include <i2c.h>
>
> +#if defined(CONFIG_SYS_I2C)
> #if defined(CONFIG_SOFT_I2C_GPIO_SCL)
> -# include <asm/gpio.h>
> -
> # ifndef I2C_GPIO_SYNC
> # define I2C_GPIO_SYNC
> # endif
> @@ -85,6 +91,7 @@
> # endif
>
> #endif
> +#endif
>
> /* #define DEBUG_I2C */
>
> @@ -109,6 +116,65 @@ DECLARE_GLOBAL_DATA_PTR;
> #define CONFIG_SYS_I2C_SOFT_SLAVE CONFIG_SYS_I2C_SLAVE
> #endif
>
> +/* DM SOFT I2C */
> +#ifdef CONFIG_DM_I2C_SOFT
> +# ifndef I2C_GPIO_SYNC
> +# define I2C_GPIO_SYNC(gpio)
> +# endif
> +
> +# ifndef I2C_INIT
> +# define I2C_INIT(scl, sda) \
> + do { } while (0)
> +# endif
> +
> +# ifndef I2C_ACTIVE
> +# define I2C_ACTIVE(sda) \
> + do { } while (0)
> +# endif
> +
> +# ifndef I2C_TRISTATE
> +# define I2C_TRISTATE(sda) \
> + do { } while (0)
> +# endif
> +
> +# ifndef I2C_READ
> +# define I2C_READ(sda) dm_gpio_get_value(sda);
> +# endif
> +
> +# ifndef I2C_SDA
> +# define I2C_SDA(sda, bit) \
> + do { \
> + if (bit) { \
> + sda->flags &= ~GPIOD_IS_OUT; \
> + sda->flags |= GPIOD_IS_IN; \
> + dm_gpio_set_dir(sda); \
> + } else { \
> + sda->flags &= ~GPIOD_IS_IN; \
> + sda->flags |= GPIOD_IS_OUT; \
> + dm_gpio_set_dir(sda); \
> + dm_gpio_set_value(sda, 0); \
> + } \
> + I2C_GPIO_SYNC(sda); \
> + } while (0)
> +# endif
> +
> +# ifndef I2C_SCL
> +# define I2C_SCL(scl, bit) \
> + do { \
> + scl->flags &= ~GPIOD_IS_IN; \
> + scl->flags |= GPIOD_IS_OUT; \
> + dm_gpio_set_dir(scl); \
> + dm_gpio_set_value(scl, bit); \
> + I2C_GPIO_SYNC(scl); \
> + } while (0)
> +# endif
> +
> +# ifndef I2C_DELAY
> +# define I2C_DELAY(us) udelay(us) /* 1/4 I2C clock duration
> */ +# endif
> +
> +#endif /* CONFIG_DM_I2C_SOFT */
> +
> /*-----------------------------------------------------------------------
> * Definitions
> */
> @@ -117,7 +183,6 @@ DECLARE_GLOBAL_DATA_PTR;
> #define I2C_ACK 0 /* PD_SDA level to
> ack a byte */ #define I2C_NOACK 1 /* PD_SDA
> level to noack a byte */
> -
> #ifdef DEBUG_I2C
> #define PRINTD(fmt,args...) do { \
> printf (fmt ,##args); \
> @@ -129,21 +194,30 @@ DECLARE_GLOBAL_DATA_PTR;
> /*-----------------------------------------------------------------------
> * Local functions
> */
> +#ifdef CONFIG_SYS_I2C
> #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
> -static void send_reset (void);
> +static void send_reset(void);
> +#endif
> +static void send_start(void);
> +static void send_stop(void);
> +static void send_ack(int);
> +static int write_byte(uchar byte);
> +static uchar read_byte(int);
> +#else
> +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); #endif
> -static void send_start (void);
> -static void send_stop (void);
> -static void send_ack (int);
> -static int write_byte (uchar byte);
> -static uchar read_byte (int);
> -
> #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
> /*-----------------------------------------------------------------------
> * 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.
