Subject: [PATCH] arm: sunxi: input: RFC: Add sysfs voltage for sun4i-lradc driver

From: [email-masked] (Hans de Goede)
Date: Tue, 27 Jan 2015 10:03:35 +0100

Hi,

On 26-01-15 23:06, Dmitry Torokhov wrote:
> On Mon, Jan 26, 2015 at 08:28:29PM +0100, Hans de Goede wrote:
>> Hi,
>>
>> On 26-01-15 17:58, Priit Laes wrote:
>>
>> No commit message? Please write an informative commit msg, like why we want this patch,
>> I guess it is to help figuring out the voltage levels for various buttons when creating
>> a dts, but I would prefer to not guess, which is where a good commit message would
>> come in handy ...
>>
>>> ---
>>>   .../ABI/testing/sysfs-driver-input-sun4i-lradc     |  4 ++
>>>   drivers/input/keyboard/sun4i-lradc-keys.c          | 49 +++++++++++++++++-----
>>>   2 files changed, 43 insertions(+), 10 deletions(-)
>>>   create mode 100644 Documentation/ABI/testing/sysfs-driver-input-sun4i-lradc
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-driver-input-sun4i-lradc b/Documentation/ABI/testing/sysfs-driver-input-sun4i-lradc
>>> new file mode 100644
>>> index 0000000..e4e6448
>>> --- /dev/null
>>> +++ b/Documentation/ABI/testing/sysfs-driver-input-sun4i-lradc
>>> @@ -0,0 +1,4 @@
>>> +What:		/sys/class/input/input(x)/device/voltage
>>> +Date:		February 2015
>>> +Contact:	Priit Laes <[email-masked]>
>>> +Description:	ADC output voltage in microvolts or 0 if device is not opened.
>>> diff --git a/drivers/input/keyboard/sun4i-lradc-keys.c b/drivers/input/keyboard/sun4i-lradc-keys.c
>>> index cc8f7dd..c0ab8ec 100644
>>> --- a/drivers/input/keyboard/sun4i-lradc-keys.c
>>> +++ b/drivers/input/keyboard/sun4i-lradc-keys.c
>>> @@ -79,10 +79,27 @@ struct sun4i_lradc_data {
>>>   	u32 vref;
>>>   };
>>>
>>> +static u32 sun4i_lradc_read_voltage(struct sun4i_lradc_data *lradc)
>>> +{
>>> +	u32 val = readl(lradc->base + LRADC_DATA0) & 0x3f;
>>> +	return val * lradc->vref / 63;
>>> +};
>>> +
>>> +static ssize_t
>>> +sun4i_lradc_dev_voltage_show(struct device *dev,
>>> +			struct device_attribute *attr, char *buf)
>>> +{
>>> +	struct sun4i_lradc_data *lradc = dev_get_drvdata(dev);
>>> +
>>> +	return sprintf(buf, "%u\n", sun4i_lradc_read_voltage(lradc));
>>> +}
>>> +
>>> +static const DEVICE_ATTR(voltage, S_IRUGO, sun4i_lradc_dev_voltage_show, NULL);
>>> +
>>>   static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
>>>   {
>>>   	struct sun4i_lradc_data *lradc = dev_id;
>>> -	u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff;
>>> +	u32 i, ints, voltage, diff, keycode = 0, closest = 0xffffffff;
>>>
>>>   	ints  = readl(lradc->base + LRADC_INTS);
>>>
>>> @@ -97,8 +114,7 @@ static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
>>>   	}
>>>
>>>   	if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {
>>> -		val = readl(lradc->base + LRADC_DATA0) & 0x3f;
>>> -		voltage = val * lradc->vref / 63;
>>> +		voltage = sun4i_lradc_read_voltage(lradc);
>>>
>>>   		for (i = 0; i < lradc->chan0_map_count; i++) {
>>>   			diff = abs(lradc->chan0_map[i].voltage - voltage);
>>> @@ -156,7 +172,7 @@ static void sun4i_lradc_close(struct input_dev *dev)
