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Subject[PATCH 1/2] leds/lm3530: calibrate ALS input voltage
Date
From: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>

This patch provides the support for auto calibration of ALS Zone
boundaries based on min/max ALS input voltage.

Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/leds/leds-lm3530.c | 67 ++++++++++++++++++++++++++++++++++---------
include/linux/led-lm3530.h | 5 +++
2 files changed, 58 insertions(+), 14 deletions(-)

diff --git a/drivers/leds/leds-lm3530.c b/drivers/leds/leds-lm3530.c
index 4d7ce76..3dd7090 100644
--- a/drivers/leds/leds-lm3530.c
+++ b/drivers/leds/leds-lm3530.c
@@ -68,17 +68,16 @@
#define LM3530_ALS2_IMP_SHIFT (4)

/* Zone Boundary Register defaults */
-#define LM3530_DEF_ZB_0 (0x33)
-#define LM3530_DEF_ZB_1 (0x66)
-#define LM3530_DEF_ZB_2 (0x99)
-#define LM3530_DEF_ZB_3 (0xCC)
+#define LM3530_ALS_ZB_MAX (4)
+#define LM3530_ALS_WINDOW_mV (1000)
+#define LM3530_ALS_OFFSET_mV (4)

/* Zone Target Register defaults */
-#define LM3530_DEF_ZT_0 (0x19)
-#define LM3530_DEF_ZT_1 (0x33)
+#define LM3530_DEF_ZT_0 (0x7F)
+#define LM3530_DEF_ZT_1 (0x66)
#define LM3530_DEF_ZT_2 (0x4C)
-#define LM3530_DEF_ZT_3 (0x66)
-#define LM3530_DEF_ZT_4 (0x7F)
+#define LM3530_DEF_ZT_3 (0x33)
+#define LM3530_DEF_ZT_4 (0x19)

struct lm3530_mode_map {
const char *mode;
@@ -150,6 +149,8 @@ static int lm3530_init_registers(struct lm3530_data *drvdata)
u8 als_imp_sel = 0;
u8 brightness;
u8 reg_val[LM3530_REG_MAX];
+ u8 zones[LM3530_ALS_ZB_MAX];
+ u32 als_vmin, als_vmax, als_vstep;
struct lm3530_platform_data *pltfm = drvdata->pdata;
struct i2c_client *client = drvdata->client;

@@ -161,6 +162,26 @@ static int lm3530_init_registers(struct lm3530_data *drvdata)
gen_config |= (LM3530_ENABLE_I2C);

if (drvdata->mode == LM3530_BL_MODE_ALS) {
+ if (pltfm->als_vmax == 0) {
+ pltfm->als_vmin = als_vmin = 0;
+ pltfm->als_vmin = als_vmax = LM3530_ALS_WINDOW_mV;
+ }
+
+ als_vmin = pltfm->als_vmin;
+ als_vmax = pltfm->als_vmax;
+
+ if ((als_vmax - als_vmin) > LM3530_ALS_WINDOW_mV)
+ pltfm->als_vmax = als_vmax =
+ als_vmin + LM3530_ALS_WINDOW_mV;
+
+ /* n zone boundary makes n+1 zones */
+ als_vstep = (als_vmax - als_vmin) / (LM3530_ALS_ZB_MAX + 1);
+
+ for (i = 0; i < LM3530_ALS_ZB_MAX; i++)
+ zones[i] = (((als_vmin + LM3530_ALS_OFFSET_mV) +
+ als_vstep + (i * als_vstep)) * LED_FULL)
+ / 1000;
+
als_config =
(pltfm->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) |
(LM3530_ENABLE_ALS) |
@@ -169,6 +190,7 @@ static int lm3530_init_registers(struct lm3530_data *drvdata)
als_imp_sel =
(pltfm->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) |
(pltfm->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT);
+
}

if (drvdata->mode == LM3530_BL_MODE_PWM)
@@ -190,10 +212,10 @@ static int lm3530_init_registers(struct lm3530_data *drvdata)
reg_val[3] = 0x00; /* LM3530_ALS_ZONE_REG */
reg_val[4] = als_imp_sel; /* LM3530_ALS_IMP_SELECT */
reg_val[5] = brightness; /* LM3530_BRT_CTRL_REG */
- reg_val[6] = LM3530_DEF_ZB_0; /* LM3530_ALS_ZB0_REG */
- reg_val[7] = LM3530_DEF_ZB_1; /* LM3530_ALS_ZB1_REG */
- reg_val[8] = LM3530_DEF_ZB_2; /* LM3530_ALS_ZB2_REG */
- reg_val[9] = LM3530_DEF_ZB_3; /* LM3530_ALS_ZB3_REG */
+ reg_val[6] = zones[0]; /* LM3530_ALS_ZB0_REG */
+ reg_val[7] = zones[1]; /* LM3530_ALS_ZB1_REG */
+ reg_val[8] = zones[2]; /* LM3530_ALS_ZB2_REG */
+ reg_val[9] = zones[3]; /* LM3530_ALS_ZB3_REG */
reg_val[10] = LM3530_DEF_ZT_0; /* LM3530_ALS_Z0T_REG */
reg_val[11] = LM3530_DEF_ZT_1; /* LM3530_ALS_Z1T_REG */
reg_val[12] = LM3530_DEF_ZT_2; /* LM3530_ALS_Z2T_REG */
@@ -265,6 +287,24 @@ static void lm3530_brightness_set(struct led_classdev *led_cdev,
}
}

+static ssize_t lm3530_mode_get(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct i2c_client *client = container_of(
+ dev->parent, struct i2c_client, dev);
+ struct lm3530_data *drvdata = i2c_get_clientdata(client);
+ int i, len = 0;
+
+ for (i = 0; i < ARRAY_SIZE(mode_map); i++)
+ if (drvdata->mode == mode_map[i].mode_val)
+ len += sprintf(buf + len, "[%s] ", mode_map[i].mode);
+ else
+ len += sprintf(buf + len, "%s ", mode_map[i].mode);
+
+ len += sprintf(buf + len, "\n");
+
+ return len;
+}

static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
*attr, const char *buf, size_t size)
@@ -298,8 +338,7 @@ static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute

return sizeof(drvdata->mode);
}
-
-static DEVICE_ATTR(mode, 0644, NULL, lm3530_mode_set);
+static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set);

static int __devinit lm3530_probe(struct i2c_client *client,
const struct i2c_device_id *id)
diff --git a/include/linux/led-lm3530.h b/include/linux/led-lm3530.h
index 58592fa..8eb1235 100644
--- a/include/linux/led-lm3530.h
+++ b/include/linux/led-lm3530.h
@@ -84,6 +84,8 @@ enum lm3530_als_mode {
* @brt_ramp_rise: rate of rise of led current
* @als1_resistor_sel: internal resistance from ALS1 input to ground
* @als2_resistor_sel: internal resistance from ALS2 input to ground
+ * @als_vmin: als input voltage calibrated for max brightness in mV
+ * @als_vmax: als input voltage calibrated for min brightness in mV
* @brt_val: brightness value (0-255)
*/
struct lm3530_platform_data {
@@ -101,6 +103,9 @@ struct lm3530_platform_data {
u8 als1_resistor_sel;
u8 als2_resistor_sel;

+ u32 als_vmin;
+ u32 als_vmax;
+
u8 brt_val;
};

--
1.7.3.2


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