* [PATCH RESEND] leds: lp5860: detect and report fault state
@ 2026-03-05 8:49 Steffen Trumtrar
2026-03-09 18:17 ` Lee Jones
0 siblings, 1 reply; 2+ messages in thread
From: Steffen Trumtrar @ 2026-03-05 8:49 UTC (permalink / raw)
To: Lee Jones, Pavel Machek; +Cc: linux-kernel, linux-leds, Steffen Trumtrar
The lp5860 can detect shorts and open circuits. If an open (LOD) or
short (LSD) is detected, the global bit in LP5860_FAULT_STATE is set.
The channel that caused this can be read from the corresponding Dot_lsdX
and Dot_lodX register and bit offset.
The global bits can be cleared by writing 0xf to the LOD/LSD_clear
register.
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
Documentation/ABI/testing/sysfs-class-spi-lp5860 | 50 +++++++++
drivers/leds/rgb/leds-lp5860-core.c | 135 +++++++++++++++++++++++
include/linux/platform_data/leds-lp5860.h | 12 +-
3 files changed, 196 insertions(+), 1 deletion(-)
diff --git a/Documentation/ABI/testing/sysfs-class-spi-lp5860 b/Documentation/ABI/testing/sysfs-class-spi-lp5860
index 80b22a9d66421..ded9eec855bd9 100644
--- a/Documentation/ABI/testing/sysfs-class-spi-lp5860
+++ b/Documentation/ABI/testing/sysfs-class-spi-lp5860
@@ -21,3 +21,53 @@ Contact: Steffen Trumtrar <kernel@pengutronix.de>
Description:
Contains and sets the global brightness for the R color group.
Can be adjusted in 128 steps from 0% to 100% of the maximum brightness.
+
+What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state
+Date: January 2026
+KernelVersion: 6.19
+Contact: Steffen Trumtrar <kernel@pengutronix.de>
+Description:
+ Contains and sets the global fault state:
+
+ * 3: Open and short detected
+ * 2: Open detected
+ * 1: Short detected
+
+ Can be cleared by writing the corresponding value back to fault_state.
+
+ Example usage::
+
+ ## Read
+ # cat /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state
+ 2
+
+ ## Write
+ # echo 2 > /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state
+
+What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state_open
+Date: January 2026
+KernelVersion: 6.19
+Contact: Steffen Trumtrar <kernel@pengutronix.de>
+Description:
+ Contains all LEDs and channels where an open condition was detected.
+ The format is ledname:channel.
+
+ Example usage::
+
+ ## Read
+ # cat /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state_open
+ rgb1:0 rgb2:4
+
+What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state_short
+Date: May 2025
+KernelVersion: 6.15
+Contact: Steffen Trumtrar <kernel@pengutronix.de>
+Description:
+ Contains all LEDs and channels where a short condition was detected.
+ The format is ledname:channel.
+
+ Example usage::
+
+ ## Read
+ # cat /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state_short
+ rgb1:0 rgb2:4
diff --git a/drivers/leds/rgb/leds-lp5860-core.c b/drivers/leds/rgb/leds-lp5860-core.c
index 79a932edd1d24..ef00577a63a73 100644
--- a/drivers/leds/rgb/leds-lp5860-core.c
+++ b/drivers/leds/rgb/leds-lp5860-core.c
@@ -19,6 +19,138 @@ static struct lp5860_led *mcled_cdev_to_led(struct led_classdev_mc *mc_cdev)
return container_of(mc_cdev, struct lp5860_led, mc_cdev);
}
+static const char *lp5860_find_led(struct lp5860 *lp, unsigned int idx)
+{
+ struct mc_subled *mc_led_info;
+ struct lp5860_led *led;
+ int i, j;
+
+ for (i = lp->leds_count - 1; i >= 0; i--) {
+ led = &lp->leds[i];
+
+ mc_led_info = led->mc_cdev.subled_info;
+
+ for (j = 0; j < led->mc_cdev.num_colors; j++) {
+ if (mc_led_info[j].channel == idx)
+ return led->mc_cdev.led_cdev.dev->kobj.name;
+ }
+ }
+
+ return 0;
+}
+
