Commit feeab87b authored by Kiran Gunda's avatar Kiran Gunda Committed by Lee Jones
Browse files

backlight: qcom-wled: Add support for short circuit handling 



Handle the short circuit interrupt and check if the short circuit
interrupt is valid. Re-enable the module to check if it goes
away. Disable the module altogether if the short circuit event
persists.

Signed-off-by: default avatarKiran Gunda <kgunda@codeaurora.org>
Reviewed-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 03b2b5e8

drivers/video/backlight/qcom-wled.c

+140 −4
Original line number Diff line number Diff line
@@ -2,6 +2,9 @@ 
/* Copyright (c) 2015, Sony Mobile Communications, AB.

 */



#include <linux/delay.h>

#include <linux/interrupt.h>

#include <linux/ktime.h>

#include <linux/kernel.h>

#include <linux/backlight.h>

#include <linux/module.h>
@@ -56,6 +59,16 @@ 
#define WLED3_SINK_REG_STR_CABC(n)			(0x66 + (n * 0x10))

#define  WLED3_SINK_REG_STR_CABC_MASK			BIT(7)



/* WLED4 specific control registers */

#define WLED4_CTRL_REG_SHORT_PROTECT			0x5e

#define  WLED4_CTRL_REG_SHORT_EN_MASK			BIT(7)



#define WLED4_CTRL_REG_SEC_ACCESS			0xd0

#define  WLED4_CTRL_REG_SEC_UNLOCK			0xa5



#define WLED4_CTRL_REG_TEST1				0xe2

#define  WLED4_CTRL_REG_TEST1_EXT_FET_DTEST2		0x09



/* WLED4 specific sink registers */

#define WLED4_SINK_REG_CURR_SINK			0x46

#define  WLED4_SINK_REG_CURR_SINK_MASK			GENMASK(7, 4)
@@ -105,17 +118,24 @@ struct wled_config { 
	bool cs_out_en;

	bool ext_gen;

	bool cabc;

	bool external_pfet;

};



struct wled {

	const char *name;

	struct device *dev;

	struct regmap *regmap;

	struct mutex lock;	/* Lock to avoid race from thread irq handler */

	ktime_t last_short_event;

	u16 ctrl_addr;

	u16 sink_addr;

	u16 max_string_count;

	u32 brightness;

	u32 max_brightness;

	u32 short_count;

	bool disabled_by_short;

	bool has_short_detect;

	int short_irq;



	struct wled_config cfg;

	int (*wled_set_brightness)(struct wled *wled, u16 brightness);
@@ -166,6 +186,9 @@ static int wled_module_enable(struct wled *wled, int val) 
{

	int rc;



	if (wled->disabled_by_short)

		return -ENXIO;



	rc = regmap_update_bits(wled->regmap, wled->ctrl_addr +

				WLED3_CTRL_REG_MOD_EN,

				WLED3_CTRL_REG_MOD_EN_MASK,
@@ -202,18 +225,19 @@ static int wled_update_status(struct backlight_device *bl) 
	    bl->props.state & BL_CORE_FBBLANK)

		brightness = 0;



	mutex_lock(&wled->lock);

	if (brightness) {

		rc = wled->wled_set_brightness(wled, brightness);

		if (rc < 0) {

			dev_err(wled->dev, "wled failed to set brightness rc:%d\n",

				rc);

			return rc;

			goto unlock_mutex;

		}



		rc = wled_sync_toggle(wled);

		if (rc < 0) {

			dev_err(wled->dev, "wled sync failed rc:%d\n", rc);

			return rc;

			goto unlock_mutex;

		}

	}
@@ -221,15 +245,61 @@ static int wled_update_status(struct backlight_device *bl) 
		rc = wled_module_enable(wled, !!brightness);

		if (rc < 0) {

			dev_err(wled->dev, "wled enable failed rc:%d\n", rc);

			return rc;

			goto unlock_mutex;

		}

	}



	wled->brightness = brightness;



unlock_mutex:

	mutex_unlock(&wled->lock);



	return rc;

}



#define WLED_SHORT_DLY_MS			20

#define WLED_SHORT_CNT_MAX			5

#define WLED_SHORT_RESET_CNT_DLY_US		USEC_PER_SEC



static irqreturn_t wled_short_irq_handler(int irq, void *_wled)

{

	struct wled *wled = _wled;

	int rc;

	s64 elapsed_time;



	wled->short_count++;

	mutex_lock(&wled->lock);

	rc = wled_module_enable(wled, false);

	if (rc < 0) {

		dev_err(wled->dev, "wled disable failed rc:%d\n", rc);

		goto unlock_mutex;

	}



	elapsed_time = ktime_us_delta(ktime_get(),

				      wled->last_short_event);

	if (elapsed_time > WLED_SHORT_RESET_CNT_DLY_US)

		wled->short_count = 1;



	if (wled->short_count > WLED_SHORT_CNT_MAX) {

		dev_err(wled->dev, "Short trigged %d times, disabling WLED forever!\n",

			wled->short_count);

		wled->disabled_by_short = true;

		goto unlock_mutex;

