diff mbox

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

Message ID F0CB8C7F-29FD-41DF-A652-9D1AF7824D5F@goldelico.com (mailing list archive)
State New, archived
Headers show

Commit Message

H. Nikolaus Schaller Oct. 23, 2016, 6:34 p.m. UTC
Hi Jonathan,

> Am 23.10.2016 um 11:57 schrieb H. Nikolaus Schaller <hns@goldelico.com>:
> 
> Hi,
> 
>>> +static int tsc2007_alloc(struct i2c_client *client, struct tsc2007 **ts,
>>> +                          struct input_dev **input_dev)
>>> +{
>>> +       int err;
>>> +       struct iio_dev *indio_dev;
>>> +
>>> +       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*ts));
>> Instead of doing this to reduce the delta between versions make 
>> iio_priv a struct tsc2007 **
>> 
>> That is have a single pointer in there and do your allocation of struct
>> tsc2007 separately.
> 
> Sorry, but I think I do not completely understand what you mean here.
> 
> The problem is that we need to allocate some struct tsc2007 in both cases.
> But in one case managed directly by &client->dev and in the other managed
> indirectly. This is why I use the private area of struct iio_dev to store
> the full struct tsc2007 and not just a pointer.

Ok, I think I finally did understand how you mean this and have started to
implement something.

The idea is to have one alloc function to return a struct tsc2007. This
can be part of the probe function, like it is in the unpatched driver.

In case of iio this struct tsc2007 is also allocated explicitly so that
a pointer can be stored in iio_priv.

This just means an additional iio_priv->ts = devm_kzalloc() in case of iio.

I have added that approach to my inlined patch and it seems to work (attached).

Sorry if I do not use the wording you would use and sometimes overlook
something you have said. I feel here like moving on thin ice and doing
guesswork about unspoken assumptions...

> 
>> 
>> Having doing that, you can have this CONFIG_IIO block as just
>> doing the iio stuff with the input elements pulled back into the main
>> probe function.
>> 
>> Then define something like
>> 
>> iio_configure (stubbed to nothing if no IIO)
>> and
>> iio_unconfigure (also stubbed to nothing if no IIO).

This seems to work (draft attached).

>> 
>> A couple of additions in the header

I think you mean tsc2007.h?

This currently contains only platform data and could IMHO be eliminated
if everything becomes DT.

>> to make it all work
>> (the struct tsc2007 and tsc2007_xfer() + a few of the
>> register defines..

Here it appears to me that I have to make a lot of so far private static
and even static inline functions public so that I can make them stubs and
call them from tsc2007_iio.c.

And for having proper parameter types I have to make most private structs
also public.

I really like the idea to have the optional iio feature in a separate source
file, but when really starting to write code, I get the impression that
it introduces more problems than it solves.

And I wonder a little why it is not done for #ifdef CONFIG_OF in tsc2007.c
as well. There are also two static function in some #ifdef #else # endif
and not going through stubs.

So is this intended to give up some static definitions?

BR and thanks,
Nikolaus

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Comments

Jonathan Cameron Oct. 23, 2016, 7 p.m. UTC | #1
On 23/10/16 19:34, H. Nikolaus Schaller wrote:
> Hi Jonathan,
> 
>> Am 23.10.2016 um 11:57 schrieb H. Nikolaus Schaller <hns@goldelico.com>:
>>
>> Hi,
>>
>>>> +static int tsc2007_alloc(struct i2c_client *client, struct tsc2007 **ts,
>>>> +                          struct input_dev **input_dev)
>>>> +{
>>>> +       int err;
>>>> +       struct iio_dev *indio_dev;
>>>> +
>>>> +       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*ts));
>>> Instead of doing this to reduce the delta between versions make 
>>> iio_priv a struct tsc2007 **
>>>
>>> That is have a single pointer in there and do your allocation of struct
>>> tsc2007 separately.
>>
>> Sorry, but I think I do not completely understand what you mean here.
>>
>> The problem is that we need to allocate some struct tsc2007 in both cases.
>> But in one case managed directly by &client->dev and in the other managed
>> indirectly. This is why I use the private area of struct iio_dev to store
>> the full struct tsc2007 and not just a pointer.
> 
> Ok, I think I finally did understand how you mean this and have started to
> implement something.
> 
oops. Didn't look on in my emails to get to this one!
> The idea is to have one alloc function to return a struct tsc2007. This
> can be part of the probe function, like it is in the unpatched driver.
> 
> In case of iio this struct tsc2007 is also allocated explicitly so that
> a pointer can be stored in iio_priv.
> 
> This just means an additional iio_priv->ts = devm_kzalloc() in case of iio.
> 
> I have added that approach to my inlined patch and it seems to work (attached).
> 
> Sorry if I do not use the wording you would use and sometimes overlook
> something you have said. I feel here like moving on thin ice and doing
> guesswork about unspoken assumptions...
That's fine.  Stuff that can appear obvious to one person is not
necessarily obvious to another!
> 
>>
>>>
>>> Having doing that, you can have this CONFIG_IIO block as just
>>> doing the iio stuff with the input elements pulled back into the main
>>> probe function.
>>>
>>> Then define something like
>>>
>>> iio_configure (stubbed to nothing if no IIO)
>>> and
>>> iio_unconfigure (also stubbed to nothing if no IIO).
> 
> This seems to work (draft attached).
> 
>>>
>>> A couple of additions in the header
> 
> I think you mean tsc2007.h?
Nope. A local header alongside the driver is what you want for this stuff.
driver/input/tsc2007.h 
> 
> This currently contains only platform data and could IMHO be eliminated
> if everything becomes DT.
> 
>>> to make it all work
>>> (the struct tsc2007 and tsc2007_xfer() + a few of the
>>> register defines..
> 
> Here it appears to me that I have to make a lot of so far private static
> and even static inline functions public so that I can make them stubs and
> call them from tsc2007_iio.c.
There will be a few.
> 
> And for having proper parameter types I have to make most private structs
> also public.
Yes a few of those as well.
> 
> I really like the idea to have the optional iio feature in a separate source
> file, but when really starting to write code, I get the impression that
> it introduces more problems than it solves.
> 
> And I wonder a little why it is not done for #ifdef CONFIG_OF in tsc2007.c
> as well. There are also two static function in some #ifdef #else # endif
> and not going through stubs.
Usually it is only done once a certain volume of code exists.
> 
> So is this intended to give up some static definitions?
Yes, that happens the moment you have multiple source files.

