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https://github.com/brain-hackers/u-boot-brain
synced 2024-09-27 23:20:26 +09:00
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>
This commit is contained in:
Michael Auchter
Heiko Schocher
parent
092d9ea26c
commit
7383edc2fb
@ -32,23 +32,32 @@ struct i2c_gpio_bus {
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int udelay;
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/* sda, scl */
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struct gpio_desc gpios[PIN_COUNT];
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int (*get_sda)(struct i2c_gpio_bus *bus);
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void (*set_sda)(struct i2c_gpio_bus *bus, int bit);
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void (*set_scl)(struct i2c_gpio_bus *bus, int bit);
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};
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static int i2c_gpio_sda_get(struct gpio_desc *sda)
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static int i2c_gpio_sda_get(struct i2c_gpio_bus *bus)
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{
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struct gpio_desc *sda = &bus->gpios[PIN_SDA];
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return dm_gpio_get_value(sda);
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}
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static void i2c_gpio_sda_set(struct gpio_desc *sda, int bit)
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static void i2c_gpio_sda_set(struct i2c_gpio_bus *bus, int bit)
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{
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struct gpio_desc *sda = &bus->gpios[PIN_SDA];
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if (bit)
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dm_gpio_set_dir_flags(sda, GPIOD_IS_IN);
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else
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dm_gpio_set_dir_flags(sda, GPIOD_IS_OUT);
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}
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static void i2c_gpio_scl_set(struct gpio_desc *scl, int bit)
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static void i2c_gpio_scl_set(struct i2c_gpio_bus *bus, int bit)
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{
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struct gpio_desc *scl = &bus->gpios[PIN_SCL];
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ulong flags = GPIOD_IS_OUT;
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if (bit)
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@ -56,65 +65,60 @@ static void i2c_gpio_scl_set(struct gpio_desc *scl, int bit)
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dm_gpio_set_dir_flags(scl, flags);
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}
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static void i2c_gpio_write_bit(struct gpio_desc *scl, struct gpio_desc *sda,
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int delay, uchar bit)
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static void i2c_gpio_write_bit(struct i2c_gpio_bus *bus, int delay, uchar bit)
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{
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i2c_gpio_scl_set(scl, 0);
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bus->set_scl(bus, 0);
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udelay(delay);
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i2c_gpio_sda_set(sda, bit);
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bus->set_sda(bus, bit);
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udelay(delay);
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i2c_gpio_scl_set(scl, 1);
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bus->set_scl(bus, 1);
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udelay(2 * delay);
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}
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static int i2c_gpio_read_bit(struct gpio_desc *scl, struct gpio_desc *sda,
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int delay)
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static int i2c_gpio_read_bit(struct i2c_gpio_bus *bus, int delay)
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{
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int value;
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i2c_gpio_scl_set(scl, 1);
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bus->set_scl(bus, 1);
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udelay(delay);
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value = i2c_gpio_sda_get(sda);
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value = bus->get_sda(bus);
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udelay(delay);
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i2c_gpio_scl_set(scl, 0);
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bus->set_scl(bus, 0);
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udelay(2 * delay);
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return value;
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}
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/* START: High -> Low on SDA while SCL is High */
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static void i2c_gpio_send_start(struct gpio_desc *scl, struct gpio_desc *sda,
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int delay)
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static void i2c_gpio_send_start(struct i2c_gpio_bus *bus, int delay)
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{
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udelay(delay);
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i2c_gpio_sda_set(sda, 1);
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bus->set_sda(bus, 1);
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udelay(delay);
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i2c_gpio_scl_set(scl, 1);
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bus->set_scl(bus, 1);
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udelay(delay);
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i2c_gpio_sda_set(sda, 0);
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bus->set_sda(bus, 0);
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udelay(delay);
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}
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/* STOP: Low -> High on SDA while SCL is High */
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static void i2c_gpio_send_stop(struct gpio_desc *scl, struct gpio_desc *sda,
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int delay)
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static void i2c_gpio_send_stop(struct i2c_gpio_bus *bus, int delay)
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{
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i2c_gpio_scl_set(scl, 0);
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bus->set_scl(bus, 0);
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udelay(delay);
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i2c_gpio_sda_set(sda, 0);
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bus->set_sda(bus, 0);
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udelay(delay);
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i2c_gpio_scl_set(scl, 1);
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bus->set_scl(bus, 1);
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udelay(delay);
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i2c_gpio_sda_set(sda, 1);
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bus->set_sda(bus, 1);
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udelay(delay);
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}
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/* ack should be I2C_ACK or I2C_NOACK */
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static void i2c_gpio_send_ack(struct gpio_desc *scl, struct gpio_desc *sda,
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int delay, int ack)
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static void i2c_gpio_send_ack(struct i2c_gpio_bus *bus, int delay, int ack)
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{
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i2c_gpio_write_bit(scl, sda, delay, ack);
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i2c_gpio_scl_set(scl, 0);
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i2c_gpio_write_bit(bus, delay, ack);
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bus->set_scl(bus, 0);
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udelay(delay);
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}
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@ -123,44 +127,41 @@ static void i2c_gpio_send_ack(struct gpio_desc *scl, struct gpio_desc *sda,
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* to clock any confused device back into an idle state. Also send a
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* <stop> at the end of the sequence for belts & suspenders.