	}



	wled->last_short_event = ktime_get();



	msleep(WLED_SHORT_DLY_MS);

	rc = wled_module_enable(wled, true);

	if (rc < 0)

		dev_err(wled->dev, "wled enable failed rc:%d\n", rc);



unlock_mutex:

	mutex_unlock(&wled->lock);



	return IRQ_HANDLED;

}



static int wled3_setup(struct wled *wled)

{

	u16 addr;
@@ -318,7 +388,7 @@ static int wled4_setup(struct wled *wled) 
	int rc, temp, i, j;

	u16 addr;

	u8 sink_en = 0;

	u32 sink_cfg = 0;

	u32 sink_cfg;



	rc = regmap_update_bits(wled->regmap,

				wled->ctrl_addr + WLED3_CTRL_REG_OVP,
@@ -340,6 +410,21 @@ static int wled4_setup(struct wled *wled) 
	if (rc < 0)

		return rc;



	if (wled->cfg.external_pfet) {

		/* Unlock the secure register access */

		rc = regmap_write(wled->regmap, wled->ctrl_addr +

				  WLED4_CTRL_REG_SEC_ACCESS,

				  WLED4_CTRL_REG_SEC_UNLOCK);

		if (rc < 0)

			return rc;



		rc = regmap_write(wled->regmap,

				  wled->ctrl_addr + WLED4_CTRL_REG_TEST1,

				  WLED4_CTRL_REG_TEST1_EXT_FET_DTEST2);

		if (rc < 0)

			return rc;

	}



	rc = regmap_read(wled->regmap, wled->sink_addr +

			 WLED4_SINK_REG_CURR_SINK, &sink_cfg);

	if (rc < 0)
@@ -425,6 +510,7 @@ static const struct wled_config wled4_config_defaults = { 
	.num_strings = 4,

	.switch_freq = 11,

	.cabc = false,

	.external_pfet = false,

};



static const u32 wled3_boost_i_limit_values[] = {
@@ -590,6 +676,7 @@ static int wled_configure(struct wled *wled, int version) 
		{ "qcom,cs-out", &cfg->cs_out_en, },

		{ "qcom,ext-gen", &cfg->ext_gen, },

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

		{ "qcom,external-pfet", &cfg->external_pfet, },

	};



	prop_addr = of_get_address(dev->of_node, 0, NULL, NULL);
@@ -678,6 +765,38 @@ static int wled_configure(struct wled *wled, int version) 
	return 0;

}



static int wled_configure_short_irq(struct wled *wled,

				    struct platform_device *pdev)

{

	int rc;



	if (!wled->has_short_detect)

		return 0;



	rc = regmap_update_bits(wled->regmap, wled->ctrl_addr +

				WLED4_CTRL_REG_SHORT_PROTECT,

				WLED4_CTRL_REG_SHORT_EN_MASK,

				WLED4_CTRL_REG_SHORT_EN_MASK);

	if (rc < 0)

		return rc;



	wled->short_irq = platform_get_irq_byname(pdev, "short");

	if (wled->short_irq < 0) {

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

		return 0;

	}



	rc = devm_request_threaded_irq(wled->dev, wled->short_irq,

				       NULL, wled_short_irq_handler,

				       IRQF_ONESHOT,

				       "wled_short_irq", wled);

	if (rc < 0)

		dev_err(wled->dev, "Unable to request short_irq (err:%d)\n",

			rc);



	return rc;

}



static const struct backlight_ops wled_ops = {

	.update_status = wled_update_status,

};
@@ -711,6 +830,7 @@ static int wled_probe(struct platform_device *pdev) 
		return -ENODEV;

	}



	mutex_init(&wled->lock);

	rc = wled_configure(wled, version);

	if (rc)

		return rc;
@@ -725,6 +845,7 @@ static int wled_probe(struct platform_device *pdev) 
		break;



	case 4:

		wled->has_short_detect = true;

		rc = wled4_setup(wled);

		if (rc) {

			dev_err(&pdev->dev, "wled4_setup failed\n");
@@ -737,6 +858,10 @@ static int wled_probe(struct platform_device *pdev) 
		break;

	}



	rc = wled_configure_short_irq(wled, pdev);

	if (rc < 0)

		return rc;



	val = WLED_DEFAULT_BRIGHTNESS;

	of_property_read_u32(pdev->dev.of_node, "default-brightness", &val);
@@ -750,6 +875,16 @@ static int wled_probe(struct platform_device *pdev) 
	return PTR_ERR_OR_ZERO(bl);

};



static int wled_remove(struct platform_device *pdev)

{

	struct wled *wled = dev_get_drvdata(&pdev->dev);



	mutex_destroy(&wled->lock);

	disable_irq(wled->short_irq);



	return 0;

}



static const struct of_device_id wled_match_table[] = {

	{ .compatible = "qcom,pm8941-wled", .data = (void *)3 },

	{ .compatible = "qcom,pmi8998-wled", .data = (void *)4 },
@@ -760,6 +895,7 @@ MODULE_DEVICE_TABLE(of, wled_match_table); 


static struct platform_driver wled_driver = {

	.probe = wled_probe,

	.remove = wled_remove,

	.driver	= {

		.name = "qcom,wled",

		.of_match_table	= wled_match_table,

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