The dm_gpio_set_dir_flags does a bitwise OR with the new flags. This means that the i2c driver cannot switch the pin from input to output or vice versa. check_dir_flags fails here:
check_dir_flags: flags 0x6 has GPIOD_IS_OUT and GPIOD_IS_IN
On my board, removing the logical OR in dm_gpio_set_dir_flags fixes the issue. The _dm_gpio_set_dir_flags function stores the passed flags directly into the descriptor. This means that by removing the logical OR all the existing flags will be lost which is also not what we want.
So the code needs to be able to unset the IN/OUT direction bits. I don't feel like I'm familiar enough with the GPIO code to do a good suggestion. Maybe Patrick could help us out here?
-----Original Message----- From: Simon Glass sjg@chromium.org To: Harm Berntsen harm.berntsen@nedap.com Cc: hs@denx.de hs@denx.de, trini@konsulko.com trini@konsulko.com, u-boot@lists.denx.de u-boot@lists.denx.de, patrick.delaunay@st.com patrick.delaunay@st.com Subject: Re: [PATCH v5 1/2] gpio: i2c-gpio: Drop use of dm_gpio_set_dir() Date: Mon, 08 Mar 2021 10:05:24 -0500
Hi Harm,
On Mon, 8 Mar 2021 at 09:35, Harm Berntsen harm.berntsen@nedap.com wrote:
I've just tested this on top of the current master (90964ab5) and this breaks my board (Kirkwood CPU with MVEBU_GPIO=y and DM_I2C_GPIO=y). I'll do some debugging to see what goes wrong.
Thank you for that.
Once we figure this out we should add a test.
-----Original Message----- From: Tom Rini trini@konsulko.com To: Heiko Schocher hs@denx.de, Harm Berntsen harm.berntsen@nedap.com Cc: Simon Glass sjg@chromium.org, U-Boot Mailing List u-boot@lists.denx.de, Patrick Delaunay patrick.delaunay@st.com Subject: Re: [PATCH v5 1/2] gpio: i2c-gpio: Drop use of dm_gpio_set_dir() Date: Mon, 08 Mar 2021 08:16:53 -0500
On Mon, Mar 08, 2021 at 05:59:45AM +0100, Heiko Schocher wrote:
Hello Simon,
On 08.03.21 04:45, Simon Glass wrote:
This is the only driver that uses this function. Update it to use the alternative which is dm_gpio_set_dir_flags().
Signed-off-by: Simon Glass sjg@chromium.org
(no changes since v1)
drivers/i2c/i2c-gpio.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-)
Reviewed-by: Heiko Schocher hs@denx.de
The series is at: https://patchwork.ozlabs.org/project/uboot/list/?series=232639&state=* and I'd really like to see a tested-by. Harm, are you able to test this still since you had to fix this area before? Thanks!
Regards, Simon