Merge tag 'tag-chrome-platform-for-v5.10' of...

Merge tag 'tag-chrome-platform-for-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux

Pull chrome platform updates from Benson Leung:
 "cros-ec:
   - Error code cleanup across cros-ec by Guenter
   - Remove cros_ec_cmd_xfer in favor of cros_ec_cmd_xfer_status

  cros_ec_typec:
   - Landed initial USB4 support in typec connector class driver for
     cros_ec
   - Role switch bugfix on disconnect, and reordering configuration
     steps

  cros_ec_lightbar:
   - Fix buffer outsize and result for get_lightbar_version

  misc:
   - Remove config MFD_CROS_EC, now that transition from MFD is complete
   - Enable KEY_LEFTMETA in new location on arm based cros-ec-keyboard
     keymap"

* tag 'tag-chrome-platform-for-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux:
  ARM: dts: cros-ec-keyboard: Add alternate keymap for KEY_LEFTMETA
  platform/chrome: Use kobj_to_dev() instead of container_of()
  platform/chrome: cros_ec_proto: Drop cros_ec_cmd_xfer()
  platform/chrome: cros_ec_proto: Update cros_ec_cmd_xfer() call-sites
  platform/chrome: Kconfig: Remove the transitional MFD_CROS_EC config
  platform/chrome: cros_ec_lightbar: Reduce ligthbar get version command
  platform/chrome: cros_ec_trace: Add fields to command traces
  platform/chrome: cros_ec_typec: Re-order connector configuration steps
  platform/chrome: cros_ec_typec: Avoid setting usb role twice during disconnect
  platform/chrome: cros_ec_typec: Send enum values to usb_role_switch_set_role()
  platform/chrome: cros_ec_typec: USB4 support
  pwm: cros-ec: Simplify EC error handling
  platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes
  platform/input: cros_ec: Replace -ENOTSUPP with -ENOPROTOOPT
  pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status
  platform/chrome: cros_ec_sysfs: Report range of error codes from EC
  cros_ec_lightbar: Accept more error codes from cros_ec_cmd_xfer_status
  iio: cros_ec: Accept -EOPNOTSUPP as 'not supported' error code

arch/arm/boot/dts/cros-ec-keyboard.dtsi

@@ -46,6 +46,7 @@ MATRIX_KEY(0x02, 0x08, KEY_LEFTBRACE)
 			MATRIX_KEY(0x02, 0x09, KEY_F8)
 			MATRIX_KEY(0x02, 0x0a, KEY_YEN)
 
+			MATRIX_KEY(0x03, 0x00, KEY_LEFTMETA)
 			MATRIX_KEY(0x03, 0x01, KEY_GRAVE)
 			MATRIX_KEY(0x03, 0x02, KEY_F2)
 			MATRIX_KEY(0x03, 0x03, KEY_5)

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;

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;

drivers/platform/chrome/Kconfig

@@ -3,16 +3,6 @@
 # Platform support for Chrome OS hardware (Chromebooks and Chromeboxes)
 #
 
-config MFD_CROS_EC
-	tristate "Platform support for Chrome hardware (transitional)"
-	select CHROME_PLATFORMS
-	select CROS_EC
-	select MFD_CROS_EC_DEV
-	depends on X86 || ARM || ARM64 || COMPILE_TEST
-	help
-	  This is a transitional Kconfig option and will be removed after
-	  everyone enables the parts individually.
-
 menuconfig CHROME_PLATFORMS
 	bool "Platform support for Chrome hardware"
 	depends on X86 || ARM || ARM64 || COMPILE_TEST

drivers/platform/chrome/cros_ec_lightbar.c

@@ -116,8 +116,10 @@ static int get_lightbar_version(struct cros_ec_dev *ec,
 
 	param = (struct ec_params_lightbar *)msg->data;
 	param->cmd = LIGHTBAR_CMD_VERSION;
+	msg->outsize = sizeof(param->cmd);
+	msg->result = sizeof(resp->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 +300,9 @@ 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;
 	}
 

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)
 {
@@ -512,19 +549,22 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev)
 EXPORT_SYMBOL(cros_ec_query_all);
 
