dm: i2c-gpio: rework gpio get/set functions

This patch reworks i2c-gpio to make it easier to switch out the
implementation of the sda/scl get/set functions. This is in preparation
for a patch to conditionally implement clock stretching support.

Signed-off-by: Michael Auchter <michael.auchter@ni.com>
Cc: Heiko Schocher <hs@denx.de>
Reviewed-by: Heiko Schocher <hs@denx.de>

diff --git a/drivers/i2c/i2c-gpio.c b/drivers/i2c/i2c-gpio.c
index d56540b4621b4acd8939c383f72a2a1288241b65..e3a21ad3b294f65bfcd634753c66178dcf69d0f8 100644 (file)
--- a/drivers/i2c/i2c-gpio.c
+++ b/drivers/i2c/i2c-gpio.c
@@ -32,23 +32,32 @@ struct i2c_gpio_bus {
        int udelay;
         /* sda, scl */
        struct gpio_desc gpios[PIN_COUNT];
+
+       int (*get_sda)(struct i2c_gpio_bus *bus);
+       void (*set_sda)(struct i2c_gpio_bus *bus, int bit);
+       void (*set_scl)(struct i2c_gpio_bus *bus, int bit);
 };
 
-static int i2c_gpio_sda_get(struct gpio_desc *sda)
+static int i2c_gpio_sda_get(struct i2c_gpio_bus *bus)
 {
+       struct gpio_desc *sda = &bus->gpios[PIN_SDA];
+
        return dm_gpio_get_value(sda);
 }
 
-static void i2c_gpio_sda_set(struct gpio_desc *sda, int bit)
+static void i2c_gpio_sda_set(struct i2c_gpio_bus *bus, int bit)
 {
+       struct gpio_desc *sda = &bus->gpios[PIN_SDA];
+
        if (bit)
                dm_gpio_set_dir_flags(sda, GPIOD_IS_IN);
        else
                dm_gpio_set_dir_flags(sda, GPIOD_IS_OUT);
 }
 
-static void i2c_gpio_scl_set(struct gpio_desc *scl, int bit)
+static void i2c_gpio_scl_set(struct i2c_gpio_bus *bus, int bit)
 {
+       struct gpio_desc *scl = &bus->gpios[PIN_SCL];
        ulong flags = GPIOD_IS_OUT;
 
        if (bit)
@@ -56,65 +65,60 @@ static void i2c_gpio_scl_set(struct gpio_desc *scl, int bit)
        dm_gpio_set_dir_flags(scl, flags);
 }
 
-static void i2c_gpio_write_bit(struct gpio_desc *scl, struct gpio_desc *sda,
-                              int delay, uchar bit)
+static void i2c_gpio_write_bit(struct i2c_gpio_bus *bus, int delay, uchar bit)
 {
-       i2c_gpio_scl_set(scl, 0);
+       bus->set_scl(bus, 0);
        udelay(delay);
-       i2c_gpio_sda_set(sda, bit);
+       bus->set_sda(bus, bit);
        udelay(delay);
-       i2c_gpio_scl_set(scl, 1);
+       bus->set_scl(bus, 1);
        udelay(2 * delay);
 }
 
-static int i2c_gpio_read_bit(struct gpio_desc *scl, struct gpio_desc *sda,
-                            int delay)
+static int i2c_gpio_read_bit(struct i2c_gpio_bus *bus, int delay)
 {
        int value;
 
-       i2c_gpio_scl_set(scl, 1);
+       bus->set_scl(bus, 1);
        udelay(delay);
-       value = i2c_gpio_sda_get(sda);
+       value = bus->get_sda(bus);
        udelay(delay);
-       i2c_gpio_scl_set(scl, 0);
+       bus->set_scl(bus, 0);
        udelay(2 * delay);
 
        return value;
 }
 
 /* START: High -> Low on SDA while SCL is High */
-static void i2c_gpio_send_start(struct gpio_desc *scl, struct gpio_desc *sda,
-                               int delay)
+static void i2c_gpio_send_start(struct i2c_gpio_bus *bus, int delay)
 {
        udelay(delay);
-       i2c_gpio_sda_set(sda, 1);
+       bus->set_sda(bus, 1);
        udelay(delay);
-       i2c_gpio_scl_set(scl, 1);
+       bus->set_scl(bus, 1);
        udelay(delay);
-       i2c_gpio_sda_set(sda, 0);
+       bus->set_sda(bus, 0);
        udelay(delay);
 }
 