+static ssize_t lp5860_fault_state_lod_lsd(struct lp5860 *led, char *buf,
+ unsigned int reg, unsigned int length)
+{
+ unsigned int value = 0;
+ unsigned int dot, bit;
+ unsigned int max_bits;
+ unsigned int offset = 0;
+ int len = 0;
+ bool match = false;
+ int ret;
+
+ for (dot = 0; dot < length; dot++) {
+ match = false;
+ ret = regmap_read(led->regmap, reg + dot, &value);
+ if (ret)
+ return ret;
+
+ max_bits = BITS_PER_BYTE;
+ /* every 3rd Dot_x register only has 2 bits */
+ if (dot % 3 == 2)
+ max_bits = 2;
+
+ for (bit = 0; bit < max_bits; bit++) {
+ offset++;
+ if (value & BIT(bit)) {
+ len += sprintf(buf + len, "%s:%d", lp5860_find_led(led, offset),
+ offset - 1);
+ match = true;
+ len += sprintf(buf + len, " ");
+ }
+ }
+ }
+
+ buf[len++] = '\n';
+
+ return len;
+}
+
+static ssize_t lp5860_fault_state_open_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct lp5860 *led = dev_get_drvdata(dev);
+ unsigned int value = 0;
+ int ret;
+
+ ret = regmap_read(led->regmap, LP5860_REG_FAULT_STATE, &value);
+ if (ret)
+ return ret;
+
+ if (!(value & LP5860_FAULT_STATE_LOD))
+ return 0;
+
+ return lp5860_fault_state_lod_lsd(led, buf, LP5860_REG_DOT_LOD_START,
+ LP5860_DOT_LOD_LENGTH);
+}
+static LP5860_DEV_ATTR_R(fault_state_open);
+
+static ssize_t lp5860_fault_state_short_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct lp5860 *led = dev_get_drvdata(dev);
+ unsigned int value = 0;
+ int ret;
+
+ ret = regmap_read(led->regmap, LP5860_REG_FAULT_STATE, &value);
+ if (ret)
+ return ret;
+
+ if (!(value & LP5860_FAULT_STATE_LSD))
+ return 0;
+
+ return lp5860_fault_state_lod_lsd(led, buf, LP5860_REG_DOT_LSD_START,
+ LP5860_DOT_LSD_LENGTH);
+}
+static LP5860_DEV_ATTR_R(fault_state_short);
+
+static ssize_t lp5860_fault_state_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct lp5860 *led = dev_get_drvdata(dev);
+ unsigned int value = 0;
+ int ret;
+
+ ret = regmap_read(led->regmap, LP5860_REG_FAULT_STATE, &value);
+ if (ret)
+ return ret;
+ return sysfs_emit(buf, "%d\n", (value & 0x3));
+}
+
+static ssize_t lp5860_fault_state_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct lp5860 *led = dev_get_drvdata(dev);
+ unsigned int value = 0;
+ int ret;
+
+ if (kstrtoint(buf, 0, &value))
+ return -EINVAL;
+
+ if (value & LP5860_FAULT_STATE_LOD)
+ ret = regmap_write(led->regmap, LP5860_REG_LOD_CLEAR, 0xf);
+ if (value & LP5860_FAULT_STATE_LSD)
+ ret = regmap_write(led->regmap, LP5860_REG_LSD_CLEAR, 0xf);
+
+ if (ret < 0)
+ return ret;
+ return len;
+}
+static LP5860_DEV_ATTR_RW(fault_state);
+
LP5860_SHOW_MODE(r_global_brightness_set, LP5860_REG_R_CURRENT_SET, LP5860_CC_GROUP_MASK, 0)
LP5860_STORE_MODE(r_global_brightness_set, LP5860_REG_R_CURRENT_SET, LP5860_CC_GROUP_MASK, 0)
DEVICE_ATTR_RW(r_global_brightness_set);
@@ -35,6 +167,9 @@ static struct attribute *lp5860_led_attrs[] = {
&dev_attr_r_global_brightness_set.attr,
&dev_attr_g_global_brightness_set.attr,
&dev_attr_b_global_brightness_set.attr,
+ &dev_attr_fault_state_open.attr,
+ &dev_attr_fault_state_short.attr,
+ &dev_attr_fault_state.attr,
NULL,
};
diff --git a/include/linux/platform_data/leds-lp5860.h b/include/linux/platform_data/leds-lp5860.h
index 94d184702b11a..d032a0e6d2617 100644
--- a/include/linux/platform_data/leds-lp5860.h
+++ b/include/linux/platform_data/leds-lp5860.h
@@ -189,6 +189,9 @@
#define LP5860_DOT_CS_OFF 0x00
/* Dot lod value */
+#define LP5860_FAULT_STATE_LOD BIT(1)
+#define LP5860_FAULT_STATE_LSD BIT(0)
+
#define LP5860_DOT_LOD0_OFFSET 0
#define LP5860_DOT_LOD1_OFFSET 1
#define LP5860_DOT_LOD2_OFFSET 2
