Re: [PATCH v9 05/18] input: cyapa: add power management interfaces supported for the device

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Mon, Nov 03, 2014 at 04:32:57PM +0800, Dudley Du wrote:
> Add suspend_scanrate_ms power management interfaces in device's
> power group, so users or applications can control the power management
> strategy of trackpad device as their requirements.
> TEST=test on Chromebooks.
> 
> Signed-off-by: Dudley Du <dudl@cypress.com>
> ---
>  drivers/input/mouse/cyapa.c | 112 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 112 insertions(+)
> 
> diff --git a/drivers/input/mouse/cyapa.c b/drivers/input/mouse/cyapa.c
> index fac361a..420696d 100644
> --- a/drivers/input/mouse/cyapa.c
> +++ b/drivers/input/mouse/cyapa.c
> @@ -505,6 +505,96 @@ u16 cyapa_pwr_cmd_to_sleep_time(u8 pwr_mode)
>  				   : (encoded_time - 5) * 20;
>  }
>  
> +#ifdef CONFIG_PM_SLEEP
> +static ssize_t cyapa_show_suspend_scanrate(struct device *dev,
> +					   struct device_attribute *attr,
> +					   char *buf)
> +{
> +	struct cyapa *cyapa = dev_get_drvdata(dev);
> +	u8 pwr_cmd = cyapa->suspend_power_mode;
> +	u16 sleep_time;
> +	int len;
> +	int ret;
> +
> +	ret = mutex_lock_interruptible(&cyapa->state_sync_lock);
> +	if (ret)
> +		return ret;
> +	pwr_cmd = cyapa->suspend_power_mode;
> +	sleep_time = cyapa->suspend_sleep_time;
> +	mutex_unlock(&cyapa->state_sync_lock);
> +
> +	if (pwr_cmd == PWR_MODE_BTN_ONLY)
> +		len = scnprintf(buf, PAGE_SIZE, "%s\n", BTN_ONLY_MODE_NAME);
> +	else if (pwr_cmd == PWR_MODE_OFF)
> +		len = scnprintf(buf, PAGE_SIZE, "%s\n", OFF_MODE_NAME);
> +	else {
> +		if (cyapa->gen == CYAPA_GEN3)
> +			sleep_time = cyapa_pwr_cmd_to_sleep_time(pwr_cmd);
> +		len = scnprintf(buf, PAGE_SIZE, "%u\n", sleep_time);
> +	}
> +
> +	return len;
> +}
> +
> +static u16 cyapa_clamp_sleep_time(u16 sleep_time)
> +{
> +	if (sleep_time > 1000)
> +		sleep_time = 1000;
> +	return sleep_time;
> +}
> +
> +static ssize_t cyapa_update_suspend_scanrate(struct device *dev,
> +					     struct device_attribute *attr,
> +					     const char *buf, size_t count)
> +{
> +	struct cyapa *cyapa = dev_get_drvdata(dev);
> +	u16 sleep_time;
> +	int ret;
> +
> +	ret = mutex_lock_interruptible(&cyapa->state_sync_lock);
> +	if (ret)
> +		return ret;
> +
> +	if (sysfs_streq(buf, BTN_ONLY_MODE_NAME))
> +		cyapa->suspend_power_mode = PWR_MODE_BTN_ONLY;
> +	else if (sysfs_streq(buf, OFF_MODE_NAME))
> +		cyapa->suspend_power_mode = PWR_MODE_OFF;
> +	else if (!kstrtou16(buf, 10, &sleep_time)) {
> +		cyapa->suspend_sleep_time = cyapa_clamp_sleep_time(sleep_time);

I'd simply do

		cyapa->suspend_sleep_time = max_t(u16, sleep_time, 1000);

here.

> +		cyapa->suspend_power_mode =
> +			cyapa_sleep_time_to_pwr_cmd(cyapa->suspend_sleep_time);
> +	} else
> +		count = 0;
> +

If one branch uses curly braces then all branches shoudl use them, even
if they contain only one statement.

> +	mutex_unlock(&cyapa->state_sync_lock);
> +	if (!count)
> +		dev_err(dev, "invalid suspend scanrate ms parameters\n");
> +	return count ? count : -EINVAL;
> +}
> +
> +static DEVICE_ATTR(suspend_scanrate_ms, S_IRUGO|S_IWUSR,
> +		   cyapa_show_suspend_scanrate,
> +		   cyapa_update_suspend_scanrate);
> +
> +static struct attribute *cyapa_power_wakeup_entries[] = {
> +	&dev_attr_suspend_scanrate_ms.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group cyapa_power_wakeup_group = {
> +	.name = power_group_name,
> +	.attrs = cyapa_power_wakeup_entries,
> +};
> +
> +static void cyapa_remove_power_wakeup_group(void *data)
> +{
> +	struct cyapa *cyapa = data;
> +
> +	sysfs_unmerge_group(&cyapa->client->dev.kobj,
> +				&cyapa_power_wakeup_group);
> +}
> +#endif /* CONFIG_PM_SLEEP */
> +
>  /*
>   * Returns:
>   *   0    Driver and device initialization successfully done.
> @@ -588,6 +678,28 @@ static int cyapa_probe(struct i2c_client *client,
>  		return ret;
>  	}
>  
> +#ifdef CONFIG_PM_SLEEP
> +	if (device_can_wakeup(dev)) {
> +		ret = sysfs_merge_group(&client->dev.kobj,
> +					&cyapa_power_wakeup_group);
> +		if (ret) {
> +			dev_err(dev, "failed to add power wakeup group, (%d)\n",
> +				ret);
> +			return ret;
> +		}
> +
> +		ret = devm_add_action(dev,
> +				cyapa_remove_power_wakeup_group, cyapa);
> +		if (ret) {
> +			cyapa_remove_power_wakeup_group(cyapa);
> +			dev_err(dev,
> +				"failed to add power cleanup action, (%d)\n",
> +				ret);
> +			return ret;
> +		}
> +	}
> +#endif /* CONFIG_PM_SLEEP */
> +
>  	return 0;
>  }
>  
> -- 
> 1.9.1
> 

-- 
Dmitry