Commit d509f8a7 authored by Guenter Roeck's avatar Guenter Roeck Committed by Enric Balletbo i Serra
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pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status 



Since commit c5cd2b47 ("platform/chrome: cros_ec_proto: Report command
not supported") we can no longer assume that cros_ec_cmd_xfer_status()
reports -EPROTO for all errors returned by the EC itself. A follow-up
patch will change cros_ec_cmd_xfer_status() to report additional errors
reported by the EC as distinguished Linux error codes.

Handle this change by no longer assuming that only -EPROTO is used
to report all errors returned by the EC itself. Instead, support both
the old and the new error codes.

Add a comment describing cros_ec_num_pwms() to explain its functionality.

Cc: Gwendal Grignou <gwendal@chromium.org>
Cc: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Cc: Prashant Malani <pmalani@chromium.org>
Cc: Brian Norris <briannorris@chromium.org>
Acked-by: default avatarThierry Reding <thierry.reding@gmail.com>
Acked-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarEnric Balletbo i Serra <enric.balletbo@collabora.com>
parent b646e7db

drivers/pwm/pwm-cros-ec.c

+22 −7
Original line number Diff line number Diff line
@@ -204,6 +204,11 @@ static const struct pwm_ops cros_ec_pwm_ops = { 
	.owner		= THIS_MODULE,

};



/*

 * Determine the number of supported PWMs. The EC does not return the number

 * of PWMs it supports directly, so we have to read the pwm duty cycle for

 * subsequent channels until we get an error.

 */

static int cros_ec_num_pwms(struct cros_ec_device *ec)

{

	int i, ret;
@@ -213,20 +218,30 @@ static int cros_ec_num_pwms(struct cros_ec_device *ec) 
		u32 result = 0;



		ret = __cros_ec_pwm_get_duty(ec, i, &result);

		/* We want to parse EC protocol errors */

		if (ret < 0 && !(ret == -EPROTO && result))

			return ret;



		/*

		 * We look for SUCCESS, INVALID_COMMAND, or INVALID_PARAM

		 * responses; everything else is treated as an error.

		 * The EC error codes either map to -EOPNOTSUPP / -EINVAL,

		 * or -EPROTO is returned and the EC error is in the result

		 * field. Check for both.

		 */

		switch (ret) {

		case -EOPNOTSUPP:	/* invalid command */

			return -ENODEV;

		case -EINVAL:		/* invalid parameter */

			return i;

		case -EPROTO:

			/* Old or new error return code: Handle both */

			if (result == EC_RES_INVALID_COMMAND)

				return -ENODEV;

			else if (result == EC_RES_INVALID_PARAM)

				return i;

		else if (result)

			return -EPROTO;

		default:

			if (ret < 0)

				return ret;

			break;

		}

	}



	return U8_MAX;