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> static void send_reset(void)
> {
> I2C_SOFT_DECLARATIONS /* intentional without ';' */
> @@ -166,11 +240,36 @@ static void send_reset(void)
> send_stop();
> I2C_TRISTATE;
> }
> +#else
> +static void send_reset(struct gpio_desc *scl, struct gpio_desc *sda,
> int delay) +{
> + I2C_SOFT_DECLARATIONS /* intentional without ';' */
> + int j;
> +
> + I2C_SCL(scl, 1);
> + I2C_SDA(sda, 1);
> +#ifdef I2C_INIT
> + I2C_INIT(scl, sda);
> +#endif
> + I2C_TRISTATE(sda);
> + 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);
> + I2C_TRISTATE(sda);
> +}
> +#endif /* CONFIG_SYS_I2C_SOFT */
> #endif
>
> /*-----------------------------------------------------------------------
> * START: High -> Low on SDA while SCL is High
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> static void send_start(void)
> {
> I2C_SOFT_DECLARATIONS /* intentional without ';' */
> @@ -184,10 +283,25 @@ static void send_start(void)
> I2C_SDA(0);
> I2C_DELAY;
> }
> +#else
> +static void send_start(struct gpio_desc *scl, struct gpio_desc *sda,
> int delay) +{
> + I2C_SOFT_DECLARATIONS /* intentional without ';' */
>
> + I2C_DELAY(delay);
> + I2C_SDA(sda, 1);
> + I2C_ACTIVE(sda);
> + I2C_DELAY(delay);
> + I2C_SCL(scl, 1);
> + I2C_DELAY(delay);
> + I2C_SDA(sda, 0);
> + I2C_DELAY(delay);
> +}
> +#endif /* CONFIG_SYS_I2C_SOFT */
> /*-----------------------------------------------------------------------
> * STOP: Low -> High on SDA while SCL is High
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> static void send_stop(void)
> {
> I2C_SOFT_DECLARATIONS /* intentional without ';' */
> @@ -203,10 +317,28 @@ static void send_stop(void)
> I2C_DELAY;
> I2C_TRISTATE;
> }
> +#else
> +static void send_stop(struct gpio_desc *scl, struct gpio_desc *sda,
> int delay) +{
> + I2C_SOFT_DECLARATIONS /* intentional without ';' */
> +
> + I2C_SCL(scl, 0);
> + I2C_DELAY(delay);
> + I2C_SDA(sda, 0);
> + I2C_ACTIVE(sda);
> + I2C_DELAY(delay);
> + I2C_SCL(scl, 1);
> + I2C_DELAY(delay);
> + I2C_SDA(sda, 1);
> + I2C_DELAY(delay);
> + I2C_TRISTATE(sda);
> +}
> +#endif /* CONFIG_SYS_I2C_SOFT */
>
> /*-----------------------------------------------------------------------
> * ack should be I2C_ACK or I2C_NOACK
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> static void send_ack(int ack)
> {
> I2C_SOFT_DECLARATIONS /* intentional without ';' */
> @@ -222,10 +354,29 @@ static void send_ack(int ack)
> I2C_SCL(0);
> I2C_DELAY;
> }
> +#else
> +static void send_ack(struct gpio_desc *scl, struct gpio_desc *sda,
> + int delay, int ack)
> +{
> + I2C_SOFT_DECLARATIONS /* intentional without ';' */
> +
> + I2C_SCL(scl, 0);
> + I2C_DELAY(delay);
> + I2C_ACTIVE(sda);
> + I2C_SDA(sda, ack);
> + I2C_DELAY(delay);
> + I2C_SCL(scl, 1);
> + I2C_DELAY(delay);
> + I2C_DELAY(delay);
> + I2C_SCL(scl, 0);
> + I2C_DELAY(delay);
> +}
> +#endif
>
> /*-----------------------------------------------------------------------
> * Send 8 bits and look for an acknowledgement.
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> static int write_byte(uchar data)
> {
> I2C_SOFT_DECLARATIONS /* intentional without ';' */
> @@ -263,11 +414,52 @@ static int write_byte(uchar data)
>
> return(nack); /* not a nack is an ack */
> }
> +#else
> +static int write_byte(struct gpio_desc *scl, struct gpio_desc *sda,
> + int delay, uchar data)
> +{
> + I2C_SOFT_DECLARATIONS /* intentional without ';' */
> + int j;
> + int nack;
> +
> + I2C_ACTIVE(sda);
> + 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_TRISTATE(sda);
> + I2C_DELAY(delay);
> + I2C_SCL(scl, 1);
> + I2C_DELAY(delay);
> + I2C_DELAY(delay);
> + nack = I2C_READ(sda);
> + I2C_SCL(scl, 0);
> + I2C_DELAY(delay);
> + I2C_ACTIVE(sda);
> +
> + return nack; /* not a nack is an ack */
> +}
> +#endif
>
> /*-----------------------------------------------------------------------
> * if ack == I2C_ACK, ACK the byte so can continue reading, else
> * send I2C_NOACK to end the read.
