mfd / platform: cros_ec: Move vbc attributes to its own driver

The entire way how cros sysfs attibutes are created is broken.
cros_ec_vbc should be its own driver and its attributes should be
associated with a vbc driver not the mfd driver. In order to retain
the path, the vbc attributes are attached to the cros_class.

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>

6 files changed, 62 insertions, 4 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc
new file mode 100644
index 000000000000..38c5aaaaa89a
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc
@@ -0,0 +1,6 @@
+What:           /sys/class/chromeos/<ec-device-name>/vbc/vboot_context
+Date:           October 2015
+KernelVersion:  4.4
+Description:
+                Read/write the verified boot context data included on a
+                small nvram space on some EC implementations.
diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index b227718e0ec2..40c98808fa1c 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -36,7 +36,6 @@ static int ec_major;
 
 static const struct attribute_group *cros_ec_groups[] = {
         &cros_ec_attr_group,
-        &cros_ec_vbc_attr_group,
         NULL,
 };
 
@@ -396,6 +395,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
 
 static const struct mfd_cell cros_ec_platform_cells[] = {
         { .name = "cros-ec-lightbar" },
+        { .name = "cros-ec-vbc" },
 };
 
 static int ec_device_probe(struct platform_device *pdev)
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 6c05752a3334..1e9dc9626e84 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -122,4 +122,15 @@ config CROS_EC_LIGHTBAR
           To compile this driver as a module, choose M here: the
           module will be called cros_ec_lightbar.
 
+config CROS_EC_VBC
+        tristate "ChromeOS EC vboot context support"
+        depends on MFD_CROS_EC_CHARDEV && OF
+        default MFD_CROS_EC_CHARDEV
+        help
+          This option exposes the ChromeOS EC vboot context nvram to
+          userspace.
+
+          To compile this driver as a module, choose M here: the
+          module will be called cros_ec_vbc.
+
 endif # CHROMEOS_PLATFORMS
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 3c29a4b405d5..4081b7179df7 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -4,7 +4,7 @@ obj-$(CONFIG_CHROMEOS_LAPTOP)		+= chromeos_laptop.o
 obj-$(CONFIG_CHROMEOS_PSTORE)           += chromeos_pstore.o
 obj-$(CONFIG_CHROMEOS_TBMC)             += chromeos_tbmc.o
 cros_ec_ctl-objs                        := cros_ec_sysfs.o \
-                                           cros_ec_vbc.o cros_ec_debugfs.o
+                                           cros_ec_debugfs.o
 obj-$(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
@@ -14,3 +14,4 @@ obj-$(CONFIG_CROS_EC_LPC)		+= cros_ec_lpcs.o
 obj-$(CONFIG_CROS_EC_PROTO)             += cros_ec_proto.o
 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
diff --git a/drivers/platform/chrome/cros_ec_vbc.c b/drivers/platform/chrome/cros_ec_vbc.c
index 5356f26bc022..da3bbf05e86f 100644
--- a/drivers/platform/chrome/cros_ec_vbc.c
+++ b/drivers/platform/chrome/cros_ec_vbc.c
@@ -22,8 +22,11 @@
 #include <linux/platform_device.h>
 #include <linux/mfd/cros_ec.h>
 #include <linux/mfd/cros_ec_commands.h>
+#include <linux/module.h>
 #include <linux/slab.h>
 
+#define DRV_NAME "cros-ec-vbc"
+
 static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj,
                                   struct bin_attribute *att, char *buf,
                                   loff_t pos, size_t count)
@@ -132,4 +135,42 @@ struct attribute_group cros_ec_vbc_attr_group = {
         .bin_attrs = cros_ec_vbc_bin_attrs,
         .is_bin_visible = cros_ec_vbc_is_visible,
 };
-EXPORT_SYMBOL(cros_ec_vbc_attr_group);
+
+static int cros_ec_vbc_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_vbc_attr_group);
+        if (ret < 0)
+                dev_err(dev, "failed to create %s attributes. err=%d\n",
+                        cros_ec_vbc_attr_group.name, ret);
+
+        return ret;
+}
+
+static int cros_ec_vbc_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_vbc_attr_group);
+
+        return 0;
+}
+
+static struct platform_driver cros_ec_vbc_driver = {
+        .driver = {
+                .name = DRV_NAME,
+        },
+        .probe = cros_ec_vbc_probe,
+        .remove = cros_ec_vbc_remove,
+};
+
+module_platform_driver(cros_ec_vbc_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Expose the vboot context nvram to userspace");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index 1e9b569564ea..fdc3152cca1d 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -327,7 +327,6 @@ u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
 
 /* sysfs stuff */
 extern struct attribute_group cros_ec_attr_group;
-extern struct attribute_group cros_ec_vbc_attr_group;
 
 /* debugfs stuff */
 int cros_ec_debugfs_init(struct cros_ec_dev *ec);