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Date: Mon, 10 Dec 2018 19:22:43 +0100
From: Enric Balletbo i Serra <enric.balletbo@...labora.com>
To: Guenter Roeck <groeck@...gle.com>
Cc: Lee Jones <lee.jones@...aro.org>,
Gwendal Grignou <gwendal@...omium.org>,
Nicolas Boichat <drinkcat@...omium.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
Guenter Roeck <groeck@...omium.org>, kernel@...labora.com,
Benson Leung <bleung@...omium.org>,
Olof Johansson <olof@...om.net>
Subject: Re: [PATCH v3 5/8] mfd / platform: cros_ec: move device sysfs
attributes to its own driver.
Hi Guenter,
On 10/12/18 19:13, Guenter Roeck wrote:
> On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> <enric.balletbo@...labora.com> wrote:
>>
>> 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@...labora.com>
>> ---
>>
>> Changes in v3:
>> - Do not print ec_platform name as is with dev_err is enough.
>>
>> Changes in v2:
>> - Create the attributes directly instead of use the attach/detach callbacks.
>>
>> .../ABI/testing/sysfs-class-chromeos | 32 +++++++++++++++++
>> drivers/mfd/Kconfig | 1 -
>> drivers/mfd/cros_ec_dev.c | 7 +---
>> drivers/platform/chrome/Kconfig | 14 ++++++--
>> drivers/platform/chrome/Makefile | 3 +-
>> drivers/platform/chrome/cros_ec_sysfs.c | 36 ++++++++++++++++++-
>> include/linux/mfd/cros_ec.h | 3 --
>> 7 files changed, 80 insertions(+), 16 deletions(-)
>> create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos
>>
>> diff --git a/Documentation/ABI/testing/sysfs-class-chromeos b/Documentation/ABI/testing/sysfs-class-chromeos
>> new file mode 100644
>> index 000000000000..a5399c4ca82d
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-class-chromeos
>> @@ -0,0 +1,32 @@
>> +What: /sys/class/chromeos/<cros-ec>/flashinfo
>
> Why "<cros-ec>" and not "cros_ec" ?
>
Maybe will be more clear if I use <cros-ec-name>?
Actually <cros-ec-name> can be cros_ec or cros_pd. I put between <> to indicate
that is not the literal name.
>> +Date: August 2015
>> +KernelVersion: 4.2
>> +Description:
>> + Show the EC flash information.
>> +
>> +What: /sys/class/chromeos/<cros-ec>/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/<cros-ec>/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/<cros-ec>/version
>> +Date: August 2015
>> +KernelVersion: 4.2
>> +Description:
>> + Show the information about the EC software and hardware.
>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> index 8c5dfdce4326..089ffb408918 100644
>> --- a/drivers/mfd/Kconfig
>> +++ b/drivers/mfd/Kconfig
>> @@ -214,7 +214,6 @@ 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.
>>
>> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
>> index 50ba8e0fb4ec..d9b16ce79319 100644
>> --- a/drivers/mfd/cros_ec_dev.c
>> +++ b/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 */
>> @@ -391,6 +385,7 @@ 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" },
>> };
>>
>> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
>> index 4e4232b47764..b709cc5173a2 100644
>> --- a/drivers/platform/chrome/Kconfig
>> +++ b/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
>> @@ -142,4 +139,15 @@ 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 y
>
> In practice this is limited to MFD_CROS_EC_CHARDEV, meaning it will be
> set to m if MFD_CROS_EC_CHARDEV=m.
> Not sure what is better here, but for consistency I would prefer
> "default MFD_CROS_EC_CHARDEV" (or default y
> in the entire series).
>
Right, makes sense that if the MFD_CROS_EC_CHARDEV is selected set also those by
default. Will prepare a new version with that small change.
>> + 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
>> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
>> index 12a5c4d18c17..fdbee501931b 100644
>> --- a/drivers/platform/chrome/Makefile
>> +++ b/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
>> diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
>> index f34a50121064..0ff5aa30c070 100644
>> --- a/drivers/platform/chrome/cros_ec_sysfs.c
>> +++ b/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);
>> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
>> index 3e4401e2ceea..f718ad9c2132 100644
>> --- a/include/linux/mfd/cros_ec.h
>> +++ b/include/linux/mfd/cros_ec.h
>> @@ -323,7 +323,4 @@ 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 */
>> --
>> 2.19.1
>>
>
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