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Message-Id: <20260129-v6-19-topic-ti-lp5860-fault-v1-1-49c812dc06da@pengutronix.de>
Date: Thu, 29 Jan 2026 12:01:44 +0100
From: Steffen Trumtrar <s.trumtrar@...gutronix.de>
To: Lee Jones <lee@...nel.org>, Pavel Machek <pavel@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
Steffen Trumtrar <s.trumtrar@...gutronix.de>
Subject: [PATCH] leds: lp5860: detect and report fault state
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@...gutronix.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@...gutronix.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@...gutronix.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@...gutronix.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@...gutronix.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@...gutronix.de>
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