From: Fenglin Wu <fenglin.wu@oss.qualcomm.com>
There is a register to clamp the flash current per LED channel when
safety timer is disabled. It needs to be updated according to the
maximum torch LED current setting to ensure the torch current won't
be clamped unexpectedly.
Fixes: 96a2e242a5dc ("leds: flash: Add driver to support flash LED module in QCOM PMICs")
Signed-off-by: Fenglin Wu <fenglin.wu@oss.qualcomm.com>
---
drivers/leds/flash/leds-qcom-flash.c | 62 +++++++++++++++++++++---------------
1 file changed, 36 insertions(+), 26 deletions(-)
diff --git a/drivers/leds/flash/leds-qcom-flash.c b/drivers/leds/flash/leds-qcom-flash.c
index 89cf5120f5d55bbb7e24faa8c3a946416f8fed46..db7c2c743adc755244f387febce663738bf3c0bd 100644
--- a/drivers/leds/flash/leds-qcom-flash.c
+++ b/drivers/leds/flash/leds-qcom-flash.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * Copyright (c) 2022, 2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) 2022, 2024-2025 Qualcomm Innovation Center, Inc. All rights reserved.
*/
#include <linux/bitfield.h>
@@ -114,36 +114,39 @@ enum {
REG_THERM_THRSH1,
REG_THERM_THRSH2,
REG_THERM_THRSH3,
+ REG_TORCH_CLAMP,
REG_MAX_COUNT,
};
static const struct reg_field mvflash_3ch_regs[REG_MAX_COUNT] = {
- REG_FIELD(0x08, 0, 7), /* status1 */
- REG_FIELD(0x09, 0, 7), /* status2 */
- REG_FIELD(0x0a, 0, 7), /* status3 */
- REG_FIELD_ID(0x40, 0, 7, 3, 1), /* chan_timer */
- REG_FIELD_ID(0x43, 0, 6, 3, 1), /* itarget */
- REG_FIELD(0x46, 7, 7), /* module_en */
- 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 */
+ [REG_STATUS1] = REG_FIELD(0x08, 0, 7),
+ [REG_STATUS2] = REG_FIELD(0x09, 0, 7),
+ [REG_STATUS3] = REG_FIELD(0x0a, 0, 7),
+ [REG_CHAN_TIMER] = REG_FIELD_ID(0x40, 0, 7, 3, 1),
+ [REG_ITARGET] = REG_FIELD_ID(0x43, 0, 6, 3, 1),
+ [REG_MODULE_EN] = REG_FIELD(0x46, 7, 7),
+ [REG_IRESOLUTION] = REG_FIELD(0x47, 0, 5),
+ [REG_CHAN_STROBE] = REG_FIELD_ID(0x49, 0, 2, 3, 1),
+ [REG_CHAN_EN] = REG_FIELD(0x4c, 0, 2),
+ [REG_THERM_THRSH1] = REG_FIELD(0x56, 0, 2),
+ [REG_THERM_THRSH2] = REG_FIELD(0x57, 0, 2),
+ [REG_THERM_THRSH3] = REG_FIELD(0x58, 0, 2),
+ [REG_TORCH_CLAMP] = REG_FIELD(0xec, 0, 6),
};
static const struct reg_field mvflash_4ch_regs[REG_MAX_COUNT] = {
- REG_FIELD(0x06, 0, 7), /* status1 */
- REG_FIELD(0x07, 0, 6), /* status2 */
- REG_FIELD(0x09, 0, 7), /* status3 */
- REG_FIELD_ID(0x3e, 0, 7, 4, 1), /* chan_timer */
- REG_FIELD_ID(0x42, 0, 6, 4, 1), /* itarget */
- REG_FIELD(0x46, 7, 7), /* module_en */
- 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 */
+ [REG_STATUS1] = REG_FIELD(0x06, 0, 7),
+ [REG_STATUS2] = REG_FIELD(0x07, 0, 6),
+ [REG_STATUS3] = REG_FIELD(0x09, 0, 7),
+ [REG_CHAN_TIMER] = REG_FIELD_ID(0x3e, 0, 7, 4, 1),
+ [REG_ITARGET] = REG_FIELD_ID(0x42, 0, 6, 4, 1),
+ [REG_MODULE_EN] = REG_FIELD(0x46, 7, 7),
+ [REG_IRESOLUTION] = REG_FIELD(0x49, 0, 3),
+ [REG_CHAN_STROBE] = REG_FIELD_ID(0x4a, 0, 6, 4, 1),
+ [REG_CHAN_EN] = REG_FIELD(0x4e, 0, 3),
+ [REG_THERM_THRSH1] = REG_FIELD(0x7a, 0, 2),
+ [REG_THERM_THRSH2] = REG_FIELD(0x78, 0, 2),
+ [REG_TORCH_CLAMP] = REG_FIELD(0xed, 0, 6),
};
struct qcom_flash_data {
@@ -156,6 +159,7 @@ struct qcom_flash_data {
u8 max_channels;
u8 chan_en_bits;
u8 revision;
+ u8 torch_clamp;
};
struct qcom_flash_led {
@@ -702,6 +706,7 @@ static int qcom_flash_register_led_device(struct device *dev,
u32 current_ua, timeout_us;
u32 channels[4];
int i, rc, count;
+ u8 torch_clamp;
count = fwnode_property_count_u32(node, "led-sources");
if (count <= 0) {
@@ -751,6 +756,12 @@ static int qcom_flash_register_led_device(struct device *dev,
