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leds: flash: leds-qcom-flash: Limit LED current based on thermal condition

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The flash module has status bits to indicate different thermal
conditions which are called as OTSTx. For each OTSTx status,
there is a recommended total flash current for all channels to
prevent the flash module entering into higher thermal level.
For example, the total flash current should be limited to 1000mA/500mA
respectively when the HW reaches the OTST1/OTST2 thermal level.

Signed-off-by: Fenglin Wu <quic_fenglinw@quicinc.com>
Link: https://lore.kernel.org/r/20240705-qcom_flash_thermal_derating-v3-1-8e2e2783e3a6@quicinc.com
Signed-off-by: Lee Jones <lee@kernel.org>
This commit is contained in:
Fenglin Wu 2024-07-05 15:55:01 +08:00 • committed by Lee Jones
parent 10cc487692
commit a0864cf320
1 changed files with 162 additions and 1 deletions
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163
drivers/leds/flash/leds-qcom-flash.c
View file

@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
* Copyright (c) 2022, 2024 Qualcomm Innovation Center, Inc. All rights reserved.
*/
#include <linux/bitfield.h>
@ -14,6 +14,9 @@
#include <media/v4l2-flash-led-class.h>
/* registers definitions */
#define FLASH_REVISION_REG 0x00
#define FLASH_4CH_REVISION_V0P1 0x01
#define FLASH_TYPE_REG 0x04
#define FLASH_TYPE_VAL 0x18
@ -73,6 +76,16 @@
#define UA_PER_MA 1000
/* thermal threshold constants */
#define OTST_3CH_MIN_VAL 3
#define OTST1_4CH_MIN_VAL 0
#define OTST1_4CH_V0P1_MIN_VAL 3
#define OTST2_4CH_MIN_VAL 0
#define OTST1_MAX_CURRENT_MA 1000
#define OTST2_MAX_CURRENT_MA 500
#define OTST3_MAX_CURRENT_MA 200
enum hw_type {
QCOM_MVFLASH_3CH,
QCOM_MVFLASH_4CH,
@ -98,6 +111,9 @@ enum {
REG_IRESOLUTION,
REG_CHAN_STROBE,
REG_CHAN_EN,
REG_THERM_THRSH1,
REG_THERM_THRSH2,
REG_THERM_THRSH3,
REG_MAX_COUNT,
};
@ -111,6 +127,9 @@ static struct reg_field mvflash_3ch_regs[REG_MAX_COUNT] = {
REG_FIELD(0x47, 0, 5), /* iresolution */
REG_FIELD_ID(0x49, 0, 2, 3, 1), /* chan_strobe */
REG_FIELD(0x4c, 0, 2), /* chan_en */
REG_FIELD(0x56, 0, 2), /* therm_thrsh1 */
REG_FIELD(0x57, 0, 2), /* therm_thrsh2 */
REG_FIELD(0x58, 0, 2), /* therm_thrsh3 */
};
static struct reg_field mvflash_4ch_regs[REG_MAX_COUNT] = {
@ -123,6 +142,8 @@ static struct reg_field mvflash_4ch_regs[REG_MAX_COUNT] = {
REG_FIELD(0x49, 0, 3), /* iresolution */
REG_FIELD_ID(0x4a, 0, 6, 4, 1), /* chan_strobe */
REG_FIELD(0x4e, 0, 3), /* chan_en */
REG_FIELD(0x7a, 0, 2), /* therm_thrsh1 */
REG_FIELD(0x78, 0, 2), /* therm_thrsh2 */
};
struct qcom_flash_data {
@ -130,9 +151,11 @@ struct qcom_flash_data {
struct regmap_field *r_fields[REG_MAX_COUNT];
struct mutex lock;
enum hw_type hw_type;
u32 total_ma;
u8 leds_count;
u8 max_channels;
u8 chan_en_bits;
u8 revision;
};
struct qcom_flash_led {
@ -143,6 +166,7 @@ struct qcom_flash_led {
u32 max_timeout_ms;
u32 flash_current_ma;
u32 flash_timeout_ms;
u32 current_in_use_ma;
u8 *chan_id;
u8 chan_count;
bool enabled;
@ -172,6 +196,127 @@ static int set_flash_module_en(struct qcom_flash_led *led, bool en)
return rc;
}
static int update_allowed_flash_current(struct qcom_flash_led *led, u32 *current_ma, bool strobe)
{
struct qcom_flash_data *flash_data = led->flash_data;
u32 therm_ma, avail_ma, thrsh[3], min_thrsh, sts;
int rc = 0;
mutex_lock(&flash_data->lock);
/*
* Put previously allocated current into allowed budget in either of these two cases:
* 1) LED is disabled;
* 2) LED is enabled repeatedly
*/
if (!strobe || led->current_in_use_ma != 0) {
if (flash_data->total_ma >= led->current_in_use_ma)
flash_data->total_ma -= led->current_in_use_ma;
else
flash_data->total_ma = 0;
led->current_in_use_ma = 0;
if (!strobe)
goto unlock;
}
/*
* Cache the default thermal threshold settings, and set them to the lowest levels before
* reading over-temp real time status. If over-temp has been triggered at the lowest
