[PATCH v4 0/7] platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes

[PATCH v4 0/7] platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes

[Guenter Roeck]

The EC reports a variety of error codes. Most of those, with the exception
of EC_RES_INVALID_VERSION, are converted to -EPROTO. As result, the actual
error code gets lost. In cros_ec_cmd_xfer_status(), convert all EC errors
to Linux error codes to report a more meaningful error to the caller to aid
debugging.

To prepare for this change, handle error codes other than -EPROTO for all
callers of cros_ec_cmd_xfer_status(). Specifically, no longer assume that
-EPROTO reflects an error from the EC and all other error codes reflect a
transfer error.

v2: Add patches 1/4 to 3/4 to handle callers of cros_ec_cmd_xfer_status()
v3: Add patches 4/6 and 5/6 to handle additional callers of
	cros_ec_cmd_xfer_status()
    Use -ENOPROTOOPT for EC_RES_INVALID_VERSION
    Implement function to convert error codes
v4: Add coments describing the functionality of cros_ec_num_pwms().
    Add patch 7/7 to clean up cros_ec_num_pwms() after the new error code
    support has been implemented.
    Rebased series to v5.8.

----------------------------------------------------------------
Guenter Roeck (7):
      iio: cros_ec: Accept -EOPNOTSUPP as 'not supported' error code
      cros_ec_lightbar: Accept more error codes from cros_ec_cmd_xfer_status
      platform/chrome: cros_ec_sysfs: Report range of error codes from EC
      pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status
      platform/input: cros_ec: Replace -ENOTSUPP with -ENOPROTOOPT
      platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes
      pwm: cros-ec: Simplify EC error handling

 .../iio/common/cros_ec_sensors/cros_ec_sensors.c   |  2 +-
 drivers/input/keyboard/cros_ec_keyb.c              |  2 +-
 drivers/platform/chrome/cros_ec_lightbar.c         | 10 ++---
 drivers/platform/chrome/cros_ec_proto.c            | 52 +++++++++++++++++-----
 drivers/platform/chrome/cros_ec_sysfs.c            | 24 ++++------
 drivers/pwm/pwm-cros-ec.c                          | 37 +++++++--------
 6 files changed, 74 insertions(+), 53 deletions(-)

[PATCH v4 1/7] iio: cros_ec: Accept -EOPNOTSUPP as 'not supported' error code

[Guenter Roeck]

A follow-up patch will extend the number of errors reported by
cros_ec_cmd_xfer_status(). Specifically, the function will return
-EOPNOTSUPP if a command is not supported by the EC. Prepare for it.

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: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v4: No change
v3: No change
v2: No change

 drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
index a66941fdb385..e3aff95493dd 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
@@ -73,7 +73,7 @@ static int cros_ec_sensors_read(struct iio_dev *indio_dev,
 		st->core.param.sensor_offset.flags = 0;
 
 		ret = cros_ec_motion_send_host_cmd(&st->core, 0);
-		if (ret == -EPROTO) {
+		if (ret == -EPROTO || ret == -EOPNOTSUPP) {
 			/* Reading calibscale is not supported on older EC. */
 			*val = 1;
 			*val2 = 0;
-- 
2.17.1

[PATCH v4 2/7] cros_ec_lightbar: Accept more error codes from cros_ec_cmd_xfer_status

[Guenter Roeck]

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 -EPROTO is used to report
all errors returned by the EC itself. Since errors reported by the EC are
already reported in text form through sysfs attributes, extend this form
of error reporting to all errors reported by cros_ec_cmd_xfer_status().

