Re: [PATCH v4 4/8] drivers:input:tsc2007: add iio interface to read external ADC input and temperature

[Jonathan Cameron]

On 17/10/16 14:57, H. Nikolaus Schaller wrote:
> The tsc2007 chip not only has a resistive touch screen controller but
> also an external AUX adc imput which can be used for an ambient
> light sensor, battery voltage monitoring or any general purpose.
> 
> Additionally it can measure the chip temperature.
> 
> This extension provides an iio interface for these adc channels.
> 
> Since it is not wasting much resources and is very straightforward,
> we simply provide all other adc channels as optional iio interfaces
> as weel. This can be used for debugging or special applications.
well
> 
> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
This could be cleaner done perhaps by factoring out the IIO stuff into a separate
file and using a header with stubs to deal with the no available case.

There will only be a handful of stubs and it'll give you a lot cleaner code
in here.

If def fun in .c files is always harder to deal with than in a header
where stubs are really obvious.

J
> ---
>  drivers/input/touchscreen/tsc2007.c | 151 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 150 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
> index c314331..b4a9504 100644
> --- a/drivers/input/touchscreen/tsc2007.c
> +++ b/drivers/input/touchscreen/tsc2007.c
> @@ -30,6 +30,7 @@
>  #include <linux/of.h>
>  #include <linux/of_gpio.h>
>  #include <linux/input/touchscreen.h>
> +#include <linux/iio/iio.h>
>  
>  #define TSC2007_MEASURE_TEMP0		(0x0 << 4)
>  #define TSC2007_MEASURE_AUX		(0x2 << 4)
> @@ -61,6 +62,16 @@
>  #define READ_X		(ADC_ON_12BIT | TSC2007_MEASURE_X)
>  #define PWRDOWN		(TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
>  
> +#define TSC2007_CHAN_IIO(_chan, _name, _type, _chan_info) \
> +{ \
> +	.datasheet_name = _name, \
> +	.type = _type, \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
> +			BIT(_chan_info), \
> +	.indexed = 1, \
> +	.channel = _chan, \
> +}
> +
>  struct ts_event {
>  	u16	x;
>  	u16	y;
> @@ -69,9 +80,13 @@ struct ts_event {
>  
>  struct tsc2007 {
>  	struct input_dev	*input;
> +#ifdef CONFIG_IIO
> +	struct iio_dev		*indio;
> +#endif
>  	char			phys[32];
>  
>  	struct i2c_client	*client;
> +	struct mutex		mlock;
>  
>  	u16			model;
>  	u16			x_plate_ohms;
> @@ -192,7 +207,10 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
>  	while (!ts->stopped && tsc2007_is_pen_down(ts)) {
>  
>  		/* pen is down, continue with the measurement */
> +
> +		mutex_lock(&ts->mlock);
>  		tsc2007_read_values(ts, &tc);
> +		mutex_unlock(&ts->mlock);
>  
>  		rt = tsc2007_calculate_resistance(ts, &tc);
>  
> @@ -319,6 +337,89 @@ static void tsc2007_close(struct input_dev *input_dev)
>  	tsc2007_stop(ts);
>  }
>  
> +#ifdef CONFIG_IIO
> +
> +static const struct iio_chan_spec tsc2007_iio_channel[] = {
> +	TSC2007_CHAN_IIO(0, "x", IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(1, "y", IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(2, "z1", IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(3, "z2", IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(4, "adc", IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(5, "rt", IIO_VOLTAGE, IIO_CHAN_INFO_RAW), /* Ohms? */
> +	TSC2007_CHAN_IIO(6, "pen", IIO_PRESSURE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(7, "temp0", IIO_TEMP, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(8, "temp1", IIO_TEMP, IIO_CHAN_INFO_RAW),
> +};
> +
> +static int tsc2007_read_raw(struct iio_dev *indio_dev,
> +	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
> +{
> +	struct  tsc2007 *tsc = iio_priv(indio_dev);
> +	int adc_chan = chan->channel;
> +	int ret = 0;
> +
> +	if (adc_chan >= ARRAY_SIZE(tsc2007_iio_channel))
> +		return -EINVAL;
> +
> +	if (mask != IIO_CHAN_INFO_RAW)
> +		return -EINVAL;
> +
> +	mutex_lock(&tsc->mlock);
> +
> +	switch (chan->channel) {
