Hi Jonathan, > Am 24.09.2016 um 18:07 schrieb Jonathan Cameron <jic23@xxxxxxxxxx>: > > On 23/09/16 13:41, 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 >> in addition to the raw x, y, z values and the estimated touch >> screen resistance. This can be used for debugging or special >> applications. > I'm unconvinced that exposing the touch related channels is terribly > useful. Mostly for debugging of if someone wants to do a (better) touch detection in user space. > Fair enough on the aux channel and temperature though. > > Otherwise a few minor bits and bobs. > > Jonathan >> >> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> >> --- >> drivers/input/touchscreen/Kconfig | 1 + >> drivers/input/touchscreen/tsc2007.c | 137 +++++++++++++++++++++++++++++++++++- >> 2 files changed, 136 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig >> index 2fb1f43..84c28e8 100644 >> --- a/drivers/input/touchscreen/Kconfig >> +++ b/drivers/input/touchscreen/Kconfig >> @@ -1019,6 +1019,7 @@ config TOUCHSCREEN_TSC2005 >> config TOUCHSCREEN_TSC2007 >> tristate "TSC2007 based touchscreens" >> depends on I2C >> + select IIO > This is pulling quite a bit of core IIO code in for a feature a lot > of users of this chip won't care about... Ah, yes. We didn't notice because we use many other IIO devices on the same board (GTA04). So I will add some #ifdef CONFIG_IIO where necessary. >> help >> Say Y here if you have a TSC2007 based touchscreen. >> >> diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c >> index e9d5086..559cbc6 100644 >> --- a/drivers/input/touchscreen/tsc2007.c >> +++ b/drivers/input/touchscreen/tsc2007.c >> @@ -30,6 +30,9 @@ >> #include <linux/of.h> >> #include <linux/of_gpio.h> >> #include <linux/input/touchscreen.h> >> +#include <linux/iio/iio.h> >> +#include <linux/iio/machine.h> > Why machine.h? (or driver.h for that reason). Good question. Header files sometimes get in during development and are forgotten to take out... Or had been necessary when development started a while ago. Indeed I don't know why they are there. > >> +#include <linux/iio/driver.h> I have checked and we really neither need machine.h nor driver.h. >> >> #define TSC2007_MEASURE_TEMP0 (0x0 << 4) >> #define TSC2007_MEASURE_AUX (0x2 << 4) >> @@ -61,6 +64,16 @@ >> #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 +82,11 @@ struct ts_event { >> >> struct tsc2007 { >> struct input_dev *input; >> + struct iio_dev *indio; >> 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 +337,86 @@ static void tsc2007_close(struct input_dev *input_dev) >> tsc2007_stop(ts); >> } >> >> +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? */ > This one needs some explanation. What is it measuring? Well, it is reporting the raw conductivity of the touch under certain conditions. But basically it is also a voltage measured by the ADC. The real pressure value reported to user space is calculated using this and the z1 and z2 values. If not pressed, conductivity is 0 and if lightly touched it jumps to some base value. When more pressed, conductivity increases while resistance goes down to some 300 Ohms or so. But I have not found an IIO_OHM or IIO_MHO constant. Which would also not be the best description because it is not scaled to real ohms. > >> + TSC2007_CHAN_IIO(6, "pen", IIO_PRESSURE, IIO_CHAN_INFO_RAW), > At the moment this is defined as barometric pressure. Ok, I see. > I suppose there > is no reason it can't extend to touch pressure though, even if it's a boolean > like this... So let's keep it this way? > >> + TSC2007_CHAN_IIO(7, "temp0", IIO_TEMP, IIO_CHAN_INFO_RAW), >> + TSC2007_CHAN_IIO(8, "temp1", IIO_TEMP, IIO_CHAN_INFO_RAW), > I would be tempted to only expose those channels that have a meaning > outside of touch screen usage (e.g. adc, temp0 and temp1). Well, for debugging and checking for non-responding or defective touch it is very handy to have them in /sys/bus/iio for direct inspection. For example we run a device test tool reading such values. You might argue that we should run our own fork for this purpose to provide a patched driver. But we want people to use the kernel from kernel.org and still be able to do such debugging without asking them to replace the kernel first. >> +}; >> + >> +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, >> +}; >> + >> #ifdef CONFIG_OF >> static int tsc2007_get_pendown_state_gpio(struct device *dev) >> { >> @@ -453,15 +551,20 @@ 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; >> + struct iio_dev *indio_dev; >> int err; >> >> if (!i2c_check_functionality(client->adapter, >> I2C_FUNC_SMBUS_READ_WORD_DATA)) >> return -EIO; >> >> - ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL); >> - if (!ts) >> + 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) >> @@ -469,10 +572,26 @@ static int tsc2007_probe(struct i2c_client *client, >> >> i2c_set_clientdata(client, ts); >> >> + 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->client = client; >> ts->irq = client->irq; >> ts->input = input_dev; >> + ts->indio = indio_dev; >> init_waitqueue_head(&ts->wait); >> + mutex_init(&ts->mlock); >> >> snprintf(ts->phys, sizeof(ts->phys), >> "%s/input0", dev_name(&client->dev)); >> @@ -548,6 +667,19 @@ 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; >> + struct iio_dev *indio_dev = ts->indio; >> + >> + input_unregister_device(input_dev); >> + >> + iio_device_unregister(indio_dev); >> + >> + return 0; >> +} >> + >> static const struct i2c_device_id tsc2007_idtable[] = { >> { "tsc2007", 0 }, >> { } >> @@ -570,6 +702,7 @@ static struct i2c_driver tsc2007_driver = { >> }, >> .id_table = tsc2007_idtable, >> .probe = tsc2007_probe, >> + .remove = tsc2007_remove, >> }; >> >> module_i2c_driver(tsc2007_driver); >> > BR and thanks, Nikolaus -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html