* [PATCH v1] video: leds: backlight: lm3533: Support getting LED sources from DT
@ 2026-11-01 14:24 Svyatoslav Ryhel
2026-11-01 14:32 ` sashiko-bot
0 siblings, 1 reply; 2+ messages in thread
From: Svyatoslav Ryhel @ 2026-11-01 14:24 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Griffin Kroah-Hartman, Daniel Thompson,
Jingoo Han, Helge Deller
Cc: linux-leds, linux-kernel, dri-devel, linux-fbdev
Add Control Bank to HVLED/LVLED muxing support based on the led-sources
defined in the device tree.
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
---
This was part of the original LM3533 controller DT/OF conversion patchset,
but it appears to have been accidentally separated during the final iteration.
Therefore, I am sending it as a follow-up.
---
drivers/leds/leds-lm3533.c | 60 +++++++++++++++++++++++++++++
drivers/video/backlight/lm3533_bl.c | 45 ++++++++++++++++++++++
2 files changed, 105 insertions(+)
diff --git a/drivers/leds/leds-lm3533.c b/drivers/leds/leds-lm3533.c
index 7259097bd6a71..a1aeff70a90fc 100644
--- a/drivers/leds/leds-lm3533.c
+++ b/drivers/leds/leds-lm3533.c
@@ -26,6 +26,11 @@
#define LM3533_ALS_CHANNEL_LV_MIN 1
#define LM3533_ALS_CHANNEL_LV_MAX 2
+#define LM3533_REG_OUTPUT_CONF1 0x10
+#define OUTPUT_CONF1_SHIFT 2
+#define OUTPUT_LVLED_MASK 0x3
+#define LM3533_REG_OUTPUT_CONF2 0x11
+#define OUTPUT_CONF2_SHIFT 6
#define LM3533_REG_CTRLBANK_BCONF_BASE 0x1b
#define LM3533_REG_PATTERN_ENABLE 0x28
#define LM3533_REG_PATTERN_LOW_TIME_BASE 0x71
@@ -54,6 +59,9 @@ struct lm3533_led {
u32 max_current;
u32 pwm;
+ int num_leds;
+ u32 leds[LM3533_LVCTRLBANK_MAX];
+
bool have_als;
};
@@ -622,8 +630,36 @@ static const struct attribute_group *lm3533_led_attribute_groups[] = {
static int lm3533_led_setup(struct lm3533_led *led)
{
+ u32 output_cfg_shift = 0;
+ u32 output_cfg_val = 0;
+ u32 output_cfg_mask = 0;
int ret;
+ if (led->num_leds) {
+ for (int i = 0; i < led->num_leds; i++) {
+ if (led->leds[i] >= LM3533_LVCTRLBANK_MAX)
+ continue;
+
+ output_cfg_shift = led->leds[i] * 2;
+ output_cfg_val |= led->id << output_cfg_shift;
+ output_cfg_mask |= OUTPUT_LVLED_MASK << output_cfg_shift;
+ }
+
+ /* LVLED1, LVLED2 and LVLED3 */
+ ret = regmap_update_bits(led->regmap, LM3533_REG_OUTPUT_CONF1,
+ output_cfg_mask << OUTPUT_CONF1_SHIFT,
+ output_cfg_val << OUTPUT_CONF1_SHIFT);
+ if (ret)
+ return ret;
+
+ /* LVLED4 and LVLED5 */
+ ret = regmap_update_bits(led->regmap, LM3533_REG_OUTPUT_CONF2,
+ output_cfg_mask >> OUTPUT_CONF2_SHIFT,
+ output_cfg_val >> OUTPUT_CONF2_SHIFT);
+ if (ret)
+ return ret;
+ }
+
ret = lm3533_ctrlbank_set_max_current(&led->cb, led->max_current);
if (ret)
return ret;
@@ -698,6 +734,30 @@ static int lm3533_led_probe(struct platform_device *pdev)
device_property_read_u32(&pdev->dev, "ti,pwm-config-mask", &led->pwm);
+ /*
+ * If led-sources property is not set then either this Control Bank uses
+ * its default LVLED or is not linked to any LVLED at all.