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*/
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static void i2c_gpio_send_reset(struct gpio_desc *scl, struct gpio_desc *sda,
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int delay)
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static void i2c_gpio_send_reset(struct i2c_gpio_bus *bus, int delay)
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{
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int j;
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for (j = 0; j < 9; j++)
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i2c_gpio_write_bit(scl, sda, delay, 1);
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i2c_gpio_write_bit(bus, delay, 1);
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i2c_gpio_send_stop(scl, sda, delay);
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i2c_gpio_send_stop(bus, delay);
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}
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/* Set sda high with low clock, before reading slave data */
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static void i2c_gpio_sda_high(struct gpio_desc *scl, struct gpio_desc *sda,
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int delay)
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static void i2c_gpio_sda_high(struct i2c_gpio_bus *bus, int delay)
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{
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i2c_gpio_scl_set(scl, 0);
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bus->set_scl(bus, 0);
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udelay(delay);
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i2c_gpio_sda_set(sda, 1);
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bus->set_sda(bus, 1);
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udelay(delay);
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}
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/* Send 8 bits and look for an acknowledgement */
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static int i2c_gpio_write_byte(struct gpio_desc *scl, struct gpio_desc *sda,
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int delay, uchar data)
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static int i2c_gpio_write_byte(struct i2c_gpio_bus *bus, int delay, uchar data)
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{
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int j;
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int nack;
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for (j = 0; j < 8; j++) {
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i2c_gpio_write_bit(scl, sda, delay, data & 0x80);
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i2c_gpio_write_bit(bus, delay, data & 0x80);
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data <<= 1;
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}
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udelay(delay);
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/* Look for an <ACK>(negative logic) and return it */
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i2c_gpio_sda_high(scl, sda, delay);
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nack = i2c_gpio_read_bit(scl, sda, delay);
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i2c_gpio_sda_high(bus, delay);
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nack = i2c_gpio_read_bit(bus, delay);
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return nack; /* not a nack is an ack */
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}
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@ -169,31 +170,29 @@ static int i2c_gpio_write_byte(struct gpio_desc *scl, struct gpio_desc *sda,
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* if ack == I2C_ACK, ACK the byte so can continue reading, else
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* send I2C_NOACK to end the read.
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*/
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static uchar i2c_gpio_read_byte(struct gpio_desc *scl, struct gpio_desc *sda,
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int delay, int ack)
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static uchar i2c_gpio_read_byte(struct i2c_gpio_bus *bus, int delay, int ack)
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{
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int data;
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int j;
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i2c_gpio_sda_high(scl, sda, delay);
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i2c_gpio_sda_high(bus, delay);
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data = 0;
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for (j = 0; j < 8; j++) {
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data <<= 1;
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data |= i2c_gpio_read_bit(scl, sda, delay);
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data |= i2c_gpio_read_bit(bus, delay);
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}
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i2c_gpio_send_ack(scl, sda, delay, ack);
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i2c_gpio_send_ack(bus, delay, ack);
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return data;
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}
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/* send start and the slave chip address */
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int i2c_send_slave_addr(struct gpio_desc *scl, struct gpio_desc *sda, int delay,
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uchar chip)
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int i2c_send_slave_addr(struct i2c_gpio_bus *bus, int delay, uchar chip)
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{
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i2c_gpio_send_start(scl, sda, delay);
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i2c_gpio_send_start(bus, delay);
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if (i2c_gpio_write_byte(scl, sda, delay, chip)) {
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i2c_gpio_send_stop(scl, sda, delay);
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if (i2c_gpio_write_byte(bus, delay, chip)) {
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i2c_gpio_send_stop(bus, delay);
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return -EIO;
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}
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@ -204,29 +203,27 @@ static int i2c_gpio_write_data(struct i2c_gpio_bus *bus, uchar chip,
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uchar *buffer, int len,
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bool end_with_repeated_start)
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{