>>>   }
>>>
>>>   static int sun4i_lradc_load_dt_keymap(struct device *dev,
>>> -				      struct sun4i_lradc_data *lradc)
>>> +				    struct sun4i_lradc_data *lradc)
>>>   {
>>>   	struct device_node *np, *pp;
>>>   	int i;
>>
>> Why this identation change ?
>>
>>> @@ -168,8 +184,8 @@ static int sun4i_lradc_load_dt_keymap(struct device *dev,
>>>
>>>   	lradc->chan0_map_count = of_get_child_count(np);
>>>   	if (lradc->chan0_map_count == 0) {
>>> -		dev_err(dev, "keymap is missing in device tree\n");
>>> -		return -EINVAL;
>>> +		dev_info(dev, "keymap is missing in device tree\n");
>>> +		return 0;
>>>   	}
>>>
>>>   	lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count,
>>
>> I assume this is so that people can still use the sysfs node, to create a dts, right
>> not sure I like this, might be better to document to simple create a dts with
>> a single button mapping for 200 mV (most board use 200 mV steps between the buttons).
>>
>>> @@ -185,19 +201,19 @@ static int sun4i_lradc_load_dt_keymap(struct device *dev,
>>>
>>>   		error = of_property_read_u32(pp, "channel", &channel);
>>>   		if (error || channel != 0) {
>>> -			dev_err(dev, "%s: Inval channel prop\n", pp->name);
>>> +			dev_err(dev, "%s: Invalid 'channel' property\n", pp->name);
>>>   			return -EINVAL;
>>>   		}
>>>
>>>   		error = of_property_read_u32(pp, "voltage", &map->voltage);
>>>   		if (error) {
>>> -			dev_err(dev, "%s: Inval voltage prop\n", pp->name);
>>> +			dev_err(dev, "%s: Invalid 'voltage' property\n", pp->name);
>>>   			return -EINVAL;
>>>   		}
>>>
>>>   		error = of_property_read_u32(pp, "linux,code", &map->keycode);
>>>   		if (error) {
>>> -			dev_err(dev, "%s: Inval linux,code prop\n", pp->name);
>>> +			dev_err(dev, "%s: Invalid 'linux,code' property\n", pp->name);
>>>   			return -EINVAL;
>>>   		}
>>>
>>
>> This hunk / 3 changes belong in a separate patch. Also please run checkpatch, I think
>> you're running over 80 chars here.
>>
>>
>>> @@ -257,14 +273,26 @@ static int sun4i_lradc_probe(struct platform_device *pdev)
>>>   	if (error)
>>>   		return error;
>>>
>>> -	error = input_register_device(lradc->input);
>>> +	error = device_create_file(dev, &dev_attr_voltage);
>>>   	if (error)
>>>   		return error;
>>>
>>> +	error = input_register_device(lradc->input);
>>> +	if (error) {
>>> +		device_remove_file(&pdev->dev, &dev_attr_voltage);
>>> +		return error;
>>> +	}
>>> +
>>>   	platform_set_drvdata(pdev, lradc);
>>>   	return 0;
>>>   }
>>>
>>> +static int sun4i_lradc_remove(struct platform_device *pdev)
>>> +{
>>> +	device_remove_file(&pdev->dev, &dev_attr_voltage);
>>> +	return 0;
>>> +}
>>> +
>>
>> This looks wrong, I think (*) that we've a bug here because we're not
>> unregistering the input device, so maybe do 2 patches, 1 fixing the
>> not unregistering bug, and then just add the device_remove_file()
>> in the sysfs patch.
>
> The unregister was not necessary since the input device is managed.

Ah right, looking at the code again I see we use devm_input_allocate_device()
is there no devm_create_file for creating sysfs entries ?

Regards,

Hans