diff options
| -rw-r--r-- | drivers/staging/greybus/Documentation/sysfs-bus-greybus | 17 | ||||
| -rw-r--r-- | drivers/staging/greybus/interface.c | 58 |
2 files changed, 75 insertions, 0 deletions
diff --git a/drivers/staging/greybus/Documentation/sysfs-bus-greybus b/drivers/staging/greybus/Documentation/sysfs-bus-greybus index 721010e22b25..62d03afe9c85 100644 --- a/drivers/staging/greybus/Documentation/sysfs-bus-greybus +++ b/drivers/staging/greybus/Documentation/sysfs-bus-greybus @@ -97,6 +97,23 @@ Contact: Greg Kroah-Hartman <greg@kroah.com> Description: Power measurement of the interface in microwatts (uW) +What: /sys/bus/greybus/devices/N-M.I/power_state +Date: March 2016 +KernelVersion: 4.XX +Contact: Greg Kroah-Hartman <greg@kroah.com> +Description: + This reflects the power state of a Greybus Interface. If the + value read from it is "on", then power is currently supplied to + the Interface. Otherwise this will read "off" and the power is + currently not supplied to the Interface. + + If the value read is "off", then writing "on" (or '1', 'y', + 'Y') to it will enable power to the Interface. If the value + read is "on", then writing "off" (or '0', 'n', 'N') to it will + disable power to the Interface. + + Writing the currently read value to it has no effect. + What: /sys/bus/greybus/devices/N-M.I/product_id Date: October 2015 KernelVersion: 4.XX diff --git a/drivers/staging/greybus/interface.c b/drivers/staging/greybus/interface.c index 3ad1c757d7e7..f5ed79c687d2 100644 --- a/drivers/staging/greybus/interface.c +++ b/drivers/staging/greybus/interface.c @@ -501,6 +501,63 @@ static ssize_t power_now_show(struct device *dev, } static DEVICE_ATTR_RO(power_now); +static ssize_t power_state_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gb_interface *intf = to_gb_interface(dev); + + if (intf->active) + return scnprintf(buf, PAGE_SIZE, "on\n"); + else + return scnprintf(buf, PAGE_SIZE, "off\n"); +} + +static ssize_t power_state_store(struct device *dev, + struct device_attribute *attr, const char *buf, + size_t len) +{ + struct gb_interface *intf = to_gb_interface(dev); + bool activate; + int ret = 0; + + if (kstrtobool(buf, &activate)) + return -EINVAL; + + mutex_lock(&intf->mutex); + + if (activate == intf->active) + goto unlock; + + if (activate) { + ret = gb_interface_activate(intf); + if (ret) { + dev_err(&intf->dev, + "failed to activate interface: %d\n", ret); + goto unlock; + } + + ret = gb_interface_enable(intf); + if (ret) { + dev_err(&intf->dev, + "failed to enable interface: %d\n", ret); + gb_interface_deactivate(intf); + goto unlock; + } + } else { + gb_interface_disable(intf); + gb_interface_deactivate(intf); + } + +unlock: + mutex_unlock(&intf->mutex); + + if (ret) + return ret; + + return len; +} +static DEVICE_ATTR_RW(power_state); + static const char *gb_interface_type_string(struct gb_interface *intf) { static const char * const types[] = { @@ -541,6 +598,7 @@ static struct attribute *interface_power_attrs[] = { &dev_attr_voltage_now.attr, &dev_attr_current_now.attr, &dev_attr_power_now.attr, + &dev_attr_power_state.attr, NULL }; |