Hi Daniel,
On 25/10/19 0:28, Nick Crews wrote:
> The EC is in charge of controlling the keyboard backlight on
> the Wilco platform. We expose a standard LED class device
> named platform::kbd_backlight.
>
> Since the EC will never change the backlight level of its own accord,
> we don't need to implement a brightness_get() method.
>
> Signed-off-by: Nick Crews <ncrews@xxxxxxxxxxxx>
> Signed-off-by: Daniel Campello <campello@xxxxxxxxxxxx>
As you know 0day reported an issue that needs to be solved, waiting for a new
version.
Thanks,
Enric
> ---
> v8 changes:
> -Removed unneeded #includes from keyboard_leds.h
>
> v7 changes:
> -Merged the LED stuff into the core wilco_ec module. This allows
> us to de-duplicate a lot of code, hide a lot of the LED internals
> from the core driver, and generally simplify things.
> -Follow reverse xmas tree variable declaration
> -Remove unneeded warning about BIOS not initializing the LEDs
> -Fix and standardize some comments and log messages.
> -Document all fields of wilco_keyboard_leds_msg
> -rm outdated and useless comment at top of core file.
>
> v6 changes:
> -Rebased patch
> -Fixed bug related to request/response buffer pointers on
> send_kbbl_mesg()
> -Now sends WILCO_KBBL_SUBCMD_SET_STATE instead of
> WILCO_KBBL_SUBCMD_GET_STATE command for keyboard_led_set_brightness()
>
> v5 changes:
> -Rename the LED device to "platform::kbd_backlight", to
> denote that this is the built-in system keyboard.
>
> v4 changes:
> -Call keyboard_led_set_brightness() directly within
> initialize_brightness(), instead of calling the library function.
>
> v3 changes:
> -Since this behaves the same as the standard Chrome OS keyboard
> backlight, rename the led device to "chromeos::kbd_backlight"
> -Move wilco_ec_keyboard_backlight_exists() into core module, so
> that the core does not depend upon the keyboard backlight driver.
> -This required moving some code into wilco-ec.h
> -Refactor out some common code in set_brightness() and
> initialize_brightness()
>
> v2 changes:
> -Remove and fix uses of led vs LED in kconfig
> -Assume BIOS initializes brightness, but double check in probe()
> -Remove get_brightness() callback, as EC never changes brightness
> by itself.
> -Use a __packed struct as message instead of opaque array
> -Add exported wilco_ec_keyboard_leds_exist() so the core driver
> now only creates a platform _device if relevant
> -Fix use of keyboard_led_set_brightness() since it can sleep
>
> BUG=b:141952530
> TEST=Built and tested on a Wilco, including rmmod and modprobe of
> wilco-ec.
>
> drivers/platform/chrome/wilco_ec/Makefile | 3 +-
> drivers/platform/chrome/wilco_ec/core.c | 13 +-
> .../platform/chrome/wilco_ec/keyboard_leds.c | 191 ++++++++++++++++++
> include/linux/platform_data/wilco-ec.h | 13 ++
> 4 files changed, 215 insertions(+), 5 deletions(-)
> create mode 100644 drivers/platform/chrome/wilco_ec/keyboard_leds.c
>
> diff --git a/drivers/platform/chrome/wilco_ec/Makefile b/drivers/platform/chrome/wilco_ec/Makefile
> index bc817164596e..ecb3145cab18 100644
> --- a/drivers/platform/chrome/wilco_ec/Makefile
> +++ b/drivers/platform/chrome/wilco_ec/Makefile
> @@ -1,6 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0
>
> -wilco_ec-objs := core.o mailbox.o properties.o sysfs.o
> +wilco_ec-objs := core.o keyboard_leds.o mailbox.o \
> + properties.o sysfs.o
> obj-$(CONFIG_WILCO_EC) += wilco_ec.o
> wilco_ec_debugfs-objs := debugfs.o
> obj-$(CONFIG_WILCO_EC_DEBUGFS) += wilco_ec_debugfs.o
> diff --git a/drivers/platform/chrome/wilco_ec/core.c b/drivers/platform/chrome/wilco_ec/core.c
> index 3724bf4b77c6..36c78e52ff3c 100644
> --- a/drivers/platform/chrome/wilco_ec/core.c
> +++ b/drivers/platform/chrome/wilco_ec/core.c
> @@ -5,10 +5,6 @@
> * Copyright 2018 Google LLC
> *
> * This is the entry point for the drivers that control the Wilco EC.