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struct gpio_desc *scl = &bus->gpios[PIN_SCL];
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struct gpio_desc *sda = &bus->gpios[PIN_SDA];
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unsigned int delay = bus->udelay;
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int failures = 0;
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debug("%s: chip %x buffer %p len %d\n", __func__, chip, buffer, len);
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if (i2c_send_slave_addr(scl, sda, delay, chip << 1)) {
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if (i2c_send_slave_addr(bus, delay, chip << 1)) {
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debug("i2c_write, no chip responded %02X\n", chip);
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return -EIO;
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}
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while (len-- > 0) {
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if (i2c_gpio_write_byte(scl, sda, delay, *buffer++))
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if (i2c_gpio_write_byte(bus, delay, *buffer++))
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failures++;
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}
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if (!end_with_repeated_start) {
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i2c_gpio_send_stop(scl, sda, delay);
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i2c_gpio_send_stop(bus, delay);
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return failures;
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}
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if (i2c_send_slave_addr(scl, sda, delay, (chip << 1) | 0x1)) {
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if (i2c_send_slave_addr(bus, delay, (chip << 1) | 0x1)) {
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debug("i2c_write, no chip responded %02X\n", chip);
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return -EIO;
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}
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@ -237,16 +234,14 @@ static int i2c_gpio_write_data(struct i2c_gpio_bus *bus, uchar chip,
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static int i2c_gpio_read_data(struct i2c_gpio_bus *bus, uchar chip,
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uchar *buffer, int len)
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{
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struct gpio_desc *scl = &bus->gpios[PIN_SCL];
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struct gpio_desc *sda = &bus->gpios[PIN_SDA];
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unsigned int delay = bus->udelay;
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debug("%s: chip %x buffer: %p len %d\n", __func__, chip, buffer, len);
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while (len-- > 0)
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*buffer++ = i2c_gpio_read_byte(scl, sda, delay, len == 0);
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*buffer++ = i2c_gpio_read_byte(bus, delay, len == 0);
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i2c_gpio_send_stop(scl, sda, delay);
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i2c_gpio_send_stop(bus, delay);
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return 0;
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}
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@ -277,14 +272,12 @@ static int i2c_gpio_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
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static int i2c_gpio_probe(struct udevice *dev, uint chip, uint chip_flags)
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{
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struct i2c_gpio_bus *bus = dev_get_priv(dev);
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struct gpio_desc *scl = &bus->gpios[PIN_SCL];
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struct gpio_desc *sda = &bus->gpios[PIN_SDA];
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unsigned int delay = bus->udelay;
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int ret;
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i2c_gpio_send_start(scl, sda, delay);
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ret = i2c_gpio_write_byte(scl, sda, delay, (chip << 1) | 0);
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i2c_gpio_send_stop(scl, sda, delay);
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i2c_gpio_send_start(bus, delay);
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ret = i2c_gpio_write_byte(bus, delay, (chip << 1) | 0);
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i2c_gpio_send_stop(bus, delay);
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debug("%s: bus: %d (%s) chip: %x flags: %x ret: %d\n",
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__func__, dev->seq, dev->name, chip, chip_flags, ret);
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@ -295,12 +288,10 @@ static int i2c_gpio_probe(struct udevice *dev, uint chip, uint chip_flags)
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static int i2c_gpio_set_bus_speed(struct udevice *dev, unsigned int speed_hz)
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{
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struct i2c_gpio_bus *bus = dev_get_priv(dev);
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struct gpio_desc *scl = &bus->gpios[PIN_SCL];
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struct gpio_desc *sda = &bus->gpios[PIN_SDA];
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bus->udelay = 1000000 / (speed_hz << 2);
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i2c_gpio_send_reset(scl, sda, bus->udelay);
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i2c_gpio_send_reset(bus, bus->udelay);
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return 0;
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}
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@ -335,6 +326,10 @@ static int i2c_gpio_ofdata_to_platdata(struct udevice *dev)
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bus->udelay = fdtdec_get_int(blob, node, "i2c-gpio,delay-us",
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DEFAULT_UDELAY);
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bus->get_sda = i2c_gpio_sda_get;
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bus->set_sda = i2c_gpio_sda_set;
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bus->set_scl = i2c_gpio_scl_set;
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return 0;
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error:
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pr_err("Can't get %s gpios! Error: %d", dev->name, ret);
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