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[PATCH] thinkpad_acpi: Add support for keyboard backlight

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  [PATCH] thinkpad_acpi: Add support for keyboard backlight Pali Rohár <pali.rohar@gmail.com> - 2015-12-24 19:50 +0100
    Re: [PATCH] thinkpad_acpi: Add support for keyboard backlight Henrique de Moraes Holschuh <hmh@hmh.eng.br> - 2015-12-28 03:50 +0100
      Re: [PATCH] thinkpad_acpi: Add support for keyboard backlight Pali Rohár <pali.rohar@gmail.com> - 2015-12-28 15:50 +0100
        Re: [PATCH] thinkpad_acpi: Add support for keyboard backlight Pali Rohár <pali.rohar@gmail.com> - 2015-12-30 23:30 +0100
    [PATCH v2] thinkpad_acpi: Add support for keyboard backlight Pali Rohár <pali.rohar@gmail.com> - 2015-12-30 23:30 +0100

#1298024 — [PATCH] thinkpad_acpi: Add support for keyboard backlight

This patch adds support for controlling keyboard backlight via standard
linux led class interface (::kbd_backlight). It uses ACPI HKEY device with
MLCG and MLCS methods.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Tested-by: Fabio D'Urso <fabiodurso@hotmail.it>
---
 drivers/platform/x86/thinkpad_acpi.c |  205 ++++++++++++++++++++++++++++++++++
 1 file changed, 205 insertions(+)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 0bed473..477afa1 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -303,6 +303,7 @@ static struct {
 	u32 hotkey_mask:1;
 	u32 hotkey_wlsw:1;
 	u32 hotkey_tablet:1;
+	u32 kbdlight:1;
 	u32 light:1;
 	u32 light_status:1;
 	u32 bright_acpimode:1;
@@ -4986,6 +4987,206 @@ static struct ibm_struct video_driver_data = {
 #endif /* CONFIG_THINKPAD_ACPI_VIDEO */
 
