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Commit be702573 authored by Chun Zhang's avatar Chun Zhang
Browse files

leds: leds-qpnp-flash: detect open circuit fault in LED usage 



There is chance hardware may come with bugs that LEDs are not
installed. When it happens, usage of flash LED may cause hardware
damage. Therefore, it is essential to detect open circuit fault so
that subsequent usage may decide whether to enable flash LED or not.

Change-Id: I69d8119902ae0d2eb587df6cfc04cb6a56f59118
Signed-off-by: default avatarChun Zhang <chunz@codeaurora.org>
parent 1acad2bb

drivers/leds/leds-qpnp-flash.c

+26 −0
Original line number Diff line number Diff line
@@ -117,6 +117,7 @@ 
#define	FLASH_LED_CURRENT_READING_DELAY_MIN			5000

#define	FLASH_LED_CURRENT_READING_DELAY_MAX			5001

#define PMI8996_SUBTYPE						19

#define	FLASH_LED_OPEN_FAULT_DETECTED				0xC



#define FLASH_UNLOCK_SECURE					0xA5

#define FLASH_LED_TORCH_ENABLE					0x00
@@ -256,6 +257,7 @@ struct qpnp_flash_led { 
	bool				charging_enabled;

	bool				strobe_debug;

	bool				dbg_feature_en;

	bool				open_fault;

};



static u8 qpnp_flash_led_ctrl_dbg_regs[] = {
@@ -1188,6 +1190,12 @@ static void qpnp_flash_led_work(struct work_struct *work) 
	if (!brightness)

		goto turn_off;



	if (led->open_fault) {

		dev_err(&led->spmi_dev->dev, "Open fault detected\n");

		mutex_unlock(&led->flash_led_lock);

		return;

	}



	if (!flash_node->flash_on && flash_node->num_regulators > 0) {

		rc = flash_regulator_enable(led, flash_node, true);

		if (rc) {
@@ -1648,6 +1656,24 @@ static void qpnp_flash_led_work(struct work_struct *work) 
	return;



turn_off:

	if (flash_node->type == TORCH) {

		/*

		 * Checking LED fault status detects hardware open fault.

		 * If fault occurs, all subsequent LED enablement requests

		 * will be rejected to protect hardware.

		 */

		rc = spmi_ext_register_readl(led->spmi_dev->ctrl,

			led->spmi_dev->sid,

			FLASH_LED_FAULT_STATUS(led->base), &val, 1);

		if (rc) {

			dev_err(&led->spmi_dev->dev,

				"Failed to read out fault status register\n");

			goto exit_flash_led_work;

		}



		led->open_fault = (val & FLASH_LED_OPEN_FAULT_DETECTED);

	}



	rc = qpnp_led_masked_write(led->spmi_dev,

			FLASH_LED_STROBE_CTRL(led->base),

			(flash_node->id == FLASH_LED_SWITCH ? FLASH_STROBE_MASK