 /* STOP: Low -> High on SDA while SCL is High */
-static void i2c_gpio_send_stop(struct gpio_desc *scl, struct gpio_desc *sda,
-                              int delay)
+static void i2c_gpio_send_stop(struct i2c_gpio_bus *bus, int delay)
 {
-       i2c_gpio_scl_set(scl, 0);
+       bus->set_scl(bus, 0);
        udelay(delay);
-       i2c_gpio_sda_set(sda, 0);
+       bus->set_sda(bus, 0);
        udelay(delay);
-       i2c_gpio_scl_set(scl, 1);
+       bus->set_scl(bus, 1);
        udelay(delay);
-       i2c_gpio_sda_set(sda, 1);
+       bus->set_sda(bus, 1);
        udelay(delay);
 }
 
 /* ack should be I2C_ACK or I2C_NOACK */
-static void i2c_gpio_send_ack(struct gpio_desc *scl, struct gpio_desc *sda,
-                             int delay, int ack)
+static void i2c_gpio_send_ack(struct i2c_gpio_bus *bus, int delay, int ack)
 {
-       i2c_gpio_write_bit(scl, sda, delay, ack);
-       i2c_gpio_scl_set(scl, 0);
+       i2c_gpio_write_bit(bus, delay, ack);
+       bus->set_scl(bus, 0);
        udelay(delay);
 }
 
@@ -123,44 +127,41 @@ static void i2c_gpio_send_ack(struct gpio_desc *scl, struct gpio_desc *sda,
  * 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 i2c_gpio_send_reset(struct gpio_desc *scl, struct gpio_desc *sda,
-                               int delay)
+static void i2c_gpio_send_reset(struct i2c_gpio_bus *bus, int delay)
 {
        int j;
 
        for (j = 0; j < 9; j++)
-               i2c_gpio_write_bit(scl, sda, delay, 1);
+               i2c_gpio_write_bit(bus, delay, 1);
 
-       i2c_gpio_send_stop(scl, sda, delay);
+       i2c_gpio_send_stop(bus, delay);
 }
 
 /* Set sda high with low clock, before reading slave data */
-static void i2c_gpio_sda_high(struct gpio_desc *scl, struct gpio_desc *sda,
-                             int delay)
+static void i2c_gpio_sda_high(struct i2c_gpio_bus *bus, int delay)
 {
-       i2c_gpio_scl_set(scl, 0);
+       bus->set_scl(bus, 0);
        udelay(delay);
-       i2c_gpio_sda_set(sda, 1);
+       bus->set_sda(bus, 1);
        udelay(delay);
 }
 
 /* Send 8 bits and look for an acknowledgement */
-static int i2c_gpio_write_byte(struct gpio_desc *scl, struct gpio_desc *sda,
-                              int delay, uchar data)
+static int i2c_gpio_write_byte(struct i2c_gpio_bus *bus, int delay, uchar data)
 {
        int j;
        int nack;
 
        for (j = 0; j < 8; j++) {
-               i2c_gpio_write_bit(scl, sda, delay, data & 0x80);
+               i2c_gpio_write_bit(bus, delay, data & 0x80);
                data <<= 1;
        }
 
        udelay(delay);
 
        /* Look for an <ACK>(negative logic) and return it */
-       i2c_gpio_sda_high(scl, sda, delay);
-       nack = i2c_gpio_read_bit(scl, sda, delay);
+       i2c_gpio_sda_high(bus, delay);
+       nack = i2c_gpio_read_bit(bus, delay);
 
        return nack;    /* not a nack is an ack */
 }
@@ -169,31 +170,29 @@ static int i2c_gpio_write_byte(struct gpio_desc *scl, struct gpio_desc *sda,
  * if ack == I2C_ACK, ACK the byte so can continue reading, else
  * send I2C_NOACK to end the read.
  */
-static uchar i2c_gpio_read_byte(struct gpio_desc *scl, struct gpio_desc *sda,
-                               int delay, int ack)
+static uchar i2c_gpio_read_byte(struct i2c_gpio_bus *bus, int delay, int ack)
 {
        int  data;
        int  j;
 
