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Date: Fri, 8 Mar 2019 17:42:39 -0800
From: RaviChandra Sadineni <ravisadineni@...omium.org>
To: ravisadineni@...omium.org
Cc: Benson Leung <bleung@...omium.org>,
Enric Balletbo i Serra <enric.balletbo@...labora.com>,
Guenter Roeck <groeck@...omium.org>,
linux-kernel@...r.kernel.org, Lee Jones <lee.jones@...aro.org>,
tbroch@...gle.com
Subject: [PATCH V5] platform/chrome: mfd/cros_ec_dev: Add sysfile to force
On chromebooks, power_manager daemon normally shuts down(S5) the device
when the battery charge falls below 4% threshold. ChromeOS EC then
normally spends an hour in S5 before hibernating. If the battery charge
falls below critical threshold in the mean time, EC does a battery cutoff
instead of hibernating. On some chromebooks, S5 is optimal enough
resulting in EC hibernating without battery cutoff. This results in
battery deep discharging. This is a bad user experience as battery
has to trickle charge before booting when the AC is plugged in the next
time.
This patch exposes a sysfs file for an userland daemon to suggest EC if it
has to do a battery cutoff instead of hibernating when the system enters
S5 next time.
This attribute is present only if EC supports EC_FEATURE_BATTERY.
Signed-off-by: RaviChandra Sadineni <ravisadineni@...omium.org>
---
V5: Expose flag only when EC_FEATURE_BATTERY is supported.
V4: Addressed comments from Enric.
V3: Make battery-cutoff generic and expose 'at-shutdown' flag.
V2: Use kstrtobool() instead of kstrtou8() and add documentation.
.../ABI/testing/sysfs-class-chromeos | 16 ++++++
drivers/mfd/cros_ec_dev.c | 4 ++
drivers/platform/chrome/cros_ec_sysfs.c | 49 +++++++++++++++++++
include/linux/mfd/cros_ec.h | 2 +
4 files changed, 71 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-class-chromeos b/Documentation/ABI/testing/sysfs-class-chromeos
index 5819699d66ec..0927704d1629 100644
--- a/Documentation/ABI/testing/sysfs-class-chromeos
+++ b/Documentation/ABI/testing/sysfs-class-chromeos
@@ -30,3 +30,19 @@ Date: August 2015
KernelVersion: 4.2
Description:
Show the information about the EC software and hardware.
+
+What: /sys/class/chromeos/<ec-device-name>/battery_cuttoff
+Date: February 2019
+Contact: Ravi Chandra Sadineni <ravisadineni@...omium.org>
+Description:
+ cros_ec battery cuttoff configuration. Only option
+ currently exposed is 'at-shutdown'.
+
+ 'at-shutdown' sends a host command to EC requesting
+ battery cutoff on next shutdown. If AC is plugged
+ in before next shutdown, EC ignores the request and
+ resets the flag.
+
+ Currently EC does not expose a host command to read
+ the status of battery cutoff configuration. Thus this
+ flag is write-only.
diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index ed809fc97df8..7580be23dfb3 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -502,6 +502,10 @@ static int ec_device_probe(struct platform_device *pdev)
retval);
}
+ /* check whether EC_FEATURE_BATTERY is supported. */
+ if (cros_ec_check_features(ec, EC_FEATURE_BATTERY))
+ ec->has_battery = true;
+
return 0;
failed:
diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
index fe0b7614ae1b..3d9ab55dddc0 100644
--- a/drivers/platform/chrome/cros_ec_sysfs.c
+++ b/drivers/platform/chrome/cros_ec_sysfs.c
@@ -308,14 +308,61 @@ static ssize_t kb_wake_angle_store(struct device *dev,
return count;
}
+/* Battery cutoff control */
+static ssize_t battery_cutoff_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct ec_params_battery_cutoff *param;
+ struct cros_ec_command *msg;
+ int ret;
+ struct cros_ec_dev *ec = to_cros_ec_dev(dev);
+ char *p;
+ int len;
+
+ msg = kmalloc(sizeof(*msg) + EC_HOST_PARAM_SIZE, GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ param = (struct ec_params_battery_cutoff *)msg->data;
+ msg->command = EC_CMD_BATTERY_CUT_OFF + ec->cmd_offset;
+ msg->version = 1;
+ msg->outsize = sizeof(*param);
+ msg->insize = 0;
+
+ p = memchr(buf, '\n', count);
+ len = p ? p - buf : count;
+
+ if (len == 11 && !strncmp(buf, "at-shutdown", len)) {
+ param->flags = EC_BATTERY_CUTOFF_FLAG_AT_SHUTDOWN;
+ } else {
+ count = -EINVAL;
+ goto exit;
+ }
+
+ ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+ if (ret < 0)
+ count = ret;
+exit:
+ kfree(msg);
+ return count;
+}
+
/* Module initialization */
static DEVICE_ATTR_RW(reboot);
static DEVICE_ATTR_RO(version);
static DEVICE_ATTR_RO(flashinfo);
static DEVICE_ATTR_RW(kb_wake_angle);
+/*
+ * Currently EC does not expose a host command to read the status of
+ * battery cutoff configuration. Also there is no requirement to read
+ * the flag from userland. So marking this attribute as write-only.
+ */
+static DEVICE_ATTR_WO(battery_cutoff);
static struct attribute *__ec_attrs[] = {
+ &dev_attr_battery_cutoff.attr,
&dev_attr_kb_wake_angle.attr,
&dev_attr_reboot.attr,
&dev_attr_version.attr,
@@ -331,6 +378,8 @@ static umode_t cros_ec_ctrl_visible(struct kobject *kobj,
if (a == &dev_attr_kb_wake_angle.attr && !ec->has_kb_wake_angle)
return 0;
+ if (a == &dev_attr_battery_cutoff.attr && !ec->has_battery)
+ return 0;
return a->mode;
}
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index 8f2a8918bfa3..de5280c96bd9 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -192,6 +192,7 @@ struct cros_ec_debugfs;
* @has_kb_wake_angle: True if at least 2 accelerometer are connected to the EC.
* @cmd_offset: Offset to apply for each command.
* @features: Features supported by the EC.
+ * @has_battery: True if EC supports EC_FEATURE_BATTERY.
*/
struct cros_ec_dev {
struct device class_dev;
@@ -202,6 +203,7 @@ struct cros_ec_dev {
bool has_kb_wake_angle;
u16 cmd_offset;
u32 features[2];
+ bool has_battery;
};
#define to_cros_ec_dev(dev) container_of(dev, struct cros_ec_dev, class_dev)
--
2.20.1
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