+ */
+ led->num_leds = device_property_count_u32(&pdev->dev, "led-sources");
+ if (led->num_leds > LM3533_LVCTRLBANK_MAX) {
+ dev_err(&pdev->dev, "num of LED sources exceeds max %d: %d\n",
+ LM3533_LVCTRLBANK_MAX, led->num_leds);
+ ret = -EINVAL;
+ goto err_deregister;
+ }
+
+ if (led->num_leds < 0)
+ led->num_leds = 0;
+
+ if (led->num_leds > 0) {
+ ret = device_property_read_u32_array(&pdev->dev, "led-sources",
+ led->leds, led->num_leds);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to get led-sources\n");
+ goto err_deregister;
+ }
+ }
+
ret = lm3533_led_setup(led);
if (ret)
goto err_deregister;
diff --git a/drivers/video/backlight/lm3533_bl.c b/drivers/video/backlight/lm3533_bl.c
index adcd6ac7cf229..e8164c8528577 100644
--- a/drivers/video/backlight/lm3533_bl.c
+++ b/drivers/video/backlight/lm3533_bl.c
@@ -7,6 +7,7 @@
* Author: Johan Hovold <jhovold@gmail.com>
*/
+#include <linux/bits.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
@@ -21,6 +22,7 @@
#define LM3533_HVCTRLBANK_COUNT 2
#define LM3533_BL_MAX_BRIGHTNESS 255
+#define LM3533_REG_OUTPUT_CONF1 0x10
#define LM3533_REG_CTRLBANK_AB_BCONF 0x1a
#define CTRLBANK_AB_BCONF_ALS(n) BIT(2 * (n))
#define CTRLBANK_AB_BCONF_MODE(n) BIT(2 * (n) + 1)
@@ -35,6 +37,9 @@ struct lm3533_bl {
u32 max_current;
u32 pwm;
+ int num_leds;
+ u32 led_strings[LM3533_HVCTRLBANK_COUNT];
+
bool have_als;
bool linear;
};
@@ -236,6 +241,8 @@ static const struct attribute_group *lm3533_bl_attribute_groups[] = {
static int lm3533_bl_setup(struct lm3533_bl *bl)
{
int ctrlbank = lm3533_bl_get_ctrlbank_id(bl);
+ u32 output_cfg_val = 0;
+ u32 output_cfg_mask = 0;
int ret;
ret = regmap_assign_bits(bl->regmap, LM3533_REG_CTRLBANK_AB_BCONF,
@@ -243,6 +250,21 @@ static int lm3533_bl_setup(struct lm3533_bl *bl)
if (ret)
return ret;
+ if (bl->num_leds) {
+ for (int i = 0; i < bl->num_leds; i++) {
+ if (bl->led_strings[i] >= LM3533_HVCTRLBANK_COUNT)
+ continue;
+
+ output_cfg_val |= ctrlbank << bl->led_strings[i];
+ output_cfg_mask |= BIT(bl->led_strings[i]);
+ }
+
+ ret = regmap_update_bits(bl->regmap, LM3533_REG_OUTPUT_CONF1,
+ output_cfg_mask, output_cfg_val);
+ if (ret)
+ return ret;
+ }
+
ret = lm3533_ctrlbank_set_max_current(&bl->cb, bl->max_current);
if (ret)
return ret;
@@ -320,6 +342,29 @@ static int lm3533_bl_probe(struct platform_device *pdev)
device_property_read_u32(&pdev->dev, "ti,pwm-config-mask", &bl->pwm);
+ /*
+ * If led-sources property is not set then either this Control Bank uses
+ * its default HVLED or is not linked to any HVLED at all.
+ */
+ bl->num_leds = device_property_count_u32(&pdev->dev, "led-sources");
+ if (bl->num_leds > LM3533_HVCTRLBANK_COUNT) {
+ dev_err(&pdev->dev, "num of LED sources %d exceeds max %d\n",
+ bl->num_leds, LM3533_HVCTRLBANK_COUNT);
+ return -EINVAL;
+ }
+
+ if (bl->num_leds < 0)
+ bl->num_leds = 0;
+
+ if (bl->num_leds > 0) {
+ ret = device_property_read_u32_array(&pdev->dev, "led-sources",
+ bl->led_strings,
+ bl->num_leds);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to get led-sources\n");
+ }
+
ret = lm3533_bl_setup(bl);
if (ret)
return ret;
--
2.53.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v1] video: leds: backlight: lm3533: Support getting LED sources from DT
2026-11-01 14:24 [PATCH v1] video: leds: backlight: lm3533: Support getting LED sources from DT Svyatoslav Ryhel
@ 2026-11-01 14:32 ` sashiko-bot
0 siblings, 0 replies; 2+ messages in thread
From: sashiko-bot @ 2026-11-01 14:32 UTC (permalink / raw)
To: Svyatoslav Ryhel; +Cc: linux-leds, dri-devel, lee
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] leds: lm3533: unmasked upper bits in lm3533_led_setup() regmap update
--
commit 65c330f7377fc6ec85de7b076ec8dcd4d456b54b
Author: Svyatoslav Ryhel <clamor95@gmail.com>
video: leds: backlight: lm3533: Support getting LED sources from DT
This commit adds Control Bank to HVLED and LVLED muxing support to the
lm3533 LED and backlight drivers based on the led-sources device tree
property.