Some losses but generally end up with clean code separation. Always a trade
off unfortunately.  Pity we can't just insist IIO is available! Rather large
to pull in for what is probable a niche use case.

Below is definitely heading in the right direction. I remember vaguely being
convinced of the worth of doing this when optional code is involved!
(was a good while ago now)

Jonathan
> 
> BR and thanks,
> Nikolaus
> 
> diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
> index 5e3c4bf..92da8f6 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>
Should not need this after introducing the new file.  Will only be
needed in the iio specific .c file.
>  
>  #define TSC2007_MEASURE_TEMP0          (0x0 << 4)
>  #define TSC2007_MEASURE_AUX            (0x2 << 4)
> @@ -98,6 +99,9 @@ struct tsc2007 {
This will definitely need to go in the header though.
>  
>         int                     (*get_pendown_state)(struct device *);
>         void                    (*clear_penirq)(void);
> +
> +       struct mutex            mlock;
> +       void                    *private;
>  };
>  
>  static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
> @@ -192,7 +196,10 @@ 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 +326,157 @@ static void tsc2007_close(struct input_dev *input_dev)
>         tsc2007_stop(ts);
>  }
>  
> +#ifdef CONFIG_IIO
> +
> +struct tsc2007_iio {
> +       struct tsc2007 *ts;
Spot on.
> +};
> +
> +#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, \
> +}
> +
> +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_iio *iio = iio_priv(indio_dev);
> +       struct tsc2007 *tsc = iio->ts;
> +       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,
> +};
> +
> +static inline int tsc2007_iio_configure(struct tsc2007 *ts)
> +{
> +       int err;
> +       struct iio_dev *indio_dev;
> +       struct tsc2007_iio *iio;
> +
> +       indio_dev = devm_iio_device_alloc(&ts->client->dev, sizeof(struct tsc2007_iio));
> +       if (!indio_dev) {
> +               dev_err(&ts->client->dev, "iio_device_alloc failed\n");
> +               return -ENOMEM;
> +       }
> +
> +       iio = iio_priv(indio_dev);
> +       iio->ts = ts;
> +       ts->private = (void *) indio_dev;
> +
> +       indio_dev->name = "tsc2007";
> +       indio_dev->dev.parent = &ts->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(&ts->client->dev, "iio_device_register() failed: %d\n",
> +                       err);
> +               return err;
> +       }
> +
> +       return 0;
> +}
> +
> +static inline void tsc2007_iio_unconfigure(struct tsc2007 *ts)
> +{
> +       struct iio_dev *indio_dev = ts->private;
> +
> +       iio_device_unregister(indio_dev);
> +}
> +
> +#else /* CONFIG_IIO */
> +
> +static inline int tsc2007_iio_configure(struct tsc2007 *ts)
> +{
> +       /* not needed */
> +}
> +
> +static inline void tsc2007_iio_unconfigure(struct tsc2007 *ts)
> +{
> +       /* not needed */
> +}
> +
> +#endif /* CONFIG_IIO */
> +
>  #ifdef CONFIG_OF
>  static int tsc2007_get_pendown_state_gpio(struct device *dev)
>  {
> @@ -472,7 +630,13 @@ static int tsc2007_probe(struct i2c_client *client,
>         ts->client = client;
>         ts->irq = client->irq;
>         ts->input = input_dev;
> +
> +       err = tsc2007_iio_configure(ts);
> +       if (err < 0)
> +               return err;
> +
>         init_waitqueue_head(&ts->wait);
> +       mutex_init(&ts->mlock);
>  
>         snprintf(ts->phys, sizeof(ts->phys),
>                  "%s/input0", dev_name(&client->dev));
> @@ -503,8 +667,10 @@ static int tsc2007_probe(struct i2c_client *client,
>                                                           ts->fuzzz, 0);
>         } else {
>                 err = tsc2007_probe_dt(client, ts);
> -               if (err)
> +               if (err) {
> +                       tsc2007_iio_unconfigure(ts);
>                         return err;
> +               }
>         }
>  
>         if (pdata) {
> @@ -516,6 +682,7 @@ static int tsc2007_probe(struct i2c_client *client,
>                                 dev_err(&client->dev,
>                                         "Failed to register exit_platform_hw action, %d\n",
>                                         err);
> +                               tsc2007_iio_unconfigure(ts);
>                                 return err;
>                         }
>                 }
> @@ -533,6 +700,7 @@ static int tsc2007_probe(struct i2c_client *client,
>         if (err) {
>                 dev_err(&client->dev, "Failed to request irq %d: %d\n",
>                         ts->irq, err);
> +               tsc2007_iio_unconfigure(ts);
Maybe need a common unwind and use a goto to get to it.
>                 return err;
>         }
>  
> @@ -543,6 +711,7 @@ static int tsc2007_probe(struct i2c_client *client,
>         if (err < 0) {
>                 dev_err(&client->dev,
>                         "Failed to setup chip: %d\n", err);
> +               tsc2007_iio_unconfigure(ts);
>                 return err;     /* usually, chip does not respond */
>         }
>  
> @@ -550,12 +719,21 @@ static int tsc2007_probe(struct i2c_client *client,
>         if (err) {
>                 dev_err(&client->dev,
>                         "Failed to register input device: %d\n", err);
> +               tsc2007_iio_unconfigure(ts);
>                 return err;
>         }
>  
>         return 0;
>  }
>  
> +static int tsc2007_remove(struct i2c_client *client)
> +{
> +       struct tsc2007 *ts = i2c_get_clientdata(client);
> +       tsc2007_iio_unconfigure(ts);
> +       input_unregister_device(ts->input);
> +       return 0;
> +}
> +
>  static const struct i2c_device_id tsc2007_idtable[] = {
>         { "tsc2007", 0 },
>         { }
> @@ -578,6 +756,7 @@ static struct i2c_driver tsc2007_driver = {
>         },
>         .id_table       = tsc2007_idtable,
>         .probe          = tsc2007_probe,
> +       .remove         = tsc2007_remove,
>  };
>  
>  module_i2c_driver(tsc2007_driver);--
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H. Nikolaus Schaller Oct. 23, 2016, 7:11 p.m. UTC | #2
Hi,

