[PATCH v3 2/2] leds: Add Spreadtrum SC27xx breathing light controller driver

From: Baolin Wang
Date: Wed May 09 2018 - 04:21:23 EST

From: Xiaotong Lu <xiaotong.lu@xxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxx>
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
---
Changes since v2:
- Add more description for the sysfs nodes.
- Change the sysfs nodes to RW.
- Reset the time values to 0 when disable the LED.
- Remove 'value' from 'struct sc27xx_led'.
- Add 'remove' interface to destroy mutex.
- Remove max_brightness setting when initializing the LED.
- Other coding style fixes.

Changes since v1:
- Add ABI documentation.
- Add mutex protection in case of concurrent access.
- Change the LED device name pattern.
- Fix build warning.
---
.../ABI/testing/sysfs-class-led-driver-sc27xx | 30 ++
drivers/leds/Kconfig | 11 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-sc27xx-bltc.c | 524 ++++++++++++++++++++
4 files changed, 566 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
create mode 100644 drivers/leds/leds-sc27xx-bltc.c

diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx b/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
new file mode 100644
index 0000000..ce9559f
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
@@ -0,0 +1,30 @@
+What: /sys/class/leds/<led>/rise_time
+What: /sys/class/leds/<led>/high_time
+What: /sys/class/leds/<led>/fall_time
+What: /sys/class/leds/<led>/low_time
+Date: May 2018
+KernelVersion: 4.18
+Contact: Xiaotong Lu <xiaotong.lu@xxxxxxxxxxxxxx>
+Description:
+ Set the pattern generator rise, high, fall and low
+ times (0..63). It's unit is 0.125s, it should be > 0.
+
+ 1 - 125 ms
+ 2 - 250 ms
+ 3 - 375 ms
+ ...
+ ...
+ ...
+ 62 - 7.75 s
+ 63 - 7.875 s
+
+ The LED can work at normal PWM mode or breathing mode.
+ For normal PWM mode, user just set the brightness value
+ to turn on/off the LED.
+
+ But for breathing mode, user not only need set the rise,
+ high, fall and low time, but also need set one brightness
+ value to turn on the breathing mode LED, and it will turn
+ off the breathing mode LED by setting brightness to 0, that
+ will also reset the rise, high, fall and low time values to
+ 0.
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 2c896c0..319449b 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -647,6 +647,17 @@ 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 91eca81..ff6917e 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_DAC124S085) += leds-dac124s085.o
diff --git a/drivers/leds/leds-sc27xx-bltc.c b/drivers/leds/leds-sc27xx-bltc.c
new file mode 100644
index 0000000..3061676
--- /dev/null
+++ b/drivers/leds/leds-sc27xx-bltc.c
@@ -0,0 +1,524 @@
+// 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_CURVE_SHIFT 8
+#define SC27XX_CURVE_L_MASK GENMASK(7, 0)
+#define SC27XX_CURVE_H_MASK GENMASK(15, 8)
+
+#define SC27XX_LEDS_OFFSET 0x10
+#define SC27XX_LEDS_MAX 3
+#define SC27XX_LEDS_TIME_MAX 63
+
+/*
+ * The SC27xx breathing light controller can support 3 outputs: red LED,
+ * green LED and blue LED. Each LED can support normal PWM mode and breathing
+ * mode.
+ *
+ * In breathing mode, the LED output curve includes rise, high, fall and low 4
+ * stages, and the duration of each stage is configurable.
+ */
+enum sc27xx_led_config {
+ SC27XX_RISE_TIME,
+ SC27XX_FALL_TIME,
+ SC27XX_HIGH_TIME,
+ SC27XX_LOW_TIME,
+};
+
+struct sc27xx_led {
+ char name[LED_MAX_NAME_SIZE];
+ struct led_classdev ldev;
+ struct sc27xx_led_priv *priv;
+ u8 line;
+ bool breath_mode;
+ 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;
+
+ if (leds->breath_mode)
+ return regmap_update_bits(regmap, ctrl_base,
+ SC27XX_LED_RUN << ctrl_shift,
+ SC27XX_LED_RUN << ctrl_shift);
+
+ 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 base = sc27xx_led_get_offset(leds);
+ u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
+ u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
+ int err;
+
+ /* Reset the rise, high, fall and low time to zero. */
+ err = regmap_write(regmap, base + SC27XX_LEDS_CURVE0, 0);
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, base + SC27XX_LEDS_CURVE1, 0);
+ if (err)
+ return err;
+
+ leds->breath_mode = false;
+
+ return regmap_update_bits(leds->priv->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_set_config(struct sc27xx_led *leds,
+ enum sc27xx_led_config config, u32 val)
+{
+ u32 base = sc27xx_led_get_offset(leds);
+ struct regmap *regmap = leds->priv->regmap;
+ int err;
+
+ mutex_lock(&leds->priv->lock);
+
+ switch (config) {
+ case SC27XX_RISE_TIME:
+ err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
+ SC27XX_CURVE_L_MASK, val);
+ break;
+ case SC27XX_FALL_TIME:
+ err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
+ SC27XX_CURVE_H_MASK,
+ val << SC27XX_CURVE_SHIFT);
+ break;
+ case SC27XX_HIGH_TIME:
