Re: [PATCH v2] mfd: cros_ec_dev: Only register PCHG device if present

Prashant Malani
2022-04-19T00:22:25Z

Hey Stephen,

On Apr 18 17:04, Stephen Boyd wrote:
> Don't create a device for the peripheral charger (PCHG) if there aren't
> any peripheral charger ports. This removes a device on most ChromeOS
> systems, because the peripheral charger functionality isn't always
> present.
>
> Cc: Prashant Malani <pmalani@chromium.org>
> Cc: Tzung-Bi Shih <tzungbi@kernel.org>
> Cc: Daisuke Nojiri <dnojiri@chromium.org>
> Cc: Benson Leung <bleung@chromium.org>
> Cc: Guenter Roeck <groeck@chromium.org>
> Cc: <chrome-platform@lists.linux.dev>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
FWIW:
Reviewed-by: Prashant Malani <pmalani@chromium.org>

> ---
>
> Changes from v1 (https://lore.kernel.org/r/20220415003253.1973106-1-swboyd@chromium.org):
> * Use cros_ec_command()
> * Drop the other patches that aren't needed anymore
>
> drivers/mfd/cros_ec_dev.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 546feef851ab..596731caf407 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -114,6 +114,9 @@ static const struct mfd_cell cros_ec_platform_cells[] = {
> { .name = "cros-ec-chardev", },
> { .name = "cros-ec-debugfs", },
> { .name = "cros-ec-sysfs", },
> +};
> +
> +static const struct mfd_cell cros_ec_pchg_cells[] = {
> { .name = "cros-ec-pchg", },
> };
>
> @@ -137,6 +140,7 @@ static int ec_device_probe(struct platform_device *pdev)
> struct device *dev = &pdev->dev;
> struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
> struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
> + struct ec_response_pchg_count pchg_count;
> int i;
>
> if (!ec)
> @@ -242,6 +246,21 @@ static int ec_device_probe(struct platform_device *pdev)
> }
> }
>
> + /*
> + * The PCHG device cannot be detected by sending EC_FEATURE_GET_CMD, but
> + * it can be detected by querying the number of peripheral chargers.
> + */
> + retval = cros_ec_command(ec->ec_dev, 0, EC_CMD_PCHG_COUNT, NULL, 0,
> + &pchg_count, sizeof(pchg_count));
> + if (retval >= 0 && pchg_count.port_count) {
> + retval = mfd_add_hotplug_devices(ec->dev,
> + cros_ec_pchg_cells,
> + ARRAY_SIZE(cros_ec_pchg_cells));
> + if (retval)
> + dev_warn(ec->dev, "failed to add pchg: %d\n",
> + retval);
Tiny nit: Can this fit in 1 line (100 chars[1])?

BR,

-Prashant

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bdc48fa11e46f867ea4d75fa59ee87a7f48be144