[PATCH 3/4] platform/chrome: cros_ec_lightbar - Add userspace lightbar control bit to EC

From: Enric Balletbo i Serra
Date: Fri Oct 28 2016 - 12:56:17 EST


From: Eric Caruso <ejcaruso@xxxxxxxxxxxx>

Some devices might want to turn off the lightbar if e.g. the
system turns the screen off due to idleness. This prevents the
kernel from going through its normal suspend/resume pathways.

Signed-off-by: Eric Caruso <ejcaruso@xxxxxxxxxxxx>
Signed-off-by: Guenter Roeck <groeck@xxxxxxxxxxxx>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
---
drivers/platform/chrome/cros_ec_lightbar.c | 38 ++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
index 4df379d..e570c1e 100644
--- a/drivers/platform/chrome/cros_ec_lightbar.c
+++ b/drivers/platform/chrome/cros_ec_lightbar.c
@@ -38,6 +38,12 @@
/* Rate-limit the lightbar interface to prevent DoS. */
static unsigned long lb_interval_jiffies = 50 * HZ / 1000;

+/*
+ * Whether or not we have given userspace control of the lightbar.
+ * If this is true, we won't do anything during suspend/resume.
+ */
+static bool userspace_control;
+
static ssize_t interval_msec_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -407,11 +413,17 @@ int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)

int lb_suspend(struct cros_ec_dev *ec)
{
+ if (userspace_control)
+ return 0;
+
return lb_send_empty_cmd(ec, LIGHTBAR_CMD_SUSPEND);
}

int lb_resume(struct cros_ec_dev *ec)
{
+ if (userspace_control)
+ return 0;
+
return lb_send_empty_cmd(ec, LIGHTBAR_CMD_RESUME);
}

@@ -528,6 +540,30 @@ static ssize_t program_store(struct device *dev, struct device_attribute *attr,
return ret;
}

+static ssize_t userspace_control_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return scnprintf(buf, PAGE_SIZE, "%d\n", userspace_control);
+}
+
+static ssize_t userspace_control_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ bool enable;
+ int ret;
+
+ ret = strtobool(buf, &enable);
+ if (ret < 0)
+ return ret;
+
+ userspace_control = enable;
+
+ return count;
+}
+
/* Module initialization */

static DEVICE_ATTR_RW(interval_msec);
@@ -536,6 +572,7 @@ static DEVICE_ATTR_WO(brightness);
static DEVICE_ATTR_WO(led_rgb);
static DEVICE_ATTR_RW(sequence);
static DEVICE_ATTR_WO(program);
+static DEVICE_ATTR_RW(userspace_control);

static struct attribute *__lb_cmds_attrs[] = {
&dev_attr_interval_msec.attr,
@@ -544,6 +581,7 @@ static struct attribute *__lb_cmds_attrs[] = {
&dev_attr_led_rgb.attr,
&dev_attr_sequence.attr,
&dev_attr_program.attr,
+ &dev_attr_userspace_control.attr,
NULL,
};

--
2.1.0