> Am 23.10.2016 um 21:00 schrieb Jonathan Cameron <jic23@kernel.org>:
> 
> On 23/10/16 19:34, H. Nikolaus Schaller wrote:
>> Hi Jonathan,
>> 
>>> Am 23.10.2016 um 11:57 schrieb H. Nikolaus Schaller <hns@goldelico.com>:
>>> 
>>> Hi,
>>> 
>>>>> +static int tsc2007_alloc(struct i2c_client *client, struct tsc2007 **ts,
>>>>> +                          struct input_dev **input_dev)
>>>>> +{
>>>>> +       int err;
>>>>> +       struct iio_dev *indio_dev;
>>>>> +
>>>>> +       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*ts));
>>>> Instead of doing this to reduce the delta between versions make 
>>>> iio_priv a struct tsc2007 **
>>>> 
>>>> That is have a single pointer in there and do your allocation of struct
>>>> tsc2007 separately.
>>> 
>>> Sorry, but I think I do not completely understand what you mean here.
>>> 
>>> The problem is that we need to allocate some struct tsc2007 in both cases.
>>> But in one case managed directly by &client->dev and in the other managed
>>> indirectly. This is why I use the private area of struct iio_dev to store
>>> the full struct tsc2007 and not just a pointer.
>> 
>> Ok, I think I finally did understand how you mean this and have started to
>> implement something.
>> 
> oops. Didn't look on in my emails to get to this one!
>> The idea is to have one alloc function to return a struct tsc2007. This
>> can be part of the probe function, like it is in the unpatched driver.
>> 
>> In case of iio this struct tsc2007 is also allocated explicitly so that
>> a pointer can be stored in iio_priv.
>> 
>> This just means an additional iio_priv->ts = devm_kzalloc() in case of iio.
>> 
>> I have added that approach to my inlined patch and it seems to work (attached).
>> 
>> Sorry if I do not use the wording you would use and sometimes overlook
>> something you have said. I feel here like moving on thin ice and doing
>> guesswork about unspoken assumptions...
> That's fine.  Stuff that can appear obvious to one person is not
> necessarily obvious to another!
>> 
>>> 
>>>> 
>>>> Having doing that, you can have this CONFIG_IIO block as just
>>>> doing the iio stuff with the input elements pulled back into the main
>>>> probe function.
>>>> 
>>>> Then define something like
>>>> 
>>>> iio_configure (stubbed to nothing if no IIO)
>>>> and
>>>> iio_unconfigure (also stubbed to nothing if no IIO).
>> 
>> This seems to work (draft attached).
>> 
>>>> 
>>>> A couple of additions in the header
>> 
>> I think you mean tsc2007.h?
> Nope. A local header alongside the driver is what you want for this stuff.
> driver/input/tsc2007.h 

Ah, ok. This makes sense.

