leds: Add Spreadtrum SC27xx breathing light controller driver

This patch adds Spreadtrum SC27xx PMIC series breathing light controller
driver, which can support 3 LEDs. Each LED can work at normal PWM mode
and breathing mode.

Signed-off-by: Xiaotong Lu <xiaotong.lu@spreadtrum.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

3 files changed, 256 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 5831814d01d0..cfeb5fb28c2d 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -660,6 +660,17 @@ config LEDS_IS31FL32XX
           LED controllers. They are I2C devices with multiple constant-current
           channels, each with independent 256-level PWM control.
 
+config LEDS_SC27XX_BLTC
+        tristate "LED support for the SC27xx breathing light controller"
+        depends on LEDS_CLASS && MFD_SC27XX_PMIC
+        depends on OF
+        help
+          Say Y here to include support for the SC27xx breathing light controller
+          LEDs.
+
+          This driver can also be built as a module. If so the module will be
+          called leds-sc27xx-bltc.
+
 comment "LED driver for blink(1) USB RGB LED is under Special HID drivers (HID_THINGM)"
 
 config LEDS_BLINKM
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 0176e7335994..2f7b5c31dc98 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -76,6 +76,7 @@ obj-$(CONFIG_LEDS_MLXREG)		+= leds-mlxreg.o
 obj-$(CONFIG_LEDS_NIC78BX)              += leds-nic78bx.o
 obj-$(CONFIG_LEDS_MT6323)               += leds-mt6323.o
 obj-$(CONFIG_LEDS_LM3692X)              += leds-lm3692x.o
+obj-$(CONFIG_LEDS_SC27XX_BLTC)          += leds-sc27xx-bltc.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_CR0014114)            += leds-cr0014114.o
diff --git a/drivers/leds/leds-sc27xx-bltc.c b/drivers/leds/leds-sc27xx-bltc.c
new file mode 100644
index 000000000000..54a90c8781b6
--- /dev/null
+++ b/drivers/leds/leds-sc27xx-bltc.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Spreadtrum Communications Inc.
+
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <uapi/linux/uleds.h>
+
+/* PMIC global control register definition */
+#define SC27XX_MODULE_EN0       0xc08
+#define SC27XX_CLK_EN0          0xc18
+#define SC27XX_RGB_CTRL         0xebc
+
+#define SC27XX_BLTC_EN          BIT(9)
+#define SC27XX_RTC_EN           BIT(7)
+#define SC27XX_RGB_PD           BIT(0)
+
+/* Breathing light controller register definition */
+#define SC27XX_LEDS_CTRL        0x00
+#define SC27XX_LEDS_PRESCALE    0x04
+#define SC27XX_LEDS_DUTY        0x08
+#define SC27XX_LEDS_CURVE0      0x0c
+#define SC27XX_LEDS_CURVE1      0x10
+
+#define SC27XX_CTRL_SHIFT       4
+#define SC27XX_LED_RUN          BIT(0)
+#define SC27XX_LED_TYPE         BIT(1)
+
+#define SC27XX_DUTY_SHIFT       8
+#define SC27XX_DUTY_MASK        GENMASK(15, 0)
+#define SC27XX_MOD_MASK         GENMASK(7, 0)
+
+#define SC27XX_LEDS_OFFSET      0x10
+#define SC27XX_LEDS_MAX         3
+
+struct sc27xx_led {
+        char name[LED_MAX_NAME_SIZE];
+        struct led_classdev ldev;
+        struct sc27xx_led_priv *priv;
+        u8 line;
+        bool active;
+};
+
+struct sc27xx_led_priv {
+        struct sc27xx_led leds[SC27XX_LEDS_MAX];
+        struct regmap *regmap;
+        struct mutex lock;
+        u32 base;
+};
+
+#define to_sc27xx_led(ldev) \
+        container_of(ldev, struct sc27xx_led, ldev)
+
+static int sc27xx_led_init(struct regmap *regmap)
+{
+        int err;
+
+        err = regmap_update_bits(regmap, SC27XX_MODULE_EN0, SC27XX_BLTC_EN,
+                                 SC27XX_BLTC_EN);
+        if (err)
+                return err;
+
+        err = regmap_update_bits(regmap, SC27XX_CLK_EN0, SC27XX_RTC_EN,
+                                 SC27XX_RTC_EN);
+        if (err)
+                return err;
+
+        return regmap_update_bits(regmap, SC27XX_RGB_CTRL, SC27XX_RGB_PD, 0);
+}
+
+static u32 sc27xx_led_get_offset(struct sc27xx_led *leds)
+{
+        return leds->priv->base + SC27XX_LEDS_OFFSET * leds->line;
+}
+
+static int sc27xx_led_enable(struct sc27xx_led *leds, enum led_brightness value)
+{
+        u32 base = sc27xx_led_get_offset(leds);
+        u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
+        u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
+        struct regmap *regmap = leds->priv->regmap;
+        int err;
+
+        err = regmap_update_bits(regmap, base + SC27XX_LEDS_DUTY,
+                                 SC27XX_DUTY_MASK,
+                                 (value << SC27XX_DUTY_SHIFT) |
+                                 SC27XX_MOD_MASK);
+        if (err)
+                return err;
+
+        return regmap_update_bits(regmap, ctrl_base,