@@ -201,7 +204,9 @@
#define LP5860_DOT_LOD_ON 0x01
#define LP5860_DOT_LOD_OFF 0x00
-/* dot lsd value */
+/* Dot lsd value */
+#define LP5860_DOT_LOD_LENGTH 0x20
+
#define LP5860_DOT_LSD0_OFFSET 0
#define LP5860_DOT_LSD1_OFFSET 1
#define LP5860_DOT_LSD2_OFFSET 2
@@ -215,6 +220,8 @@
#define LP5860_DOT_LSD_OFF 0x00
/* Register lod state */
+#define LP5860_DOT_LSD_LENGTH 0x20
+
#define LP5860_GLOBAL_LOD_OFFSET 1
#define LP5860_GLOBAL_LOD_STATE BIT(1)
#define LP5860_GLOBAL_LSD_OFFSET 0
@@ -248,6 +255,9 @@
*/
#define LP5860_MAX_LED_CHANNELS 4
+#define LP5860_DEV_ATTR_R(name) \
+ DEVICE_ATTR(name, 0444, lp5860_##name##_show, NULL)
+
#define LP5860_DEV_ATTR_RW(name) \
DEVICE_ATTR(name, 0644, lp5860_##name##_show, lp5860_##name##_store)
---
base-commit: d60f615f21e161506b3ac9bee8add471f0e27a8c
change-id: 20260129-v6-19-topic-ti-lp5860-fault-c8bd1f59fc3f
Best regards,
--
Steffen Trumtrar <s.trumtrar@pengutronix.de>
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH RESEND] leds: lp5860: detect and report fault state
2026-03-05 8:49 [PATCH RESEND] leds: lp5860: detect and report fault state Steffen Trumtrar
@ 2026-03-09 18:17 ` Lee Jones
0 siblings, 0 replies; 2+ messages in thread
From: Lee Jones @ 2026-03-09 18:17 UTC (permalink / raw)
To: Steffen Trumtrar; +Cc: Pavel Machek, linux-kernel, linux-leds
On Thu, 05 Mar 2026, Steffen Trumtrar wrote:
> The lp5860 can detect shorts and open circuits. If an open (LOD) or
> short (LSD) is detected, the global bit in LP5860_FAULT_STATE is set.
> The channel that caused this can be read from the corresponding Dot_lsdX
> and Dot_lodX register and bit offset.
>
> The global bits can be cleared by writing 0xf to the LOD/LSD_clear
> register.
>
> Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
> ---
> Documentation/ABI/testing/sysfs-class-spi-lp5860 | 50 +++++++++
> drivers/leds/rgb/leds-lp5860-core.c | 135 +++++++++++++++++++++++
> include/linux/platform_data/leds-lp5860.h | 12 +-
> 3 files changed, 196 insertions(+), 1 deletion(-)
I don't have a general issue with this.
Couple of nits to fix.
Also give the LED community chance to take a better look.
> diff --git a/Documentation/ABI/testing/sysfs-class-spi-lp5860 b/Documentation/ABI/testing/sysfs-class-spi-lp5860
> index 80b22a9d66421..ded9eec855bd9 100644
> --- a/Documentation/ABI/testing/sysfs-class-spi-lp5860
> +++ b/Documentation/ABI/testing/sysfs-class-spi-lp5860
> @@ -21,3 +21,53 @@ Contact: Steffen Trumtrar <kernel@pengutronix.de>
> Description:
> Contains and sets the global brightness for the R color group.
> Can be adjusted in 128 steps from 0% to 100% of the maximum brightness.
What is this applied to?
> +
> +What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state
> +Date: January 2026
> +KernelVersion: 6.19
Update.
> +Contact: Steffen Trumtrar <kernel@pengutronix.de>
> +Description:
> + Contains and sets the global fault state:
> +
> + * 3: Open and short detected
> + * 2: Open detected
> + * 1: Short detected
> +
> + Can be cleared by writing the corresponding value back to fault_state.
> +
> + Example usage::
> +
> + ## Read
> + # cat /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state
> + 2
> +
> + ## Write
> + # echo 2 > /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state
> +
> +What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state_open
> +Date: January 2026
> +KernelVersion: 6.19
> +Contact: Steffen Trumtrar <kernel@pengutronix.de>
> +Description:
> + Contains all LEDs and channels where an open condition was detected.
> + The format is ledname:channel.
