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arch/arm64/src/imx9/imx9_lpi2c.c: Fix bus reset

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imx9_lpi2c_reset didn't quite work. It tried to toggle scl line as GPIO, but the line was not even muxed properly.

Instead, set the bus to relaxed mode, and drive address 0 to the bus. This toggles the clock, and also generates start and stop sequences on the bus.

"Relaxed mode" is a new feature on the LPI2C block used in imx93.

Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
This commit is contained in:
Jukka Laitinen 2024-11-25 12:30:18 +02:00 • committed by Xiang Xiao
parent 78e41861e6
commit 3cf28dd0b2
1 changed files with 28 additions and 120 deletions
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148
arch/arm64/src/imx9/imx9_lpi2c.c
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@ -178,10 +178,6 @@ struct imx9_lpi2c_config_s
uint8_t filtsda; /* Glitch Filter for SDA pin */
iomux_cfg_t scl_pin; /* Peripheral configuration for SCL as SCL */
iomux_cfg_t sda_pin; /* Peripheral configuration for SDA as SDA */
#if defined(CONFIG_I2C_RESET)
gpio_pinset_t reset_scl_pin; /* GPIO configuration for SCL as GPIO */
gpio_pinset_t reset_sda_pin; /* GPIO configuration for SDA as GPIO */
#endif
uint8_t mode; /* Master or Slave mode */
#ifndef CONFIG_I2C_POLLED
uint32_t irq; /* Event IRQ */
@ -340,10 +336,6 @@ static const struct imx9_lpi2c_config_s imx9_lpi2c1_config =
.filtsda = CONFIG_IMX9_LPI2C1_FILTSDA,
.scl_pin = MUX_LPI2C1_SCL,
.sda_pin = MUX_LPI2C1_SDA,
#if defined(CONFIG_I2C_RESET)
.reset_scl_pin = GPIO_LPI2C1_SCL_RESET,
.reset_sda_pin = GPIO_LPI2C1_SDA_RESET,
#endif
#ifndef CONFIG_I2C_SLAVE
.mode = LPI2C_MASTER,
#else
@ -388,10 +380,6 @@ static const struct imx9_lpi2c_config_s imx9_lpi2c2_config =
.filtsda = CONFIG_IMX9_LPI2C2_FILTSDA,
.scl_pin = MUX_LPI2C2_SCL,
.sda_pin = MUX_LPI2C2_SDA,
#if defined(CONFIG_I2C_RESET)
.reset_scl_pin = GPIO_LPI2C2_SCL_RESET,
.reset_sda_pin = GPIO_LPI2C2_SDA_RESET,
#endif
#ifndef CONFIG_I2C_SLAVE
.mode = LPI2C_MASTER,
#else
@ -436,10 +424,6 @@ static const struct imx9_lpi2c_config_s imx9_lpi2c3_config =
.filtsda = CONFIG_IMX9_LPI2C3_FILTSDA,
.scl_pin = MUX_LPI2C3_SCL,
.sda_pin = MUX_LPI2C3_SDA,
#if defined(CONFIG_I2C_RESET)
.reset_scl_pin = GPIO_LPI2C3_SCL_RESET,
.reset_sda_pin = GPIO_LPI2C3_SDA_RESET,
#endif
#ifndef CONFIG_I2C_SLAVE
.mode = LPI2C_MASTER,
#else
@ -484,10 +468,6 @@ static const struct imx9_lpi2c_config_s imx9_lpi2c4_config =
.filtsda = CONFIG_IMX9_LPI2C4_FILTSDA,
.scl_pin = MUX_LPI2C4_SCL,
.sda_pin = MUX_LPI2C4_SDA,
#if defined(CONFIG_I2C_RESET)
.reset_scl_pin = GPIO_LPI2C4_SCL_RESET,
.reset_sda_pin = GPIO_LPI2C4_SDA_RESET,
#endif
#ifndef CONFIG_I2C_SLAVE
.mode = LPI2C_MASTER,
#else
@ -532,10 +512,6 @@ static const struct imx9_lpi2c_config_s imx9_lpi2c5_config =
.filtsda = CONFIG_IMX9_LPI2C5_FILTSDA,
.scl_pin = MUX_LPI2C5_SCL,
.sda_pin = MUX_LPI2C5_SDA,
#if defined(CONFIG_I2C_RESET)
.reset_scl_pin = GPIO_LPI2C5_SCL_RESET,
.reset_sda_pin = GPIO_LPI2C5_SDA_RESET,
#endif
#ifndef CONFIG_I2C_SLAVE
.mode = LPI2C_MASTER,
#else
@ -580,10 +556,6 @@ static const struct imx9_lpi2c_config_s imx9_lpi2c6_config =
.filtsda = CONFIG_IMX9_LPI2C6_FILTSDA,
.scl_pin = MUX_LPI2C6_SCL,
.sda_pin = MUX_LPI2C6_SDA,
#if defined(CONFIG_I2C_RESET)
.reset_scl_pin = GPIO_LPI2C6_SCL_RESET,
.reset_sda_pin = GPIO_LPI2C6_SDA_RESET,
