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

Signed-off-by: Ian Pilcher <arequip...@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 481b2d142db2..88e2a11af1a9 100644
--- a/drivers/leds/trigger/ledtrig-blkdev.c
+++ b/drivers/leds/trigger/ledtrig-blkdev.c
@@ -591,3 +591,70 @@ 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 (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


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