+                        (SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift,
+                        (SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift);
+}
+
+static int sc27xx_led_disable(struct sc27xx_led *leds)
+{
+        struct regmap *regmap = leds->priv->regmap;
+        u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
+        u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
+
+        return regmap_update_bits(regmap, ctrl_base,
+                        (SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift, 0);
+}
+
+static int sc27xx_led_set(struct led_classdev *ldev, enum led_brightness value)
+{
+        struct sc27xx_led *leds = to_sc27xx_led(ldev);
+        int err;
+
+        mutex_lock(&leds->priv->lock);
+
+        if (value == LED_OFF)
+                err = sc27xx_led_disable(leds);
+        else
+                err = sc27xx_led_enable(leds, value);
+
+        mutex_unlock(&leds->priv->lock);
+
+        return err;
+}
+
+static int sc27xx_led_register(struct device *dev, struct sc27xx_led_priv *priv)
+{
+        int i, err;
+
+        err = sc27xx_led_init(priv->regmap);
+        if (err)
+                return err;
+
+        for (i = 0; i < SC27XX_LEDS_MAX; i++) {
+                struct sc27xx_led *led = &priv->leds[i];
+
+                if (!led->active)
+                        continue;
+
+                led->line = i;
+                led->priv = priv;
+                led->ldev.name = led->name;
+                led->ldev.brightness_set_blocking = sc27xx_led_set;
+
+                err = devm_led_classdev_register(dev, &led->ldev);
+                if (err)
+                        return err;
+        }
+
+        return 0;
+}
+
+static int sc27xx_led_probe(struct platform_device *pdev)
+{
+        struct device *dev = &pdev->dev;
+        struct device_node *np = dev->of_node, *child;
+        struct sc27xx_led_priv *priv;
+        const char *str;
+        u32 base, count, reg;
+        int err;
+
+        count = of_get_child_count(np);
+        if (!count || count > SC27XX_LEDS_MAX)
+                return -EINVAL;
+
+        err = of_property_read_u32(np, "reg", &base);
+        if (err) {
+                dev_err(dev, "fail to get reg of property\n");
+                return err;
+        }
+
+        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+        if (!priv)
+                return -ENOMEM;
+
+        platform_set_drvdata(pdev, priv);
+        mutex_init(&priv->lock);
+        priv->base = base;
+        priv->regmap = dev_get_regmap(dev->parent, NULL);
+        if (IS_ERR(priv->regmap)) {
+                err = PTR_ERR(priv->regmap);
+                dev_err(dev, "failed to get regmap: %d\n", err);
+                return err;
+        }
+
+        for_each_child_of_node(np, child) {
+                err = of_property_read_u32(child, "reg", &reg);
+                if (err) {
+                        of_node_put(child);
+                        mutex_destroy(&priv->lock);
+                        return err;
+                }
+
+                if (reg >= SC27XX_LEDS_MAX || priv->leds[reg].active) {
+                        of_node_put(child);
+                        mutex_destroy(&priv->lock);
+                        return -EINVAL;
+                }
+
+                priv->leds[reg].active = true;
+
+                err = of_property_read_string(child, "label", &str);
+                if (err)
+                        snprintf(priv->leds[reg].name, LED_MAX_NAME_SIZE,
+                                 "sc27xx::");
+                else
+                        snprintf(priv->leds[reg].name, LED_MAX_NAME_SIZE,
+                                 "sc27xx:%s", str);
+        }
+
+        err = sc27xx_led_register(dev, priv);
+        if (err)
+                mutex_destroy(&priv->lock);
+
+        return err;
+}
+
+static int sc27xx_led_remove(struct platform_device *pdev)
+{
+        struct sc27xx_led_priv *priv = platform_get_drvdata(pdev);
+
+        mutex_destroy(&priv->lock);
+        return 0;
+}
+
+static const struct of_device_id sc27xx_led_of_match[] = {
+        { .compatible = "sprd,sc2731-bltc", },
+        { }
+};
+MODULE_DEVICE_TABLE(of, sc27xx_led_of_match);
+
+static struct platform_driver sc27xx_led_driver = {
+        .driver = {
+                .name = "sprd-bltc",
+                .of_match_table = sc27xx_led_of_match,
+        },
+        .probe = sc27xx_led_probe,
+        .remove = sc27xx_led_remove,
+};
+
+module_platform_driver(sc27xx_led_driver);
+
+MODULE_DESCRIPTION("Spreadtrum SC27xx breathing light controller driver");
+MODULE_AUTHOR("Xiaotong Lu <xiaotong.lu@spreadtrum.com>");
+MODULE_LICENSE("GPL v2");