Hi!
On 13.03.23 03:55, Bough Chen wrote:
-----Original Message----- From: Bough Chen haibo.chen@nxp.com Sent: 2023年2月10日 17:27 To: hs@denx.de; al.kochet@gmail.com; marex@denx.de Cc: u-boot@lists.denx.de; dl-uboot-imx uboot-imx@nxp.com; xypron.glpk@gmx.de; Bough Chen haibo.chen@nxp.com Subject: [PATCH] i2c: correct I2C deblock logic
From: Haibo Chen haibo.chen@nxp.com
Current code use dm_gpio_get_value() to get SDA and SCL value, and the value depends on the flag GPIOD_ACTIVE_LOW. When toggle SCL to wait slave release SDA, the SDA are config as GPIOD_IS_IN, and whether contain the GPIOD_ACTIVE_LOW depends on the DTS setting. Usually, for I2C GPIO, we use GPIOD_ACTIVE_LOW flag in DTS, so if the SDA is in low level, then dm_gpio_get_value() will return 1, current code logic will stop the SCL toggle wrongly, cause the I2C deblock not work as expect.
This patch force set the GPIOD_ACTIVE_LOW for both GPIOD_IS_IN and GPIOD_IS_OUT, and make the return value of i2c_gpio_get_pin() eaqual to the physical voltage logic level.
Hi,
Any comments for this patch, just a reminder in case you miss it.
Indeed, I missed this patch, sorry! Your explanation sounds reasonable to me, but I wonder if nobody tapped into this problem... it would be good to have some test reports from others! Also added Simon, as he did a lot of work in this space.
Thanks!
bye, Heiko
Best Regards Haibo Chen
Fixes: aa54192d4a87 ("dm: i2c: implement gpio-based I2C deblock") Signed-off-by: Haibo Chen haibo.chen@nxp.com
drivers/i2c/i2c-uclass.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c index 8d9a89ed89..4dc707c659 100644 --- a/drivers/i2c/i2c-uclass.c +++ b/drivers/i2c/i2c-uclass.c @@ -505,7 +505,8 @@ uint i2c_get_chip_addr_offset_mask(struct udevice *dev) static void i2c_gpio_set_pin(struct gpio_desc *pin, int bit) { if (bit)
dm_gpio_set_dir_flags(pin, GPIOD_IS_IN);
dm_gpio_set_dir_flags(pin, GPIOD_IS_IN |GPIOD_ACTIVE_LOW);@@ -514,7 +515,7 @@ static void i2c_gpio_set_pin(struct gpio_desc *pin, int bit)
static int i2c_gpio_get_pin(struct gpio_desc *pin) {
- return dm_gpio_get_value(pin);
- return !dm_gpio_get_value(pin);
}
int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin,
2.34.1