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>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v4: No change
v3: No change
v2: Added patch

 drivers/platform/chrome/cros_ec_lightbar.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
index b59180bff5a3..8445cda57927 100644
--- a/drivers/platform/chrome/cros_ec_lightbar.c
+++ b/drivers/platform/chrome/cros_ec_lightbar.c
@@ -117,7 +117,7 @@ static int get_lightbar_version(struct cros_ec_dev *ec,
 	param = (struct ec_params_lightbar *)msg->data;
 	param->cmd = LIGHTBAR_CMD_VERSION;
 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
-	if (ret < 0) {
+	if (ret < 0 && ret != -EINVAL) {
 		ret = 0;
 		goto exit;
 	}
@@ -298,11 +298,9 @@ static ssize_t sequence_show(struct device *dev,
 		goto exit;
 
 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
-	if (ret == -EPROTO) {
-		ret = scnprintf(buf, PAGE_SIZE,
-				"ERROR: EC returned %d\n", msg->result);
-		goto exit;
-	} else if (ret < 0) {
+	if (ret < 0) {
+		ret = scnprintf(buf, PAGE_SIZE, "XFER / EC ERROR %d / %d\n",
+				ret, msg->result);
 		goto exit;
 	}
 
-- 
2.17.1

[PATCH v4 3/7] platform/chrome: cros_ec_sysfs: Report range of error codes from EC

[Guenter Roeck]

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.

Prepare for this change by always reporting both the Linux error code
and the EC error code in sysfs attributes.

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>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v4: No change
v3: No change
v2: Added patch

 drivers/platform/chrome/cros_ec_sysfs.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
index d45ea5d5bfa4..9c1e0998a721 100644
--- a/drivers/platform/chrome/cros_ec_sysfs.c
+++ b/drivers/platform/chrome/cros_ec_sysfs.c
@@ -150,12 +150,10 @@ static ssize_t version_show(struct device *dev,
 	msg->command = EC_CMD_GET_BUILD_INFO + ec->cmd_offset;
 	msg->insize = EC_HOST_PARAM_SIZE;
 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
-	if (ret == -EPROTO) {
-		count += scnprintf(buf + count, PAGE_SIZE - count,
-				   "Build info:    EC error %d\n", msg->result);
-	} else if (ret < 0) {
+	if (ret < 0) {
 		count += scnprintf(buf + count, PAGE_SIZE - count,
-				   "Build info:    XFER ERROR %d\n", ret);
+				   "Build info:    XFER / EC ERROR %d / %d\n",
+				   ret, msg->result);
 	} else {
 		msg->data[EC_HOST_PARAM_SIZE - 1] = '\0';
 		count += scnprintf(buf + count, PAGE_SIZE - count,
@@ -166,12 +164,10 @@ static ssize_t version_show(struct device *dev,
 	msg->command = EC_CMD_GET_CHIP_INFO + ec->cmd_offset;
 	msg->insize = sizeof(*r_chip);
 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
-	if (ret == -EPROTO) {
-		count += scnprintf(buf + count, PAGE_SIZE - count,
-				   "Chip info:     EC error %d\n", msg->result);
-	} else if (ret < 0) {
+	if (ret < 0) {
 		count += scnprintf(buf + count, PAGE_SIZE - count,
-				   "Chip info:     XFER ERROR %d\n", ret);
+				   "Chip info:     XFER / EC ERROR %d / %d\n",
+				   ret, msg->result);
 	} else {
 		r_chip = (struct ec_response_get_chip_info *)msg->data;
 
@@ -190,12 +186,10 @@ static ssize_t version_show(struct device *dev,
 	msg->command = EC_CMD_GET_BOARD_VERSION + ec->cmd_offset;
 	msg->insize = sizeof(*r_board);
 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
-	if (ret == -EPROTO) {
-		count += scnprintf(buf + count, PAGE_SIZE - count,
-				   "Board version: EC error %d\n", msg->result);
-	} else if (ret < 0) {
+	if (ret < 0) {
 		count += scnprintf(buf + count, PAGE_SIZE - count,
-				   "Board version: XFER ERROR %d\n", ret);
+				   "Board version: XFER / EC ERROR %d / %d\n",
+				   ret, msg->result);
 	} else {
 		r_board = (struct ec_response_board_version *)msg->data;
 
-- 
2.17.1

[PATCH v4 4/7] pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status

[Guenter Roeck]

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.