>> 
>> This currently contains only platform data and could IMHO be eliminated
>> if everything becomes DT.
>> 
>>>> to make it all work
>>>> (the struct tsc2007 and tsc2007_xfer() + a few of the
>>>> register defines..
>> 
>> Here it appears to me that I have to make a lot of so far private static
>> and even static inline functions public so that I can make them stubs and
>> call them from tsc2007_iio.c.
> There will be a few.
>> 
>> And for having proper parameter types I have to make most private structs
>> also public.
> Yes a few of those as well.
>> 
>> I really like the idea to have the optional iio feature in a separate source
>> file, but when really starting to write code, I get the impression that
>> it introduces more problems than it solves.
>> 
>> And I wonder a little why it is not done for #ifdef CONFIG_OF in tsc2007.c
>> as well. There are also two static function in some #ifdef #else # endif
>> and not going through stubs.
> Usually it is only done once a certain volume of code exists.
>> 
>> So is this intended to give up some static definitions?
> Yes, that happens the moment you have multiple source files.
> 
> Some losses but generally end up with clean code separation. Always a trade
> off unfortunately.  Pity we can't just insist IIO is available! Rather large
> to pull in for what is probable a niche use case.
> 
> Below is definitely heading in the right direction. I remember vaguely being
> convinced of the worth of doing this when optional code is involved!
> (was a good while ago now)

Ok. I think I can now integrate it and then post as PATCH v5 (together with
some other fixes for the patch set).

> 
> Jonathan
>> 
>> BR and thanks,
>> Nikolaus
>> 
>> diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
>> index 5e3c4bf..92da8f6 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>
> Should not need this after introducing the new file.  Will only be
> needed in the iio specific .c file.
>> 
>> #define TSC2007_MEASURE_TEMP0          (0x0 << 4)
>> #define TSC2007_MEASURE_AUX            (0x2 << 4)
>> @@ -98,6 +99,9 @@ struct tsc2007 {
> This will definitely need to go in the header though.
>> 
>>        int                     (*get_pendown_state)(struct device *);
>>        void                    (*clear_penirq)(void);
>> +
>> +       struct mutex            mlock;
>> +       void                    *private;
>> };
>> 
>> static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
>> @@ -192,7 +196,10 @@ 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 +326,157 @@ static void tsc2007_close(struct input_dev *input_dev)
>>        tsc2007_stop(ts);
>> }
>> 
>> +#ifdef CONFIG_IIO
>> +
>> +struct tsc2007_iio {
>> +       struct tsc2007 *ts;
> Spot on.
>> +};
>> +
>> +#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, \
>> +}
>> +
>> +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_iio *iio = iio_priv(indio_dev);
>> +       struct tsc2007 *tsc = iio->ts;
>> +       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,
>> +};
>> +
>> +static inline int tsc2007_iio_configure(struct tsc2007 *ts)
>> +{
>> +       int err;
>> +       struct iio_dev *indio_dev;
>> +       struct tsc2007_iio *iio;
>> +
>> +       indio_dev = devm_iio_device_alloc(&ts->client->dev, sizeof(struct tsc2007_iio));
>> +       if (!indio_dev) {
>> +               dev_err(&ts->client->dev, "iio_device_alloc failed\n");
>> +               return -ENOMEM;
>> +       }
>> +
>> +       iio = iio_priv(indio_dev);
>> +       iio->ts = ts;
>> +       ts->private = (void *) indio_dev;
>> +
>> +       indio_dev->name = "tsc2007";
>> +       indio_dev->dev.parent = &ts->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(&ts->client->dev, "iio_device_register() failed: %d\n",
>> +                       err);
>> +               return err;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static inline void tsc2007_iio_unconfigure(struct tsc2007 *ts)
>> +{
>> +       struct iio_dev *indio_dev = ts->private;
>> +
>> +       iio_device_unregister(indio_dev);
>> +}
>> +
>> +#else /* CONFIG_IIO */
>> +
>> +static inline int tsc2007_iio_configure(struct tsc2007 *ts)
>> +{
>> +       /* not needed */
>> +}
>> +
>> +static inline void tsc2007_iio_unconfigure(struct tsc2007 *ts)
>> +{
>> +       /* not needed */
>> +}
>> +
>> +#endif /* CONFIG_IIO */
>> +
>> #ifdef CONFIG_OF
>> static int tsc2007_get_pendown_state_gpio(struct device *dev)
>> {
>> @@ -472,7 +630,13 @@ static int tsc2007_probe(struct i2c_client *client,
>>        ts->client = client;
>>        ts->irq = client->irq;
>>        ts->input = input_dev;
>> +
>> +       err = tsc2007_iio_configure(ts);
>> +       if (err < 0)
>> +               return err;
>> +
>>        init_waitqueue_head(&ts->wait);
>> +       mutex_init(&ts->mlock);
>> 
>>        snprintf(ts->phys, sizeof(ts->phys),
>>                 "%s/input0", dev_name(&client->dev));
>> @@ -503,8 +667,10 @@ static int tsc2007_probe(struct i2c_client *client,
>>                                                          ts->fuzzz, 0);
>>        } else {
>>                err = tsc2007_probe_dt(client, ts);
>> -               if (err)
>> +               if (err) {
>> +                       tsc2007_iio_unconfigure(ts);
>>                        return err;
>> +               }
>>        }
>> 
>>        if (pdata) {
>> @@ -516,6 +682,7 @@ static int tsc2007_probe(struct i2c_client *client,
>>                                dev_err(&client->dev,
>>                                        "Failed to register exit_platform_hw action, %d\n",
>>                                        err);
>> +                               tsc2007_iio_unconfigure(ts);
>>                                return err;
>>                        }
>>                }
>> @@ -533,6 +700,7 @@ static int tsc2007_probe(struct i2c_client *client,
>>        if (err) {
>>                dev_err(&client->dev, "Failed to request irq %d: %d\n",
>>                        ts->irq, err);
>> +               tsc2007_iio_unconfigure(ts);
> Maybe need a common unwind and use a goto to get to it.

