[PATCH v9 5/7] leds: Add driver for ASUS Transformer LEDs

[Svyatoslav Ryhel <clamor95@gmail.com>]

From: Michał Mirosław <mirq-linux@rere.qmqm.pl>

ASUS Transformer tablets have a green and an amber LED on both the Pad
and the Dock. If both LEDs are enabled simultaneously, the emitted light
will be yellow.

Co-developed-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
---
 drivers/leds/Kconfig                    |  11 +++
 drivers/leds/Makefile                   |   1 +
 drivers/leds/leds-asus-transformer-ec.c | 125 ++++++++++++++++++++++++
 3 files changed, 137 insertions(+)
 create mode 100644 drivers/leds/leds-asus-transformer-ec.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index f4a0a3c8c870..f637d23400a8 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -120,6 +120,17 @@ config LEDS_OSRAM_AMS_AS3668
 	  To compile this driver as a module, choose M here: the module
 	  will be called leds-as3668.
 
+config LEDS_ASUS_TRANSFORMER_EC
+	tristate "LED Support for Asus Transformer charging LED"
+	depends on LEDS_CLASS
+	depends on MFD_ASUS_TRANSFORMER_EC
+	help
+	  This option enables support for charging indicator on
+	  Asus Transformer's Pad and it's Dock.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called leds-asus-transformer-ec.
+
 config LEDS_AW200XX
 	tristate "LED support for Awinic AW20036/AW20054/AW20072/AW20108"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 8fdb45d5b439..d5395c3f1124 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_LEDS_AN30259A)		+= leds-an30259a.o
 obj-$(CONFIG_LEDS_APU)			+= leds-apu.o
 obj-$(CONFIG_LEDS_ARIEL)		+= leds-ariel.o
 obj-$(CONFIG_LEDS_AS3668)		+= leds-as3668.o
+obj-$(CONFIG_LEDS_ASUS_TRANSFORMER_EC)	+= leds-asus-transformer-ec.o
 obj-$(CONFIG_LEDS_AW200XX)		+= leds-aw200xx.o
 obj-$(CONFIG_LEDS_AW2013)		+= leds-aw2013.o
 obj-$(CONFIG_LEDS_BCM6328)		+= leds-bcm6328.o
diff --git a/drivers/leds/leds-asus-transformer-ec.c b/drivers/leds/leds-asus-transformer-ec.c
new file mode 100644
index 000000000000..4421d629911e
--- /dev/null
+++ b/drivers/leds/leds-asus-transformer-ec.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/err.h>
+#include <linux/leds.h>
+#include <linux/mfd/asus-transformer-ec.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+enum {
+	ASUSEC_LED_AMBER,
+	ASUSEC_LED_GREEN,
+	ASUSEC_LED_MAX
+};
+
+struct asus_ec_led_config {
+	const char *name;
+	unsigned int color;
+	u64 ctrl_bit;
+};
+
+struct asus_ec_led {
+	struct asus_ec_leds_data *ddata;
+	struct led_classdev cdev;
+	u64 ctrl_bit;
+};
+
+struct asus_ec_leds_data {
+	const struct asusec_core *ec;
+	struct asus_ec_led leds[ASUSEC_LED_MAX];
+};
+
+static const struct asus_ec_led_config asus_ec_leds[] = {
+	[ASUSEC_LED_AMBER] = {
+		.name = "amber",
+		.color = LED_COLOR_ID_AMBER,
+		.ctrl_bit = ASUSEC_CTL_LED_AMBER,
+	},
+	[ASUSEC_LED_GREEN] = {
+		.name = "green",
+		.color = LED_COLOR_ID_GREEN,
+		.ctrl_bit = ASUSEC_CTL_LED_GREEN,
+	},
+};
+
+static enum led_brightness asus_ec_led_get_brightness(struct led_classdev *cdev)
+{
+	struct asus_ec_led *led = container_of(cdev, struct asus_ec_led, cdev);
+	const struct asusec_core *ec = led->ddata->ec;
+	u64 ctl;
+	int ret;
+
+	ret = asus_dockram_access_ctl(ec->dockram, &ctl, 0, 0);
+	if (ret)
+		return LED_OFF;
+
+	return ctl & led->ctrl_bit ? LED_ON : LED_OFF;
+}
+
+static int asus_ec_led_set_brightness(struct led_classdev *cdev,
+				      enum led_brightness brightness)
+{
+	struct asus_ec_led *led = container_of(cdev, struct asus_ec_led, cdev);
+	const struct asusec_core *ec = led->ddata->ec;
+
+	if (brightness)
+		return asus_dockram_access_ctl(ec->dockram, NULL,
+					       led->ctrl_bit, led->ctrl_bit);
+
+	return asus_dockram_access_ctl(ec->dockram, NULL, led->ctrl_bit, 0);
+}
+
+static int asus_ec_led_probe(struct platform_device *pdev)
+{
+	const struct asusec_core *ec = dev_get_drvdata(pdev->dev.parent);
+	struct asus_ec_leds_data *ddata;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, ddata);
+	ddata->ec = ec;
+
+	for (int i = 0; i < ASUSEC_LED_MAX; i++) {
+		const struct asus_ec_led_config *cfg = &asus_ec_leds[i];
+		struct asus_ec_led *led = &ddata->leds[i];
+
+		led->cdev.name = devm_kasprintf(dev, GFP_KERNEL, "%s::%s",
+						ddata->ec->name, cfg->name);
+		if (!led->cdev.name)
+			return -ENOMEM;
+
+		led->cdev.max_brightness = 1;
+		led->cdev.color = cfg->color;
+		led->cdev.flags = LED_CORE_SUSPENDRESUME | LED_RETAIN_AT_SHUTDOWN;
+		led->cdev.brightness_get = asus_ec_led_get_brightness;
+		led->cdev.brightness_set_blocking = asus_ec_led_set_brightness;
+
+		led->ddata = ddata;
+		led->ctrl_bit = cfg->ctrl_bit;
+
+		ret = devm_led_classdev_register(dev, &led->cdev);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "Failed to register %s LED\n",
+					     cfg->name);
+	}
+
+	return 0;
+}
+
+static struct platform_driver asus_ec_led_driver = {
+	.driver.name = "asus-transformer-ec-led",
+	.probe = asus_ec_led_probe,
+};
+module_platform_driver(asus_ec_led_driver);
+
+MODULE_ALIAS("platform:asus-transformer-ec-led");
+MODULE_AUTHOR("Michał Mirosław <mirq-linux@rere.qmqm.pl>");
+MODULE_AUTHOR("Svyatoslav Ryhel <clamor95@gmail.com>");
+MODULE_DESCRIPTION("ASUS Transformer's charging LED driver");
+MODULE_LICENSE("GPL");
-- 
2.53.0