> diff --git a/drivers/leds/leds-lm3533.c b/drivers/leds/leds-lm3533.c
> index 7259097bd6a71..a1aeff70a90fc 100644
> --- a/drivers/leds/leds-lm3533.c
> +++ b/drivers/leds/leds-lm3533.c
> @@ -26,6 +26,11 @@
> #define LM3533_ALS_CHANNEL_LV_MIN 1
> #define LM3533_ALS_CHANNEL_LV_MAX 2
>
> +#define LM3533_REG_OUTPUT_CONF1 0x10
> +#define OUTPUT_CONF1_SHIFT 2
> +#define OUTPUT_LVLED_MASK 0x3
> +#define LM3533_REG_OUTPUT_CONF2 0x11
> +#define OUTPUT_CONF2_SHIFT 6
> #define LM3533_REG_CTRLBANK_BCONF_BASE 0x1b
> #define LM3533_REG_PATTERN_ENABLE 0x28
> #define LM3533_REG_PATTERN_LOW_TIME_BASE 0x71
> @@ -54,6 +59,9 @@ struct lm3533_led {
> u32 max_current;
> u32 pwm;
>
> + int num_leds;
> + u32 leds[LM3533_LVCTRLBANK_MAX];
> +
> bool have_als;
> };
>
> @@ -622,8 +630,36 @@ static const struct attribute_group *lm3533_led_attribute_groups[] = {
>
> static int lm3533_led_setup(struct lm3533_led *led)
> {
> + u32 output_cfg_shift = 0;
> + u32 output_cfg_val = 0;
> + u32 output_cfg_mask = 0;
> int ret;
>
> + if (led->num_leds) {
> + for (int i = 0; i < led->num_leds; i++) {
> + if (led->leds[i] >= LM3533_LVCTRLBANK_MAX)
> + continue;
> +
> + output_cfg_shift = led->leds[i] * 2;
> + output_cfg_val |= led->id << output_cfg_shift;
> + output_cfg_mask |= OUTPUT_LVLED_MASK << output_cfg_shift;
> + }
> +
> + /* LVLED1, LVLED2 and LVLED3 */
> + ret = regmap_update_bits(led->regmap, LM3533_REG_OUTPUT_CONF1,
> + output_cfg_mask << OUTPUT_CONF1_SHIFT,
> + output_cfg_val << OUTPUT_CONF1_SHIFT);
[Severity: Medium]
In drivers/leds/leds-lm3533.c, when lm3533_led_setup() configures LVLED4
(3) or LVLED5 (4) on control bank D, E, or F (led->id > 0), output_cfg_mask
and output_cfg_val have bits [9:6] set. Left-shifting them by
OUTPUT_CONF1_SHIFT (2) without masking to 8 bits leaves bits [11:8] set
when updating the 8-bit register LM3533_REG_OUTPUT_CONF1.
In drivers/base/regmap/regmap.c:_regmap_update_bits():
ret = _regmap_read(map, reg, &orig);
if (ret != 0)
return ret;
tmp = orig & ~mask;
tmp |= val & mask;
if (force_write || (tmp != orig) || map->force_write_field) {
ret = _regmap_write(map, reg, tmp);
Because orig is an 8-bit value (<= 0xff) and val & mask has bits [11:8]
set, tmp exceeds 0xff and tmp != orig is always true. This forces a
register write with tmp > 0xff, which causes regmap_smbus_byte_reg_write()
in drivers/base/regmap/regmap-i2c.c:
if (val > 0xff || reg > 0xff)
return -EINVAL;
to reject the write with -EINVAL and fail lm3533_led_probe() on SMBus
byte-data I2C controllers, or issue an unnecessary write on raw I2C
controllers.
Should the mask and value passed to regmap_update_bits() for
LM3533_REG_OUTPUT_CONF1 be masked to 8 bits (e.g. & 0xff or u8)?
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261101142435.130520-1-clamor95@gmail.com?part=1
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