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> static uchar read_byte(int ack)
> {
> I2C_SOFT_DECLARATIONS /* intentional without ';' */
> @@ -293,10 +485,38 @@ static uchar read_byte(int ack)
>
> return(data);
> }
> +#else
> +static uchar read_byte(struct gpio_desc *scl, struct gpio_desc *sda,
> + int delay, int ack)
> +{
> + I2C_SOFT_DECLARATIONS /* intentional without ';' */
> + int data;
> + int j;
> +
> + /*
> + * Read 8 bits, MSB first.
> + */
> + I2C_TRISTATE(sda);
> + 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;
> +}
> +#endif /* CONFIG_SYS_I2C_SOFT */
> /*-----------------------------------------------------------------------
> * Initialization
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> static void soft_i2c_init(struct i2c_adapter *adap, int speed, int
> slaveaddr) {
> #if defined(CONFIG_SYS_I2C_INIT_BOARD)
> @@ -314,12 +534,14 @@ static void soft_i2c_init(struct i2c_adapter
> *adap, int speed, int slaveaddr) send_reset ();
> #endif
> }
> +#endif
>
> /*-----------------------------------------------------------------------
> * Probe to see if a chip is present. Also good for checking for the
> * completion of EEPROM writes since the chip stops responding until
> * the write completes (typically 10mSec).
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> static int soft_i2c_probe(struct i2c_adapter *adap, uint8_t addr)
> {
> int rc;
> @@ -334,10 +556,12 @@ static int soft_i2c_probe(struct i2c_adapter
> *adap, uint8_t addr)
> return (rc ? 1 : 0);
> }
> +#endif
>
> /*-----------------------------------------------------------------------
> * Read bytes
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> static int soft_i2c_read(struct i2c_adapter *adap, uchar chip, uint
> addr, int alen, uchar *buffer, int len)
> {
> @@ -409,10 +633,12 @@ static int soft_i2c_read(struct i2c_adapter
> *adap, uchar chip, uint addr, send_stop();
> return(0);
> }
> +#endif
>
> /*-----------------------------------------------------------------------
> * Write bytes
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> static int soft_i2c_write(struct i2c_adapter *adap, uchar chip,
> uint addr, int alen, uchar *buffer, int len)
> {
> @@ -444,10 +670,12 @@ static int soft_i2c_write(struct i2c_adapter
> *adap, uchar chip, uint addr, send_stop();
> return(failures);
> }
> +#endif
>
> /*
> * Register soft i2c adapters
> */
> +#ifdef CONFIG_SYS_I2C_SOFT
> U_BOOT_I2C_ADAP_COMPLETE(soft0, soft_i2c_init, soft_i2c_probe,
> soft_i2c_read, soft_i2c_write, NULL,
> CONFIG_SYS_I2C_SOFT_SPEED,
> CONFIG_SYS_I2C_SOFT_SLAVE, @@ -473,3 +701,163 @@
> U_BOOT_I2C_ADAP_COMPLETE(soft3, soft_i2c_init, soft_i2c_probe,
> CONFIG_SYS_I2C_SOFT_SLAVE_4, 3)
> #endif
> +#endif /* CONFIG_SYS_I2C_SOFT */
> +
> +#ifdef CONFIG_DM_I2C_SOFT
> +struct soft_i2c_bus {
> + unsigned int speed;
> + unsigned long delay;
> + struct gpio_desc scl;
> + struct gpio_desc sda;
> +};
> +
> +static int i2c_write_data(struct soft_i2c_bus *i2c_bus, uchar chip,
> + uchar *buffer, int len, bool
> end_with_repeated_start) +{
> + struct gpio_desc *scl = &i2c_bus->scl;
> + struct gpio_desc *sda = &i2c_bus->sda;
> + unsigned int delay = i2c_bus->delay;