> +
> + Example usage::
> +
> + ## Read
> + # cat /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state_open
> + rgb1:0 rgb2:4
> +
> +What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state_short
> +Date: May 2025
> +KernelVersion: 6.15
> +Contact: Steffen Trumtrar <kernel@pengutronix.de>
> +Description:
> + Contains all LEDs and channels where a short condition was detected.
> + The format is ledname:channel.
> +
> + Example usage::
> +
> + ## Read
> + # cat /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fault_state_short
> + rgb1:0 rgb2:4
> diff --git a/drivers/leds/rgb/leds-lp5860-core.c b/drivers/leds/rgb/leds-lp5860-core.c
> index 79a932edd1d24..ef00577a63a73 100644
> --- a/drivers/leds/rgb/leds-lp5860-core.c
> +++ b/drivers/leds/rgb/leds-lp5860-core.c
> @@ -19,6 +19,138 @@ static struct lp5860_led *mcled_cdev_to_led(struct led_classdev_mc *mc_cdev)
> return container_of(mc_cdev, struct lp5860_led, mc_cdev);
> }
>
> +static const char *lp5860_find_led(struct lp5860 *lp, unsigned int idx)
lp5860_led_name()
> +{
> + struct mc_subled *mc_led_info;
> + struct lp5860_led *led;
You could define these inside the scope.
> + int i, j;
> +
> + for (i = lp->leds_count - 1; i >= 0; i--) {
What's the reason for counting downwards?
> + led = &lp->leds[i];
> +
> + mc_led_info = led->mc_cdev.subled_info;
> +
> + for (j = 0; j < led->mc_cdev.num_colors; j++) {
for (int j ... ?
> + if (mc_led_info[j].channel == idx)
Is there no guarantee that j == channel?
Are there gaps?
> + return led->mc_cdev.led_cdev.dev->kobj.name;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static ssize_t lp5860_fault_state_lod_lsd(struct lp5860 *led, char *buf,
What does that name even mean?
Can it be improved?
> + unsigned int reg, unsigned int length)
> +{
> + unsigned int value = 0;
> + unsigned int dot, bit;
> + unsigned int max_bits;
> + unsigned int offset = 0;
> + int len = 0;
> + bool match = false;
This doesn't need to be initialised.
> + int ret;
> +
> + for (dot = 0; dot < length; dot++) {
> + match = false;
-ENOSQUISH - add a '\n'
> + ret = regmap_read(led->regmap, reg + dot, &value)
> + if (ret)
> + return ret;
> +
> + max_bits = BITS_PER_BYTE;
> + /* every 3rd Dot_x register only has 2 bits */
Sentences start with an uppercase char.
> + if (dot % 3 == 2)
> + max_bits = 2;
> +
> + for (bit = 0; bit < max_bits; bit++) {
> + offset++;
-ENOSQUISH - add a '\n'
> + if (value & BIT(bit)) {
> + len += sprintf(buf + len, "%s:%d", lp5860_find_led(led, offset),
> + offset - 1);
> + match = true;
> + len += sprintf(buf + len, " ");
> + }
> + }
> + }
> +
> + buf[len++] = '\n';
> +
> + return len;
> +}
> +
> +static ssize_t lp5860_fault_state_open_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct lp5860 *led = dev_get_drvdata(dev);
> + unsigned int value = 0;
> + int ret;
> +
> + ret = regmap_read(led->regmap, LP5860_REG_FAULT_STATE, &value);
> + if (ret)
> + return ret;
> +
> + if (!(value & LP5860_FAULT_STATE_LOD))
> + return 0;
> +
> + return lp5860_fault_state_lod_lsd(led, buf, LP5860_REG_DOT_LOD_START,
> + LP5860_DOT_LOD_LENGTH);
> +}
> +static LP5860_DEV_ATTR_R(fault_state_open);
> +
> +static ssize_t lp5860_fault_state_short_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct lp5860 *led = dev_get_drvdata(dev);
> + unsigned int value = 0;
Can regmap_read() succeed and not initialise value?
