On Sat, Mar 28, 2015 at 7:02 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> On 28/03/15 00:43, Andrew Bresticker wrote:
>> Add a polled input driver for a keypad in which the buttons are connected
>> in resistor ladders to an ADC. The IIO framework is used to claim and
>> read the ADC channels.
>>
>> Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
>> +static int adc_keypad_probe(struct platform_device *pdev)
>> +{
>> + struct adc_keypad *keypad;
>> + struct input_polled_dev *poll_dev;
>> + struct input_dev *input;
>> + unsigned int i;
>> + int ret;
>> +
>> + keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
>> + if (!keypad)
>> + return -ENOMEM;
>> + keypad->dev = &pdev->dev;
>> + platform_set_drvdata(pdev, keypad);
>> +
>> + keypad->iio_chans = iio_channel_get_all(&pdev->dev);
>> + if (IS_ERR(keypad->iio_chans)) {
>> + dev_err(&pdev->dev, "Failed to get IIO channels: %ld\n",
>> + PTR_ERR(keypad->iio_chans));
>> + return PTR_ERR(keypad->iio_chans);
>> + }
>> +
>> + i = 0;
>> + while (keypad->iio_chans[i].channel != NULL)
>> + i++;
>> + keypad->num_chans = i;
>> + keypad->chan_map = devm_kcalloc(&pdev->dev, keypad->num_chans,
>> + sizeof(*keypad->chan_map), GFP_KERNEL);
>> + if (!keypad->chan_map) {
>> + ret = -ENOMEM;
>> + goto put_chans;
>> + }
>> +
>> + ret = adc_keypad_of_parse(keypad);
>> + if (ret < 0)
>> + goto put_chans;
>> +
>> + poll_dev = devm_input_allocate_polled_device(&pdev->dev);
>> + if (!poll_dev) {
>> + ret = -ENOMEM;
>> + goto put_chans;
>> + }
>> + keypad->poll_dev = poll_dev;
>> +
>> + poll_dev->private = keypad;
>> + poll_dev->poll = adc_keypad_poll;
>> + poll_dev->poll_interval = keypad->poll_interval;
>> +
>> + input = poll_dev->input;
>> + input->name = pdev->name;
>> + input->phys = "adc-keys/input0";
>> +
>> + input->id.bustype = BUS_HOST;
>> + input->id.vendor = 0x0001;
>> + input->id.product = 0x0001;
>> + input->id.version = 0x0100;
> Why these particular values?
I just chose these because these are the values most other platform
input devices use, including gpio_keys and gpio_keys_polled.
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