[PATCH 03/17] staging: nuc-wmi: add support for changing S0 brightness

Mauro Carvalho Chehab
2021-05-16T10:53:53Z

Now that the core logic is in place, let's add support to
adjust the S0 brightness level.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
drivers/staging/nuc-led/nuc-wmi.c | 79 +++++++++++++++++++++++++++++++
1 file changed, 79 insertions(+)

diff --git a/drivers/staging/nuc-led/nuc-wmi.c b/drivers/staging/nuc-led/nuc-wmi.c
index b75ddd47e443..62c2764814dd 100644
--- a/drivers/staging/nuc-led/nuc-wmi.c
+++ b/drivers/staging/nuc-led/nuc-wmi.c
@@ -392,7 +392,85 @@ static ssize_t store_indicator(struct device *dev,
return -EINVAL;
}

+/* Get S0 brightness */
+static ssize_t show_s0_brightness(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct led_classdev *cdev = dev_get_drvdata(dev);
+ struct nuc_nmi_led *led = container_of(cdev, struct nuc_nmi_led, cdev);
+ u8 cmd, input[NUM_INPUT_ARGS] = { 0 };
+ u8 output[NUM_OUTPUT_ARGS];
+ int ret;
+
+ cmd = LED_NEW_GET_STATUS;
+ input[0] = LED_NEW_GET_CONTROL_ITEM;
+ input[1] = led->id;
+ input[2] = led->indicator;
+ input[3] = 0;
+
+ ret = nuc_nmi_cmd(dev, cmd, input, output);
+ if (ret)
+ return ret;
+
+ /* Multicolor uses a scale from 0 to 100 */
+ if (led->color_type & (LED_BLUE_AMBER | LED_BLUE_WHITE | LED_RGB))
+ return scnprintf(buf, PAGE_SIZE, "%d%%\n", output[0]);
+
+ /* single color uses 0, 50% and 100% */
+ return scnprintf(buf, PAGE_SIZE, "%d%%\n", output[0] * 50);
+}
+
+/* Change S0 brightness */
+static ssize_t store_s0_brightness(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct led_classdev *cdev = dev_get_drvdata(dev);
+ struct nuc_nmi_led *led = container_of(cdev, struct nuc_nmi_led, cdev);
+ u8 cmd, input[NUM_INPUT_ARGS] = { 0 };
+ int ret;
+ u8 val;
+
+ if (led->indicator == LED_IND_DISABLE) {
+ dev_dbg(dev, "Led %s is disabled. ignoring it.\n", cdev->name);
+ return -EACCES;
+ }
+
+ if (kstrtou8(buf, 0, &val) || val > 100)
+ return -EINVAL;
+
+ /*
+ * For single-color LEDs, the value should be between 0 to 2, but,
+ * in order to have a consistent API, let's always handle it as if
+ * it is a percentage, for both multicolor and single color LEDs.
+ * So:
+ * value == 0 will disable the LED
+ * value up to 74% will set it the brightness to 50%
+ * value equal or above 75% will use the maximum brightness.
+ */
+ if (!(led->color_type & (LED_BLUE_AMBER | LED_BLUE_WHITE | LED_RGB))) {
+ if (val > 0 && val < 75)
+ val = 1;
+ if (val >= 75)
+ val = 2;
+ }
+
+ cmd = LED_SET_VALUE;
+ input[0] = led->id;
+ input[1] = led->indicator;
+ input[2] = 0; /* FIXME: replace by an enum */
+ input[3] = val;
+
+ ret = nuc_nmi_cmd(dev, cmd, input, NULL);
+ if (ret)
+ return ret;
+
+ return len;
+}
+
static LED_ATTR_RW(indicator);
+static LED_ATTR_RW(s0_brightness);

/*
* Attributes for multicolor LEDs
@@ -400,6 +478,7 @@ static LED_ATTR_RW(indicator);

static struct attribute *nuc_wmi_multicolor_led_attr[] = {
&dev_attr_indicator.attr,
+ &dev_attr_s0_brightness.attr,
NULL,
};

--
2.31.1