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: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v4: Added comments describing cros_ec_num_pwms() in more detail
    Added Thierry's Acked-by: tag
v3: Added patch

 drivers/pwm/pwm-cros-ec.c | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/drivers/pwm/pwm-cros-ec.c b/drivers/pwm/pwm-cros-ec.c
index 09c08dee099e..94d3dff9b0e5 100644
--- a/drivers/pwm/pwm-cros-ec.c
+++ b/drivers/pwm/pwm-cros-ec.c
@@ -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.
 		 */
-		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

Re: [PATCH v4 4/7] pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status

[Uwe Kleine-König]

[-- Attachment #1: Type: text/plain, Size: 1233 bytes --]

Hello,

On Thu, Aug 06, 2020 at 08:33:05AM -0700, Guenter Roeck wrote:
> 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.
> 
> 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: Thierry Reding <thierry.reding@gmail.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[PATCH v4 5/7] platform/input: cros_ec: Replace -ENOTSUPP with -ENOPROTOOPT

[Guenter Roeck]

-ENOTSUPP is not a SUSV4 error code and should not be used. Use
-ENOPROTOOPT instead to report EC_RES_INVALID_VERSION responses
from the EC. This matches match the NFS response for unsupported
protocol versions.

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: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v4: Added Dmitry's Acked-by: tag
v3: Added patch

 drivers/input/keyboard/cros_ec_keyb.c   | 2 +-
 drivers/platform/chrome/cros_ec_proto.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
index fc1793ca2f17..15d17c717081 100644
--- a/drivers/input/keyboard/cros_ec_keyb.c
+++ b/drivers/input/keyboard/cros_ec_keyb.c
@@ -348,7 +348,7 @@ static int cros_ec_keyb_info(struct cros_ec_device *ec_dev,
 	params->event_type = event_type;
 
 	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
-	if (ret == -ENOTSUPP) {
+	if (ret == -ENOPROTOOPT) {
 		/* With older ECs we just return 0 for everything */
 		memset(result, 0, result_size);
 		ret = 0;
diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 3e745e0fe092..e5bbec979a2a 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -555,7 +555,7 @@ EXPORT_SYMBOL(cros_ec_cmd_xfer);
  *
  * Return:
  * >=0 - The number of bytes transferred
- * -ENOTSUPP - Operation not supported
+ * -ENOPROTOOPT - Operation not supported
  * -EPROTO - Protocol error
  */
 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
@@ -569,7 +569,7 @@ int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
 	} else if (msg->result == EC_RES_INVALID_VERSION) {
 		dev_dbg(ec_dev->dev, "Command invalid version (err:%d)\n",
 			msg->result);
-		return -ENOTSUPP;
+		return -ENOPROTOOPT;
 	} else if (msg->result != EC_RES_SUCCESS) {
 		dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
 		return -EPROTO;
-- 
2.17.1

[PATCH v4 6/7] platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes

[Guenter Roeck]

The EC reports a variety of error codes. Most of those, with the exception
of EC_RES_INVALID_VERSION, are converted to -EPROTO. As result, the actual
EC error code gets lost. Introduce cros_ec_map_error() to map EC error
codes to Linux error codes, and use it in cros_ec_cmd_xfer_status() to
report more meaningful errors to the caller. With this change, callers of
cros_ec_cmd_xfer_status() can implement a more distinguished action without
having to rely on the EC error code. At the same time, debugging is improved
in situations where the Linux error code is reported to userspace and/or in
the kernel log.

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>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v4: Added Brian's Reviewed-by: tag
v3: Use -ENOPROTOOPT for EC_RES_INVALID_VERSION
    Implement function to convert error codes
v2: No change

 drivers/platform/chrome/cros_ec_proto.c | 52 ++++++++++++++++++++-----
 1 file changed, 42 insertions(+), 10 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index e5bbec979a2a..a081b8245682 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -15,6 +15,43 @@
 
