Acer Iconia Tab A500 is an Android tablet device which has two LEDs
embedded into the Power Button. Orange LED indicates "battery charging"
status and white LED indicates "wake-up/charge-done" status. The new LED
driver provides control over both LEDs to userspace.
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/leds/Kconfig | 7 ++
drivers/leds/Makefile | 1 +
drivers/leds/leds-acer-a500.c | 129 ++++++++++++++++++++++++++++++++++
3 files changed, 137 insertions(+)
create mode 100644 drivers/leds/leds-acer-a500.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 4f6464a169d5..4c39b53bcf1f 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -921,6 +921,13 @@ config LEDS_SGM3140
This option enables support for the SGM3140 500mA Buck/Boost Charge
Pump LED Driver.
+config LEDS_ACER_A500
+ tristate "Power button LED support for Acer Iconia Tab A500"
+ depends on LEDS_CLASS && MFD_ACER_A500_EC
+ help
+ This option enables support for the Power Button LED of
+ Acer Iconia Tab A500.
+
comment "LED Triggers"
source "drivers/leds/trigger/Kconfig"
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 778cb4bb8c52..73e603e1727e 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_LEDS_TRIGGERS) += led-triggers.o
# LED Platform Drivers (keep this sorted, M-| sort)
obj-$(CONFIG_LEDS_88PM860X) += leds-88pm860x.o
obj-$(CONFIG_LEDS_AAT1290) += leds-aat1290.o
+obj-$(CONFIG_LEDS_ACER_A500) += leds-acer-a500.o
obj-$(CONFIG_LEDS_ADP5520) += leds-adp5520.o
obj-$(CONFIG_LEDS_AN30259A) += leds-an30259a.o
obj-$(CONFIG_LEDS_APU) += leds-apu.o
diff --git a/drivers/leds/leds-acer-a500.c b/drivers/leds/leds-acer-a500.c
new file mode 100644
index 000000000000..8cf0b11f4390
--- /dev/null
+++ b/drivers/leds/leds-acer-a500.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define A500_EC_LED_DELAY_USEC (100 * 1000)
+
+enum {
+ REG_RESET_LEDS = 0x40,
+ REG_POWER_LED_ON = 0x42,
+ REG_CHARGE_LED_ON = 0x43,
+ REG_ANDROID_LEDS_OFF = 0x5a,
+};
+
+struct a500_led {
+ struct led_classdev cdev;
+ const struct reg_sequence *enable_seq;
+ struct a500_led *other;
+ struct regmap *rmap;
+};
+
+static const struct reg_sequence a500_ec_leds_reset_seq[] = {
+ REG_SEQ(REG_RESET_LEDS, 0x0, A500_EC_LED_DELAY_USEC),
+ REG_SEQ(REG_ANDROID_LEDS_OFF, 0x0, A500_EC_LED_DELAY_USEC),
+};
+
+static const struct reg_sequence a500_ec_white_led_enable_seq[] = {
+ REG_SEQ(REG_POWER_LED_ON, 0x0, A500_EC_LED_DELAY_USEC),
+};
+
+static const struct reg_sequence a500_ec_orange_led_enable_seq[] = {
+ REG_SEQ(REG_CHARGE_LED_ON, 0x0, A500_EC_LED_DELAY_USEC),
+};
+
+static int a500_ec_led_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness value)
+{
+ struct a500_led *led = container_of(led_cdev, struct a500_led, cdev);
+ struct reg_sequence control_seq[2];
+ unsigned int num_regs = 1;
+
+ if (value) {
+ control_seq[0] = led->enable_seq[0];
+ } else {
+ /*
+ * There is no separate controls which can disable LEDs
+ * individually, there is only RESET_LEDS command that turns
+ * off both LEDs.
+ *
+ * RESET_LEDS turns off both LEDs, thus restore other LED if
+ * it's turned ON.
+ */
+ if (led->other->cdev.brightness)
+ num_regs = 2;
+
+ control_seq[0] = a500_ec_leds_reset_seq[0];
+ control_seq[1] = led->other->enable_seq[0];
+ }
+
+ return regmap_multi_reg_write(led->rmap, control_seq, num_regs);
+}
+
+static int a500_ec_leds_probe(struct platform_device *pdev)
+{
+ struct a500_led *white_led, *orange_led;
+ struct regmap *rmap;
+ int err;
+
+ rmap = dev_get_regmap(pdev->dev.parent, "KB930");
+ if (!rmap)
+ return -EINVAL;
+
+ /* reset and turn off LEDs */
+ regmap_multi_reg_write(rmap, a500_ec_leds_reset_seq, 2);
+
+ white_led = devm_kzalloc(&pdev->dev, sizeof(*white_led), GFP_KERNEL);
+ if (!white_led)
+ return -ENOMEM;
+
+ white_led->cdev.name = "power:white";
+ white_led->cdev.brightness_set_blocking = a500_ec_led_brightness_set;
+ white_led->cdev.flags = LED_CORE_SUSPENDRESUME;
+ white_led->cdev.max_brightness = 1;
+ white_led->enable_seq = a500_ec_white_led_enable_seq;
+ white_led->rmap = rmap;
+
+ orange_led = devm_kzalloc(&pdev->dev, sizeof(*orange_led), GFP_KERNEL);
+ if (!orange_led)
+ return -ENOMEM;
+
+ orange_led->cdev.name = "power:orange";
+ orange_led->cdev.brightness_set_blocking = a500_ec_led_brightness_set;
+ orange_led->cdev.flags = LED_CORE_SUSPENDRESUME;
+ orange_led->cdev.max_brightness = 1;
+ orange_led->enable_seq = a500_ec_orange_led_enable_seq;
+ orange_led->rmap = rmap;
+
+ white_led->other = orange_led;
+ orange_led->other = white_led;
+
+ err = devm_led_classdev_register(&pdev->dev, &white_led->cdev);
+ if (err) {
+ dev_err(&pdev->dev, "failed to register white LED\n");
+ return err;
+ }
+
+ err = devm_led_classdev_register(&pdev->dev, &orange_led->cdev);
+ if (err) {
+ dev_err(&pdev->dev, "failed to register orange LED\n");
+ return err;
+ }
+
+ return 0;
+}
+
+static struct platform_driver a500_ec_leds_driver = {
+ .driver = {
+ .name = "acer-a500-iconia-leds",
+ },
+ .probe = a500_ec_leds_probe,
+};
+module_platform_driver(a500_ec_leds_driver);
+
+MODULE_DESCRIPTION("LED driver for Acer Iconia Tab A500 Power Button");
+MODULE_AUTHOR("Dmitry Osipenko <digetx@xxxxxxxxx>");
+MODULE_ALIAS("platform:acer-a500-iconia-leds");
+MODULE_LICENSE("GPL");
--
2.27.0
