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    SubjectRe: [PATCH v3 2/8] mfd / platform: cros_ec: move lightbar attributes to its own driver.
    On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
    <enric.balletbo@collabora.com> wrote:
    >
    > The entire way how cros sysfs attibutes are created is broken.
    > cros_ec_lightbar should be its own driver and its attributes should be
    > associated with a lightbar driver not the mfd driver. In order to retain
    > the path, the lightbar 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>

    > ---
    >
    > Changes in v3:
    > - Removed unneded check for ec_dev.
    >
    > Changes in v2:
    > - Removed the two exported functions to attach/detach to the cros_class.
    > - Use dev_warn instead of dev_err when adding the lightbar.
    >
    > ...sfs-class-chromeos-driver-cros-ec-lightbar | 74 +++++++++++++++
    > drivers/mfd/cros_ec_dev.c | 24 ++---
    > drivers/mfd/cros_ec_dev.h | 6 --
    > drivers/platform/chrome/Kconfig | 10 ++
    > drivers/platform/chrome/Makefile | 3 +-
    > drivers/platform/chrome/cros_ec_lightbar.c | 95 ++++++++++++++-----
    > include/linux/mfd/cros_ec.h | 1 -
    > 7 files changed, 172 insertions(+), 41 deletions(-)
    > create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
    >
    > diff --git a/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
    > new file mode 100644
    > index 000000000000..4893fd2e956f
    > --- /dev/null
    > +++ b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
    > @@ -0,0 +1,74 @@
    > +What: /sys/class/chromeos/<cros-ec>/lightbar/brightness
    > +Date: August 2015
    > +KernelVersion: 4.2
    > +Description:
    > + Writing to this file adjusts the overall brightness of
    > + the lightbar, separate from any color intensity. The
    > + valid range is 0 (off) to 255 (maximum brightness).
    > +
    > +What: /sys/class/chromeos/<cros-ec>/lightbar/interval_msec
    > +Date: August 2015
    > +KernelVersion: 4.2
    > +Description:
    > + The lightbar is controlled by an embedded controller (EC),
    > + which also manages the keyboard, battery charging, fans,
    > + and other system hardware. To prevent unprivileged users
    > + from interfering with the other EC functions, the rate at
    > + which the lightbar control files can be read or written is
    > + limited.
    > +
    > + Reading this file will return the number of milliseconds
    > + that must elapse between accessing any of the lightbar
    > + functions through this interface. Going faster will simply
    > + block until the necessary interval has lapsed. The interval
    > + applies uniformly to all accesses of any kind by any user.
    > +
    > +What: /sys/class/chromeos/<cros-ec>/lightbar/led_rgb
    > +Date: August 2015
    > +KernelVersion: 4.2
    > +Description:
    > + This allows you to control each LED segment. If the
    > + lightbar is already running one of the automatic
    > + sequences, you probably won’t see anything change because
    > + your color setting will be almost immediately replaced.
    > + To get useful results, you should stop the lightbar
    > + sequence first.
    > +
    > + The values written to this file are sets of four integers,
    > + indicating LED, RED, GREEN, BLUE. The LED number is 0 to 3
    > + to select a single segment, or 4 to set all four segments
    > + to the same value at once. The RED, GREEN, and BLUE
    > + numbers should be in the range 0 (off) to 255 (maximum).
    > + You can update more than one segment at a time by writing
    > + more than one set of four integers.
    > +
    > +What: /sys/class/chromeos/<cros-ec>/lightbar/program
    > +Date: August 2015
    > +KernelVersion: 4.2
    > +Description:
    > + This allows you to upload and run custom lightbar sequences.
    > +
    > +What: /sys/class/chromeos/<cros-ec>/lightbar/sequence
    > +Date: August 2015
    > +KernelVersion: 4.2
    > +Description:
    > + The Pixel lightbar has a number of built-in sequences
    > + that it displays under various conditions, such as at
    > + power on, shut down, or while running. Reading from this
    > + file displays the current sequence that the lightbar is
    > + displaying. Writing to this file allows you to change the
    > + sequence.
    > +
    > +What: /sys/class/chromeos/<cros-ec>/lightbar/userspace_control
    > +Date: August 2015
    > +KernelVersion: 4.2
    > +Description:
    > + This allows you to take the control of the lightbar. This
    > + prevents the kernel from going through its normal
    > + sequences.
    > +
    > +What: /sys/class/chromeos/<cros-ec>/lightbar/version
    > +Date: August 2015
    > +KernelVersion: 4.2
    > +Description:
    > + Show the information about the lightbar version.
    > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
    > index ff788d3e6d5f..614f888c9d6d 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_lightbar_attr_group,
    > &cros_ec_vbc_attr_group,
    > NULL,
    > };
    > @@ -390,6 +389,10 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
    > { .name = "cros-usbpd-charger" }
    > };
    >
    > +static const struct mfd_cell cros_ec_platform_cells[] = {
    > + { .name = "cros-ec-lightbar" },
    > +};
    > +
    > static int ec_device_probe(struct platform_device *pdev)
    > {
    > int retval = -ENOMEM;
    > @@ -464,9 +467,6 @@ static int ec_device_probe(struct platform_device *pdev)
    > retval);
    > }
    >
    > - /* Take control of the lightbar from the EC. */
    > - lb_manual_suspend_ctrl(ec, 1);
    > -
    > /* We can now add the sysfs class, we know which parameter to show */
    > retval = cdev_device_add(&ec->cdev, &ec->class_dev);
    > if (retval) {
    > @@ -474,6 +474,15 @@ static int ec_device_probe(struct platform_device *pdev)
    > goto failed;
    > }
    >
    > + retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
    > + cros_ec_platform_cells,
    > + ARRAY_SIZE(cros_ec_platform_cells),
    > + NULL, 0, NULL);
    > + if (retval)
    > + dev_warn(ec->dev,
    > + "failed to add cros-ec platform devices: %d\n",
    > + retval);
    > +
    > if (cros_ec_debugfs_init(ec))
    > dev_warn(dev, "failed to create debugfs directory\n");
    >
    > @@ -488,9 +497,6 @@ static int ec_device_remove(struct platform_device *pdev)
    > {
    > struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
    >
    > - /* Let the EC take over the lightbar again. */
    > - lb_manual_suspend_ctrl(ec, 0);
    > -
    > cros_ec_debugfs_remove(ec);
    >
    > mfd_remove_devices(ec->dev);
    > @@ -519,8 +525,6 @@ static __maybe_unused int ec_device_suspend(struct device *dev)
    >
    > cros_ec_debugfs_suspend(ec);
    >
    > - lb_suspend(ec);
    > -
    > return 0;
    > }
    >
    > @@ -530,8 +534,6 @@ static __maybe_unused int ec_device_resume(struct device *dev)
    >
    > cros_ec_debugfs_resume(ec);
    >
    > - lb_resume(ec);
    > -
    > return 0;
    > }
    >
    > diff --git a/drivers/mfd/cros_ec_dev.h b/drivers/mfd/cros_ec_dev.h
    > index 978d836a0248..ec750433455a 100644
    > --- a/drivers/mfd/cros_ec_dev.h
    > +++ b/drivers/mfd/cros_ec_dev.h
    > @@ -44,10 +44,4 @@ struct cros_ec_readmem {
    > #define CROS_EC_DEV_IOCXCMD _IOWR(CROS_EC_DEV_IOC, 0, struct cros_ec_command)
    > #define CROS_EC_DEV_IOCRDMEM _IOWR(CROS_EC_DEV_IOC, 1, struct cros_ec_readmem)
    >
    > -/* Lightbar utilities */
    > -extern bool ec_has_lightbar(struct cros_ec_dev *ec);
    > -extern int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable);
    > -extern int lb_suspend(struct cros_ec_dev *ec);
    > -extern int lb_resume(struct cros_ec_dev *ec);
    > -
    > #endif /* _CROS_EC_DEV_H_ */
    > diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
    > index 16b1615958aa..05bcefbe1926 100644
    > --- a/drivers/platform/chrome/Kconfig
    > +++ b/drivers/platform/chrome/Kconfig
    > @@ -111,4 +111,14 @@ config CROS_KBD_LED_BACKLIGHT
    > To compile this driver as a module, choose M here: the
    > module will be called cros_kbd_led_backlight.
    >
    > +config CROS_EC_LIGHTBAR
    > + tristate "Chromebook Pixel's lightbar support"
    > + depends on MFD_CROS_EC_CHARDEV
    > + help
    > + This option exposes the Chromebook Pixel's lightbar to
    > + userspace.
    > +
    > + To compile this driver as a module, choose M here: the
    > + module will be called cros_ec_lightbar.
