[PATCH] platform/chrome: wilco_ec: Add version sysfs entries

[Raul E Rangel]

Add the ability to extract version information from the EC.

Signed-off-by: Raul E Rangel <rrangel@xxxxxxxxxxxx>
---

This patch is rebased on platform/chrome: wilco_ec: Add Boot on AC support.
https://lkml.org/lkml/2019/4/16/1374

That patch wasn't in the for-next branch, so I'm not 100% sure if it
applies cleanly to for-next.

Example Output:
/sys/bus/platform/devices/GOOG000C:00/version # tail *
==> build_date <==
04/25/19

==> build_revision <==
d2592cae0

==> label <==
00.00.14

==> model_number <==
08B6

 .../ABI/testing/sysfs-platform-wilco-ec       | 33 +++++++
 drivers/platform/chrome/wilco_ec/sysfs.c      | 97 ++++++++++++++++++-
 2 files changed, 128 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-platform-wilco-ec b/Documentation/ABI/testing/sysfs-platform-wilco-ec
index 6694df8d4172f..00bc8e7c3b9c2 100644
--- a/Documentation/ABI/testing/sysfs-platform-wilco-ec
+++ b/Documentation/ABI/testing/sysfs-platform-wilco-ec
@@ -102,3 +102,36 @@ KernelVersion: 5.3
 Description:
 		Read or write the battery percentage threshold for which the
 		peak shift policy is used. The valid range is [15, 100].
+
+What:          /sys/bus/platform/devices/GOOG000C\:00/version/label
+Date:          May 2019
+KernelVersion: 5.3
+Description:
+               Display Wilco Embedded Controller firmware version label.
+               Output will a version string be similar to the example below:
+               95.00.06
+
+What:          /sys/bus/platform/devices/GOOG000C\:00/version/build_revision
+
+Date:          May 2019
+KernelVersion: 5.3
+Description:
+               Display Wilco Embedded Controller build revision.
+               Output will a version string be similar to the example below:
+               d2592cae0
+
+What:          /sys/bus/platform/devices/GOOG000C\:00/version/model_number
+
+Date:          May 2019
+KernelVersion: 5.3
+Description:
+               Display Wilco Embedded Controller model number.
+               Output will a version string be similar to the example below:
+               08B6
+
+What:          /sys/bus/platform/devices/GOOG000C\:00/version/build_date
+Date:          May 2019
+KernelVersion: 5.3
+Description:
+               Display Wilco Embedded Controller firmware build date.
+               Output will a MM/DD/YY string.
diff --git a/drivers/platform/chrome/wilco_ec/sysfs.c b/drivers/platform/chrome/wilco_ec/sysfs.c
index 6573a6cf9cb31..9bfb9dfde73d1 100644
--- a/drivers/platform/chrome/wilco_ec/sysfs.c
+++ b/drivers/platform/chrome/wilco_ec/sysfs.c
@@ -43,6 +43,25 @@ struct usb_power_share_response {
 	u8 val;		/* When getting, set by EC to either 0 or 1 */
 } __packed;
 
+#define CMD_EC_INFO			0x38
+enum get_ec_info_op {
+	CMD_GET_EC_LABEL	= 0,
+	CMD_GET_EC_REV		= 1,
+	CMD_GET_EC_MODEL	= 2,
+	CMD_GET_EC_BUILD_DATE	= 3,
+};
+
+struct get_ec_info_req {
+	u8 cmd;			/* Always CMD_EC_INFO */
+	u8 reserved;
+	u8 op;			/* One of enum get_ec_info_op */
+} __packed;
+
+struct get_ec_info_resp {
+	u8 reserved[2];
+	char value[9]; /* __nonstring: might not be null terminated */
+} __packed;
+
 static ssize_t boot_on_ac_store(struct device *dev,
 				struct device_attribute *attr,
 				const char *buf, size_t count)
@@ -158,12 +177,86 @@ static struct attribute_group wilco_dev_attr_group = {
 	.attrs = wilco_dev_attrs,
 };
 
+static ssize_t get_info(struct device *dev, char *buf, enum get_ec_info_op op)
+{
+	struct wilco_ec_device *ec = dev_get_drvdata(dev);
+	struct get_ec_info_req req = { .cmd = CMD_EC_INFO, .op = op };
+	struct get_ec_info_resp resp;
+	int ret;
+
+	struct wilco_ec_message msg = {
+		.type = WILCO_EC_MSG_LEGACY,
+		.request_data = &req,
+		.request_size = sizeof(req),
+		.response_data = &resp,
+		.response_size = sizeof(resp),
+	};
+
+	ret = wilco_ec_mailbox(ec, &msg);
+	if (ret < 0)
+		return ret;
+
+	return scnprintf(buf, PAGE_SIZE, "%.*s\n", (int)sizeof(resp.value),
+			 (char *)&resp.value);
+}
+
+static ssize_t label_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	return get_info(dev, buf, CMD_GET_EC_LABEL);
+}
+
+static DEVICE_ATTR_RO(label);
+
+static ssize_t build_revision_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	return get_info(dev, buf, CMD_GET_EC_REV);
+}
+
+static DEVICE_ATTR_RO(build_revision);
+
+static ssize_t build_date_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	return get_info(dev, buf, CMD_GET_EC_BUILD_DATE);
+}
+
+static DEVICE_ATTR_RO(build_date);
+
+static ssize_t model_number_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	return get_info(dev, buf, CMD_GET_EC_MODEL);
+}
+
+static DEVICE_ATTR_RO(model_number);
+
+static struct attribute *wilco_version_attrs[] = {
+	&dev_attr_label.attr,
+	&dev_attr_build_revision.attr,
+	&dev_attr_build_date.attr,
+	&dev_attr_model_number.attr,
+	NULL,
+};
+
+static struct attribute_group wilco_version_group = {
+	.name = "version",
+	.attrs = wilco_version_attrs,
+};
+
+static const struct attribute_group *wilco_dev_attr_groups[] = {
+	&wilco_dev_attr_group,
+	&wilco_version_group,
+	NULL
+};
+
 int wilco_ec_add_sysfs(struct wilco_ec_device *ec)
 {
-	return sysfs_create_group(&ec->dev->kobj, &wilco_dev_attr_group);
+	return sysfs_create_groups(&ec->dev->kobj, wilco_dev_attr_groups);
 }
 
 void wilco_ec_remove_sysfs(struct wilco_ec_device *ec)
 {
-	sysfs_remove_group(&ec->dev->kobj, &wilco_dev_attr_group);
+	sysfs_remove_groups(&ec->dev->kobj, wilco_dev_attr_groups);
 }
-- 
2.21.0.1020.gf2820cf01a-goog