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Commit d02fbd0d authored by Jishnu Prakash's avatar Jishnu Prakash
Browse files

backlight: qcom-spmi-wled: Add support for exponential dimming 



Add support to enable writing a lookup table of brightness values
into WLED_SINK peripheral to enable more granular control over
brightness, to help end user see brightness change smoothly
instead of in visible steps.

Change-Id: Ifd2dd382bf3e1274a5b994e8d83b87833c975970
Signed-off-by: default avatarJishnu Prakash <jprakash@codeaurora.org>
parent ff3868e2

drivers/video/backlight/qcom-spmi-wled.c

+109 −0
Original line number Original line Diff line number Diff line
@@ -180,6 +180,21 @@ 




#define  WLED5_SINK_FLASH_SHDN_CLR_REG	0xb6

#define  WLED5_SINK_FLASH_SHDN_CLR_REG	0xb6





#define WLED5_SINK_BRIGHTNESS_SLEW_RATE_CTL_REG	0xb8

#define WLED5_EN_SLEW_CTL	BIT(7)

#define WLED5_EN_EXP_LUT	BIT(6)



#define WLED5_SINK_DIMMING_EXP_LUT0_LSB_REG	0xc0

#define WLED5_SINK_DIMMING_EXP_LUT0_MSB_REG	0xc1

#define WLED5_SINK_DIMMING_EXP_LUT1_LSB_REG	0xc2

#define WLED5_SINK_DIMMING_EXP_LUT1_MSB_REG	0xc3

#define WLED5_SINK_DIMMING_EXP_LUT_LSB_MASK	GENMASK(7, 0)

#define WLED5_SINK_DIMMING_EXP_LUT_MSB_MASK	GENMASK(6, 0)



#define WLED5_SINK_EXP_LUT_INDEX_REG	0xc9



#define EXP_DIMMING_TABLE_SIZE	256



enum wled_version {

enum wled_version {

	WLED_PMI8998 = 4,

	WLED_PMI8998 = 4,

	WLED_PM660L,

	WLED_PM660L,
@@ -211,6 +226,7 @@ struct wled_config { 
	bool en_cabc;

	bool en_cabc;

	bool ext_pfet_sc_pro_en;

	bool ext_pfet_sc_pro_en;

	bool auto_calib_enabled;

	bool auto_calib_enabled;

	bool use_exp_dimming;

};

};





struct wled_flash_config {

struct wled_flash_config {
@@ -258,6 +274,7 @@ struct wled { 
	enum wled_flash_mode flash_mode;

	enum wled_flash_mode flash_mode;

	u8 num_strings;

	u8 num_strings;

	u32 leds_per_string;

	u32 leds_per_string;

	u32 exp_map[EXP_DIMMING_TABLE_SIZE];

};

};





enum wled5_mod_sel {

enum wled5_mod_sel {
@@ -1099,6 +1116,78 @@ static inline u8 get_wled_safety_time(int time_ms) 
	return 0;

	return 0;

}

}





static int wled_read_exp_dimming_map(struct device_node *node, struct wled *wled)

{

	int rc = 0, len;



	if (*wled->version != WLED_PM7325B) {

		pr_err("Exponential dimming not supported for WLED version %d\n", *wled->version);

		return 0;

	}



	len = of_property_count_elems_of_size(node, "qcom,exp-dimming-map", sizeof(u32));

	if (len != EXP_DIMMING_TABLE_SIZE) {

		pr_err("Invalid exponential map length: %d, must be 256 bytes length\n", len);

		return -EINVAL;

	}



	rc = of_property_read_u32_array(node, "qcom,exp-dimming-map",

					wled->exp_map, EXP_DIMMING_TABLE_SIZE);

	if (rc < 0)

		pr_err("Error in reading qcom,exp-dimming-map, rc=%d\n", rc);



	return rc;

}



static int wled_program_exp_dimming(struct wled *wled)

{

	int rc = 0, i;

	u8 val[4];



	if (*wled->version != WLED_PM7325B) {

		pr_err("Exponential dimming not supported for WLED version %d\n", *wled->version);

		return 0;

	}



	wled_module_enable(wled, 0);



	rc = regmap_update_bits(wled->regmap,

			wled->sink_addr + WLED5_SINK_BRIGHTNESS_SLEW_RATE_CTL_REG,

			WLED5_EN_EXP_LUT, WLED5_EN_EXP_LUT);

	if (rc < 0) {

		wled_module_enable(wled, 1);

		return rc;