 /*************************************************************************
+ * Keyboard backlight subdriver
+ */
+
+static int kbdlight_set_level(int level)
+{
+	if (!hkey_handle)
+		return -ENXIO;
+
+	if (!acpi_evalf(hkey_handle, NULL, "MLCS", "dd", level))
+		return -EIO;
+
+	return 0;
+}
+
+static int kbdlight_get_level(void)
+{
+	int status = 0;
+
+	if (!hkey_handle)
+		return -ENXIO;
+
+	if (!acpi_evalf(hkey_handle, &status, "MLCG", "dd", 0))
+		return -EIO;
+
+	if (status < 0)
+		return status;
+
+	return status & 0x3;
+}
+
+static bool kbdlight_is_supported(void)
+{
+	int status = 0;
+
+	if (!hkey_handle)
+		return false;
+
+	if (!acpi_has_method(hkey_handle, "MLCG")) {
+		vdbg_printk(TPACPI_DBG_INIT, "kbdlight MLCG is unavailable\n");
+		return false;
+	}
+
+	if (!acpi_evalf(hkey_handle, &status, "MLCG", "qdd", 0)) {
+		vdbg_printk(TPACPI_DBG_INIT, "kbdlight MLCG failed\n");
+		return false;
+	}
+
+	if (status < 0) {
+		vdbg_printk(TPACPI_DBG_INIT, "kbdlight MLCG err: %d\n", status);
+		return false;
+	}
+
+	vdbg_printk(TPACPI_DBG_INIT, "kbdlight MLCG returned 0x%x\n", status);
+	/*
+	 * Guessed test for keyboard backlight:
+	 *
+	 * Machines with backlight keyboard return:
+	 *   b010100000010000000XX - ThinkPad X1 Carbon 3rd
+	 *   b110100010010000000XX - ThinkPad x230
+	 *   b010100000010000000XX - ThinkPad x240
+	 *   b010100000010000000XX - ThinkPad W541
+	 * (XX is current backlight level)
+	 *
+	 * Machines without backlight keyboard return:
+	 *   b10100001000000000000 - ThinkPad x230
+	 *   b10110001000000000000 - ThinkPad E430
+	 *   b00000000000000000000 - ThinkPad E450
+	 *
+	 * Candidate BITs for detection test (XOR):
+	 *   b01000000001000000000
+	 *              ^
+	 */
+	return status & BIT(9);
+}
+
+static void kbdlight_set_worker(struct work_struct *work)
+{
+	struct tpacpi_led_classdev *data =
+			container_of(work, struct tpacpi_led_classdev, work);
+
+	if (likely(tpacpi_lifecycle == TPACPI_LIFE_RUNNING))
+		kbdlight_set_level(data->new_state);
+}
+
+static void kbdlight_sysfs_set(struct led_classdev *led_cdev,
+			enum led_brightness brightness)
+{
+	struct tpacpi_led_classdev *data =
+			container_of(led_cdev,
+				     struct tpacpi_led_classdev,
+				     led_classdev);
+	data->new_state = brightness;
+	queue_work(tpacpi_wq, &data->work);
+}
+
+static enum led_brightness kbdlight_sysfs_get(struct led_classdev *led_cdev)
+{
+	int level;
+
+	level = kbdlight_get_level();
+	if (level < 0)
+		return 0;
+
+	return level;
+}
+
+static struct tpacpi_led_classdev tpacpi_led_kbdlight = {
+	.led_classdev = {
+		.name		= "tpacpi::kbd_backlight",
+		.max_brightness	= 2,
+		.brightness_set	= &kbdlight_sysfs_set,
+		.brightness_get	= &kbdlight_sysfs_get,
+	}
+};
+
+static int __init kbdlight_init(struct ibm_init_struct *iibm)
+{
+	int rc;
+
+	vdbg_printk(TPACPI_DBG_INIT, "initializing kbdlight subdriver\n");
+
+	TPACPI_ACPIHANDLE_INIT(hkey);
+	INIT_WORK(&tpacpi_led_kbdlight.work, kbdlight_set_worker);
+
+	if (!kbdlight_is_supported()) {
+		tp_features.kbdlight = 0;
+		vdbg_printk(TPACPI_DBG_INIT, "kbdlight is unsupported\n");
+		return 1;
+	}
+
+	tp_features.kbdlight = 1;
+
+	rc = led_classdev_register(&tpacpi_pdev->dev,
+				   &tpacpi_led_kbdlight.led_classdev);
+	if (rc < 0) {
+		tp_features.kbdlight = 0;
+		return rc;
+	}
+
+	return 0;
+}
+
+static void kbdlight_exit(void)
+{
+	if (tp_features.kbdlight)
+		led_classdev_unregister(&tpacpi_led_kbdlight.led_classdev);
+	flush_workqueue(tpacpi_wq);
+}
+
+static int kbdlight_read(struct seq_file *m)
+{
+	int level;
+
+	if (!tp_features.kbdlight) {
+		seq_printf(m, "status:\t\tnot supported\n");
+	} else {
+		level = kbdlight_get_level();
+		if (level < 0)
+			seq_printf(m, "status:\t\terror %d\n", level);
+		else
+			seq_printf(m, "status:\t\t%d\n", level);
+		seq_printf(m, "commands:\t0, 1, 2\n");
+	}
+
+	return 0;
+}
+
+static int kbdlight_write(char *buf)
+{
+	char *cmd;
+	int level = -1;
+
+	if (!tp_features.kbdlight)
+		return -ENODEV;
+
+	while ((cmd = next_cmd(&buf))) {
+		if (strlencmp(cmd, "0") == 0)
+			level = 0;
+		else if (strlencmp(cmd, "1") == 0)
+			level = 1;
+		else if (strlencmp(cmd, "2") == 0)
+			level = 2;
+		else
+			return -EINVAL;
+	}
+
+	if (level == -1)
+		return -EINVAL;
+
+	return kbdlight_set_level(level);
+}
+
+static struct ibm_struct kbdlight_driver_data = {
+	.name = "kbdlight",
+	.read = kbdlight_read,
+	.write = kbdlight_write,
+	.exit = kbdlight_exit,
+};
+
+/*************************************************************************
  * Light (thinklight) subdriver
  */
 
@@ -9207,6 +9408,10 @@ static struct ibm_init_struct ibms_init[] __initdata = {
 	},
 #endif
 	{
+		.init = kbdlight_init,
+		.data = &kbdlight_driver_data,
+	},
+	{
 		.init = light_init,
 		.data = &light_driver_data,
 	},
-- 
1.7.9.5

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#1298455

On Thu, 24 Dec 2015, Pali Rohár wrote:
> This patch adds support for controlling keyboard backlight via standard
> linux led class interface (::kbd_backlight). It uses ACPI HKEY device with
> MLCG and MLCS methods.
> 
> Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> Tested-by: Fabio D'Urso <fabiodurso@hotmail.it>

It looks good at a first glance.  But at init you might need to take steps
so that the current state is not changed.  Did you test this?

Also, is it working properly across suspend+resume?

