[PATCH v3] leds: ariel: Add driver for status LEDs on Dell Wyse 3020

Lubomir Rintel
2020-03-22T07:41:45Z

This adds support for controlling the LEDs attached to the Embedded
Controller on a Dell Wyse 3020 "Ariel" board.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>

---
Changes since v2:
- Hopefully sending out the correct patch this time...

Changes since v1:
- Reduce code duplication with a loop
- Drop "ariel:" prefix from led names
- Do not print a message after a successful probe
---
drivers/leds/Kconfig | 11 ++++
drivers/leds/Makefile | 1 +
drivers/leds/leds-ariel.c | 133 ++++++++++++++++++++++++++++++++++++++
3 files changed, 145 insertions(+)
create mode 100644 drivers/leds/leds-ariel.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index d82f1dea37111..66424ee54cc01 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -83,6 +83,17 @@ config LEDS_APU
To compile this driver as a module, choose M here: the
module will be called leds-apu.

+config LEDS_ARIEL
+ tristate "Dell Wyse 3020 status LED support"
+ depends on LEDS_CLASS
+ depends on (MACH_MMP3_DT && MFD_ENE_KB3930) || COMPILE_TEST
+ help
+ This driver adds support for controlling the front panel status
+ LEDs on Dell Wyse 3020 (Ariel) board via the KB3930 Embedded
+ Controller.
+
+ Say Y to if your machine is a Dell Wyse 3020 thin client.
+
config LEDS_AS3645A
tristate "AS3645A and LM3555 LED flash controllers support"
depends on I2C && LEDS_CLASS_FLASH
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index d7e1107753fb1..bf3b22038d113 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_LEDS_TRIGGERS) += led-triggers.o
obj-$(CONFIG_LEDS_88PM860X) += leds-88pm860x.o
obj-$(CONFIG_LEDS_AAT1290) += leds-aat1290.o
obj-$(CONFIG_LEDS_APU) += leds-apu.o
+obj-$(CONFIG_LEDS_ARIEL) += leds-ariel.o
obj-$(CONFIG_LEDS_AS3645A) += leds-as3645a.o
obj-$(CONFIG_LEDS_AN30259A) += leds-an30259a.o
obj-$(CONFIG_LEDS_BCM6328) += leds-bcm6328.o
diff --git a/drivers/leds/leds-ariel.c b/drivers/leds/leds-ariel.c
new file mode 100644
index 0000000000000..8fc56722e12f4
--- /dev/null
+++ b/drivers/leds/leds-ariel.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0-or-later
+/*
+ * Dell Wyse 3020 a.k.a. "Ariel" Embedded Controller LED Driver
+ *
+ * Copyright (C) 2020 Lubomir Rintel
+ */
+
+#include <linux/module.h>
+#include <linux/leds.h>
+#include <linux/regmap.h>
+#include <linux/of_platform.h>
+
+enum ec_index {
+ EC_BLUE_LED = 0x01,
+ EC_AMBER_LED = 0x02,
+ EC_GREEN_LED = 0x03,
+};
+
+enum {
+ EC_LED_OFF = 0x00,
+ EC_LED_STILL = 0x01,
+ EC_LED_FADE = 0x02,
+ EC_LED_BLINK = 0x03,
+};
+
+struct ariel_led {
+ struct regmap *ec_ram;
+ enum ec_index ec_index;
+ struct led_classdev led_cdev;
+};
+
+#define led_cdev_to_ariel_led(c) container_of(c, struct ariel_led, led_cdev)
+
+static enum led_brightness ariel_led_get(struct led_classdev *led_cdev)
+{
+ struct ariel_led *led = led_cdev_to_ariel_led(led_cdev);
+ unsigned int led_status = 0;
+
+ if (regmap_read(led->ec_ram, led->ec_index, &led_status))
+ return LED_OFF;
+
+ if (led_status == EC_LED_STILL)
+ return LED_FULL;
+ else
+ return LED_OFF;
+}
+
+static void ariel_led_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct ariel_led *led = led_cdev_to_ariel_led(led_cdev);
+
+ if (brightness == LED_OFF)
+ regmap_write(led->ec_ram, led->ec_index, EC_LED_OFF);
+ else
+ regmap_write(led->ec_ram, led->ec_index, EC_LED_STILL);
+}
+
+static int ariel_blink_set(struct led_classdev *led_cdev,
+ unsigned long *delay_on, unsigned long *delay_off)
+{
+ struct ariel_led *led = led_cdev_to_ariel_led(led_cdev);
+
+ if (*delay_on == 0 && *delay_off == 0)
+ return -EINVAL;
+
+ if (*delay_on == 0) {
+ regmap_write(led->ec_ram, led->ec_index, EC_LED_OFF);
+ } else if (*delay_off == 0) {
+ regmap_write(led->ec_ram, led->ec_index, EC_LED_STILL);
+ } else {
+ *delay_on = 500;
+ *delay_off = 500;
+ regmap_write(led->ec_ram, led->ec_index, EC_LED_BLINK);
+ }
+
+ return 0;
+}
+
+#define NLEDS 3
+
+static int ariel_led_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct ariel_led *leds;
+ struct regmap *ec_ram;
+ int ret;
+ int i;
+
+ leds = devm_kcalloc(dev, NLEDS, sizeof(*leds), GFP_KERNEL);
+ if (!leds)
+ return -ENOMEM;
+
+ ec_ram = dev_get_regmap(dev->parent, "ec_ram");
+ if (!ec_ram)
+ return -ENODEV;
+
+ leds[0].ec_index = EC_BLUE_LED;
+ leds[0].led_cdev.name = "blue:power",
+ leds[0].led_cdev.default_trigger = "default-on";
+
+ leds[1].ec_index = EC_AMBER_LED;
+ leds[1].led_cdev.name = "amber:status",
+
+ leds[2].ec_index = EC_GREEN_LED;
+ leds[2].led_cdev.name = "green:status",
+ leds[2].led_cdev.default_trigger = "default-on";
+
+ for (i = 0; i < NLEDS; i++) {
+ leds[0].ec_ram = ec_ram;
+ leds[0].led_cdev.brightness_get = ariel_led_get;
+ leds[0].led_cdev.brightness_set = ariel_led_set;
+ leds[0].led_cdev.blink_set = ariel_blink_set;
+
+ ret = devm_led_classdev_register(dev, &leds[0].led_cdev);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static struct platform_driver ariel_led_driver = {
+ .probe = ariel_led_probe,
+ .driver = {
+ .name = "dell-wyse-ariel-led",
+ },
+};
+module_platform_driver(ariel_led_driver);
+
+MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
+MODULE_DESCRIPTION("Dell Wyse 3020 Status LEDs Driver");
+MODULE_LICENSE("Dual BSD/GPL");
--
2.26.0.rc2