 /**
- * cros_ec_cmd_xfer() - Send a command to the ChromeOS EC.
+ * cros_ec_cmd_xfer_status() - Send a command to the ChromeOS EC.
  * @ec_dev: EC device.
  * @msg: Message to write.
  *
- * Call this to send a command to the ChromeOS EC.  This should be used
- * instead of calling the EC's cmd_xfer() callback directly.
+ * Call this to send a command to the ChromeOS EC. This should be used instead of calling the EC's
+ * cmd_xfer() callback directly. It returns success status only if both the command was transmitted
+ * successfully and the EC replied with success status.
  *
- * Return: 0 on success or negative error code.
+ * Return:
+ * >=0 - The number of bytes transferred
+ * <0 - Linux error code
  */
-static int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
+int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
 			    struct cros_ec_command *msg)
 {
-	int ret;
+	int ret, mapped;
 
 	mutex_lock(&ec_dev->lock);
 	if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
@@ -561,42 +601,15 @@ static int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
 			return -EMSGSIZE;
 		}
 	}
+
 	ret = send_command(ec_dev, msg);
 	mutex_unlock(&ec_dev->lock);
 
-	return ret;
-}
-
-/**
- * cros_ec_cmd_xfer_status() - Send a command to the ChromeOS EC.
- * @ec_dev: EC device.
- * @msg: Message to write.
- *
- * This function is identical to cros_ec_cmd_xfer, except it returns success
- * status only if both the command was transmitted successfully and the EC
- * replied with success status. It's not necessary to check msg->result when
- * using this function.
- *
- * Return:
- * >=0 - The number of bytes transferred
- * -ENOTSUPP - Operation not supported
- * -EPROTO - Protocol error
- */
-int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
-			    struct cros_ec_command *msg)
-{
-	int ret;
-
-	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 -ENOTSUPP;
-	} else if (msg->result != EC_RES_SUCCESS) {
-		dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
-		return -EPROTO;
+	mapped = cros_ec_map_error(msg->result);
+	if (mapped) {
+		dev_dbg(ec_dev->dev, "Command result (err: %d [%d])\n",
+			msg->result, mapped);
+		ret = mapped;
 	}
 
 	return ret;
@@ -615,7 +628,7 @@ static int get_next_event_xfer(struct cros_ec_device *ec_dev,
 	msg->insize = size;
 	msg->outsize = 0;
 
-	ret = cros_ec_cmd_xfer(ec_dev, msg);
+	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
 	if (ret > 0) {
 		ec_dev->event_size = ret - 1;
 		ec_dev->event_data = *event;
@@ -659,7 +672,7 @@ static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
 	msg->insize = sizeof(ec_dev->event_data.data);
 	msg->outsize = 0;
 
-	ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg);
+	ec_dev->event_size = cros_ec_cmd_xfer_status(ec_dev, msg);
 	ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX;
 	memcpy(&ec_dev->event_data.data, msg->data,
 	       sizeof(ec_dev->event_data.data));
@@ -848,11 +861,9 @@ int cros_ec_get_sensor_count(struct cros_ec_dev *ec)
 	params = (struct ec_params_motion_sense *)msg->data;
 	params->cmd = MOTIONSENSE_CMD_DUMP;
 
-	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (ret < 0) {
 		sensor_count = ret;
-	} else if (msg->result != EC_RES_SUCCESS) {
-		sensor_count = -EPROTO;
 	} else {
 		resp = (struct ec_response_motion_sense *)msg->data;
 		sensor_count = resp->dump.sensor_count;
@@ -863,9 +874,7 @@ int cros_ec_get_sensor_count(struct cros_ec_dev *ec)
 	 * Check legacy mode: Let's find out if sensors are accessible
 	 * via LPC interface.
 	 */
-	if (sensor_count == -EPROTO &&
-	    ec->cmd_offset == 0 &&
-	    ec_dev->cmd_readmem) {
+	if (sensor_count < 0 && ec->cmd_offset == 0 && ec_dev->cmd_readmem) {
 		ret = ec_dev->cmd_readmem(ec_dev, EC_MEMMAP_ACC_STATUS,
 				1, &status);
 		if (ret >= 0 &&
@@ -880,9 +889,6 @@ int cros_ec_get_sensor_count(struct cros_ec_dev *ec)
 			 */
 			sensor_count = 0;
 		}
-	} else if (sensor_count == -EPROTO) {
-		/* EC responded, but does not understand DUMP command. */
-		sensor_count = 0;
 	}
 	return sensor_count;
 }

