leds: cpcap: new driver

Motorola CPCAP is a PMIC (power management integrated circuit) found
in multiple smartphones. This driver adds support for the chip's LED
controllers. This introduces support for all controllers used by the
Droid 4. According to Motorola's driver (no datasheets available)
there a couple of more LED controllers. I did not add support for
them, since I cannot verify that they work with my modifications.

Signed-off-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

1 files changed, 239 insertions, 0 deletions

diff --git a/drivers/leds/leds-cpcap.c b/drivers/leds/leds-cpcap.c
new file mode 100644
index 000000000000..f0f28c442807
--- /dev/null
+++ b/drivers/leds/leds-cpcap.c
@@ -0,0 +1,239 @@
+/*
+ * Copyright (c) 2017 Sebastian Reichel <sre@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 or
+ * later as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/leds.h>
+#include <linux/mfd/motorola-cpcap.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#define CPCAP_LED_NO_CURRENT 0x0001
+
+struct cpcap_led_info {
+	u16 reg;
+	u16 mask;
+	u16 limit;
+	u16 init_mask;
+	u16 init_val;
+};
+
+static const struct cpcap_led_info cpcap_led_red = {
+	.reg	= CPCAP_REG_REDC,
+	.mask	= 0x03FF,
+	.limit	= 31,
+};
+
+static const struct cpcap_led_info cpcap_led_green = {
+	.reg	= CPCAP_REG_GREENC,
+	.mask	= 0x03FF,
+	.limit	= 31,
+};
+
+static const struct cpcap_led_info cpcap_led_blue = {
+	.reg	= CPCAP_REG_BLUEC,
+	.mask	= 0x03FF,
+	.limit	= 31,
+};
+
+/* aux display light */
+static const struct cpcap_led_info cpcap_led_adl = {
+	.reg		= CPCAP_REG_ADLC,
+	.mask		= 0x000F,
+	.limit		= 1,
+	.init_mask	= 0x7FFF,
+	.init_val	= 0x5FF0,
+};
+
+/* camera privacy led */
+static const struct cpcap_led_info cpcap_led_cp = {
+	.reg		= CPCAP_REG_CLEDC,
+	.mask		= 0x0007,
+	.limit		= 1,
+	.init_mask	= 0x03FF,
+	.init_val	= 0x0008,
+};
+
+struct cpcap_led {
+	struct led_classdev led;
+	const struct cpcap_led_info *info;
+	struct device *dev;
+	struct regmap *regmap;
+	struct mutex update_lock;
+	struct regulator *vdd;
+	bool powered;
+
+	u32 current_limit;
+};
+
+static u16 cpcap_led_val(u8 current_limit, u8 duty_cycle)
+{
+	current_limit &= 0x1f; /* 5 bit */
+	duty_cycle &= 0x0f; /* 4 bit */
+
+	return current_limit << 4 | duty_cycle;
+}
+
+static int cpcap_led_set_power(struct cpcap_led *led, bool status)
+{
+	int err;
+
+	if (status == led->powered)
+		return 0;
+
+	if (status)
+		err = regulator_enable(led->vdd);
+	else
+		err = regulator_disable(led->vdd);
+
+	if (err) {
+		dev_err(led->dev, "regulator failure: %d", err);
+		return err;
+	}
+
+	led->powered = status;
+
+	return 0;
+}
+
+static int cpcap_led_set(struct led_classdev *ledc, enum led_brightness value)
+{
+	struct cpcap_led *led = container_of(ledc, struct cpcap_led, led);
+	int brightness;
+	int err;
+
+	mutex_lock(&led->update_lock);
+
+	if (value > LED_OFF) {
+		err = cpcap_led_set_power(led, true);
+		if (err)
+			goto exit;
+	}
+
+	if (value == LED_OFF) {
+		/* Avoid HW issue by turning off current before duty cycle */
+		err = regmap_update_bits(led->regmap,
+			led->info->reg, led->info->mask, CPCAP_LED_NO_CURRENT);
+		if (err) {
+			dev_err(led->dev, "regmap failed: %d", err);
+			goto exit;
+		}
+
+		brightness = cpcap_led_val(value, LED_OFF);
+	} else {
+		brightness = cpcap_led_val(value, LED_ON);
+	}
+
+	err = regmap_update_bits(led->regmap, led->info->reg, led->info->mask,
+		brightness);
+	if (err) {
+		dev_err(led->dev, "regmap failed: %d", err);
+		goto exit;
+	}
+
+	if (value == LED_OFF) {
+		err = cpcap_led_set_power(led, false);
+		if (err)
+			goto exit;
+	}
+
+exit:
+	mutex_unlock(&led->update_lock);
+	return err;
+}
+
+static const struct of_device_id cpcap_led_of_match[] = {
+	{ .compatible = "motorola,cpcap-led-red", .data = &cpcap_led_red },
+	{ .compatible = "motorola,cpcap-led-green", .data = &cpcap_led_green },
+	{ .compatible = "motorola,cpcap-led-blue",  .data = &cpcap_led_blue },
+	{ .compatible = "motorola,cpcap-led-adl", .data = &cpcap_led_adl },
+	{ .compatible = "motorola,cpcap-led-cp", .data = &cpcap_led_cp },
+	{},
+};
+MODULE_DEVICE_TABLE(of, cpcap_led_of_match);
+
+static int cpcap_led_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+	struct cpcap_led *led;
+	int err;
+
+	match = of_match_device(of_match_ptr(cpcap_led_of_match), &pdev->dev);
+	if (!match || !match->data)
+		return -EINVAL;
+
+	led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
+	if (!led)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, led);
+	led->info = match->data;
+	led->dev = &pdev->dev;
+
+	if (led->info->reg == 0x0000) {
+		dev_err(led->dev, "Unsupported LED");
+		return -ENODEV;
+	}
+
+	led->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!led->regmap)
+		return -ENODEV;
+
+	led->vdd = devm_regulator_get(&pdev->dev, "vdd");
+	if (IS_ERR(led->vdd)) {
+		err = PTR_ERR(led->vdd);
+		dev_err(led->dev, "Couldn't get regulator: %d", err);
+		return err;
+	}
+
+	err = device_property_read_string(&pdev->dev, "label", &led->led.name);
+	if (err) {
+		dev_err(led->dev, "Couldn't read LED label: %d", err);
+		return err;
+	}
+
+	if (led->info->init_mask) {
+		err = regmap_update_bits(led->regmap, led->info->reg,
+			led->info->init_mask, led->info->init_val);
+		if (err) {
+			dev_err(led->dev, "regmap failed: %d", err);
+			return err;
+		}
+	}
+
+	mutex_init(&led->update_lock);
+
+	led->led.max_brightness = led->info->limit;
+	led->led.brightness_set_blocking = cpcap_led_set;
+	err = devm_led_classdev_register(&pdev->dev, &led->led);
+	if (err) {
+		dev_err(led->dev, "Couldn't register LED: %d", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static struct platform_driver cpcap_led_driver = {
+	.probe = cpcap_led_probe,
+	.driver = {
+		.name = "cpcap-led",
+		.of_match_table = cpcap_led_of_match,
+	},
+};
+module_platform_driver(cpcap_led_driver);
+
+MODULE_DESCRIPTION("CPCAP LED driver");
+MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
+MODULE_LICENSE("GPL");