summaryrefslogtreecommitdiff
path: root/drivers/i2c/i2c-gpio.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/i2c/i2c-gpio.c')
-rw-r--r--drivers/i2c/i2c-gpio.c170
1 files changed, 101 insertions, 69 deletions
diff --git a/drivers/i2c/i2c-gpio.c b/drivers/i2c/i2c-gpio.c
index 4e8fa21473..07fdd343f2 100644
--- a/drivers/i2c/i2c-gpio.c
+++ b/drivers/i2c/i2c-gpio.c
@@ -32,23 +32,50 @@ 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];
+ int count = 0;
+
+ if (bit) {
+ dm_gpio_set_dir_flags(scl, GPIOD_IS_IN);
+ while (!dm_gpio_get_value(scl) && count++ < 100000)
+ udelay(1);
+
+ if (!dm_gpio_get_value(scl))
+ pr_err("timeout waiting on slave to release scl\n");
+ } else {
+ dm_gpio_set_dir_flags(scl, GPIOD_IS_OUT);
+ }
+}
+
+/* variant for output only gpios which cannot support clock stretching */
+static void i2c_gpio_scl_set_output_only(struct i2c_gpio_bus *bus, int bit)
+{
+ struct gpio_desc *scl = &bus->gpios[PIN_SCL];
ulong flags = GPIOD_IS_OUT;
if (bit)
@@ -56,65 +83,60 @@ 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 +145,41 @@ 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 +188,29 @@ 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 +221,27 @@ 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 +252,14 @@ 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 +290,12 @@ 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 +306,25 @@ 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;
+}
+
+static int i2c_gpio_drv_probe(struct udevice *dev)
+{
+ if (dev_read_bool(dev, "i2c-gpio,deblock")) {
+ /* @200kHz 9 clocks = 44us, 62us is ok */
+ const unsigned int DELAY_ABORT_SEQ = 62;
+ struct i2c_gpio_bus *bus = dev_get_priv(dev);
+
+ return i2c_deblock_gpio_loop(&bus->gpios[PIN_SDA],
+ &bus->gpios[PIN_SCL],
+ 16, 5, DELAY_ABORT_SEQ);
+ }
return 0;
}
@@ -320,6 +344,13 @@ 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;
+ if (fdtdec_get_bool(blob, node, "i2c-gpio,scl-output-only"))
+ bus->set_scl = i2c_gpio_scl_set_output_only;
+ else
+ bus->set_scl = i2c_gpio_scl_set;
+
return 0;
error:
pr_err("Can't get %s gpios! Error: %d", dev->name, ret);
@@ -341,6 +372,7 @@ U_BOOT_DRIVER(i2c_gpio) = {
.name = "i2c-gpio",
.id = UCLASS_I2C,
.of_match = i2c_gpio_ids,
+ .probe = i2c_gpio_drv_probe,
.ofdata_to_platdata = i2c_gpio_ofdata_to_platdata,
.priv_auto_alloc_size = sizeof(struct i2c_gpio_bus),
.ops = &i2c_gpio_ops,
generated by cgit (git 2.34.1) at 2025-01-17 22:42:52 +0000