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;
 
@@ -326,7 +320,7 @@ static struct attribute *__ec_attrs[] = {
 static umode_t cros_ec_ctrl_visible(struct kobject *kobj,
 				    struct attribute *a, int n)
 {
-	struct device *dev = container_of(kobj, struct device, kobj);
+	struct device *dev = kobj_to_dev(kobj);
 	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
 
 	if (a == &dev_attr_kb_wake_angle.attr && !ec->has_kb_wake_angle)

drivers/platform/chrome/cros_ec_trace.h

@@ -23,14 +23,22 @@ TRACE_EVENT(cros_ec_request_start,
 	TP_ARGS(cmd),
 	TP_STRUCT__entry(
 		__field(uint32_t, version)
+		__field(uint32_t, offset)
 		__field(uint32_t, command)
+		__field(uint32_t, outsize)
+		__field(uint32_t, insize)
 	),
 	TP_fast_assign(
 		__entry->version = cmd->version;
-		__entry->command = cmd->command;
+		__entry->offset = cmd->command / EC_CMD_PASSTHRU_OFFSET(1);
+		__entry->command = cmd->command % EC_CMD_PASSTHRU_OFFSET(1);
+		__entry->outsize = cmd->outsize;
+		__entry->insize = cmd->insize;
 	),
-	TP_printk("version: %u, command: %s", __entry->version,
-		  __print_symbolic(__entry->command, EC_CMDS))
+	TP_printk("version: %u, offset: %d, command: %s, outsize: %u, insize: %u",
+		  __entry->version, __entry->offset,
+		  __print_symbolic(__entry->command, EC_CMDS),
+		  __entry->outsize, __entry->insize)
 );
 
 TRACE_EVENT(cros_ec_request_done,
@@ -38,19 +46,26 @@ TRACE_EVENT(cros_ec_request_done,
 	TP_ARGS(cmd, retval),
 	TP_STRUCT__entry(
 		__field(uint32_t, version)
+		__field(uint32_t, offset)
 		__field(uint32_t, command)
+		__field(uint32_t, outsize)
+		__field(uint32_t, insize)
 		__field(uint32_t, result)
 		__field(int, retval)
 	),
 	TP_fast_assign(
 		__entry->version = cmd->version;
-		__entry->command = cmd->command;
+		__entry->offset = cmd->command / EC_CMD_PASSTHRU_OFFSET(1);
+		__entry->command = cmd->command % EC_CMD_PASSTHRU_OFFSET(1);
+		__entry->outsize = cmd->outsize;
+		__entry->insize = cmd->insize;
 		__entry->result = cmd->result;
 		__entry->retval = retval;
 	),
-	TP_printk("version: %u, command: %s, ec result: %s, retval: %d",
-		  __entry->version,
+	TP_printk("version: %u, offset: %d, command: %s, outsize: %u, insize: %u, ec result: %s, retval: %u",
+		  __entry->version, __entry->offset,
 		  __print_symbolic(__entry->command, EC_CMDS),
+		  __entry->outsize, __entry->insize,
 		  __print_symbolic(__entry->result, EC_RESULT),
 		  __entry->retval)
 );

drivers/platform/chrome/cros_ec_typec.c

@@ -13,6 +13,7 @@
 #include <linux/platform_data/cros_ec_proto.h>
 #include <linux/platform_data/cros_usbpd_notify.h>
 #include <linux/platform_device.h>
+#include <linux/usb/pd.h>
 #include <linux/usb/typec.h>
 #include <linux/usb/typec_altmode.h>
 #include <linux/usb/typec_dp.h>
@@ -496,6 +497,34 @@ static int cros_typec_enable_dp(struct cros_typec_data *typec,
 	return typec_mux_set(port->mux, &port->state);
 }
 