> - * This driver is responsible for several tasks:
> - * - Initialize the register interface that is used by wilco_ec_mailbox()
> - * - Create a platform device which is picked up by the debugfs driver
> - * - Create a platform device which is picked up by the RTC driver
> */
>
> #include <linux/acpi.h>
> @@ -87,6 +83,15 @@ static int wilco_ec_probe(struct platform_device *pdev)
> goto unregister_debugfs;
> }
>
> + /* Set up the keyboard backlight LEDs. */
> + ret = wilco_keyboard_leds_init(ec);
> + if (ret < 0) {
> + dev_err(dev,
> + "Failed to initialize keyboard LEDs: %d\n",
> + ret);
> + goto unregister_rtc;
> + }
> +
> ret = wilco_ec_add_sysfs(ec);
> if (ret < 0) {
> dev_err(dev, "Failed to create sysfs entries: %d", ret);
> diff --git a/drivers/platform/chrome/wilco_ec/keyboard_leds.c b/drivers/platform/chrome/wilco_ec/keyboard_leds.c
> new file mode 100644
> index 000000000000..bb0edf51dfda
> --- /dev/null
> +++ b/drivers/platform/chrome/wilco_ec/keyboard_leds.c
> @@ -0,0 +1,191 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Keyboard backlight LED driver for the Wilco Embedded Controller
> + *
> + * Copyright 2019 Google LLC
> + *
> + * Since the EC will never change the backlight level of its own accord,
> + * we don't need to implement a brightness_get() method.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/leds.h>
> +#include <linux/platform_data/wilco-ec.h>
> +#include <linux/slab.h>
> +
> +#define WILCO_EC_COMMAND_KBBL 0x75
> +#define WILCO_KBBL_MODE_FLAG_PWM BIT(1) /* Set brightness by percent. */
> +#define WILCO_KBBL_DEFAULT_BRIGHTNESS 0
> +
> +struct wilco_keyboard_leds {
> + struct wilco_ec_device *ec;
> + struct led_classdev keyboard;
> +};
> +
> +enum wilco_kbbl_subcommand {
> + WILCO_KBBL_SUBCMD_GET_FEATURES = 0x00,
> + WILCO_KBBL_SUBCMD_GET_STATE = 0x01,
> + WILCO_KBBL_SUBCMD_SET_STATE = 0x02,
> +};
> +
> +/**
> + * struct wilco_keyboard_leds_msg - Message to/from EC for keyboard LED control.
> + * @command: Always WILCO_EC_COMMAND_KBBL.
> + * @status: Set by EC to 0 on success, 0xFF on failure.
> + * @subcmd: One of enum wilco_kbbl_subcommand.
> + * @reserved3: Should be 0.
> + * @mode: Bit flags for used mode, we want to use WILCO_KBBL_MODE_FLAG_PWM.
> + * @reserved5to8: Should be 0.
> + * @percent: Brightness in 0-100. Only meaningful in PWM mode.
> + * @reserved10to15: Should be 0.
> + */
> +struct wilco_keyboard_leds_msg {
> + u8 command;
> + u8 status;
> + u8 subcmd;
> + u8 reserved3;
> + u8 mode;
> + u8 reserved5to8[4];
> + u8 percent;
> + u8 reserved10to15[6];
> +} __packed;
> +
> +/* Send a request, get a response, and check that the response is good. */
> +static int send_kbbl_msg(struct wilco_ec_device *ec,
> + struct wilco_keyboard_leds_msg *request,
> + struct wilco_keyboard_leds_msg *response)
> +{
> + struct wilco_ec_message msg;
> + int ret;
> +
> + memset(&msg, 0, sizeof(msg));
> + msg.type = WILCO_EC_MSG_LEGACY;
> + msg.request_data = request;
> + msg.request_size = sizeof(*request);
> + msg.response_data = response;
> + msg.response_size = sizeof(*response);
> +
> + ret = wilco_ec_mailbox(ec, &msg);
> + if (ret < 0) {
> + dev_err(ec->dev,
> + "Failed sending keyboard LEDs command: %d", ret);
> + return ret;
> + }
> +
> + if (response->status) {
> + dev_err(ec->dev,
> + "EC reported failure sending keyboard LEDs command: %d",
> + response->status);
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +static int set_kbbl(struct wilco_ec_device *ec, enum led_brightness brightness)
> +{
> + struct wilco_keyboard_leds_msg request;
> + struct wilco_keyboard_leds_msg response;
> +
> + memset(&request, 0, sizeof(request));
> + request.command = WILCO_EC_COMMAND_KBBL;
> + request.subcmd = WILCO_KBBL_SUBCMD_SET_STATE;
> + request.mode = WILCO_KBBL_MODE_FLAG_PWM;
> + request.percent = brightness;
> +
> + return send_kbbl_msg(ec, &request, &response);
> +}
> +
> +static int kbbl_exist(struct wilco_ec_device *ec, bool *exists)
> +{
> + struct wilco_keyboard_leds_msg request;
> + struct wilco_keyboard_leds_msg response;
> + int ret;
> +
> + memset(&request, 0, sizeof(request));
> + request.command = WILCO_EC_COMMAND_KBBL;
> + request.subcmd = WILCO_KBBL_SUBCMD_GET_FEATURES;
> +
> + ret = send_kbbl_msg(ec, &request, &response);
> + if (ret < 0)
> + return ret;
> +
> + *exists = response.status != 0xFF;
> +
> + return 0;
> +}
> +
> +/**
> + * kbbl_init() - Initialize the state of the keyboard backlight.
