From 2d8251d98ce0be96d79aec708aa70cab2b4f6f17 Mon Sep 17 00:00:00 2001 From: Gwendal Grignou Date: Fri, 30 Jan 2026 00:13:50 -0800 Subject: [PATCH] platform/chrome: lightbar: Report number of segments Add attribue `num_segments` to return the number of exposed LED segments in the lightbar. It can be smaller than the number of physical leds in the lightbar. Test: Check the attribute is present and returns a value when read. Signed-off-by: Gwendal Grignou Link: https://lore.kernel.org/r/20260130081351.487517-1-gwendal@google.com Signed-off-by: Tzung-Bi Shih --- drivers/platform/chrome/cros_ec_lightbar.c | 43 +++++++++++++++++++ .../linux/platform_data/cros_ec_commands.h | 11 +++++ 2 files changed, 54 insertions(+) diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c index 3702baff5d4f1..8ee7614503949 100644 --- a/drivers/platform/chrome/cros_ec_lightbar.c +++ b/drivers/platform/chrome/cros_ec_lightbar.c @@ -180,6 +180,47 @@ static ssize_t version_show(struct device *dev, return sysfs_emit(buf, "%d %d\n", version, flags); } +static ssize_t num_segments_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct ec_params_lightbar *param; + struct ec_response_lightbar *resp; + struct cros_ec_command *msg; + struct cros_ec_dev *ec = to_cros_ec_dev(dev); + uint32_t num = 0; + int ret; + + ret = lb_throttle(); + if (ret) + return ret; + + msg = alloc_lightbar_cmd_msg(ec); + if (!msg) + return -ENOMEM; + + param = (struct ec_params_lightbar *)msg->data; + param->cmd = LIGHTBAR_CMD_GET_PARAMS_V3; + msg->outsize = sizeof(param->cmd); + msg->insize = sizeof(resp->get_params_v3); + ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); + if (ret < 0 && ret != -EINVAL) + goto exit; + + if (msg->result == EC_RES_SUCCESS) { + resp = (struct ec_response_lightbar *)msg->data; + num = resp->get_params_v3.reported_led_num; + } + + /* + * Anything else (ie, EC_RES_INVALID_COMMAND) - no direct control over + * LEDs, return that no leds are supported. + */ + ret = sysfs_emit(buf, "%u\n", num); +exit: + kfree(msg); + return ret; +} + static ssize_t brightness_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) @@ -512,6 +553,7 @@ static ssize_t userspace_control_store(struct device *dev, /* Module initialization */ static DEVICE_ATTR_RW(interval_msec); +static DEVICE_ATTR_RO(num_segments); static DEVICE_ATTR_RO(version); static DEVICE_ATTR_WO(brightness); static DEVICE_ATTR_WO(led_rgb); @@ -521,6 +563,7 @@ static DEVICE_ATTR_RW(userspace_control); static struct attribute *__lb_cmds_attrs[] = { &dev_attr_interval_msec.attr, + &dev_attr_num_segments.attr, &dev_attr_version.attr, &dev_attr_brightness.attr, &dev_attr_led_rgb.attr, diff --git a/include/linux/platform_data/cros_ec_commands.h b/include/linux/platform_data/cros_ec_commands.h index 69294f79cc88a..9cbf024f56c3e 100644 --- a/include/linux/platform_data/cros_ec_commands.h +++ b/include/linux/platform_data/cros_ec_commands.h @@ -2005,6 +2005,14 @@ struct lightbar_params_v2_colors { struct rgb_s color[8]; /* 0-3 are Google colors */ } __ec_todo_packed; +struct lightbar_params_v3 { + /* + * Number of LEDs reported by the EC. + * May be less than the actual number of LEDs in the lightbar. + */ + uint8_t reported_led_num; +} __ec_todo_packed; + /* Lightbar program. */ #define EC_LB_PROG_LEN 192 struct lightbar_program { @@ -2086,6 +2094,8 @@ struct ec_response_lightbar { struct lightbar_params_v2_thresholds get_params_v2_thlds; struct lightbar_params_v2_colors get_params_v2_colors; + struct lightbar_params_v3 get_params_v3; + struct __ec_todo_unpacked { uint32_t num; uint32_t flags; @@ -2143,6 +2153,7 @@ enum lightbar_command { LIGHTBAR_CMD_SET_PARAMS_V2_THRESHOLDS = 31, LIGHTBAR_CMD_GET_PARAMS_V2_COLORS = 32, LIGHTBAR_CMD_SET_PARAMS_V2_COLORS = 33, + LIGHTBAR_CMD_GET_PARAMS_V3 = 34, LIGHTBAR_NUM_CMDS }; -- 2.47.3