#endif
#ifndef CONFIG_I2C_SLAVE
.mode = LPI2C_MASTER,
#else
@ -628,10 +600,6 @@ static const struct imx9_lpi2c_config_s imx9_lpi2c7_config =
.filtsda = CONFIG_IMX9_LPI2C7_FILTSDA,
.scl_pin = MUX_LPI2C7_SCL,
.sda_pin = MUX_LPI2C7_SDA,
#if defined(CONFIG_I2C_RESET)
.reset_scl_pin = GPIO_LPI2C7_SCL_RESET,
.reset_sda_pin = GPIO_LPI2C7_SDA_RESET,
#endif
#ifndef CONFIG_I2C_SLAVE
.mode = LPI2C_MASTER,
#else
@ -676,10 +644,6 @@ static const struct imx9_lpi2c_config_s imx9_lpi2c8_config =
.filtsda = CONFIG_IMX9_LPI2C8_FILTSDA,
.scl_pin = MUX_LPI2C8_SCL,
.sda_pin = MUX_LPI2C8_SDA,
#if defined(CONFIG_I2C_RESET)
.reset_scl_pin = GPIO_LPI2C8_SCL_RESET,
.reset_sda_pin = GPIO_LPI2C8_SDA_RESET,
#endif
#ifndef CONFIG_I2C_SLAVE
.mode = LPI2C_MASTER,
#else
@ -2189,11 +2153,8 @@ static int imx9_lpi2c_transfer(struct i2c_master_s *dev,
static int imx9_lpi2c_reset(struct i2c_master_s *dev)
{
struct imx9_lpi2c_priv_s *priv = (struct imx9_lpi2c_priv_s *)dev;
unsigned int clock_count;
unsigned int stretch_count;
uint32_t scl_gpio;
uint32_t sda_gpio;
uint32_t frequency;
uint32_t status;
unsigned count;
int ret;
DEBUGASSERT(dev);
@ -2210,95 +2171,42 @@ static int imx9_lpi2c_reset(struct i2c_master_s *dev)
return ret;
}
ret = -EIO;
/* Save the current frequency */
frequency = priv->frequency;
/* De-init the port */
imx9_lpi2c_deinit(priv);
/* Use GPIO configuration to un-wedge the bus */
imx9_iomux_gpio(priv->config->scl_pin, true);
imx9_iomux_gpio(priv->config->sda_pin, true);
scl_gpio = priv->config->reset_scl_pin;
sda_gpio = priv->config->reset_sda_pin;
imx9_config_gpio(scl_gpio);
imx9_config_gpio(sda_gpio);
/* Let SDA go high */
imx9_gpio_write(sda_gpio, 1);
/* Clock the bus until any slaves currently driving it let it go. */
clock_count = 0;
while (!imx9_gpio_read(sda_gpio))
{
/* Give up if we have tried too hard */
if (clock_count++ > 10)
{
goto out;
}
/* Sniff to make sure that clock stretching has finished.
*
* If the bus never relaxes, the reset has failed.
*/
stretch_count = 0;
while (!imx9_gpio_read(scl_gpio))
{
/* Give up if we have tried too hard */
if (stretch_count++ > 10)
{
goto out;
}
up_udelay(10);
}
/* Drive SCL low */
imx9_gpio_write(scl_gpio, 0);
up_udelay(10);
/* Drive SCL high again */
imx9_gpio_write(scl_gpio, 1);
up_udelay(10);
}
/* Generate a start followed by a stop to reset slave
* state machines.
*/
imx9_gpio_write(sda_gpio, 0);
up_udelay(10);
imx9_gpio_write(scl_gpio, 0);
up_udelay(10);
imx9_gpio_write(scl_gpio, 1);
up_udelay(10);
imx9_gpio_write(sda_gpio, 1);
up_udelay(10);
/* Re-init the port */
imx9_lpi2c_init(priv);
/* Restore the frequency */
/* Set bus to relaxed mode - this allows clocking the bus even when it
* is busy
*/
imx9_lpi2c_setclock(priv, frequency);
ret = OK;
imx9_lpi2c_modifyreg(priv, IMX9_LPI2C_MCFGR0_OFFSET,
0, LPI2C_MCFG0_RELAX);
out:
/* Clock the bus until it gets freed (max 10 times) */
count = 0;
status = imx9_lpi2c_getstatus(priv);
while ((status & LPI2C_MSR_BBF) != 0 && count++ < 10)
{
i2cerr("Bus %d busy!\n", priv->config->clk_root - CCM_CR_LPI2C1 + 1);
imx9_lpi2c_sendstart(priv, 0);
imx9_lpi2c_sendstop(priv);
usleep(1000);
status = imx9_lpi2c_getstatus(priv);
}
/* Check that the bus is now free */
ret = (status & LPI2C_MSR_BBF) == 0 ? OK : -EIO;
/* Exit relaxed mode */
imx9_lpi2c_modifyreg(priv, IMX9_LPI2C_MCFGR0_OFFSET,
LPI2C_MCFG0_RELAX, 0);
/* Release the port for reuse by other clients */