[PATCH v4 3/7] mfd / platform: cros_ec: move vbc attributes to its own driver

From: Enric Balletbo i Serra
Date: Tue Dec 11 2018 - 12:59:54 EST

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@xxxxxxxxxxxxx>
Reviewed-by: Guenter Roeck <groeck@xxxxxxxxxxxx>
Acked-for-MFD-by: Lee Jones <lee.jones@xxxxxxxxxx>
---

Changes in v4:
- Use <ec-device-name> instead of <cros-ec> in documentation.

Changes in v3:
- Fixed build error as reported by the kbuild test robot.

Changes in v2:
- Removed unneeded check of ec_dev.

.../sysfs-class-chromeos-driver-cros-ec-vbc | 6 +++
drivers/mfd/cros_ec_dev.c | 2 +-
drivers/platform/chrome/Kconfig | 11 +++++
drivers/platform/chrome/Makefile | 3 +-
drivers/platform/chrome/cros_ec_vbc.c | 43 ++++++++++++++++++-
include/linux/mfd/cros_ec.h | 1 -
6 files changed, 62 insertions(+), 4 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc

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 b6beba3031ba..bbbe416fd573 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -325,7 +325,6 @@ 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);
--
2.19.2