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh
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#1298662

[Multipart message — attachments visible in raw view] — view raw

On Monday 28 December 2015 00:14:17 Henrique de Moraes Holschuh wrote:
> On Thu, 24 Dec 2015, Pali Rohár wrote:
> > This patch adds support for controlling keyboard backlight via
> > standard linux led class interface (::kbd_backlight). It uses ACPI
> > HKEY device with MLCG and MLCS methods.
> > 
> > Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> > Tested-by: Fabio D'Urso <fabiodurso@hotmail.it>
> 
> It looks good at a first glance.  But at init you might need to take
> steps so that the current state is not changed.  Did you test this?

Tested. Modprobing driver does not change keyboard backlight level.

> Also, is it working properly across suspend+resume?

When doing resume from suspend or hibernate BIOS turning keyboard 
backlight automatically off.

But driver at any time report correct backlight level from sysfs node.

-- 
Pali Rohár
pali.rohar@gmail.com

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#1299523

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On Monday 28 December 2015 15:48:14 Pali Rohár wrote:
> > Also, is it working properly across suspend+resume?
> 
> When doing resume from suspend or hibernate BIOS turning keyboard
> backlight automatically off.

Fixed in v2.

-- 
Pali Rohár
pali.rohar@gmail.com

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#1299524 — [PATCH v2] thinkpad_acpi: Add support for keyboard backlight

This patch adds support for controlling keyboard backlight via standard
linux led class interface (::kbd_backlight). It uses ACPI HKEY device with
MLCG and MLCS methods.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Tested-by: Fabio D'Urso <fabiodurso@hotmail.it>
---
Changes since v1:
* Added LED_CORE_SUSPENDRESUME to preserve led state across suspend/hibernate
---
 drivers/platform/x86/thinkpad_acpi.c |  206 ++++++++++++++++++++++++++++++++++
 1 file changed, 206 insertions(+)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 0bed473..a268a7a 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -303,6 +303,7 @@ static struct {
 	u32 hotkey_mask:1;
 	u32 hotkey_wlsw:1;
 	u32 hotkey_tablet:1;
+	u32 kbdlight:1;
 	u32 light:1;
 	u32 light_status:1;
 	u32 bright_acpimode:1;
@@ -4986,6 +4987,207 @@ static struct ibm_struct video_driver_data = {
 #endif /* CONFIG_THINKPAD_ACPI_VIDEO */
 
