2 files changed, 143 insertions, 0 deletions

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 000000000000..45b1e605d355
--- /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 9d9b7aab843f..fecf27fb1cdc 100644
--- 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");