current_ua = min_t(u32, current_ua, TORCH_CURRENT_MAX_UA * led->chan_count);
led->max_torch_current_ma = current_ua / UA_PER_MA;
+ torch_clamp = (current_ua / led->chan_count) / TORCH_IRES_UA;
+ if (torch_clamp != 0)
+ torch_clamp--;
+
+ flash_data->torch_clamp = max_t(u8, flash_data->torch_clamp, torch_clamp);
+
if (fwnode_property_present(node, "flash-max-microamp")) {
flash->led_cdev.flags |= LED_DEV_CAP_FLASH;
@@ -917,8 +928,7 @@ static int qcom_flash_led_probe(struct platform_device *pdev)
flash_data->leds_count++;
}
- return 0;
-
+ return regmap_field_write(flash_data->r_fields[REG_TORCH_CLAMP], flash_data->torch_clamp);
release:
while (flash_data->v4l2_flash[flash_data->leds_count] && flash_data->leds_count)
v4l2_flash_release(flash_data->v4l2_flash[flash_data->leds_count--]);
--
2.34.1On 7/29/25 6:51 AM, Fenglin Wu via B4 Relay wrote:
> From: Fenglin Wu <fenglin.wu@oss.qualcomm.com>
>
> There is a register to clamp the flash current per LED channel when
> safety timer is disabled. It needs to be updated according to the
> maximum torch LED current setting to ensure the torch current won't
> be clamped unexpectedly.
>
> Fixes: 96a2e242a5dc ("leds: flash: Add driver to support flash LED module in QCOM PMICs")
> Signed-off-by: Fenglin Wu <fenglin.wu@oss.qualcomm.com>
> ---
I'd prefer the regfield change was done in a separate commit,
but it's not groundbreaking so I don't mind that much
[...]
> struct qcom_flash_led {
> @@ -702,6 +706,7 @@ static int qcom_flash_register_led_device(struct device *dev,
> u32 current_ua, timeout_us;
> u32 channels[4];
> int i, rc, count;
> + u8 torch_clamp;
>
> count = fwnode_property_count_u32(node, "led-sources");
> if (count <= 0) {
> @@ -751,6 +756,12 @@ static int qcom_flash_register_led_device(struct device *dev,
> current_ua = min_t(u32, current_ua, TORCH_CURRENT_MAX_UA * led->chan_count);
> led->max_torch_current_ma = current_ua / UA_PER_MA;
>
> + torch_clamp = (current_ua / led->chan_count) / TORCH_IRES_UA;
> + if (torch_clamp != 0)
> + torch_clamp--;
> +
> + flash_data->torch_clamp = max_t(u8, flash_data->torch_clamp, torch_clamp);
Please confirm if I understand correctly, we may have N flash LEDs
connected, and this additional safety hardware can only compare any
individual LED's current draw against a single maximum value, which
we're setting here
Konrad
On 7/29/2025 7:01 PM, Konrad Dybcio wrote: >> + torch_clamp = (current_ua / led->chan_count) / TORCH_IRES_UA; >> + if (torch_clamp != 0) >> + torch_clamp--; >> + >> + flash_data->torch_clamp = max_t(u8, flash_data->torch_clamp, torch_clamp); > Please confirm if I understand correctly, we may have N flash LEDs > connected, and this additional safety hardware can only compare any > individual LED's current draw against a single maximum value, which > we're setting here Yes, your understanding is correct!
On 7/31/25 3:43 AM, Fenglin Wu wrote: > > On 7/29/2025 7:01 PM, Konrad Dybcio wrote: >>> + torch_clamp = (current_ua / led->chan_count) / TORCH_IRES_UA; >>> + if (torch_clamp != 0) >>> + torch_clamp--; >>> + >>> + flash_data->torch_clamp = max_t(u8, flash_data->torch_clamp, torch_clamp); >> Please confirm if I understand correctly, we may have N flash LEDs >> connected, and this additional safety hardware can only compare any >> individual LED's current draw against a single maximum value, which >> we're setting here > Yes, your understanding is correct! Great, thank you for confirming Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com> Konrad
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