Yes, makes sense.

>>                return err;
>>        }
>> 
>> @@ -543,6 +711,7 @@ static int tsc2007_probe(struct i2c_client *client,
>>        if (err < 0) {
>>                dev_err(&client->dev,
>>                        "Failed to setup chip: %d\n", err);
>> +               tsc2007_iio_unconfigure(ts);
>>                return err;     /* usually, chip does not respond */
>>        }
>> 
>> @@ -550,12 +719,21 @@ static int tsc2007_probe(struct i2c_client *client,
>>        if (err) {
>>                dev_err(&client->dev,
>>                        "Failed to register input device: %d\n", err);
>> +               tsc2007_iio_unconfigure(ts);
>>                return err;
>>        }
>> 
>>        return 0;
>> }
>> 
>> +static int tsc2007_remove(struct i2c_client *client)
>> +{
>> +       struct tsc2007 *ts = i2c_get_clientdata(client);
>> +       tsc2007_iio_unconfigure(ts);
>> +       input_unregister_device(ts->input);
>> +       return 0;
>> +}
>> +
>> static const struct i2c_device_id tsc2007_idtable[] = {
>>        { "tsc2007", 0 },
>>        { }
>> @@ -578,6 +756,7 @@ static struct i2c_driver tsc2007_driver = {
>>        },
>>        .id_table       = tsc2007_idtable,
>>        .probe          = tsc2007_probe,
>> +       .remove         = tsc2007_remove,
>> };
>> 
>> module_i2c_driver(tsc2007_driver);--
>> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html

BR and thanks,
Nikolaus


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H. Nikolaus Schaller Oct. 24, 2016, 7:14 p.m. UTC | #3
Hi Jonathan,

