From: RaviChandra Sadineni <[email protected]> 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. Signed-off-by: RaviChandra Sadineni <[email protected]> --- 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/platform/chrome/cros_ec_sysfs.c | 47 +++++++++++++++++++ 2 files changed, 63 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 <[email protected]> +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/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c index fe0b7614ae1b..a35e1188f28f 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, -- 2.20.1