> + int ret;
> +
> + ret = regmap_read(led->regmap, LP5860_REG_FAULT_STATE, &value);
> + if (ret)
> + return ret;
> +
> + if (!(value & LP5860_FAULT_STATE_LSD))
> + return 0;
> +
> + return lp5860_fault_state_lod_lsd(led, buf, LP5860_REG_DOT_LSD_START,
> + LP5860_DOT_LSD_LENGTH);
> +}
> +static LP5860_DEV_ATTR_R(fault_state_short);
> +
> +static ssize_t lp5860_fault_state_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct lp5860 *led = dev_get_drvdata(dev);
> + unsigned int value = 0;
> + int ret;
> +
> + ret = regmap_read(led->regmap, LP5860_REG_FAULT_STATE, &value);
> + if (ret)
> + return ret;
-ENOSQUISH - add a '\n'
> + return sysfs_emit(buf, "%d\n", (value & 0x3));
> +}
> +
> +static ssize_t lp5860_fault_state_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t len)
> +{
> + struct lp5860 *led = dev_get_drvdata(dev);
> + unsigned int value = 0;
> + int ret;
> +
> + if (kstrtoint(buf, 0, &value))
> + return -EINVAL;
> +
> + if (value & LP5860_FAULT_STATE_LOD)
> + ret = regmap_write(led->regmap, LP5860_REG_LOD_CLEAR, 0xf);
> + if (value & LP5860_FAULT_STATE_LSD)
> + ret = regmap_write(led->regmap, LP5860_REG_LSD_CLEAR, 0xf);
> +
> + if (ret < 0)
> + return ret;
-ENOSQUISH - add a '\n'
> + return len;
> +}
> +static LP5860_DEV_ATTR_RW(fault_state);
> +
> LP5860_SHOW_MODE(r_global_brightness_set, LP5860_REG_R_CURRENT_SET, LP5860_CC_GROUP_MASK, 0)
> LP5860_STORE_MODE(r_global_brightness_set, LP5860_REG_R_CURRENT_SET, LP5860_CC_GROUP_MASK, 0)
> DEVICE_ATTR_RW(r_global_brightness_set);
> @@ -35,6 +167,9 @@ static struct attribute *lp5860_led_attrs[] = {
> &dev_attr_r_global_brightness_set.attr,
> &dev_attr_g_global_brightness_set.attr,
> &dev_attr_b_global_brightness_set.attr,
> + &dev_attr_fault_state_open.attr,
> + &dev_attr_fault_state_short.attr,
> + &dev_attr_fault_state.attr,
> NULL,
> };
>
> diff --git a/include/linux/platform_data/leds-lp5860.h b/include/linux/platform_data/leds-lp5860.h
> index 94d184702b11a..d032a0e6d2617 100644
> --- a/include/linux/platform_data/leds-lp5860.h
> +++ b/include/linux/platform_data/leds-lp5860.h
> @@ -189,6 +189,9 @@
> #define LP5860_DOT_CS_OFF 0x00
>
> /* Dot lod value */
> +#define LP5860_FAULT_STATE_LOD BIT(1)
> +#define LP5860_FAULT_STATE_LSD BIT(0)
I don't see the point of defines if the nomenclature isn't self explanatory.
> #define LP5860_DOT_LOD0_OFFSET 0
> #define LP5860_DOT_LOD1_OFFSET 1
> #define LP5860_DOT_LOD2_OFFSET 2
> @@ -201,7 +204,9 @@
> #define LP5860_DOT_LOD_ON 0x01
> #define LP5860_DOT_LOD_OFF 0x00
>
> -/* dot lsd value */
> +/* Dot lsd value */
> +#define LP5860_DOT_LOD_LENGTH 0x20
> +
> #define LP5860_DOT_LSD0_OFFSET 0
> #define LP5860_DOT_LSD1_OFFSET 1
> #define LP5860_DOT_LSD2_OFFSET 2
> @@ -215,6 +220,8 @@
> #define LP5860_DOT_LSD_OFF 0x00
>
> /* Register lod state */
> +#define LP5860_DOT_LSD_LENGTH 0x20
> +
> #define LP5860_GLOBAL_LOD_OFFSET 1
> #define LP5860_GLOBAL_LOD_STATE BIT(1)
> #define LP5860_GLOBAL_LSD_OFFSET 0
> @@ -248,6 +255,9 @@
> */
> #define LP5860_MAX_LED_CHANNELS 4
>
> +#define LP5860_DEV_ATTR_R(name) \
> + DEVICE_ATTR(name, 0444, lp5860_##name##_show, NULL)
> +
> #define LP5860_DEV_ATTR_RW(name) \
> DEVICE_ATTR(name, 0644, lp5860_##name##_show, lp5860_##name##_store)
>
>
> ---
> base-commit: d60f615f21e161506b3ac9bee8add471f0e27a8c
> change-id: 20260129-v6-19-topic-ti-lp5860-fault-c8bd1f59fc3f
>
> Best regards,
> --
> Steffen Trumtrar <s.trumtrar@pengutronix.de>
>
>
--
Lee Jones [李琼斯]
^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-03-05 8:49 [PATCH RESEND] leds: lp5860: detect and report fault state Steffen Trumtrar
2026-03-09 18:17 ` Lee Jones
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