+ err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
+ SC27XX_CURVE_L_MASK, val);
+ break;
+ case SC27XX_LOW_TIME:
+ err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
+ SC27XX_CURVE_H_MASK,
+ val << SC27XX_CURVE_SHIFT);
+ break;
+ default:
+ err = -ENOTSUPP;
+ break;
+ }
+
+ if (!err && !leds->breath_mode)
+ leds->breath_mode = true;
+
+ mutex_unlock(&leds->priv->lock);
+
+ return err;
+}
+
+static int sc27xx_led_read_config(struct sc27xx_led *leds,
+ enum sc27xx_led_config config, u32 *val)
+{
+ u32 base = sc27xx_led_get_offset(leds);
+ struct regmap *regmap = leds->priv->regmap;
+ int err;
+
+ mutex_lock(&leds->priv->lock);
+
+ switch (config) {
+ case SC27XX_RISE_TIME:
+ err = regmap_read(regmap, base + SC27XX_LEDS_CURVE0, val);
+ if (err)
+ goto out;
+
+ *val &= SC27XX_CURVE_L_MASK;
+ break;
+ case SC27XX_FALL_TIME:
+ err = regmap_read(regmap, base + SC27XX_LEDS_CURVE0, val);
+ if (err)
+ goto out;
+
+ *val = (*val & SC27XX_CURVE_H_MASK) >> SC27XX_CURVE_SHIFT;
+ break;
+ case SC27XX_HIGH_TIME:
+ err = regmap_read(regmap, base + SC27XX_LEDS_CURVE1, val);
+ if (err)
+ goto out;
+
+ *val &= SC27XX_CURVE_L_MASK;
+ break;
+ case SC27XX_LOW_TIME:
+ err = regmap_read(regmap, base + SC27XX_LEDS_CURVE1, val);
+ if (err)
+ goto out;
+
+ *val = (*val & SC27XX_CURVE_H_MASK) >> SC27XX_CURVE_SHIFT;
+ break;
+ default:
+ err = -ENOTSUPP;
+ break;
+ }
+
+out:
+ mutex_unlock(&leds->priv->lock);
+
+ return err;
+}
+
+static ssize_t rise_time_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct led_classdev *ldev = dev_get_drvdata(dev);
+ struct sc27xx_led *leds = to_sc27xx_led(ldev);
+ u32 val;
+ int err;
+
+ if (kstrtou32(buf, 10, &val) || val > SC27XX_LEDS_TIME_MAX)
+ return -EINVAL;
+
+ err = sc27xx_led_set_config(leds, SC27XX_RISE_TIME, val);
+ if (err)
+ return err;
+
+ return size;
+}
+
+static ssize_t rise_time_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *ldev = dev_get_drvdata(dev);
+ struct sc27xx_led *leds = to_sc27xx_led(ldev);
+ u32 val;
+ int err;
+
+ err = sc27xx_led_read_config(leds, SC27XX_RISE_TIME, &val);
+ if (err)
+ return err;
+
+ return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t fall_time_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct led_classdev *ldev = dev_get_drvdata(dev);
+ struct sc27xx_led *leds = to_sc27xx_led(ldev);
+ u32 val;
+ int err;
+
+ if (kstrtou32(buf, 10, &val) || val > SC27XX_LEDS_TIME_MAX)
+ return -EINVAL;
+
+ err = sc27xx_led_set_config(leds, SC27XX_FALL_TIME, val);
+ if (err)
+ return err;
+
+ return size;
+}
+
+static ssize_t fall_time_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *ldev = dev_get_drvdata(dev);
+ struct sc27xx_led *leds = to_sc27xx_led(ldev);
+ u32 val;
+ int err;
+
+ err = sc27xx_led_read_config(leds, SC27XX_FALL_TIME, &val);
+ if (err)
+ return err;
+
+ return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t high_time_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct led_classdev *ldev = dev_get_drvdata(dev);
+ struct sc27xx_led *leds = to_sc27xx_led(ldev);
+ u32 val;
+ int err;
+
+ if (kstrtou32(buf, 10, &val) || val > SC27XX_LEDS_TIME_MAX)
+ return -EINVAL;
+
+ err = sc27xx_led_set_config(leds, SC27XX_HIGH_TIME, val);
+ if (err)
+ return err;
+
+ return size;
+}
+
+static ssize_t high_time_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *ldev = dev_get_drvdata(dev);
+ struct sc27xx_led *leds = to_sc27xx_led(ldev);
+ u32 val;
+ int err;
+
+ err = sc27xx_led_read_config(leds, SC27XX_HIGH_TIME, &val);
+ if (err)
+ return err;
+
+ return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t low_time_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct led_classdev *ldev = dev_get_drvdata(dev);
+ struct sc27xx_led *leds = to_sc27xx_led(ldev);
+ u32 val;
+ int err;
+
+ if (kstrtou32(buf, 10, &val) || val > SC27XX_LEDS_TIME_MAX)
+ return -EINVAL;
+
+ err = sc27xx_led_set_config(leds, SC27XX_LOW_TIME, val);
+ if (err)
+ return err;
+
+ return size;
+}
+
+static ssize_t low_time_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *ldev = dev_get_drvdata(dev);
+ struct sc27xx_led *leds = to_sc27xx_led(ldev);
+ u32 val;
+ int err;
+
+ err = sc27xx_led_read_config(leds, SC27XX_LOW_TIME, &val);
+ if (err)
+ return err;
+
+ return sprintf(buf, "%u\n", val);
+}
+
+static DEVICE_ATTR_RW(rise_time);
+static DEVICE_ATTR_RW(fall_time);
+static DEVICE_ATTR_RW(high_time);
+static DEVICE_ATTR_RW(low_time);
+
+static struct attribute *sc27xx_led_attrs[] = {
+ &dev_attr_rise_time.attr,
+ &dev_attr_fall_time.attr,
+ &dev_attr_high_time.attr,
+ &dev_attr_low_time.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(sc27xx_led);
+
+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;
+ led->ldev.groups = sc27xx_led_groups;
+
+ 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@xxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5