+static int cros_typec_enable_usb4(struct cros_typec_data *typec,
+				  int port_num,
+				  struct ec_response_usb_pd_control_v2 *pd_ctrl)
+{
+	struct cros_typec_port *port = typec->ports[port_num];
+	struct enter_usb_data data;
+
+	data.eudo = EUDO_USB_MODE_USB4 << EUDO_USB_MODE_SHIFT;
+
+	/* Cable Speed */
+	data.eudo |= pd_ctrl->cable_speed << EUDO_CABLE_SPEED_SHIFT;
+
+	/* Cable Type */
+	if (pd_ctrl->control_flags & USB_PD_CTRL_OPTICAL_CABLE)
+		data.eudo |= EUDO_CABLE_TYPE_OPTICAL << EUDO_CABLE_TYPE_SHIFT;
+	else if (pd_ctrl->control_flags & USB_PD_CTRL_ACTIVE_CABLE)
+		data.eudo |= EUDO_CABLE_TYPE_RE_TIMER << EUDO_CABLE_TYPE_SHIFT;
+
+	data.active_link_training = !!(pd_ctrl->control_flags &
+				       USB_PD_CTRL_ACTIVE_LINK_UNIDIR);
+
+	port->state.alt = NULL;
+	port->state.data = &data;
+	port->state.mode = TYPEC_MODE_USB4;
+
+	return typec_mux_set(port->mux, &port->state);
+}
+
 static int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
 				uint8_t mux_flags,
 				struct ec_response_usb_pd_control_v2 *pd_ctrl)
@@ -516,7 +545,15 @@ static int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
 	if (ret)
 		return ret;
 
-	if (mux_flags & USB_PD_MUX_TBT_COMPAT_ENABLED) {
+	ret = usb_role_switch_set_role(typec->ports[port_num]->role_sw,
+					pd_ctrl->role & PD_CTRL_RESP_ROLE_DATA
+					? USB_ROLE_HOST : USB_ROLE_DEVICE);
+	if (ret)
+		return ret;
+
+	if (mux_flags & USB_PD_MUX_USB4_ENABLED) {
+		ret = cros_typec_enable_usb4(typec, port_num, pd_ctrl);
+	} else if (mux_flags & USB_PD_MUX_TBT_COMPAT_ENABLED) {
 		ret = cros_typec_enable_tbt(typec, port_num, pd_ctrl);
 	} else if (mux_flags & USB_PD_MUX_DP_ENABLED) {
 		ret = cros_typec_enable_dp(typec, port_num, pd_ctrl);
@@ -590,8 +627,7 @@ static int cros_typec_port_update(struct cros_typec_data *typec, int port_num)
 	if (ret)
 		dev_warn(typec->dev, "Configure muxes failed, err = %d\n", ret);
 
-	return usb_role_switch_set_role(typec->ports[port_num]->role_sw,
-					!!(resp.role & PD_CTRL_RESP_ROLE_DATA));
+	return ret;
 }
 
 static int cros_typec_get_cmd_version(struct cros_typec_data *typec)

drivers/platform/chrome/cros_ec_vbc.c

@@ -17,7 +17,7 @@ static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj,
 				  struct bin_attribute *att, char *buf,
 				  loff_t pos, size_t count)
 {
-	struct device *dev = container_of(kobj, struct device, kobj);
+	struct device *dev = kobj_to_dev(kobj);
 	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
 	struct cros_ec_device *ecdev = ec->ec_dev;
 	struct ec_params_vbnvcontext *params;
@@ -57,7 +57,7 @@ static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj,
 				   struct bin_attribute *attr, char *buf,
 				   loff_t pos, size_t count)
 {
-	struct device *dev = container_of(kobj, struct device, kobj);
+	struct device *dev = kobj_to_dev(kobj);
 	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
 	struct cros_ec_device *ecdev = ec->ec_dev;
 	struct ec_params_vbnvcontext *params;

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)
 {
@@ -204,29 +196,34 @@ 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;
 
 	/* 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);
-		/* We want to parse EC protocol errors */
-		if (ret < 0 && !(ret == -EPROTO && result))
-			return ret;
-
+		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 map to -EOPNOTSUPP and -EINVAL,
+		 * so check for those.
 		 */
-		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)
-			return -EPROTO;
+		default:
+			if (ret < 0)
+				return ret;
+			break;
+		}
 	}
 
 	return U8_MAX;