 #define EC_COMMAND_RETRIES	50
 
+static const int cros_ec_error_map[] = {
+	[EC_RES_INVALID_COMMAND] = -EOPNOTSUPP,
+	[EC_RES_ERROR] = -EIO,
+	[EC_RES_INVALID_PARAM] = -EINVAL,
+	[EC_RES_ACCESS_DENIED] = -EACCES,
+	[EC_RES_INVALID_RESPONSE] = -EPROTO,
+	[EC_RES_INVALID_VERSION] = -ENOPROTOOPT,
+	[EC_RES_INVALID_CHECKSUM] = -EBADMSG,
+	[EC_RES_IN_PROGRESS] = -EINPROGRESS,
+	[EC_RES_UNAVAILABLE] = -ENODATA,
+	[EC_RES_TIMEOUT] = -ETIMEDOUT,
+	[EC_RES_OVERFLOW] = -EOVERFLOW,
+	[EC_RES_INVALID_HEADER] = -EBADR,
+	[EC_RES_REQUEST_TRUNCATED] = -EBADR,
+	[EC_RES_RESPONSE_TOO_BIG] = -EFBIG,
+	[EC_RES_BUS_ERROR] = -EFAULT,
+	[EC_RES_BUSY] = -EBUSY,
+	[EC_RES_INVALID_HEADER_VERSION] = -EBADMSG,
+	[EC_RES_INVALID_HEADER_CRC] = -EBADMSG,
+	[EC_RES_INVALID_DATA_CRC] = -EBADMSG,
+	[EC_RES_DUP_UNAVAILABLE] = -ENODATA,
+};
+
+static int cros_ec_map_error(uint32_t result)
+{
+	int ret = 0;
+
+	if (result != EC_RES_SUCCESS) {
+		if (result < ARRAY_SIZE(cros_ec_error_map) && cros_ec_error_map[result])
+			ret = cros_ec_error_map[result];
+		else
+			ret = -EPROTO;
+	}
+
+	return ret;
+}
+
 static int prepare_packet(struct cros_ec_device *ec_dev,
 			  struct cros_ec_command *msg)
 {
@@ -555,8 +592,7 @@ EXPORT_SYMBOL(cros_ec_cmd_xfer);
  *
  * Return:
  * >=0 - The number of bytes transferred
- * -ENOPROTOOPT - Operation not supported
- * -EPROTO - Protocol error
+ * <0 - Linux error code
  */
 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
 			    struct cros_ec_command *msg)
@@ -566,15 +602,11 @@ int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
 	ret = cros_ec_cmd_xfer(ec_dev, msg);
 	if (ret < 0) {
 		dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
-	} else if (msg->result == EC_RES_INVALID_VERSION) {
-		dev_dbg(ec_dev->dev, "Command invalid version (err:%d)\n",
-			msg->result);
-		return -ENOPROTOOPT;
-	} else if (msg->result != EC_RES_SUCCESS) {
-		dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
-		return -EPROTO;
+	} else {
+		ret = cros_ec_map_error(msg->result);
+		if (ret)
+			dev_dbg(ec_dev->dev, "Command result (err: %d [%d])\n", msg->result, ret);
 	}
-
 	return ret;
 }
 EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
-- 
2.17.1

[PATCH v4 7/7] pwm: cros-ec: Simplify EC error handling

[Guenter Roeck]

With enhanced error reporting from cros_ec_cmd_xfer_status() in place,
we can fully use it and no longer rely on EC error codes.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/pwm/pwm-cros-ec.c | 26 ++++----------------------
 1 file changed, 4 insertions(+), 22 deletions(-)

diff --git a/drivers/pwm/pwm-cros-ec.c b/drivers/pwm/pwm-cros-ec.c
index 94d3dff9b0e5..c1c337969e4e 100644
--- a/drivers/pwm/pwm-cros-ec.c
+++ b/drivers/pwm/pwm-cros-ec.c
@@ -81,8 +81,7 @@ static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty)
 	return cros_ec_cmd_xfer_status(ec, msg);
 }
 
-static int __cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index,
-				  u32 *result)
+static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
 {
 	struct {
 		struct cros_ec_command msg;
@@ -107,19 +106,12 @@ static int __cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index,
 	params->index = index;
 
 	ret = cros_ec_cmd_xfer_status(ec, msg);
-	if (result)
-		*result = msg->result;
 	if (ret < 0)
 		return ret;
 
 	return resp->duty;
 }
 
-static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
-{
-	return __cros_ec_pwm_get_duty(ec, index, NULL);
-}
-
 static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			     const struct pwm_state *state)
 {
@@ -215,28 +207,18 @@ static int cros_ec_num_pwms(struct cros_ec_device *ec)
 