> + 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 -ENODEV;
> + }
> +
> + while (len-- > 0) {
> + if (write_byte(scl, sda, delay, *buffer++))
> + failures++;
> + }
> +
> + send_stop(scl, sda, delay);
> +
> + return failures;
> +}
> +
> +static int i2c_read_data(struct soft_i2c_bus *i2c_bus, uchar chip,
> + uchar *buffer, int len)
> +{
> + struct gpio_desc *scl = &i2c_bus->scl;
> + struct gpio_desc *sda = &i2c_bus->sda;
> + unsigned int delay = i2c_bus->delay;
> +
> + 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 soft_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
> int nmsgs) +{
> + struct soft_i2c_bus *i2c_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(i2c_bus, msg->addr,
> msg->buf,
> + msg->len);
> + } else {
> + ret = i2c_write_data(i2c_bus, msg->addr,
> msg->buf,
> + msg->len, next_is_read);
> + }
> + if (ret)
> + return -EREMOTEIO;
> + }
> +
> + return 0;
> +}
> +
> +static int soft_i2c_probe(struct udevice *dev, uint chip, uint
> chip_flags) +{
> + struct soft_i2c_bus *i2c_bus = dev_get_priv(dev);
> + struct gpio_desc *scl = &i2c_bus->scl;
> + struct gpio_desc *sda = &i2c_bus->sda;
> + unsigned int delay = i2c_bus->delay;
> + 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 soft_i2c_set_bus_speed(struct udevice *dev, unsigned int
> speed) +{
> + struct soft_i2c_bus *i2c_bus = dev_get_priv(dev);
> + struct gpio_desc *scl = &i2c_bus->scl;
> + struct gpio_desc *sda = &i2c_bus->sda;
> +
> + i2c_bus->speed = speed;
> + i2c_bus->delay = lldiv(1000000, speed << 2);
> +
> + send_reset(scl, sda, i2c_bus->delay);
> +
> + PRINTD("%s: bus: %d (%s) speed: %u Hz (1/4 of period: %lu
> us)\n",
> + __func__, dev->seq, dev->name, speed, i2c_bus->delay);
> +
> + return 0;
> +}
> +
> +static int soft_i2c_ofdata_to_platdata(struct udevice *dev)
> +{
> + struct soft_i2c_bus *i2c_bus = dev_get_priv(dev);
> + const void *blob = gd->fdt_blob;
> + char *pin_name;
> + int ret;
> +
> + pin_name = "clock-pin";
> + ret = gpio_request_by_name_nodev(blob, dev->of_offset,
> pin_name,
> + 0, &i2c_bus->scl,
> GPIOD_IS_OUT);
> + if (ret)
> + goto error;
> +
> + pin_name = "data-pin";
> + ret = gpio_request_by_name_nodev(blob, dev->of_offset,
> pin_name,
> + 0, &i2c_bus->sda,
> GPIOD_IS_OUT);
> + if (ret)
> + goto error;
> +
> + PRINTD("%s: bus: %d (%s) fdt node ok\n", __func__, dev->seq,
> dev->name); +
> + return 0;
> +error:
> + error("Can't get %s for soft i2c dev: %s", pin_name,
> dev->name);
> + return ret;
> +}
> +
> +static const struct dm_i2c_ops soft_i2c_ops = {
> + .xfer = soft_i2c_xfer,
> + .probe_chip = soft_i2c_probe,
> + .set_bus_speed = soft_i2c_set_bus_speed,
> +};
> +
> +static const struct udevice_id soft_i2c_ids[] = {
> + { .compatible = "soft-i2c" },
> + { }
> +};
> +
> +U_BOOT_DRIVER(soft_i2c) = {
> + .name = "soft-i2c",
> + .id = UCLASS_I2C,
> + .of_match = soft_i2c_ids,
> + .ofdata_to_platdata = soft_i2c_ofdata_to_platdata,
> + .priv_auto_alloc_size = sizeof(struct soft_i2c_bus),
> + .ops = &soft_i2c_ops,
> +};
> +#endif /* CONFIG_DM_I2C_SOFT */
Reviewed-by: Lukasz Majewski <l.majew...@samsung.com>
--
Best regards,
Lukasz Majewski
Samsung R&D Institute Poland (SRPOL) | Linux Platform Group
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