[PATCH 17/18] ledtrig-blkdev: Add mode (read/write/rw) sysfs attributue

Ian Pilcher
2021-09-03T20:46:20Z

Show all modes, with current mode in square brackets, in show function

Signed-off-by: Ian Pilcher <arequipeno@gmail.com>
---
drivers/leds/trigger/ledtrig-blkdev.c | 67 +++++++++++++++++++++++++++
1 file changed, 67 insertions(+)

diff --git a/drivers/leds/trigger/ledtrig-blkdev.c b/drivers/leds/trigger/ledtrig-blkdev.c
index b23a5c98de98..ec167633e329 100644
--- a/drivers/leds/trigger/ledtrig-blkdev.c
+++ b/drivers/leds/trigger/ledtrig-blkdev.c
@@ -620,3 +620,70 @@ static ssize_t blkdev_time_store(struct device *const dev,

return count;
}
+
+
+/*
+ *
+ * LED mode device attribute
+ *
+ */
+
+static const struct {
+ const char *name;
+ const char *show;
+} blkdev_modes[] = {
+ [LEDTRIG_BLKDEV_MODE_RO] = {
+ .name = "read",
+ .show = "[read] write rw\n",
+ },
+ [LEDTRIG_BLKDEV_MODE_WO] = {
+ .name = "write",
+ .show = "read [write] rw\n",
+ },
+ [LEDTRIG_BLKDEV_MODE_RW] = {
+ .name = "rw",
+ .show = "read write [rw]\n",
+ },
+};
+
+static ssize_t blkdev_mode_show(struct device *const dev,
+ struct device_attribute *const attr,
+ char *const buf)
+{
+ const struct ledtrig_blkdev_led *const led =
+ led_trigger_get_drvdata(dev);
+
+ return sprintf(buf, blkdev_modes[READ_ONCE(led->mode)].show);
+}
+
+static ssize_t blkdev_mode_store(struct device *const dev,
+ struct device_attribute *const attr,
+ const char *const buf, const size_t count)
+{
+ struct ledtrig_blkdev_led *const led = led_trigger_get_drvdata(dev);
+ const char *const mode_name = blkdev_skip_space(buf);
+ const char *const endp = blkdev_find_space(mode_name);
+ const ptrdiff_t name_len = endp - mode_name; /* always >= 0 */
+ enum ledtrig_blkdev_mode mode;
+
+ if (name_len == 0) {
+ pr_info("blkdev LED: empty mode\n");
+ return -EINVAL;
+ }
+
+ for (mode = LEDTRIG_BLKDEV_MODE_RO;
+ mode <= LEDTRIG_BLKDEV_MODE_RW; ++mode) {
+
+ if (ledtrig_blkdev_streq(blkdev_modes[mode].name,
+ mode_name, name_len)) {
+ WRITE_ONCE(led->mode, mode);
+ return count;
+ }
+ }
+
+ pr_info("blkdev LED: invalid mode (%.*s)\n", (int)name_len, mode_name);
+ return -EINVAL;
+}
+
+static struct device_attribute ledtrig_blkdev_attr_mode =
+ __ATTR(mode, 0644, blkdev_mode_show, blkdev_mode_store);
--
2.31.1