    > +
    > endif # CHROMEOS_PLATFORMS
    > diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
    > index cd591bf872bb..3c29a4b405d5 100644
    > --- a/drivers/platform/chrome/Makefile
    > +++ b/drivers/platform/chrome/Makefile
    > @@ -3,7 +3,7 @@
    > obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o
    > obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o
    > obj-$(CONFIG_CHROMEOS_TBMC) += chromeos_tbmc.o
    > -cros_ec_ctl-objs := cros_ec_sysfs.o cros_ec_lightbar.o \
    > +cros_ec_ctl-objs := cros_ec_sysfs.o \
    > cros_ec_vbc.o cros_ec_debugfs.o
    > obj-$(CONFIG_CROS_EC_CTL) += cros_ec_ctl.o
    > obj-$(CONFIG_CROS_EC_I2C) += cros_ec_i2c.o
    > @@ -13,3 +13,4 @@ cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
    > 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
    > diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
    > index 68193bb53383..80eed6317570 100644
    > --- a/drivers/platform/chrome/cros_ec_lightbar.c
    > +++ b/drivers/platform/chrome/cros_ec_lightbar.c
    > @@ -33,6 +33,8 @@
    > #include <linux/uaccess.h>
    > #include <linux/slab.h>
    >
    > +#define DRV_NAME "cros-ec-lightbar"
    > +
    > /* Rate-limit the lightbar interface to prevent DoS. */
    > static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
    >
    > @@ -373,7 +375,7 @@ static int lb_send_empty_cmd(struct cros_ec_dev *ec, uint8_t cmd)
    > return ret;
    > }
    >
    > -int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
    > +static int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
    > {
    > struct ec_params_lightbar *param;
    > struct cros_ec_command *msg;
    > @@ -408,25 +410,6 @@ int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
    >
    > return ret;
    > }
    > -EXPORT_SYMBOL(lb_manual_suspend_ctrl);
    > -
    > -int lb_suspend(struct cros_ec_dev *ec)
    > -{
    > - if (userspace_control || ec != ec_with_lightbar)
    > - return 0;
    > -
    > - return lb_send_empty_cmd(ec, LIGHTBAR_CMD_SUSPEND);
    > -}
    > -EXPORT_SYMBOL(lb_suspend);
    > -
    > -int lb_resume(struct cros_ec_dev *ec)
    > -{
    > - if (userspace_control || ec != ec_with_lightbar)
    > - return 0;
    > -
    > - return lb_send_empty_cmd(ec, LIGHTBAR_CMD_RESUME);
    > -}
    > -EXPORT_SYMBOL(lb_resume);
    >
    > static ssize_t sequence_store(struct device *dev, struct device_attribute *attr,
    > const char *buf, size_t count)
    > @@ -584,7 +567,7 @@ static struct attribute *__lb_cmds_attrs[] = {
    > NULL,
    > };
    >
    > -bool ec_has_lightbar(struct cros_ec_dev *ec)
    > +static bool ec_has_lightbar(struct cros_ec_dev *ec)
    > {
    > return !!get_lightbar_version(ec, NULL, NULL);
    > }
    > @@ -616,4 +599,72 @@ struct attribute_group cros_ec_lightbar_attr_group = {
    > .attrs = __lb_cmds_attrs,
    > .is_visible = cros_ec_lightbar_attrs_are_visible,
    > };
    > -EXPORT_SYMBOL(cros_ec_lightbar_attr_group);
    > +
    > +static int cros_ec_lightbar_probe(struct platform_device *pd)
    > +{
    > + struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
    > + struct device *dev = &pd->dev;
    > + int ret;
    > +
    > + /* Take control of the lightbar from the EC. */
    > + lb_manual_suspend_ctrl(ec_dev, 1);
    > +
    > + ret = sysfs_create_group(&ec_dev->class_dev.kobj,
    > + &cros_ec_lightbar_attr_group);
    > + if (ret < 0)
    > + dev_err(dev, "failed to create %s attributes. err=%d\n",
    > + cros_ec_lightbar_attr_group.name, ret);
    > +
    > + return ret;
    > +}
    > +
    > +static int cros_ec_lightbar_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_lightbar_attr_group);
    > +
    > + /* Let the EC take over the lightbar again. */
    > + lb_manual_suspend_ctrl(ec_dev, 0);
    > +
    > + return 0;
    > +}
    > +
    > +static int __maybe_unused cros_ec_lightbar_resume(struct device *dev)
    > +{
    > + struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
    > +
    > + if (userspace_control || ec_dev != ec_with_lightbar)
    > + return 0;
    > +
    > + return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_RESUME);
    > +}
    > +
    > +static int __maybe_unused cros_ec_lightbar_suspend(struct device *dev)
    > +{
    > + struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
    > +
    > + if (userspace_control || ec_dev != ec_with_lightbar)
    > + return 0;
    > +
    > + return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_SUSPEND);
    > +}
    > +
    > +static SIMPLE_DEV_PM_OPS(cros_ec_lightbar_pm_ops,
    > + cros_ec_lightbar_suspend, cros_ec_lightbar_resume);
    > +
    > +static struct platform_driver cros_ec_lightbar_driver = {
    > + .driver = {
    > + .name = DRV_NAME,
    > + .pm = &cros_ec_lightbar_pm_ops,
    > + },
    > + .probe = cros_ec_lightbar_probe,
    > + .remove = cros_ec_lightbar_remove,
    > +};
    > +
    > +module_platform_driver(cros_ec_lightbar_driver);
    > +
    > +MODULE_LICENSE("GPL");
    > +MODULE_DESCRIPTION("Expose the Chromebook Pixel's lightbar to userspace");
    > +MODULE_ALIAS("platform:" DRV_NAME);
    > diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
    > index 706dd724de52..b6beba3031ba 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_lightbar_attr_group;
    > extern struct attribute_group cros_ec_vbc_attr_group;
    >
    > /* debugfs stuff */
    > --
    > 2.19.1
    >

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