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 --- drivers/i2c/i2c-gpio.c | 133 ++++++++++++++++++++--------------------- 1 file changed, 64 insertions(+), 69 deletions(-)
diff --git a/drivers/i2c/i2c-gpio.c b/drivers/i2c/i2c-gpio.c index 4e8fa21473..d989449513 100644 --- 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; } @@ -320,6 +311,10 @@ 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);