linux-kernel - [PATCH v3 4/6] pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer

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Date:   Sun, 26 Jul 2020 15:00:59 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     Jonathan Cameron <jic23@...nel.org>,
        Benson Leung <bleung@...omium.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Gwendal Grignou <gwendal@...omium.org>,
        Brian Norris <briannorris@...omium.org>,
        linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-input@...r.kernel.org, linux-pwm@...r.kernel.org,
        Guenter Roeck <linux@...ck-us.net>,
        Yu-Hsuan Hsu <yuhsuan@...omium.org>,
        Prashant Malani <pmalani@...omium.org>
Subject: [PATCH v3 4/6] pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status

Since commit c5cd2b47b203 ("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.

Cc: Gwendal Grignou <gwendal@...omium.org>
Cc: Yu-Hsuan Hsu <yuhsuan@...omium.org>
Cc: Prashant Malani <pmalani@...omium.org>
Cc: Brian Norris <briannorris@...omium.org>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
v3: Added patch

 drivers/pwm/pwm-cros-ec.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/pwm/pwm-cros-ec.c b/drivers/pwm/pwm-cros-ec.c
index 09c08dee099e..ef05fba1bd37 100644
--- a/drivers/pwm/pwm-cros-ec.c
+++ b/drivers/pwm/pwm-cros-ec.c
@@ -213,20 +213,27 @@ 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.
 		 */
-		if (result == EC_RES_INVALID_COMMAND)
+		switch (ret) {
+		case -EOPNOTSUPP:	/* invalid command */
 			return -ENODEV;
-		else if (result == EC_RES_INVALID_PARAM)
+		case -EINVAL:		/* invalid parameter */
 			return i;
-		else if (result)
+		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;
 			return -EPROTO;
+		default:
+			if (ret < 0)
+				return ret;
+			break;
+		}
 	}
 
 	return U8_MAX;
-- 
2.17.1