mediatek: import driver for Adtran SmartRG RGBW LED

Import driver for I2C-connected HolTek MCU controlling the RGBW LED
found in Adtran SmartRG devices.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

1 files changed, 239 insertions, 0 deletions

diff --git a/target/linux/mediatek/files/drivers/leds/leds-smartrg-system.c b/target/linux/mediatek/files/drivers/leds/leds-smartrg-system.c
new file mode 100644
index 0000000000..1679555068
--- /dev/null
+++ b/target/linux/mediatek/files/drivers/leds/leds-smartrg-system.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/version.h>
+
+/**
+ * Driver for SmartRG RGBW LED microcontroller.
+ * RGBW LED is connected to a Holtek HT45F0062 that is on the I2C bus.
+ *
+ */
+
+struct srg_led_ctrl;
+struct srg_led {
+	u8 index;
+	struct led_classdev led;
+	struct srg_led_ctrl *ctrl;
+};
+
+struct srg_led_ctrl {
+	struct mutex lock;
+	struct i2c_client *client;
+	struct srg_led channel[4];
+	u8 control[5];
+};
+
+static int
+srg_led_i2c_write(struct srg_led_ctrl *sysled_ctrl, u8 reg, u8 value)
+{
+	return i2c_smbus_write_byte_data(sysled_ctrl->client, reg, value);
+}
+
+/*
+ * MC LED Command: 0 = OFF, 1 = ON, 2 = Flash, 3 = Pulse, 4 = Blink
+ * */
+static int
+srg_led_control_sync(struct srg_led_ctrl *sysled_ctrl)
+{
+	int i, ret;
+
+	for (i = 1; i < 5; i++) {
+		ret = srg_led_i2c_write(sysled_ctrl, i, sysled_ctrl->control[i]);
+		if (ret)
+			break;
+	}
+	return ret;
+}
+
+/*
+ * This function overrides the led driver timer trigger to offload
+ * flashing to the micro-controller.  The negative effect of this
+ * is the inability to configure the delay_on and delay_off periods.
+ *
+ * */
+static int
+srg_led_set_pulse(struct led_classdev *led_cdev,
+		  unsigned long *delay_on,
+		  unsigned long *delay_off)
+{
+	struct srg_led *sysled = container_of(led_cdev, struct srg_led, led);
+	struct srg_led_ctrl *sysled_ctrl = sysled->ctrl;
+	bool blinking = false, pulsing = false;
+	u8 cbyte;
+	int ret;
+
+	if (delay_on && delay_off && (*delay_on > 100) && (*delay_on <= 500)) {
+		pulsing = true;
+		*delay_on = 500;
+		*delay_off = 500;
+	} else if (delay_on && delay_off && (*delay_on >= 50) && (*delay_on <= 100)) {
+		blinking = true;
+		*delay_on = 50;
+		*delay_off = 50;
+	}
+
+	cbyte = pulsing ? 3 : blinking ? 2 : 0;
+	mutex_lock(&sysled_ctrl->lock);
+	ret = srg_led_i2c_write(sysled_ctrl, sysled->index + 4,
+				(blinking || pulsing) ? 255 : 0);
+	if (!ret) {
+		sysled_ctrl->control[sysled->index] = cbyte;
+		ret = srg_led_control_sync(sysled_ctrl);
+	}
+	mutex_unlock(&sysled_ctrl->lock);
+
+	return !cbyte;
+}
+
+static int
+srg_led_set_brightness(struct led_classdev *led_cdev,
+			enum led_brightness value)
+{
+	struct srg_led *sysled = container_of(led_cdev, struct srg_led, led);
+	struct srg_led_ctrl *sysled_ctrl = sysled->ctrl;
+	int ret;
+
+	mutex_lock(&sysled_ctrl->lock);
+	ret = srg_led_i2c_write(sysled_ctrl, sysled->index + 4, value);
+	if (!ret) {
+		sysled_ctrl->control[sysled->index] = !!value;
+		ret = srg_led_control_sync(sysled_ctrl);
+	}