> + * @ec: EC device to talk to.
> + *
> + * Gets the current brightness, ensuring that the BIOS already initialized the
> + * backlight to PWM mode. If not in PWM mode, then the current brightness is
> + * meaningless, so set the brightness to WILCO_KBBL_DEFAULT_BRIGHTNESS.
> + *
> + * Return: Final brightness of the keyboard, or negative error code on failure.
> + */
> +static int kbbl_init(struct wilco_ec_device *ec)
> +{
> + struct wilco_keyboard_leds_msg request;
> + struct wilco_keyboard_leds_msg response;
> + int ret;
> +
> + memset(&request, 0, sizeof(request));
> + request.command = WILCO_EC_COMMAND_KBBL;
> + request.subcmd = WILCO_KBBL_SUBCMD_GET_STATE;
> +
> + ret = send_kbbl_msg(ec, &request, &response);
> + if (ret < 0)
> + return ret;
> +
> + if (response.mode & WILCO_KBBL_MODE_FLAG_PWM)
> + return response.percent;
> +
> + ret = set_kbbl(ec, WILCO_KBBL_DEFAULT_BRIGHTNESS);
> + if (ret < 0)
> + return ret;
> +
> + return WILCO_KBBL_DEFAULT_BRIGHTNESS;
> +}
> +
> +static int wilco_keyboard_leds_set(struct led_classdev *cdev,
> + enum led_brightness brightness)
> +{
> + struct wilco_keyboard_leds *wkl =
> + container_of(cdev, struct wilco_keyboard_leds, keyboard);
> + return set_kbbl(wkl->ec, brightness);
> +}
> +
> +int wilco_keyboard_leds_init(struct wilco_ec_device *ec)
> +{
> + struct wilco_keyboard_leds *wkl;
> + bool leds_exist;
> + int ret;
> +
> + ret = kbbl_exist(ec, &leds_exist);
> + if (ret < 0) {
> + dev_err(ec->dev,
> + "Failed checking keyboard LEDs support: %d", ret);
> + return ret;
> + }
> + if (!leds_exist)
> + return 0;
> +
> + wkl = devm_kzalloc(ec->dev, sizeof(*wkl), GFP_KERNEL);
> + if (!wkl)
> + return -ENOMEM;
> +
> + wkl->ec = ec;
> + wkl->keyboard.name = "platform::kbd_backlight";
> + wkl->keyboard.max_brightness = 100;
> + wkl->keyboard.flags = LED_CORE_SUSPENDRESUME;
> + wkl->keyboard.brightness_set_blocking = wilco_keyboard_leds_set;
> + ret = kbbl_init(ec);
> + if (ret < 0)
> + return ret;
> + wkl->keyboard.brightness = ret;
> +
> + return devm_led_classdev_register(ec->dev, &wkl->keyboard);
> +}
> diff --git a/include/linux/platform_data/wilco-ec.h b/include/linux/platform_data/wilco-ec.h
> index ad03b586a095..0f7df3498a24 100644
> --- a/include/linux/platform_data/wilco-ec.h
> +++ b/include/linux/platform_data/wilco-ec.h
> @@ -120,6 +120,19 @@ struct wilco_ec_message {
> */
> int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);
>
> +/**
> + * wilco_keyboard_leds_init() - Set up the keyboard backlight LEDs.
> + * @ec: EC device to query.
> + *
> + * After this call, the keyboard backlight will be exposed through a an LED
> + * device at /sys/class/leds.
> + *
> + * This may sleep because it uses wilco_ec_mailbox().
> + *
> + * Return: 0 on success, negative error code on failure.
> + */
> +int wilco_keyboard_leds_init(struct wilco_ec_device *ec);
> +
> /*
> * A Property is typically a data item that is stored to NVRAM
> * by the EC. Each of these data items has an index associated
>