 	/* The index field is only 8 bits */
 	for (i = 0; i <= U8_MAX; i++) {
-		u32 result = 0;
-
-		ret = __cros_ec_pwm_get_duty(ec, i, &result);
+		ret = cros_ec_pwm_get_duty(ec, i);
 		/*
 		 * 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.
+		 * The EC error codes map to -EOPNOTSUPP and -EINVAL,
+		 * so check for those.
 		 */
 		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;
-			return -EPROTO;
 		default:
 			if (ret < 0)
 				return ret;
-- 
2.17.1

Re: [PATCH v4 7/7] pwm: cros-ec: Simplify EC error handling

[Uwe Kleine-König]

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On Thu, Aug 06, 2020 at 08:33:08AM -0700, Guenter Roeck wrote:
> With enhanced error reporting from cros_ec_cmd_xfer_status() in place,
> we can fully use it and no longer rely on EC error codes.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Thanks
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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Re: [PATCH v4 7/7] pwm: cros-ec: Simplify EC error handling

[Brian Norris]

On Thu, Aug 6, 2020 at 8:33 AM Guenter Roeck <linux@roeck-us.net> wrote:
>
> With enhanced error reporting from cros_ec_cmd_xfer_status() in place,
> we can fully use it and no longer rely on EC error codes.
>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Reviewed-by: Brian Norris <briannorris@chromium.org>

Re: [PATCH v4 0/7] platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes

[Enric Balletbo i Serra]

Hi Guenter et all,

On 6/8/20 17:33, Guenter Roeck wrote:
> The EC reports a variety of error codes. Most of those, with the exception
> of EC_RES_INVALID_VERSION, are converted to -EPROTO. As result, the actual
> error code gets lost. In cros_ec_cmd_xfer_status(), convert all EC errors
> to Linux error codes to report a more meaningful error to the caller to aid
> debugging.
> 
> To prepare for this change, handle error codes other than -EPROTO for all
> callers of cros_ec_cmd_xfer_status(). Specifically, no longer assume that
> -EPROTO reflects an error from the EC and all other error codes reflect a
> transfer error.
> 
> v2: Add patches 1/4 to 3/4 to handle callers of cros_ec_cmd_xfer_status()
> v3: Add patches 4/6 and 5/6 to handle additional callers of
> 	cros_ec_cmd_xfer_status()
>     Use -ENOPROTOOPT for EC_RES_INVALID_VERSION
>     Implement function to convert error codes
> v4: Add coments describing the functionality of cros_ec_num_pwms().
>     Add patch 7/7 to clean up cros_ec_num_pwms() after the new error code
>     support has been implemented.
>     Rebased series to v5.8.
> 
> ----------------------------------------------------------------
> Guenter Roeck (7):
>       iio: cros_ec: Accept -EOPNOTSUPP as 'not supported' error code
>       cros_ec_lightbar: Accept more error codes from cros_ec_cmd_xfer_status
>       platform/chrome: cros_ec_sysfs: Report range of error codes from EC
>       pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status
>       platform/input: cros_ec: Replace -ENOTSUPP with -ENOPROTOOPT
>       platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes
>       pwm: cros-ec: Simplify EC error handling
> 
>  .../iio/common/cros_ec_sensors/cros_ec_sensors.c   |  2 +-
>  drivers/input/keyboard/cros_ec_keyb.c              |  2 +-
>  drivers/platform/chrome/cros_ec_lightbar.c         | 10 ++---
>  drivers/platform/chrome/cros_ec_proto.c            | 52 +++++++++++++++++-----
>  drivers/platform/chrome/cros_ec_sysfs.c            | 24 ++++------
>  drivers/pwm/pwm-cros-ec.c                          | 37 +++++++--------
>  6 files changed, 74 insertions(+), 53 deletions(-)
> 

The patches LGTM, and if the other maintainers are fine, I'd like to queue all
these through the chrome-platform tree.

