Re: [PATCH v2 3/5] mfd: axp20x: Allow multiple regulators

Chris Morgan
2024-12-07T17:45:38Z

On Mon, Oct 07, 2024 at 01:14:06AM +0100, Andre Przywara wrote:
> At the moment trying to register a second AXP chip makes the probe fail,
> as some sysfs registration fails due to a duplicate name:
>
> ...
> [ 3.688215] axp20x-i2c 0-0035: AXP20X driver loaded
> [ 3.695610] axp20x-i2c 0-0036: AXP20x variant AXP323 found
> [ 3.706151] sysfs: cannot create duplicate filename '/bus/platform/devices/axp20x-regulator'
> [ 3.714718] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.0-rc1-00026-g50bf2e2c079d-dirty #192
> [ 3.724020] Hardware name: Avaota A1 (DT)
> [ 3.728029] Call trace:
> [ 3.730477] dump_backtrace+0x94/0xec
> [ 3.734146] show_stack+0x18/0x24
> [ 3.737462] dump_stack_lvl+0x80/0xf4
> [ 3.741128] dump_stack+0x18/0x24
> [ 3.744444] sysfs_warn_dup+0x64/0x80
> [ 3.748109] sysfs_do_create_link_sd+0xf0/0xf8
> [ 3.752553] sysfs_create_link+0x20/0x40
> [ 3.756476] bus_add_device+0x64/0x104
> [ 3.760229] device_add+0x310/0x760
> [ 3.763717] platform_device_add+0x10c/0x238
> [ 3.767990] mfd_add_device+0x4ec/0x5c8
> [ 3.771829] mfd_add_devices+0x88/0x11c
> [ 3.775666] axp20x_device_probe+0x70/0x184
> [ 3.779851] axp20x_i2c_probe+0x9c/0xd8
> ...
>
> This is because we use PLATFORM_DEVID_NONE for the mfd_add_devices()
> call, which would number the child devices in the same 0-based way, even
> for the second (or any other) instance.
>
> Use PLATFORM_DEVID_AUTO instead, which automatically assigns
> non-conflicting device numbers.
>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> Reviewed-by: Chen-Yu Tsai <wens@csie.org>
> ---
> drivers/mfd/axp20x.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
> index 5ceea359289f4..bc08ae4332604 100644
> --- a/drivers/mfd/axp20x.c
> +++ b/drivers/mfd/axp20x.c
> @@ -1419,7 +1419,7 @@ int axp20x_device_probe(struct axp20x_dev *axp20x)
> }
> }
>
> - ret = mfd_add_devices(axp20x->dev, -1, axp20x->cells,
> + ret = mfd_add_devices(axp20x->dev, PLATFORM_DEVID_AUTO, axp20x->cells,
> axp20x->nr_cells, NULL, 0, NULL);
>
> if (ret) {
> --
> 2.46.2
>

Using git bisect, I found that this patch breaks the CONFIG_AXP20X_ADC
option which is used by some of the battery and charger drivers for the
axp20x PMIC series. My current assumption is that the
devm_iio_channel_get() call made by these drivers worked correctly
previously when the PLATFORM_DEVID_NONE, but now it's not working
anymore. I'm still testing possible solutions for that problem.

Thank you,
Chris