Re: [PATCH v4 4/8] drivers:input:tsc2007: add iio interface to read external ADC input and temperature
From: H. Nikolaus Schaller
Date: Sat Oct 22 2016 - 16:46:46 EST
Hi Jonathan,
> Am 22.10.2016 um 20:33 schrieb Jonathan Cameron <jic23@xxxxxxxxxx>:
>
> 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.
Yes, it became a lot of #ifdefs spread over the source file.
The easiest thing would be to require IIO to be enabled :)
With your proposal to consider refactoring, I think the crucial part
is the conditional allocation either through devm_iio_device_alloc()
or devm_kzalloc(). This can be refactored into some conditional
tsc2007_alloc().
I have tried some draft (not tested and not tidied up) to check if the
direction is good.
This reduces the number of #ifdef CONFIG_IIO from 7 to 2 without introducing
new files or includes. There are also 2 other #ifdef CONFIG_OF so it doesn't
seem to be very complex now in comparison. And the patch itself has only a
handful of hunks (8).
Moving tsc2007_alloc into a separate file tsc2007_iio.c would only move around
one #ifdef CONFIG_OF from tsc2007.c but IMHO makes it more difficult to understand
because it is not really iio specific and one has to switch between two source
files. And I would have to touch the Makefile as well.
What do you think?
If generally ok, I can include that in [PATCH v5].
BR and thanks,
Nikolaus
diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
index 5e3c4bf..691e79f 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)
@@ -69,9 +70,13 @@ 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 +197,10 @@ 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 +327,162 @@ static void tsc2007_close(struct input_dev *input_dev)
tsc2007_stop(ts);
}
+#ifdef CONFIG_IIO
+
+#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 *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,
+};
+
+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));
+ if (!indio_dev) {
+ dev_err(&client->dev, "iio_device_alloc failed\n");
+ return -ENOMEM;
+ }
+
+ *ts = iio_priv(indio_dev);
+
+ *input_dev = devm_input_allocate_device(&client->dev);
+ if (!*input_dev)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, *ts);
+ (*ts)->indio = indio_dev;
+
+ 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;
+ }
+
+ return 0;
+}
+
+#define tsc2007_iio_device_unregister(ts) iio_device_unregister(ts->indio)
+
+#else /* CONFIG_IIO */
+
+static int tsc2007_alloc(struct i2c_client *client, struct tsc2007 **ts,
+ struct input_dev **input_dev)
+{
+ int err;
+
+ *ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
+ if (!*ts)
+ return -ENOMEM;
+
+ *input_dev = devm_input_allocate_device(&client->dev);
+ if (!*input_dev)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, *ts);
+
+ return 0;
+}
+
+#define tsc2007_iio_device_unregister(ts) /* not needed */
+
+#endif /* CONFIG_IIO */
+
#ifdef CONFIG_OF
static int tsc2007_get_pendown_state_gpio(struct device *dev)
{
@@ -459,20 +623,15 @@ static int tsc2007_probe(struct i2c_client *client,
I2C_FUNC_SMBUS_READ_WORD_DATA))
return -EIO;
- ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
- if (!ts)
- return -ENOMEM;
-
- input_dev = devm_input_allocate_device(&client->dev);
- if (!input_dev)
- return -ENOMEM;
-
- i2c_set_clientdata(client, ts);
+ err = tsc2007_alloc(client, &ts, &input_dev);
+ if (err < 0)
+ return err;
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));
@@ -543,6 +702,7 @@ static int tsc2007_probe(struct i2c_client *client,
if (err < 0) {
dev_err(&client->dev,
"Failed to setup chip: %d\n", err);
+ tsc2007_iio_device_unregister(ts);
return err; /* usually, chip does not respond */
}
@@ -556,6 +716,14 @@ 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);
+ input_unregister_device(ts->input);
+ tsc2007_iio_device_unregister(ts);
+ return 0;
+}
+
static const struct i2c_device_id tsc2007_idtable[] = {
{ "tsc2007", 0 },
{ }
@@ -578,6 +746,7 @@ static struct i2c_driver tsc2007_driver = {
},
.id_table = tsc2007_idtable,
.probe = tsc2007_probe,
+ .remove = tsc2007_remove,
};
module_i2c_driver(tsc2007_driver);