> +	case 0:
> +		*val = tsc2007_xfer(tsc, READ_X);
> +		break;
> +	case 1:
> +		*val = tsc2007_xfer(tsc, READ_Y);
> +		break;
> +	case 2:
> +		*val = tsc2007_xfer(tsc, READ_Z1);
> +		break;
> +	case 3:
> +		*val = tsc2007_xfer(tsc, READ_Z2);
> +		break;
> +	case 4:
> +		*val = tsc2007_xfer(tsc, (ADC_ON_12BIT | TSC2007_MEASURE_AUX));
> +		break;
> +	case 5: {
> +		struct ts_event tc;
> +
> +		tc.x = tsc2007_xfer(tsc, READ_X);
> +		tc.z1 = tsc2007_xfer(tsc, READ_Z1);
> +		tc.z2 = tsc2007_xfer(tsc, READ_Z2);
> +		*val = tsc2007_calculate_resistance(tsc, &tc);
> +		break;
> +	}
> +	case 6:
> +		*val = tsc2007_is_pen_down(tsc);
> +		break;
> +	case 7:
> +		*val = tsc2007_xfer(tsc,
> +				    (ADC_ON_12BIT | TSC2007_MEASURE_TEMP0));
> +		break;
> +	case 8:
> +		*val = tsc2007_xfer(tsc,
> +				    (ADC_ON_12BIT | TSC2007_MEASURE_TEMP1));
> +		break;
> +	}
> +
> +	/* Prepare for next touch reading - power down ADC, enable PENIRQ */
> +	tsc2007_xfer(tsc, PWRDOWN);
> +
> +	mutex_unlock(&tsc->mlock);
> +
> +	ret = IIO_VAL_INT;
> +
> +	return ret;
> +}
> +
> +static const struct iio_info tsc2007_iio_info = {
> +	.read_raw = tsc2007_read_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +#endif
> +
>  #ifdef CONFIG_OF
>  static int tsc2007_get_pendown_state_gpio(struct device *dev)
>  {
> @@ -453,26 +554,56 @@ static int tsc2007_probe(struct i2c_client *client,
>  	const struct tsc2007_platform_data *pdata = dev_get_platdata(&client->dev);
>  	struct tsc2007 *ts;
>  	struct input_dev *input_dev;
> +#ifdef CONFIG_IIO
> +	struct iio_dev *indio_dev;
> +#endif
>  	int err;
>  
>  	if (!i2c_check_functionality(client->adapter,
>  				     I2C_FUNC_SMBUS_READ_WORD_DATA))
>  		return -EIO;
>  
> +#ifdef CONFIG_IIO
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*ts));
> +	if (!indio_dev) {
> +		dev_err(&client->dev, "iio_device_alloc failed\n");
> +		return -ENOMEM;
> +	}
> +
> +	ts = iio_priv(indio_dev);
> +#else
>  	ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
>  	if (!ts)
>  		return -ENOMEM;
> -
> +#endif
>  	input_dev = devm_input_allocate_device(&client->dev);
>  	if (!input_dev)
>  		return -ENOMEM;
>  
>  	i2c_set_clientdata(client, ts);
>  
> +#ifdef CONFIG_IIO
> +	indio_dev->name = "tsc2007";
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &tsc2007_iio_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = tsc2007_iio_channel;
> +	indio_dev->num_channels = ARRAY_SIZE(tsc2007_iio_channel);
> +
> +	err = iio_device_register(indio_dev);
> +	if (err < 0) {
> +		dev_err(&client->dev, "iio_device_register() failed: %d\n",
> +			err);
> +		return err;
> +	}
> +	ts->indio = indio_dev;
> +#endif
> +
>  	ts->client = client;
>  	ts->irq = client->irq;
>  	ts->input = input_dev;
>  	init_waitqueue_head(&ts->wait);
> +	mutex_init(&ts->mlock);
>  
>  	snprintf(ts->phys, sizeof(ts->phys),
>  		 "%s/input0", dev_name(&client->dev));
> @@ -543,7 +674,9 @@ static int tsc2007_probe(struct i2c_client *client,
>  	if (err < 0) {
>  		dev_err(&client->dev,
>  			"Failed to setup chip: %d\n", err);
> +#ifdef CONFIG_IIO
>  		iio_device_unregister(indio_dev);
> +#endif
>  		return err;	/* usually, chip does not respond */
>  	}
>  
> @@ -557,6 +690,21 @@ static int tsc2007_probe(struct i2c_client *client,
>  	return 0;
>  }
>  
> +static int tsc2007_remove(struct i2c_client *client)
> +{
> +	struct tsc2007 *ts = i2c_get_clientdata(client);
> +	struct input_dev *input_dev = ts->input;
> +#ifdef CONFIG_IIO
> +	struct iio_dev *indio_dev = ts->indio;
> +#endif
> +	input_unregister_device(input_dev);
> +
> +#ifdef CONFIG_IIO
> +	iio_device_unregister(indio_dev);
> +#endif
> +	return 0;
> +}
> +
>  static const struct i2c_device_id tsc2007_idtable[] = {
>  	{ "tsc2007", 0 },
>  	{ }
> @@ -579,6 +727,7 @@ static struct i2c_driver tsc2007_driver = {
>  	},
>  	.id_table	= tsc2007_idtable,
>  	.probe		= tsc2007_probe,
> +	.remove		= tsc2007_remove,
>  };
>  
>  module_i2c_driver(tsc2007_driver);
>