> Am 23.10.2016 um 21:00 schrieb Jonathan Cameron <jic23@kernel.org>:
> 
> On 23/10/16 19:34, H. Nikolaus Schaller wrote:
>> Hi Jonathan,
>> 
>>> Am 23.10.2016 um 11:57 schrieb H. Nikolaus Schaller <hns@goldelico.com>:
>>> 
>>> Hi,
>>> 
>>>>> +static int tsc2007_alloc(struct i2c_client *client, struct tsc2007 **ts,
>>>>> +                          struct input_dev **input_dev)
>>>>> +{
>>>>> +       int err;
>>>>> +       struct iio_dev *indio_dev;
>>>>> +
>>>>> +       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*ts));
>>>> Instead of doing this to reduce the delta between versions make 
>>>> iio_priv a struct tsc2007 **
>>>> 
>>>> That is have a single pointer in there and do your allocation of struct
>>>> tsc2007 separately.
>>> 
>>> Sorry, but I think I do not completely understand what you mean here.
>>> 
>>> The problem is that we need to allocate some struct tsc2007 in both cases.
>>> But in one case managed directly by &client->dev and in the other managed
>>> indirectly. This is why I use the private area of struct iio_dev to store
>>> the full struct tsc2007 and not just a pointer.
>> 
>> Ok, I think I finally did understand how you mean this and have started to
>> implement something.
>> 
> oops. Didn't look on in my emails to get to this one!
>> The idea is to have one alloc function to return a struct tsc2007. This
>> can be part of the probe function, like it is in the unpatched driver.
>> 
>> In case of iio this struct tsc2007 is also allocated explicitly so that
>> a pointer can be stored in iio_priv.
>> 
>> This just means an additional iio_priv->ts = devm_kzalloc() in case of iio.
>> 
>> I have added that approach to my inlined patch and it seems to work (attached).
>> 
>> Sorry if I do not use the wording you would use and sometimes overlook
>> something you have said. I feel here like moving on thin ice and doing
>> guesswork about unspoken assumptions...
> That's fine.  Stuff that can appear obvious to one person is not
> necessarily obvious to another!
>> 
>>> 
>>>> 
>>>> Having doing that, you can have this CONFIG_IIO block as just
>>>> doing the iio stuff with the input elements pulled back into the main
>>>> probe function.
>>>> 
>>>> Then define something like
>>>> 
>>>> iio_configure (stubbed to nothing if no IIO)
>>>> and
>>>> iio_unconfigure (also stubbed to nothing if no IIO).
>> 
>> This seems to work (draft attached).
>> 
>>>> 
>>>> A couple of additions in the header
>> 
>> I think you mean tsc2007.h?
> Nope. A local header alongside the driver is what you want for this stuff.
> driver/input/tsc2007.h 
>> 
>> This currently contains only platform data and could IMHO be eliminated
>> if everything becomes DT.
>> 
>>>> to make it all work
>>>> (the struct tsc2007 and tsc2007_xfer() + a few of the
>>>> register defines..
>> 
>> Here it appears to me that I have to make a lot of so far private static
>> and even static inline functions public so that I can make them stubs and
>> call them from tsc2007_iio.c.
> There will be a few.
>> 
>> And for having proper parameter types I have to make most private structs
>> also public.
> Yes a few of those as well.
>> 
>> I really like the idea to have the optional iio feature in a separate source
>> file, but when really starting to write code, I get the impression that
>> it introduces more problems than it solves.
>> 
>> And I wonder a little why it is not done for #ifdef CONFIG_OF in tsc2007.c
>> as well. There are also two static function in some #ifdef #else # endif
>> and not going through stubs.
> Usually it is only done once a certain volume of code exists.
>> 
>> So is this intended to give up some static definitions?
> Yes, that happens the moment you have multiple source files.
> 
> Some losses but generally end up with clean code separation. Always a trade
> off unfortunately.  Pity we can't just insist IIO is available! Rather large
> to pull in for what is probable a niche use case.
> 
> Below is definitely heading in the right direction. I remember vaguely being
> convinced of the worth of doing this when optional code is involved!
> (was a good while ago now)
> 
> Jonathan
>> 
>> BR and thanks,
>> Nikolaus
>> 
>> diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
>> index 5e3c4bf..92da8f6 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>
> Should not need this after introducing the new file.  Will only be
> needed in the iio specific .c file.
>> 
>> #define TSC2007_MEASURE_TEMP0          (0x0 << 4)
>> #define TSC2007_MEASURE_AUX            (0x2 << 4)
>> @@ -98,6 +99,9 @@ struct tsc2007 {
> This will definitely need to go in the header though.

Now I have split the code into:

tsc2007.h (constants, structs and stubs)
tsc2007_iio.c (the iio stuff)
tsc2007.c (most parts of the original driver)

but I have a problem of correctly modifying the Makefile.

It currently looks like:

obj-$(CONFIG_TOUCHSCREEN_TSC2007)	+= tsc2007.o
obj-$(CONFIG_IIO)			+= tsc2007_iio.o

We have configured CONFIG_TOUCHSCREEN_TSC2007=m and CONFIG_IIO=y.

This obviously compiles tsc2007_iio.o into the kernel.

This means that tsc2007_iio.o references tsc2007_xfer which is part of
the module.

I would like to get both linked into the module, but the iio part
obviously only if CONFIG_IIO is defined (either -y or -m).

How can I define this?

Or can I define

obj-$(CONFIG_TOUCHSCREEN_TSC2007)	+= tsc2007.o tsc2007_iio.o

and embrace all code in tsc2007_iio with a big #ifdef CONFIG_IIO
so that it is compiled into an empty object file in the non-iio case?

