[PATCH v6 4/6] drivers: leds: Add the iEi WT61P803 PUZZLE LED driver

[Luka Kovacic <luka.kovacic@sartura.hr>]

Add support for the iEi WT61P803 PUZZLE LED driver.
Currently only the front panel power LED is supported,
since it is the only LED on this board wired through the
MCU.

The LED is wired directly to the on-board MCU controller
and is toggled using an MCU command.

Support for more LEDs is going to be added in case more
boards implement this microcontroller, as LEDs use many
different GPIOs.

This driver depends on the iEi WT61P803 PUZZLE MFD driver.

Signed-off-by: Luka Kovacic <luka.kovacic@sartura.hr>
Cc: Luka Perkov <luka.perkov@sartura.hr>
Cc: Robert Marko <robert.marko@sartura.hr>
---
 drivers/leds/Kconfig                    |   8 ++
 drivers/leds/Makefile                   |   1 +
 drivers/leds/leds-iei-wt61p803-puzzle.c | 147 ++++++++++++++++++++++++
 3 files changed, 156 insertions(+)
 create mode 100644 drivers/leds/leds-iei-wt61p803-puzzle.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 1c181df24eae..8a25fb753dec 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -332,6 +332,14 @@ config LEDS_IPAQ_MICRO
 	  Choose this option if you want to use the notification LED on
 	  Compaq/HP iPAQ h3100 and h3600.
 