I noticed, thought, that KernelCI reported a regression on Kevin that I'll try
to debug at the beginning of next week.

[    3.821203] cros-ec-spi spi2.0: Wrong size 1/3: 0 != 4
[    3.827320] cros-ec-keyb ff200000.spi:ec@0:keyboard-controller: cannot
register non-matrix inputs: -71
[    3.838506] cros-ec-keyb: probe of ff200000.spi:ec@0:keyboard-controller
failed with error -71
[    3.853492] cros-ec-spi spi2.0: Chrome EC device registered

Thanks,
 Enric

Re: [PATCH v4 0/7] platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes

[Guenter Roeck]

On 8/21/20 1:21 AM, Enric Balletbo i Serra wrote:
> Hi Guenter et all,
> 
> On 6/8/20 17:33, Guenter Roeck wrote:
>> The EC reports a variety of error codes. Most of those, with the exception
>> of EC_RES_INVALID_VERSION, are converted to -EPROTO. As result, the actual
>> error code gets lost. In cros_ec_cmd_xfer_status(), convert all EC errors
>> to Linux error codes to report a more meaningful error to the caller to aid
>> debugging.
>>
>> To prepare for this change, handle error codes other than -EPROTO for all
>> callers of cros_ec_cmd_xfer_status(). Specifically, no longer assume that
>> -EPROTO reflects an error from the EC and all other error codes reflect a
>> transfer error.
>>
>> v2: Add patches 1/4 to 3/4 to handle callers of cros_ec_cmd_xfer_status()
>> v3: Add patches 4/6 and 5/6 to handle additional callers of
>> 	cros_ec_cmd_xfer_status()
>>     Use -ENOPROTOOPT for EC_RES_INVALID_VERSION
>>     Implement function to convert error codes
>> v4: Add coments describing the functionality of cros_ec_num_pwms().
>>     Add patch 7/7 to clean up cros_ec_num_pwms() after the new error code
>>     support has been implemented.
>>     Rebased series to v5.8.
>>
>> ----------------------------------------------------------------
>> Guenter Roeck (7):
>>       iio: cros_ec: Accept -EOPNOTSUPP as 'not supported' error code
>>       cros_ec_lightbar: Accept more error codes from cros_ec_cmd_xfer_status
>>       platform/chrome: cros_ec_sysfs: Report range of error codes from EC
>>       pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status
>>       platform/input: cros_ec: Replace -ENOTSUPP with -ENOPROTOOPT
>>       platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes
>>       pwm: cros-ec: Simplify EC error handling
>>
>>  .../iio/common/cros_ec_sensors/cros_ec_sensors.c   |  2 +-
>>  drivers/input/keyboard/cros_ec_keyb.c              |  2 +-
>>  drivers/platform/chrome/cros_ec_lightbar.c         | 10 ++---
>>  drivers/platform/chrome/cros_ec_proto.c            | 52 +++++++++++++++++-----
>>  drivers/platform/chrome/cros_ec_sysfs.c            | 24 ++++------
>>  drivers/pwm/pwm-cros-ec.c                          | 37 +++++++--------
>>  6 files changed, 74 insertions(+), 53 deletions(-)
>>
> 
> The patches LGTM, and if the other maintainers are fine, I'd like to queue all
> these through the chrome-platform tree.
> 
> I noticed, thought, that KernelCI reported a regression on Kevin that I'll try
> to debug at the beginning of next week.
> 
> [    3.821203] cros-ec-spi spi2.0: Wrong size 1/3: 0 != 4
> [    3.827320] cros-ec-keyb ff200000.spi:ec@0:keyboard-controller: cannot
> register non-matrix inputs: -71
> [    3.838506] cros-ec-keyb: probe of ff200000.spi:ec@0:keyboard-controller
> failed with error -71
> [    3.853492] cros-ec-spi spi2.0: Chrome EC device registered
> 

Easy to debug. cros_ec_cmd_xfer_status() now returns 0 for success and < 0 for errors.
It needs to return the receive length if there is no error. I'll send v5 with a fix,
and sorry for the trouble.

Thanks,
Guenter