	}



	for (i = 0; i < EXP_DIMMING_TABLE_SIZE / 2; i++) {

		val[0] = wled->exp_map[2 * i] & WLED5_SINK_DIMMING_EXP_LUT_LSB_MASK;

		val[1] = (wled->exp_map[2 * i] >> 8) & WLED5_SINK_DIMMING_EXP_LUT_MSB_MASK;

		val[2] = wled->exp_map[2 * i + 1] & WLED5_SINK_DIMMING_EXP_LUT_LSB_MASK;

		val[3] = (wled->exp_map[2 * i + 1] >> 8) & WLED5_SINK_DIMMING_EXP_LUT_MSB_MASK;



		rc = regmap_write(wled->regmap, wled->sink_addr + WLED5_SINK_EXP_LUT_INDEX_REG, i);

		if (rc < 0)

			goto exp_dimm_fail;



		rc = regmap_bulk_write(wled->regmap,

				wled->sink_addr + WLED5_SINK_DIMMING_EXP_LUT0_LSB_REG,

				val, sizeof(val));

		if (rc < 0)

			goto exp_dimm_fail;

	}



	wled_module_enable(wled, 1);

	return rc;



exp_dimm_fail:

	regmap_update_bits(wled->regmap,

			wled->sink_addr + WLED5_SINK_BRIGHTNESS_SLEW_RATE_CTL_REG,

			WLED5_EN_EXP_LUT, 0);



	wled_module_enable(wled, 1);

	return rc;

}



static int wled5_setup(struct wled *wled)

static int wled5_setup(struct wled *wled)

{

{

	int rc, temp, i;

	int rc, temp, i;
@@ -1199,6 +1288,14 @@ static int wled5_setup(struct wled *wled) 
	if (rc < 0)

	if (rc < 0)

		return rc;

		return rc;





	if (wled->cfg.use_exp_dimming) {

		rc = wled_program_exp_dimming(wled);

		if (rc < 0) {

			pr_err("Programming exponential dimming map failed, rc=%d\n", rc);

			return rc;

		}

	}



	if (wled->ovp_irq >= 0) {

	if (wled->ovp_irq >= 0) {

		rc = devm_request_threaded_irq(&wled->pdev->dev, wled->ovp_irq,

		rc = devm_request_threaded_irq(&wled->pdev->dev, wled->ovp_irq,

				NULL, wled_ovp_irq_handler, IRQF_ONESHOT,

				NULL, wled_ovp_irq_handler, IRQF_ONESHOT,
@@ -1374,6 +1471,7 @@ static const struct wled_config wled4_config_defaults = { 
	.en_cabc = 0,

	.en_cabc = 0,

	.ext_pfet_sc_pro_en = 0,

	.ext_pfet_sc_pro_en = 0,

	.auto_calib_enabled = 0,

	.auto_calib_enabled = 0,

	.use_exp_dimming = 0,

};

};





static const struct wled_config wled5_config_defaults = {

static const struct wled_config wled5_config_defaults = {
@@ -1387,6 +1485,7 @@ static const struct wled_config wled5_config_defaults = { 
	.en_cabc = 0,

	.en_cabc = 0,

	.ext_pfet_sc_pro_en = 0,

	.ext_pfet_sc_pro_en = 0,

	.auto_calib_enabled = 0,

	.auto_calib_enabled = 0,

	.use_exp_dimming = 0,

};

};





struct wled_var_cfg {

struct wled_var_cfg {
@@ -2252,6 +2351,7 @@ static int wled_configure(struct wled *wled, struct device *dev) 
		{ "qcom,en-cabc", &cfg->en_cabc, },

		{ "qcom,en-cabc", &cfg->en_cabc, },

		{ "qcom,ext-pfet-sc-pro", &cfg->ext_pfet_sc_pro_en, },

		{ "qcom,ext-pfet-sc-pro", &cfg->ext_pfet_sc_pro_en, },

		{ "qcom,auto-calibration", &cfg->auto_calib_enabled, },

		{ "qcom,auto-calibration", &cfg->auto_calib_enabled, },

		{ "qcom,use-exp-dimming", &cfg->use_exp_dimming, },

	};

	};





	prop_addr = of_get_address(dev->of_node, 0, NULL, NULL);

	prop_addr = of_get_address(dev->of_node, 0, NULL, NULL);
@@ -2324,6 +2424,15 @@ static int wled_configure(struct wled *wled, struct device *dev) 
			*bool_opts[i].val_ptr = true;

			*bool_opts[i].val_ptr = true;

	}

	}





	if (wled->cfg.use_exp_dimming) {

		rc = wled_read_exp_dimming_map(dev->of_node, wled);

		if (rc < 0) {

			dev_err(&wled->pdev->dev,

				"Reading exponential dimming map failed, rc=%d\n", rc);

			return rc;

		}

	}



	wled->sc_irq = platform_get_irq_byname(wled->pdev, "sc-irq");

	wled->sc_irq = platform_get_irq_byname(wled->pdev, "sc-irq");

	if (wled->sc_irq < 0)

	if (wled->sc_irq < 0)

		dev_dbg(&wled->pdev->dev, "sc irq is not used\n");

		dev_dbg(&wled->pdev->dev, "sc irq is not used\n");