leds: sc27xx: Add pattern_set/clear interfaces for LED controller

This patch implements the 'pattern_set'and 'pattern_clear'
interfaces to support SC27XX LED breathing mode.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Pavel Machek <pavel@ucw.c>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx b/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
new file mode 100644 (file)
index 0000000..45b1e60
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
@@ -0,0 +1,22 @@
+What:          /sys/class/leds/<led>/hw_pattern
+Date:          September 2018
+KernelVersion: 4.20
+Description:
+               Specify a hardware pattern for the SC27XX LED. For the SC27XX
+               LED controller, it only supports 4 stages to make a single
+               hardware pattern, which is used to configure the rise time,
+               high time, fall time and low time for the breathing mode.
+
+               For the breathing mode, the SC27XX LED only expects one brightness
+               for the high stage. To be compatible with the hardware pattern
+               format, we should set brightness as 0 for rise stage, fall
+               stage and low stage.
+
+               Min stage duration: 125 ms
+               Max stage duration: 31875 ms
+
+               Since the stage duration step is 125 ms, the duration should be
+               a multiplier of 125, like 125ms, 250ms, 375ms, 500ms ... 31875ms.
+
+               Thus the format of the hardware pattern values should be:
+               "0 rise_duration brightness high_duration 0 fall_duration 0 low_duration".

diff --git a/drivers/leds/leds-sc27xx-bltc.c b/drivers/leds/leds-sc27xx-bltc.c
index 9d9b7aa..fecf27f 100644 (file)
--- a/drivers/leds/leds-sc27xx-bltc.c
+++ b/drivers/leds/leds-sc27xx-bltc.c
@@ -32,8 +32,18 @@
 #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_PATTERN_CNT        4
+/* Stage duration step, in milliseconds */
+#define SC27XX_LEDS_STEP       125
+/* Minimum and maximum duration, in milliseconds */
+#define SC27XX_DELTA_T_MIN     SC27XX_LEDS_STEP
+#define SC27XX_DELTA_T_MAX     (SC27XX_LEDS_STEP * 255)
 
 struct sc27xx_led {
        char name[LED_MAX_NAME_SIZE];
@@ -122,6 +132,113 @@ static int sc27xx_led_set(struct led_classdev *ldev, enum led_brightness value)
        return err;
 }
 
+static void sc27xx_led_clamp_align_delta_t(u32 *delta_t)
+{
+       u32 v, offset, t = *delta_t;
+
+       v = t + SC27XX_LEDS_STEP / 2;
+       v = clamp_t(u32, v, SC27XX_DELTA_T_MIN, SC27XX_DELTA_T_MAX);
+       offset = v - SC27XX_DELTA_T_MIN;
+       offset = SC27XX_LEDS_STEP * (offset / SC27XX_LEDS_STEP);
+
+       *delta_t = SC27XX_DELTA_T_MIN + offset;
+}
+
+static int sc27xx_led_pattern_clear(struct led_classdev *ldev)
+{
+       struct sc27xx_led *leds = to_sc27xx_led(ldev);
+       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;
+
+       mutex_lock(&leds->priv->lock);
+
+       /* Reset the rise, high, fall and low time to zero. */
+       regmap_write(regmap, base + SC27XX_LEDS_CURVE0, 0);
+       regmap_write(regmap, base + SC27XX_LEDS_CURVE1, 0);
+
+       err = regmap_update_bits(regmap, ctrl_base,
+                       (SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift, 0);
+
+       ldev->brightness = LED_OFF;
+
+       mutex_unlock(&leds->priv->lock);
+
+       return err;
+}
+
+static int sc27xx_led_pattern_set(struct led_classdev *ldev,
+                                 struct led_pattern *pattern,
+                                 u32 len, int repeat)
+{
+       struct sc27xx_led *leds = to_sc27xx_led(ldev);
+       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;
+
+       /*
+        * Must contain 4 tuples to configure the rise time, high time, fall
+        * time and low time to enable the breathing mode.
+        */
+       if (len != SC27XX_LEDS_PATTERN_CNT)
+               return -EINVAL;
+
+       mutex_lock(&leds->priv->lock);
+
+       sc27xx_led_clamp_align_delta_t(&pattern[0].delta_t);
+       err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
+                                SC27XX_CURVE_L_MASK,
+                                pattern[0].delta_t / SC27XX_LEDS_STEP);
+       if (err)
+               goto out;
+
+       sc27xx_led_clamp_align_delta_t(&pattern[1].delta_t);
+       err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
+                                SC27XX_CURVE_L_MASK,
+                                pattern[1].delta_t / SC27XX_LEDS_STEP);
+       if (err)
+               goto out;
+
+       sc27xx_led_clamp_align_delta_t(&pattern[2].delta_t);
+       err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
+                                SC27XX_CURVE_H_MASK,
+                                (pattern[2].delta_t / SC27XX_LEDS_STEP) <<
+                                SC27XX_CURVE_SHIFT);
+       if (err)
+               goto out;
+
+       sc27xx_led_clamp_align_delta_t(&pattern[3].delta_t);
+       err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
+                                SC27XX_CURVE_H_MASK,
+                                (pattern[3].delta_t / SC27XX_LEDS_STEP) <<
+                                SC27XX_CURVE_SHIFT);
+       if (err)
+               goto out;
+
+       err = regmap_update_bits(regmap, base + SC27XX_LEDS_DUTY,
+                                SC27XX_DUTY_MASK,
+                                (pattern[1].brightness << SC27XX_DUTY_SHIFT) |
+                                SC27XX_MOD_MASK);
+       if (err)
+               goto out;
+
+       /* Enable the LED breathing mode */
+       err = regmap_update_bits(regmap, ctrl_base,
+                                SC27XX_LED_RUN << ctrl_shift,
+                                SC27XX_LED_RUN << ctrl_shift);
+       if (!err)
+               ldev->brightness = pattern[1].brightness;
+
+out:
+       mutex_unlock(&leds->priv->lock);
+
+       return err;
+}
+
 static int sc27xx_led_register(struct device *dev, struct sc27xx_led_priv *priv)
 {
        int i, err;
@@ -140,6 +257,9 @@ static int sc27xx_led_register(struct device *dev, struct sc27xx_led_priv *priv)
                led->priv = priv;
                led->ldev.name = led->name;
                led->ldev.brightness_set_blocking = sc27xx_led_set;
+               led->ldev.pattern_set = sc27xx_led_pattern_set;
+               led->ldev.pattern_clear = sc27xx_led_pattern_clear;
+               led->ldev.default_trigger = "pattern";
 
                err = devm_led_classdev_register(dev, &led->ldev);
                if (err)
@@ -241,4 +361,5 @@ module_platform_driver(sc27xx_led_driver);
 
 MODULE_DESCRIPTION("Spreadtrum SC27xx breathing light controller driver");
 MODULE_AUTHOR("Xiaotong Lu <xiaotong.lu@spreadtrum.com>");
+MODULE_AUTHOR("Baolin Wang <baolin.wang@linaro.org>");
 MODULE_LICENSE("GPL v2");