+	mutex_unlock(&sysled_ctrl->lock);
+	return ret;
+}
+
+static int
+srg_led_init_led(struct srg_led_ctrl *sysled_ctrl, struct device_node *np)
+{
+	struct led_init_data init_data = {};
+	struct led_classdev *led_cdev;
+	struct srg_led *sysled;
+	int index, ret;
+
+	if (!np)
+		return -ENOENT;
+
+	ret = of_property_read_u32(np, "reg", &index);
+	if (ret) {
+		dev_err(&sysled_ctrl->client->dev,
+			"srg_led_init_led: no reg defined in np!\n");
+		return ret;
+	}
+
+	if (index < 1 || index > 4)
+		return -EINVAL;
+
+	sysled = &sysled_ctrl->channel[index - 1];
+	led_cdev = &sysled->led;
+
+	sysled->index = index;
+	sysled->ctrl = sysled_ctrl;
+
+	init_data.fwnode = of_fwnode_handle(np);
+
+	led_cdev->name = of_get_property(np, "label", NULL) ? : np->name;
+	led_cdev->brightness = LED_OFF;
+	led_cdev->max_brightness = LED_FULL;
+	led_cdev->brightness_set_blocking = srg_led_set_brightness;
+	led_cdev->blink_set = srg_led_set_pulse;
+
+	srg_led_i2c_write(sysled_ctrl, index + 4, 0);
+
+	ret = devm_led_classdev_register_ext(&sysled_ctrl->client->dev,
+						led_cdev, &init_data);
+	if (ret) {
+		dev_err(&sysled_ctrl->client->dev,
+			"srg_led_init_led: led register %s error ret %d!n",
+			led_cdev->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int
+srg_led_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct srg_led_ctrl *sysled_ctrl;
+
+	sysled_ctrl = devm_kzalloc(&client->dev, sizeof(*sysled_ctrl), GFP_KERNEL);
+	if (!sysled_ctrl)
+		return -ENOMEM;
+
+	sysled_ctrl->client = client;
+
+	mutex_init(&sysled_ctrl->lock);
+
+	i2c_set_clientdata(client, sysled_ctrl);
+
+	for_each_child_of_node(np, child) {
+		if (srg_led_init_led(sysled_ctrl, child))
+			continue;
+
+		msleep(5);
+	}
+
+	return srg_led_control_sync(sysled_ctrl);;
+}
+
+static void srg_led_disable(struct i2c_client *client)
+{
+	struct srg_led_ctrl *sysled_ctrl = i2c_get_clientdata(client);
+	int i;
+
+	for (i = 1; i < 10; i++)
+		srg_led_i2c_write(sysled_ctrl, i, 0);
+}
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,16,0)
+static void
+#else
+static int
+#endif
+srg_led_remove(struct i2c_client *client)
+{
+	struct srg_led_ctrl *sysled_ctrl = i2c_get_clientdata(client);
+
+	srg_led_disable(client);
+	mutex_destroy(&sysled_ctrl->lock);
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5,16,0)
+	return 0;
+#endif
+}
+
+static const struct i2c_device_id srg_led_id[] = {
+	{ "srg-sysled", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, srg_led_id);
+
+static const struct of_device_id of_srg_led_match[] = {
+	{ .compatible = "srg,sysled", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_srg_led_match);
+
+static struct i2c_driver srg_sysled_driver = {
+	.driver = {
+		.name	= "srg-sysled",
+		.of_match_table = of_srg_led_match,
+	},
+	.probe		= srg_led_probe,
+	.remove		= srg_led_remove,
+	.id_table	= srg_led_id,
+};
+module_i2c_driver(srg_sysled_driver);
+
+MODULE_DESCRIPTION("SmartRG system LED driver");
+MODULE_AUTHOR("Shen Loh <shen.loh@adtran.com>");
+MODULE_AUTHOR("Daniel Golle <daniel@makrotopia.org>");
+MODULE_LICENSE("GPL v2");