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Commit 5f35057d authored by Chun Zhang's avatar Chun Zhang
Browse files

leds: leds-qpnp-flash: add max current prediction 



PMIC based flash LED cannot support full LED intensity when battery
level is low. When battery level is low and a user wants to use full
intensity, PMIC clamps LED current to avoid under voltage lock
out(UVLO). Therefore, before flash LED assigns brightness, it checks
for maximum allowed current at current battery level. If current
requested is larger than PMIC can provide, flash LED current will
be truncated.

Change-Id: I17f1ef27358c91c13e4f5f8df08761fc944e9345
Signed-off-by: default avatarChun Zhang <chunz@codeaurora.org>
parent 3511ae2a

Documentation/devicetree/bindings/leds/leds-qpnp-flash.txt

+3 −0
Original line number Diff line number Diff line
@@ -49,6 +49,9 @@ Optional properties: 
				   for LED channel 0

- qcom,headroom-sense-ch1-enabled: Boolean type. This configures headroom sensing enablement

				   for LED channel 1

- qcom,power-detect-enabled	: Boolean type. This enables driver to get maximum flash LED

				  current at current battery level to avoid intensity clamp

				  when battery voltage is low



Required properties inside child node. Chile node contains settings for each individual LED:

- label			: type of led that will be used, either "flash" or "torch".

drivers/leds/leds-qpnp-flash.c

+41 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <linux/of.h>

#include <linux/regulator/consumer.h>

#include <linux/workqueue.h>

#include <linux/power_supply.h>

#include "leds.h"



#define FLASH_LED_PERIPHERAL_SUBTYPE(base)			(base + 0x05)
@@ -90,6 +91,7 @@ 
#define	FLASH_LED_VPH_DROOP_THRESHOLD_MIN_MV			2500

#define	FLASH_LED_VPH_DROOP_THRESHOLD_DIVIDER			100

#define FLASH_LED_HDRM_SNS_ENABLE				0x81

#define	FLASH_LED_UA_PER_MA					1000



#define FLASH_UNLOCK_SECURE					0xA5

#define FLASH_LED_TORCH_ENABLE					0x00
@@ -177,6 +179,7 @@ struct flash_led_platform_data { 
	bool				vph_pwr_droop_en;

	bool				hdrm_sns_ch0_en;

	bool				hdrm_sns_ch1_en;

	bool				power_detect_en;

};



/*
@@ -186,6 +189,7 @@ struct qpnp_flash_led { 
	struct spmi_device		*spmi_dev;

	struct flash_led_platform_data	*pdata;

	struct flash_node_data		*flash_node;

	struct power_supply		*battery_psy;

	struct mutex			flash_led_lock;

	int				num_leds;

	u16				base;
@@ -442,7 +446,9 @@ static void qpnp_flash_led_work(struct work_struct *work) 
				struct flash_node_data, work);

	struct qpnp_flash_led *led =

			dev_get_drvdata(&flash_node->spmi_dev->dev);

	union power_supply_propval prop;

	int rc, brightness = flash_node->cdev.brightness;

	u16 max_curr_avail_ma;

	u8 val;



	mutex_lock(&led->flash_led_lock);
@@ -536,6 +542,38 @@ static void qpnp_flash_led_work(struct work_struct *work) 
			goto exit_flash_led_work;

		}

	} else if (flash_node->type == FLASH) {

		if (led->pdata->power_detect_en) {

			if (!led->battery_psy)

				led->battery_psy =

					power_supply_get_by_name("battery");



			if (led->battery_psy) {

				led->battery_psy->get_property(led->battery_psy,

					POWER_SUPPLY_PROP_FLASH_CURRENT_MAX,

					&prop);

				if (!prop.intval) {

					dev_err(&led->spmi_dev->dev,

						"battery too low for flash\n");

					goto exit_flash_led_work;

				}

			} else {

				dev_err(&led->spmi_dev->dev,

					"failed to query battery level\n");

				goto exit_flash_led_work;

			}



			max_curr_avail_ma = (u16)(prop.intval /

							FLASH_LED_UA_PER_MA);

			max_curr_avail_ma = max_curr_avail_ma / 2;



			if (max_curr_avail_ma < flash_node->prgm_current) {

				dev_err(&led->spmi_dev->dev,

					"battery only supports %d mA.\n",

					max_curr_avail_ma);

				flash_node->prgm_current = max_curr_avail_ma;

			}

		}



		val = (u8)((flash_node->duration - FLASH_DURATION_DIVIDER)

						/ FLASH_DURATION_DIVIDER);

		rc = qpnp_led_masked_write(led->spmi_dev,
@@ -1126,6 +1164,9 @@ static int qpnp_flash_led_parse_common_dt( 
	led->pdata->hdrm_sns_ch1_en = of_property_read_bool(node,

						"qcom,headroom-sense-ch1-enabled");



	led->pdata->power_detect_en = of_property_read_bool(node,

						"qcom,power-detect-enabled");



	return 0;

}