 /*************************************************************************
+ * Keyboard backlight subdriver
+ */
+
+static int kbdlight_set_level(int level)
+{
+	if (!hkey_handle)
+		return -ENXIO;
+
+	if (!acpi_evalf(hkey_handle, NULL, "MLCS", "dd", level))
+		return -EIO;
+
+	return 0;
+}
+
+static int kbdlight_get_level(void)
+{
+	int status = 0;
+
+	if (!hkey_handle)
+		return -ENXIO;
+
+	if (!acpi_evalf(hkey_handle, &status, "MLCG", "dd", 0))
+		return -EIO;
+
+	if (status < 0)
+		return status;
+
+	return status & 0x3;
+}
+
+static bool kbdlight_is_supported(void)
+{
+	int status = 0;
+
+	if (!hkey_handle)
+		return false;
+
+	if (!acpi_has_method(hkey_handle, "MLCG")) {
+		vdbg_printk(TPACPI_DBG_INIT, "kbdlight MLCG is unavailable\n");
+		return false;
+	}
+
+	if (!acpi_evalf(hkey_handle, &status, "MLCG", "qdd", 0)) {
+		vdbg_printk(TPACPI_DBG_INIT, "kbdlight MLCG failed\n");
+		return false;
+	}
+
+	if (status < 0) {
+		vdbg_printk(TPACPI_DBG_INIT, "kbdlight MLCG err: %d\n", status);
+		return false;
+	}
+
+	vdbg_printk(TPACPI_DBG_INIT, "kbdlight MLCG returned 0x%x\n", status);
+	/*
+	 * Guessed test for keyboard backlight:
+	 *
+	 * Machines with backlight keyboard return:
+	 *   b010100000010000000XX - ThinkPad X1 Carbon 3rd
+	 *   b110100010010000000XX - ThinkPad x230
+	 *   b010100000010000000XX - ThinkPad x240
+	 *   b010100000010000000XX - ThinkPad W541
+	 * (XX is current backlight level)
+	 *
+	 * Machines without backlight keyboard return:
+	 *   b10100001000000000000 - ThinkPad x230
+	 *   b10110001000000000000 - ThinkPad E430
+	 *   b00000000000000000000 - ThinkPad E450
+	 *
+	 * Candidate BITs for detection test (XOR):
+	 *   b01000000001000000000
+	 *              ^
+	 */
+	return status & BIT(9);
+}
+
+static void kbdlight_set_worker(struct work_struct *work)
+{
+	struct tpacpi_led_classdev *data =
+			container_of(work, struct tpacpi_led_classdev, work);
+
+	if (likely(tpacpi_lifecycle == TPACPI_LIFE_RUNNING))
+		kbdlight_set_level(data->new_state);
+}
+
+static void kbdlight_sysfs_set(struct led_classdev *led_cdev,
+			enum led_brightness brightness)
+{
+	struct tpacpi_led_classdev *data =
+			container_of(led_cdev,
+				     struct tpacpi_led_classdev,
+				     led_classdev);
+	data->new_state = brightness;
+	queue_work(tpacpi_wq, &data->work);
+}
+
+static enum led_brightness kbdlight_sysfs_get(struct led_classdev *led_cdev)
+{
+	int level;
+
+	level = kbdlight_get_level();
+	if (level < 0)
+		return 0;
+
+	return level;
+}
+
+static struct tpacpi_led_classdev tpacpi_led_kbdlight = {
+	.led_classdev = {
+		.name		= "tpacpi::kbd_backlight",
+		.max_brightness	= 2,
+		.brightness_set	= &kbdlight_sysfs_set,
+		.brightness_get	= &kbdlight_sysfs_get,
+		.flags		= LED_CORE_SUSPENDRESUME,
+	}
+};
+
+static int __init kbdlight_init(struct ibm_init_struct *iibm)
+{
+	int rc;
+
+	vdbg_printk(TPACPI_DBG_INIT, "initializing kbdlight subdriver\n");
+
+	TPACPI_ACPIHANDLE_INIT(hkey);
+	INIT_WORK(&tpacpi_led_kbdlight.work, kbdlight_set_worker);
+
+	if (!kbdlight_is_supported()) {
+		tp_features.kbdlight = 0;
+		vdbg_printk(TPACPI_DBG_INIT, "kbdlight is unsupported\n");
+		return 1;
+	}
+
+	tp_features.kbdlight = 1;
+
+	rc = led_classdev_register(&tpacpi_pdev->dev,
+				   &tpacpi_led_kbdlight.led_classdev);
+	if (rc < 0) {
+		tp_features.kbdlight = 0;
+		return rc;
+	}
+
+	return 0;
+}
+
+static void kbdlight_exit(void)
+{
+	if (tp_features.kbdlight)
+		led_classdev_unregister(&tpacpi_led_kbdlight.led_classdev);
+	flush_workqueue(tpacpi_wq);
+}
+
+static int kbdlight_read(struct seq_file *m)
+{
+	int level;
+
+	if (!tp_features.kbdlight) {
+		seq_printf(m, "status:\t\tnot supported\n");
+	} else {
+		level = kbdlight_get_level();
+		if (level < 0)
+			seq_printf(m, "status:\t\terror %d\n", level);
+		else
+			seq_printf(m, "status:\t\t%d\n", level);
+		seq_printf(m, "commands:\t0, 1, 2\n");
+	}
+
+	return 0;
+}
+
+static int kbdlight_write(char *buf)
+{
+	char *cmd;
+	int level = -1;
+
+	if (!tp_features.kbdlight)
+		return -ENODEV;
+
+	while ((cmd = next_cmd(&buf))) {
+		if (strlencmp(cmd, "0") == 0)
+			level = 0;
+		else if (strlencmp(cmd, "1") == 0)
+			level = 1;
+		else if (strlencmp(cmd, "2") == 0)
+			level = 2;
+		else
+			return -EINVAL;
+	}
+
+	if (level == -1)
+		return -EINVAL;
+
+	return kbdlight_set_level(level);
+}
+
+static struct ibm_struct kbdlight_driver_data = {
+	.name = "kbdlight",
+	.read = kbdlight_read,
+	.write = kbdlight_write,
+	.exit = kbdlight_exit,
+};
+
+/*************************************************************************
  * Light (thinklight) subdriver
  */
 
@@ -9207,6 +9409,10 @@ static struct ibm_init_struct ibms_init[] __initdata = {
 	},
 #endif
 	{
+		.init = kbdlight_init,
+		.data = &kbdlight_driver_data,
+	},
+	{
 		.init = light_init,
 		.data = &light_driver_data,
 	},
-- 
1.7.9.5

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