* threshold, it's very likely that it would be triggered at a higher (default) threshold
* when more flash current is requested. Prevent device from triggering over-temp condition
* by limiting the flash current for the new request.
*/
rc = regmap_field_read(flash_data->r_fields[REG_THERM_THRSH1], &thrsh[0]);
if (rc < 0)
goto unlock;
rc = regmap_field_read(flash_data->r_fields[REG_THERM_THRSH2], &thrsh[1]);
if (rc < 0)
goto unlock;
if (flash_data->hw_type == QCOM_MVFLASH_3CH) {
rc = regmap_field_read(flash_data->r_fields[REG_THERM_THRSH3], &thrsh[2]);
if (rc < 0)
goto unlock;
}
min_thrsh = OTST_3CH_MIN_VAL;
if (flash_data->hw_type == QCOM_MVFLASH_4CH)
min_thrsh = (flash_data->revision == FLASH_4CH_REVISION_V0P1) ?
OTST1_4CH_V0P1_MIN_VAL : OTST1_4CH_MIN_VAL;
rc = regmap_field_write(flash_data->r_fields[REG_THERM_THRSH1], min_thrsh);
if (rc < 0)
goto unlock;
if (flash_data->hw_type == QCOM_MVFLASH_4CH)
min_thrsh = OTST2_4CH_MIN_VAL;
/*
* The default thermal threshold settings have been updated hence
* restore them if any fault happens starting from here.
*/
rc = regmap_field_write(flash_data->r_fields[REG_THERM_THRSH2], min_thrsh);
if (rc < 0)
goto restore;
if (flash_data->hw_type == QCOM_MVFLASH_3CH) {
rc = regmap_field_write(flash_data->r_fields[REG_THERM_THRSH3], min_thrsh);
if (rc < 0)
goto restore;
}
/* Read thermal level status to get corresponding derating flash current */
rc = regmap_field_read(flash_data->r_fields[REG_STATUS2], &sts);
if (rc)
goto restore;
therm_ma = FLASH_TOTAL_CURRENT_MAX_UA / 1000;
if (flash_data->hw_type == QCOM_MVFLASH_3CH) {
if (sts & FLASH_STS_3CH_OTST3)
therm_ma = OTST3_MAX_CURRENT_MA;
else if (sts & FLASH_STS_3CH_OTST2)
therm_ma = OTST2_MAX_CURRENT_MA;
else if (sts & FLASH_STS_3CH_OTST1)
therm_ma = OTST1_MAX_CURRENT_MA;
} else {
if (sts & FLASH_STS_4CH_OTST2)
therm_ma = OTST2_MAX_CURRENT_MA;
else if (sts & FLASH_STS_4CH_OTST1)
therm_ma = OTST1_MAX_CURRENT_MA;
}
/* Calculate the allowed flash current for the request */
if (therm_ma <= flash_data->total_ma)
avail_ma = 0;
else
avail_ma = therm_ma - flash_data->total_ma;
*current_ma = min_t(u32, *current_ma, avail_ma);
led->current_in_use_ma = *current_ma;
flash_data->total_ma += led->current_in_use_ma;
dev_dbg(led->flash.led_cdev.dev, "allowed flash current: %dmA, total current: %dmA\n",
led->current_in_use_ma, flash_data->total_ma);
restore:
/* Restore to default thermal threshold settings */
rc = regmap_field_write(flash_data->r_fields[REG_THERM_THRSH1], thrsh[0]);
if (rc < 0)
goto unlock;
rc = regmap_field_write(flash_data->r_fields[REG_THERM_THRSH2], thrsh[1]);
if (rc < 0)
goto unlock;
if (flash_data->hw_type == QCOM_MVFLASH_3CH)
rc = regmap_field_write(flash_data->r_fields[REG_THERM_THRSH3], thrsh[2]);
unlock:
mutex_unlock(&flash_data->lock);
return rc;
}
static int set_flash_current(struct qcom_flash_led *led, u32 current_ma, enum led_mode mode)
{
struct qcom_flash_data *flash_data = led->flash_data;
@ -313,6 +458,10 @@ static int qcom_flash_strobe_set(struct led_classdev_flash *fled_cdev, bool stat
if (rc)
return rc;
rc = update_allowed_flash_current(led, &led->flash_current_ma, state);
if (rc < 0)
return rc;
rc = set_flash_current(led, led->flash_current_ma, FLASH_MODE);
if (rc)
return rc;
@ -429,6 +578,10 @@ static int qcom_flash_led_brightness_set(struct led_classdev *led_cdev,
if (rc)
return rc;
rc = update_allowed_flash_current(led, &current_ma, enable);
if (rc < 0)
return rc;
rc = set_flash_current(led, current_ma, TORCH_MODE);
if (rc)
return rc;
@ -707,6 +860,14 @@ static int qcom_flash_led_probe(struct platform_device *pdev)
flash_data->hw_type = QCOM_MVFLASH_4CH;
flash_data->max_channels = 4;
regs = mvflash_4ch_regs;
rc = regmap_read(regmap, reg_base + FLASH_REVISION_REG, &val);
if (rc < 0) {
dev_err(dev, "Failed to read flash LED module revision, rc=%d\n", rc);
return rc;
}
flash_data->revision = val;
} else {
dev_err(dev, "flash LED subtype %#x is not yet supported\n", val);
return -ENODEV;