BR and thanks,
Nikolaus

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Jonathan Cameron Oct. 25, 2016, 4:54 p.m. UTC | #4
On 24/10/16 20:14, H. Nikolaus Schaller wrote:
> Hi Jonathan,
> 
>> Am 23.10.2016 um 21:00 schrieb Jonathan Cameron <jic23@kernel.org>:
>>
>> On 23/10/16 19:34, H. Nikolaus Schaller wrote:
>>> Hi Jonathan,
>>>
>>>> Am 23.10.2016 um 11:57 schrieb H. Nikolaus Schaller <hns@goldelico.com>:
>>>>
>>>> Hi,
>>>>
>>>>>> +static int tsc2007_alloc(struct i2c_client *client, struct tsc2007 **ts,
>>>>>> +                          struct input_dev **input_dev)
>>>>>> +{
>>>>>> +       int err;
>>>>>> +       struct iio_dev *indio_dev;
>>>>>> +
>>>>>> +       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*ts));
>>>>> Instead of doing this to reduce the delta between versions make 
>>>>> iio_priv a struct tsc2007 **
>>>>>
>>>>> That is have a single pointer in there and do your allocation of struct
>>>>> tsc2007 separately.
>>>>
>>>> Sorry, but I think I do not completely understand what you mean here.
>>>>
>>>> The problem is that we need to allocate some struct tsc2007 in both cases.
>>>> But in one case managed directly by &client->dev and in the other managed
>>>> indirectly. This is why I use the private area of struct iio_dev to store
>>>> the full struct tsc2007 and not just a pointer.
>>>
>>> Ok, I think I finally did understand how you mean this and have started to
>>> implement something.
>>>
>> oops. Didn't look on in my emails to get to this one!
>>> The idea is to have one alloc function to return a struct tsc2007. This
>>> can be part of the probe function, like it is in the unpatched driver.
>>>
>>> In case of iio this struct tsc2007 is also allocated explicitly so that
>>> a pointer can be stored in iio_priv.
>>>
>>> This just means an additional iio_priv->ts = devm_kzalloc() in case of iio.
>>>
>>> I have added that approach to my inlined patch and it seems to work (attached).
>>>
>>> Sorry if I do not use the wording you would use and sometimes overlook
>>> something you have said. I feel here like moving on thin ice and doing
>>> guesswork about unspoken assumptions...
>> That's fine.  Stuff that can appear obvious to one person is not
>> necessarily obvious to another!
>>>
>>>>
>>>>>
>>>>> Having doing that, you can have this CONFIG_IIO block as just
>>>>> doing the iio stuff with the input elements pulled back into the main
>>>>> probe function.
>>>>>
>>>>> Then define something like
>>>>>
>>>>> iio_configure (stubbed to nothing if no IIO)
>>>>> and
>>>>> iio_unconfigure (also stubbed to nothing if no IIO).
>>>
>>> This seems to work (draft attached).
>>>
>>>>>
>>>>> A couple of additions in the header
>>>
>>> I think you mean tsc2007.h?
>> Nope. A local header alongside the driver is what you want for this stuff.
>> driver/input/tsc2007.h 
>>>
>>> This currently contains only platform data and could IMHO be eliminated
>>> if everything becomes DT.
>>>
>>>>> to make it all work
>>>>> (the struct tsc2007 and tsc2007_xfer() + a few of the
>>>>> register defines..
>>>
>>> Here it appears to me that I have to make a lot of so far private static
>>> and even static inline functions public so that I can make them stubs and
>>> call them from tsc2007_iio.c.
>> There will be a few.
>>>
>>> And for having proper parameter types I have to make most private structs
>>> also public.
>> Yes a few of those as well.
>>>
>>> I really like the idea to have the optional iio feature in a separate source
>>> file, but when really starting to write code, I get the impression that
>>> it introduces more problems than it solves.
>>>
>>> And I wonder a little why it is not done for #ifdef CONFIG_OF in tsc2007.c
>>> as well. There are also two static function in some #ifdef #else # endif
>>> and not going through stubs.
>> Usually it is only done once a certain volume of code exists.
>>>
>>> So is this intended to give up some static definitions?
>> Yes, that happens the moment you have multiple source files.
>>
>> Some losses but generally end up with clean code separation. Always a trade
>> off unfortunately.  Pity we can't just insist IIO is available! Rather large
>> to pull in for what is probable a niche use case.
>>
>> Below is definitely heading in the right direction. I remember vaguely being
>> convinced of the worth of doing this when optional code is involved!
>> (was a good while ago now)
>>
>> Jonathan
>>>
>>> BR and thanks,
>>> Nikolaus
>>>
>>> diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
>>> index 5e3c4bf..92da8f6 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>
>> Should not need this after introducing the new file.  Will only be
>> needed in the iio specific .c file.
>>>
>>> #define TSC2007_MEASURE_TEMP0          (0x0 << 4)
>>> #define TSC2007_MEASURE_AUX            (0x2 << 4)
>>> @@ -98,6 +99,9 @@ struct tsc2007 {
>> This will definitely need to go in the header though.
> 
> Now I have split the code into:
> 
> tsc2007.h (constants, structs and stubs)
> tsc2007_iio.c (the iio stuff)
> tsc2007.c (most parts of the original driver)
> 
> but I have a problem of correctly modifying the Makefile.
> 
> It currently looks like:
> 
> obj-$(CONFIG_TOUCHSCREEN_TSC2007)	+= tsc2007.o
> obj-$(CONFIG_IIO)			+= tsc2007_iio.o
> 
> We have configured CONFIG_TOUCHSCREEN_TSC2007=m and CONFIG_IIO=y.
> 
> This obviously compiles tsc2007_iio.o into the kernel.
> 
> This means that tsc2007_iio.o references tsc2007_xfer which is part of
> the module.
> 
> I would like to get both linked into the module, but the iio part
> obviously only if CONFIG_IIO is defined (either -y or -m).
> 
> How can I define this?
> 
> Or can I define
> 
> obj-$(CONFIG_TOUCHSCREEN_TSC2007)	+= tsc2007.o tsc2007_iio.o
This is a common problem with optional support. Various ways of 
handling it.