+config LEDS_IEI_WT61P803_PUZZLE
+	tristate "LED Support for the iEi WT61P803 PUZZLE MCU"
+	depends on LEDS_CLASS
+	depends on MFD_IEI_WT61P803_PUZZLE
+	help
+	  This option enables support for LEDs controlled by the iEi WT61P803
+	  M801 MCU.
+
 config LEDS_HP6XX
 	tristate "LED Support for the HP Jornada 6xx"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index c2c7d7ade0d0..cd362437fefd 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_LEDS_HP6XX)		+= leds-hp6xx.o
 obj-$(CONFIG_LEDS_INTEL_SS4200)		+= leds-ss4200.o
 obj-$(CONFIG_LEDS_IP30)			+= leds-ip30.o
 obj-$(CONFIG_LEDS_IPAQ_MICRO)		+= leds-ipaq-micro.o
+obj-$(CONFIG_LEDS_IEI_WT61P803_PUZZLE)	+= leds-iei-wt61p803-puzzle.o
 obj-$(CONFIG_LEDS_IS31FL319X)		+= leds-is31fl319x.o
 obj-$(CONFIG_LEDS_IS31FL32XX)		+= leds-is31fl32xx.o
 obj-$(CONFIG_LEDS_KTD2692)		+= leds-ktd2692.o
diff --git a/drivers/leds/leds-iei-wt61p803-puzzle.c b/drivers/leds/leds-iei-wt61p803-puzzle.c
new file mode 100644
index 000000000000..ca5c19c9df8c
--- /dev/null
+++ b/drivers/leds/leds-iei-wt61p803-puzzle.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* iEi WT61P803 PUZZLE MCU LED Driver
+ *
+ * Copyright (C) 2020 Sartura Ltd.
+ * Author: Luka Kovacic <luka.kovacic@sartura.hr>
+ */
+
+#include <linux/leds.h>
+#include <linux/mfd/iei-wt61p803-puzzle.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+
+enum iei_wt61p803_puzzle_led_state {
+	IEI_LED_OFF = 0x30,
+	IEI_LED_ON = 0x31,
+	IEI_LED_BLINK_5HZ = 0x32,
+	IEI_LED_BLINK_1HZ = 0x33,
+};
+
+/**
+ * struct iei_wt61p803_puzzle_led - MCU LED Driver
+ *
+ * @cdev:		LED classdev
+ * @mcu:		MCU struct pointer
+ * @response_buffer	Global MCU response buffer allocation
+ * @lock:		General mutex lock to protect simultaneous R/W access to led_power_state
+ * @led_power_state:	State of the front panel power LED
+ */
+struct iei_wt61p803_puzzle_led {
+	struct led_classdev cdev;
+	struct iei_wt61p803_puzzle *mcu;
+	unsigned char *response_buffer;
+	struct mutex lock;
+	int led_power_state;
+};
+
+static inline struct iei_wt61p803_puzzle_led *cdev_to_iei_wt61p803_puzzle_led
+	(struct led_classdev *led_cdev)
+{
+	return container_of(led_cdev, struct iei_wt61p803_puzzle_led, cdev);
+}
+
+static int iei_wt61p803_puzzle_led_brightness_set_blocking(struct led_classdev *cdev,
+							   enum led_brightness brightness)
+{
+	struct iei_wt61p803_puzzle_led *priv = cdev_to_iei_wt61p803_puzzle_led(cdev);
+	unsigned char *resp_buf = priv->response_buffer;
+	unsigned char led_power_cmd[5] = {};
+	size_t reply_size;
+
+	led_power_cmd[0] = IEI_WT61P803_PUZZLE_CMD_HEADER_START;
+	led_power_cmd[1] = IEI_WT61P803_PUZZLE_CMD_LED;
+	led_power_cmd[2] = IEI_WT61P803_PUZZLE_CMD_LED_POWER;
+	led_power_cmd[3] = brightness == LED_OFF ? IEI_LED_OFF : IEI_LED_ON;
+
+	mutex_lock(&priv->lock);
+	priv->led_power_state = brightness;
+	mutex_unlock(&priv->lock);
+
+	return iei_wt61p803_puzzle_write_command(priv->mcu, led_power_cmd,
+			sizeof(led_power_cmd), resp_buf, &reply_size);
+}
+
+static enum led_brightness iei_wt61p803_puzzle_led_brightness_get(struct led_classdev *cdev)
+{
+	struct iei_wt61p803_puzzle_led *priv = cdev_to_iei_wt61p803_puzzle_led(cdev);
+	int led_state;
+
+	mutex_lock(&priv->lock);
+	led_state = priv->led_power_state;
+	mutex_unlock(&priv->lock);
+
+	return led_state;
+}
+
+static int iei_wt61p803_puzzle_led_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev->parent);
+	struct iei_wt61p803_puzzle_led *priv;
+	struct led_init_data init_data = {};
+	struct fwnode_handle *child;
+	int ret;
+	u32 reg;
+
+	if (device_get_child_node_count(dev) != 1)
+		return -EINVAL;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->response_buffer = devm_kzalloc(dev, IEI_WT61P803_PUZZLE_BUF_SIZE, GFP_KERNEL);
+	if (!priv->response_buffer)
+		return -ENOMEM;
+
+	priv->mcu = mcu;
+	priv->led_power_state = 1;
+	mutex_init(&priv->lock);
+	dev_set_drvdata(dev, priv);
+
+	child = device_get_next_child_node(dev, NULL);
+
+	ret = fwnode_property_read_u32(child, "reg", &reg);
+	if (ret || reg > 1) {
+		dev_err(dev, "Could not register 'reg' (%u)\n", reg);
+		ret = -EINVAL;
+		goto err_child_node;
+	}
+
+	priv->cdev.brightness_set_blocking = iei_wt61p803_puzzle_led_brightness_set_blocking;
+	priv->cdev.brightness_get = iei_wt61p803_puzzle_led_brightness_get;
+	priv->cdev.max_brightness = 1;
+	init_data.fwnode = child;
+
+	ret = devm_led_classdev_register_ext(dev, &priv->cdev, &init_data);
+	if (ret) {
+		dev_err(dev, "Could not register LED\n");
+		goto err_child_node;
+	}
+err_child_node:
+	fwnode_handle_put(child);
+	return ret;
+}
+
+static const struct of_device_id iei_wt61p803_puzzle_led_of_match[] = {
+	{ .compatible = "iei,wt61p803-puzzle-leds" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, iei_wt61p803_puzzle_led_of_match);
+
+static struct platform_driver iei_wt61p803_puzzle_led_driver = {
+	.driver = {
+		.name = "iei-wt61p803-puzzle-led",
+		.of_match_table = iei_wt61p803_puzzle_led_of_match,
+	},
+	.probe = iei_wt61p803_puzzle_led_probe,
+};
+module_platform_driver(iei_wt61p803_puzzle_led_driver);
+
+MODULE_DESCRIPTION("iEi WT61P803 PUZZLE front panel LED driver");
+MODULE_AUTHOR("Luka Kovacic <luka.kovacic@sartura.hr>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:leds-iei-wt61p803-puzzle");
-- 
2.26.2