mfd / platform: cros_ec: Move device sysfs attributes to its own driver

The entire way how cros debugfs attibutes are created is broken.
cros_ec_sysfs should be its own driver and its attributes should be
associated with the sysfs driver not the mfd driver.

The patch also adds the sysfs documentation.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/ABI/testing/sysfs-class-chromeos

+What:		/sys/class/chromeos/<ec-device-name>/flashinfo
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		Show the EC flash information.
+
+What:		/sys/class/chromeos/<ec-device-name>/kb_wake_angle
+Date:		March 2018
+KernelVersion:	4.17
+Description:
+		Control the keyboard wake lid angle. Values are between
+		0 and 360. This file will also show the keyboard wake lid
+		angle by querying the hardware.
+
+What:		/sys/class/chromeos/<ec-device-name>/reboot
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		Tell the EC to reboot in various ways. Options are:
+		"cancel": Cancel a pending reboot.
+		"ro": Jump to RO without rebooting.
+		"rw": Jump to RW without rebooting.
+		"cold": Cold reboot.
+		"disable-jump": Disable jump until next reboot.
+		"hibernate": Hibernate the EC.
+		"at-shutdown": Reboot after an AP shutdown.
+
+What:		/sys/class/chromeos/<ec-device-name>/version
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		Show the information about the EC software and hardware.

drivers/mfd/Kconfig

@@ -215,7 +215,6 @@ config MFD_CROS_EC
 config MFD_CROS_EC_CHARDEV
         tristate "Chrome OS Embedded Controller userspace device interface"
         depends on MFD_CROS_EC
-        select CROS_EC_CTL
         ---help---
           This driver adds support to talk with the ChromeOS EC from userspace.
 

drivers/mfd/cros_ec_dev.c

@@ -34,15 +34,9 @@
 #define CROS_MAX_DEV 128
 static int ec_major;
 
-static const struct attribute_group *cros_ec_groups[] = {
-	&cros_ec_attr_group,
-	NULL,
-};
-
 static struct class cros_class = {
 	.owner          = THIS_MODULE,
 	.name           = "chromeos",
-	.dev_groups     = cros_ec_groups,
 };
 
 /* Basic communication */
@@ -396,6 +390,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
 static const struct mfd_cell cros_ec_platform_cells[] = {
 	{ .name = "cros-ec-debugfs" },
 	{ .name = "cros-ec-lightbar" },
+	{ .name = "cros-ec-sysfs" },
 	{ .name = "cros-ec-vbc" },
 };
 

drivers/platform/chrome/Kconfig

@@ -49,9 +49,6 @@ config CHROMEOS_TBMC
 	  To compile this driver as a module, choose M here: the
 	  module will be called chromeos_tbmc.
 
-config CROS_EC_CTL
-        tristate
-
 config CROS_EC_I2C
 	tristate "ChromeOS Embedded Controller (I2C)"
 	depends on MFD_CROS_EC && I2C
@@ -144,4 +141,15 @@ config CROS_EC_DEBUGFS
 	  To compile this driver as a module, choose M here: the
 	  module will be called cros_ec_debugfs.
 
+config CROS_EC_SYSFS
+	tristate "ChromeOS EC control and information through sysfs"
+	depends on MFD_CROS_EC_CHARDEV && SYSFS
+	default MFD_CROS_EC_CHARDEV
+	help
+	  This option exposes some sysfs attributes to control and get
+	  information from ChromeOS EC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cros_ec_sysfs.
+
 endif # CHROMEOS_PLATFORMS

drivers/platform/chrome/Makefile

@@ -3,8 +3,6 @@
 obj-$(CONFIG_CHROMEOS_LAPTOP)		+= chromeos_laptop.o
 obj-$(CONFIG_CHROMEOS_PSTORE)		+= chromeos_pstore.o
 obj-$(CONFIG_CHROMEOS_TBMC)		+= chromeos_tbmc.o
-cros_ec_ctl-objs			:= cros_ec_sysfs.o
-obj-$(CONFIG_CROS_EC_CTL)		+= cros_ec_ctl.o
 obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
 obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
 cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_reg.o
@@ -15,3 +13,4 @@ obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)	+= cros_kbd_led_backlight.o
 obj-$(CONFIG_CROS_EC_LIGHTBAR)		+= cros_ec_lightbar.o
 obj-$(CONFIG_CROS_EC_VBC)		+= cros_ec_vbc.o
 obj-$(CONFIG_CROS_EC_DEBUGFS)		+= cros_ec_debugfs.o
+obj-$(CONFIG_CROS_EC_SYSFS)		+= cros_ec_sysfs.o

drivers/platform/chrome/cros_ec_lightbar.c

@@ -594,7 +594,7 @@ static umode_t cros_ec_lightbar_attrs_are_visible(struct kobject *kobj,
 	return 0;
 }
 
-struct attribute_group cros_ec_lightbar_attr_group = {
+static struct attribute_group cros_ec_lightbar_attr_group = {
 	.name = "lightbar",
 	.attrs = __lb_cmds_attrs,
 	.is_visible = cros_ec_lightbar_attrs_are_visible,

drivers/platform/chrome/cros_ec_sysfs.c

@@ -34,6 +34,8 @@
 #include <linux/types.h>
 #include <linux/uaccess.h>
 
+#define DRV_NAME "cros-ec-sysfs"
+
 /* Accessor functions */
 
 static ssize_t reboot_show(struct device *dev,
@@ -353,7 +355,39 @@ struct attribute_group cros_ec_attr_group = {
 	.attrs = __ec_attrs,
 	.is_visible = cros_ec_ctrl_visible,
 };
-EXPORT_SYMBOL(cros_ec_attr_group);
+
+static int cros_ec_sysfs_probe(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+	struct device *dev = &pd->dev;
+	int ret;
+
+	ret = sysfs_create_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
+	if (ret < 0)
+		dev_err(dev, "failed to create attributes. err=%d\n", ret);
+
+	return ret;
+}
+
+static int cros_ec_sysfs_remove(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+
+	sysfs_remove_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
+
+	return 0;
+}
+
+static struct platform_driver cros_ec_sysfs_driver = {
+	.driver = {
+		.name = DRV_NAME,
+	},
+	.probe = cros_ec_sysfs_probe,
+	.remove = cros_ec_sysfs_remove,
+};
+
+module_platform_driver(cros_ec_sysfs_driver);
 
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("ChromeOS EC control driver");
+MODULE_ALIAS("platform:" DRV_NAME);

include/linux/mfd/cros_ec.h

@@ -325,7 +325,4 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event);
  */
 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
 
-/* sysfs stuff */
-extern struct attribute_group cros_ec_attr_group;
-
 #endif /* __LINUX_MFD_CROS_EC_H */