A simple one would be:
#Define the stuff that always forms part of the .o file
magic_tsc2007-y := tsc2007.o
#Define the optional bit to build the resulting magic_tsc2007.o file
magic_tsc2007-$(CONFIG_IIO) += tsc2007_iio.o
#Use this magic combined file
obj-$(CONFIG_TOUCHSCREEN_TSC2007) += magic_tsc2007.o

With sensible naming of course ;)

Jonathan
> 
> and embrace all code in tsc2007_iio with a big #ifdef CONFIG_IIO
> so that it is compiled into an empty object file in the non-iio case?
> 
> BR and thanks,
> Nikolaus
> 
> --
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> the body of a message to majordomo@vger.kernel.org
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> 

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diff mbox

Patch

diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
index 5e3c4bf..92da8f6 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)
@@ -98,6 +99,9 @@  struct tsc2007 {
 
        int                     (*get_pendown_state)(struct device *);
        void                    (*clear_penirq)(void);
+
+       struct mutex            mlock;
+       void                    *private;
 };
 
 static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
@@ -192,7 +196,10 @@  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 +326,157 @@  static void tsc2007_close(struct input_dev *input_dev)
        tsc2007_stop(ts);
 }
 
+#ifdef CONFIG_IIO
+
+struct tsc2007_iio {
+       struct tsc2007 *ts;
+};
+
+#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, \
+}
+
+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_iio *iio = iio_priv(indio_dev);
+       struct tsc2007 *tsc = iio->ts;
+       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,
+};
+
+static inline int tsc2007_iio_configure(struct tsc2007 *ts)
+{
+       int err;
+       struct iio_dev *indio_dev;
+       struct tsc2007_iio *iio;
+
+       indio_dev = devm_iio_device_alloc(&ts->client->dev, sizeof(struct tsc2007_iio));
+       if (!indio_dev) {
+               dev_err(&ts->client->dev, "iio_device_alloc failed\n");
+               return -ENOMEM;
+       }
+
+       iio = iio_priv(indio_dev);
+       iio->ts = ts;
+       ts->private = (void *) indio_dev;
+
+       indio_dev->name = "tsc2007";
+       indio_dev->dev.parent = &ts->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(&ts->client->dev, "iio_device_register() failed: %d\n",
+                       err);
+               return err;
+       }
+
+       return 0;
+}
+
+static inline void tsc2007_iio_unconfigure(struct tsc2007 *ts)
+{
+       struct iio_dev *indio_dev = ts->private;
+
+       iio_device_unregister(indio_dev);
+}
+
+#else /* CONFIG_IIO */
+
+static inline int tsc2007_iio_configure(struct tsc2007 *ts)
+{
+       /* not needed */
+}
+
+static inline void tsc2007_iio_unconfigure(struct tsc2007 *ts)
+{
+       /* not needed */
+}
+
+#endif /* CONFIG_IIO */
+
 #ifdef CONFIG_OF
 static int tsc2007_get_pendown_state_gpio(struct device *dev)
 {
@@ -472,7 +630,13 @@  static int tsc2007_probe(struct i2c_client *client,
        ts->client = client;
        ts->irq = client->irq;
        ts->input = input_dev;
+
+       err = tsc2007_iio_configure(ts);
+       if (err < 0)
+               return err;
+
        init_waitqueue_head(&ts->wait);
+       mutex_init(&ts->mlock);
 
        snprintf(ts->phys, sizeof(ts->phys),
                 "%s/input0", dev_name(&client->dev));
@@ -503,8 +667,10 @@  static int tsc2007_probe(struct i2c_client *client,
                                                          ts->fuzzz, 0);
        } else {
                err = tsc2007_probe_dt(client, ts);
-               if (err)
+               if (err) {
+                       tsc2007_iio_unconfigure(ts);
                        return err;
+               }
        }
 
        if (pdata) {
@@ -516,6 +682,7 @@  static int tsc2007_probe(struct i2c_client *client,
                                dev_err(&client->dev,
                                        "Failed to register exit_platform_hw action, %d\n",
                                        err);
+                               tsc2007_iio_unconfigure(ts);
                                return err;
                        }
                }
@@ -533,6 +700,7 @@  static int tsc2007_probe(struct i2c_client *client,
        if (err) {
                dev_err(&client->dev, "Failed to request irq %d: %d\n",
                        ts->irq, err);
+               tsc2007_iio_unconfigure(ts);
                return err;
        }
 
@@ -543,6 +711,7 @@  static int tsc2007_probe(struct i2c_client *client,
        if (err < 0) {
                dev_err(&client->dev,
                        "Failed to setup chip: %d\n", err);
+               tsc2007_iio_unconfigure(ts);
                return err;     /* usually, chip does not respond */
        }
 
@@ -550,12 +719,21 @@  static int tsc2007_probe(struct i2c_client *client,
        if (err) {
                dev_err(&client->dev,
                        "Failed to register input device: %d\n", err);
+               tsc2007_iio_unconfigure(ts);
                return err;
        }
 
        return 0;
 }
 
+static int tsc2007_remove(struct i2c_client *client)
+{
+       struct tsc2007 *ts = i2c_get_clientdata(client);
+       tsc2007_iio_unconfigure(ts);
+       input_unregister_device(ts->input);
+       return 0;
+}
+
 static const struct i2c_device_id tsc2007_idtable[] = {
        { "tsc2007", 0 },
        { }
@@ -578,6 +756,7 @@  static struct i2c_driver tsc2007_driver = {
        },
        .id_table       = tsc2007_idtable,
        .probe          = tsc2007_probe,
+       .remove         = tsc2007_remove,
 };
 
 module_i2c_driver(tsc2007_driver);--