-       i2c_gpio_sda_high(scl, sda, delay);
+       i2c_gpio_sda_high(bus, delay);
        data = 0;
        for (j = 0; j < 8; j++) {
                data <<= 1;
-               data |= i2c_gpio_read_bit(scl, sda, delay);
+               data |= i2c_gpio_read_bit(bus, delay);
        }
-       i2c_gpio_send_ack(scl, sda, delay, ack);
+       i2c_gpio_send_ack(bus, delay, ack);
 
        return data;
 }
 
 /* send start and the slave chip address */
-int i2c_send_slave_addr(struct gpio_desc *scl, struct gpio_desc *sda, int delay,
-                       uchar chip)
+int i2c_send_slave_addr(struct i2c_gpio_bus *bus, int delay, uchar chip)
 {
-       i2c_gpio_send_start(scl, sda, delay);
+       i2c_gpio_send_start(bus, delay);
 
-       if (i2c_gpio_write_byte(scl, sda, delay, chip)) {
-               i2c_gpio_send_stop(scl, sda, delay);
+       if (i2c_gpio_write_byte(bus, delay, chip)) {
+               i2c_gpio_send_stop(bus, delay);
                return -EIO;
        }
 
@@ -204,29 +203,27 @@ static int i2c_gpio_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;
 
        debug("%s: chip %x buffer %p len %d\n", __func__, chip, buffer, len);
 
-       if (i2c_send_slave_addr(scl, sda, delay, chip << 1)) {
+       if (i2c_send_slave_addr(bus, delay, chip << 1)) {
                debug("i2c_write, no chip responded %02X\n", chip);
                return -EIO;
        }
 
        while (len-- > 0) {
-               if (i2c_gpio_write_byte(scl, sda, delay, *buffer++))
+               if (i2c_gpio_write_byte(bus, delay, *buffer++))
                        failures++;
        }
 
        if (!end_with_repeated_start) {
-               i2c_gpio_send_stop(scl, sda, delay);
+               i2c_gpio_send_stop(bus, delay);
                return failures;
        }
 
-       if (i2c_send_slave_addr(scl, sda, delay, (chip << 1) | 0x1)) {
+       if (i2c_send_slave_addr(bus, delay, (chip << 1) | 0x1)) {
                debug("i2c_write, no chip responded %02X\n", chip);
                return -EIO;
        }
@@ -237,16 +234,14 @@ static int i2c_gpio_write_data(struct i2c_gpio_bus *bus, uchar chip,
 static int i2c_gpio_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;
 
        debug("%s: chip %x buffer: %p len %d\n", __func__, chip, buffer, len);
 
        while (len-- > 0)
-               *buffer++ = i2c_gpio_read_byte(scl, sda, delay, len == 0);
+               *buffer++ = i2c_gpio_read_byte(bus, delay, len == 0);
 
-       i2c_gpio_send_stop(scl, sda, delay);
+       i2c_gpio_send_stop(bus, delay);
 
        return 0;
 }
@@ -277,14 +272,12 @@ static int i2c_gpio_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
 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;
 
-       i2c_gpio_send_start(scl, sda, delay);
-       ret = i2c_gpio_write_byte(scl, sda, delay, (chip << 1) | 0);
-       i2c_gpio_send_stop(scl, sda, delay);
+       i2c_gpio_send_start(bus, delay);
+       ret = i2c_gpio_write_byte(bus, delay, (chip << 1) | 0);
+       i2c_gpio_send_stop(bus, delay);
 
        debug("%s: bus: %d (%s) chip: %x flags: %x ret: %d\n",
              __func__, dev->seq, dev->name, chip, chip_flags, ret);
@@ -295,12 +288,10 @@ static int i2c_gpio_probe(struct udevice *dev, uint chip, uint chip_flags)
 static int i2c_gpio_set_bus_speed(struct udevice *dev, unsigned int speed_hz)
 {
        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->udelay = 1000000 / (speed_hz << 2);
 
-       i2c_gpio_send_reset(scl, sda, bus->udelay);
+       i2c_gpio_send_reset(bus, bus->udelay);
 
        return 0;
 }
@@ -335,6 +326,10 @@ static int i2c_gpio_ofdata_to_platdata(struct udevice *dev)
        bus->udelay = fdtdec_get_int(blob, node, "i2c-gpio,delay-us",
                                     DEFAULT_UDELAY);
 
+       bus->get_sda = i2c_gpio_sda_get;
+       bus->set_sda = i2c_gpio_sda_set;
+       bus->set_scl = i2c_gpio_scl_set;
+
        return 0;
 error:
        pr_err("Can't get %s gpios! Error: %d", dev->name, ret);