[PATCH v3 1/2] platform/chrome: wilco_ec: Add Boot on AC support

[Nick Crews]

Boot on AC is a policy which makes the device boot from S5 when AC
power is connected. This is useful for users who want to run their
device headless or with a dock.

v3 changes:
- Add docstring to wilco_ec_add_sysfs()
- Tweak a comment
- Use val > 1 instead of val != 0 && val != 1
v2 changes:
- Move documentation to Documentation/ABI/testing/sysfs-platform-wilco-ec

Signed-off-by: Nick Crews <ncrews@xxxxxxxxxxxx>
---
 .../ABI/testing/sysfs-platform-wilco-ec       | 11 +++
 drivers/platform/chrome/wilco_ec/Makefile     |  2 +-
 drivers/platform/chrome/wilco_ec/core.c       |  9 +++
 drivers/platform/chrome/wilco_ec/sysfs.c      | 77 +++++++++++++++++++
 include/linux/platform_data/wilco-ec.h        | 12 +++
 5 files changed, 110 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/testing/sysfs-platform-wilco-ec
 create mode 100644 drivers/platform/chrome/wilco_ec/sysfs.c

diff --git a/Documentation/ABI/testing/sysfs-platform-wilco-ec b/Documentation/ABI/testing/sysfs-platform-wilco-ec
new file mode 100644
index 000000000000..e074c203cd32
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-platform-wilco-ec
@@ -0,0 +1,11 @@
+What:		/sys/bus/platform/devices/GOOG000C\:00/boot_on_ac
+Date:		April 2019
+KernelVersion:	5.2
+Description:
+		Boot on AC is a policy which makes the device boot from S5
+		when AC power is connected. This is useful for users who
+		want to run their device headless or with a dock.
+
+		Input should be parseable by kstrtou8() to 0 or 1.
+		Output will be either "0\n" or "1\n".
+
diff --git a/drivers/platform/chrome/wilco_ec/Makefile b/drivers/platform/chrome/wilco_ec/Makefile
index 063e7fb4ea17..1281dd7737c4 100644
--- a/drivers/platform/chrome/wilco_ec/Makefile
+++ b/drivers/platform/chrome/wilco_ec/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
-wilco_ec-objs				:= core.o mailbox.o
+wilco_ec-objs				:= core.o mailbox.o sysfs.o
 obj-$(CONFIG_WILCO_EC)			+= wilco_ec.o
 wilco_ec_debugfs-objs			:= debugfs.o
 obj-$(CONFIG_WILCO_EC_DEBUGFS)		+= wilco_ec_debugfs.o
diff --git a/drivers/platform/chrome/wilco_ec/core.c b/drivers/platform/chrome/wilco_ec/core.c
index 05e1e2be1c91..abd15d04e57b 100644
--- a/drivers/platform/chrome/wilco_ec/core.c
+++ b/drivers/platform/chrome/wilco_ec/core.c
@@ -89,8 +89,16 @@ static int wilco_ec_probe(struct platform_device *pdev)
 		goto unregister_debugfs;
 	}
 
+	ret = wilco_ec_add_sysfs(ec);
+	if (ret < 0) {
+		dev_err(dev, "Failed to create sysfs entries: %d", ret);
+		goto unregister_rtc;
+	}
+
 	return 0;
 
+unregister_rtc:
+	platform_device_unregister(ec->rtc_pdev);
 unregister_debugfs:
 	if (ec->debugfs_pdev)
 		platform_device_unregister(ec->debugfs_pdev);
@@ -102,6 +110,7 @@ static int wilco_ec_remove(struct platform_device *pdev)
 {
 	struct wilco_ec_device *ec = platform_get_drvdata(pdev);
 
+	wilco_ec_remove_sysfs(ec);
 	platform_device_unregister(ec->rtc_pdev);
 	if (ec->debugfs_pdev)
 		platform_device_unregister(ec->debugfs_pdev);
diff --git a/drivers/platform/chrome/wilco_ec/sysfs.c b/drivers/platform/chrome/wilco_ec/sysfs.c
new file mode 100644
index 000000000000..959b5da2eb16
--- /dev/null
+++ b/drivers/platform/chrome/wilco_ec/sysfs.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ *
+ * Sysfs properties to view and modify EC-controlled features on Wilco devices.
+ * The entries will appear under /sys/bus/platform/devices/GOOG000C:00/
+ *
+ * See Documentation/ABI/testing/sysfs-platform-wilco-ec for more information.
+ */
+
+#include <linux/platform_data/wilco-ec.h>
+#include <linux/sysfs.h>
+
+#define CMD_KB_CMOS			0x7C
+#define SUB_CMD_KB_CMOS_AUTO_ON		0x03
+
+struct boot_on_ac_request {
+	u8 cmd;			/* Always CMD_KB_CMOS */
+	u8 reserved1;
+	u8 sub_cmd;		/* Always SUB_CMD_KB_CMOS_AUTO_ON */
+	u8 reserved3to5[3];
+	u8 val;			/* Either 0 or 1 */
+	u8 reserved7;
+} __packed;
+
+static ssize_t boot_on_ac_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct wilco_ec_device *ec = dev_get_drvdata(dev);
+	struct boot_on_ac_request rq;
+	struct wilco_ec_message msg;
+	int ret;
+	u8 val;
+
+	ret = kstrtou8(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+	if (val > 1)
+		return -EINVAL;
+
+	memset(&rq, 0, sizeof(rq));
+	rq.cmd = CMD_KB_CMOS;
+	rq.sub_cmd = SUB_CMD_KB_CMOS_AUTO_ON;
+	rq.val = val;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.type = WILCO_EC_MSG_LEGACY;
+	msg.request_data = &rq;
+	msg.request_size = sizeof(rq);
+	ret = wilco_ec_mailbox(ec, &msg);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR_WO(boot_on_ac);
+
+static struct attribute *wilco_dev_attrs[] = {
+	&dev_attr_boot_on_ac.attr,
+	NULL,
+};
+
+static struct attribute_group wilco_dev_attr_group = {
+	.attrs = wilco_dev_attrs,
+};
+
+int wilco_ec_add_sysfs(struct wilco_ec_device *ec)
+{
+	return sysfs_create_group(&ec->dev->kobj, &wilco_dev_attr_group);
+}
+
+void wilco_ec_remove_sysfs(struct wilco_ec_device *ec)
+{
+	sysfs_create_group(&ec->dev->kobj, &wilco_dev_attr_group);
+}
diff --git a/include/linux/platform_data/wilco-ec.h b/include/linux/platform_data/wilco-ec.h
index 1ff224793c99..7809b098ce27 100644
--- a/include/linux/platform_data/wilco-ec.h
+++ b/include/linux/platform_data/wilco-ec.h
@@ -123,4 +123,16 @@ struct wilco_ec_message {
  */
 int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);
 
+/**
+ * wilco_ec_add_sysfs() - Create sysfs entries
+ * @ec: Wilco EC device
+ *
+ * wilco_ec_remove_sysfs() needs to be called afterwards
+ * to perform the necessary cleanup.
+ *
+ * Return: 0 on success or negative error code on failure.
+ */
+int wilco_ec_add_sysfs(struct wilco_ec_device *ec);
+void wilco_ec_remove_sysfs(struct wilco_ec_device *ec);
+
 #endif /* WILCO_EC_H */
-- 
2.20.1