Re: [PATCH v3 3/8] drivers:input:tsc2007: add iio interface to read external ADC input, temperature and raw conversion values
From: Jonathan Cameron <hidden>
Date: 2016-09-24 16:07:24
Also in:
linux-iio, linux-input, linux-omap, lkml
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. Fair enough on the aux channel and temperature though. Otherwise a few minor bits and bobs. Jonathan
quoted hunk ↗ jump to hunk
Signed-off-by: H. Nikolaus Schaller <redacted> --- 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...
quoted hunk ↗ jump to hunk
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).
quoted hunk ↗ jump to hunk
+#include <linux/iio/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?
+ TSC2007_CHAN_IIO(6, "pen", IIO_PRESSURE, IIO_CHAN_INFO_RAW),
At the moment this is defined as barometric pressure. I suppose there is no reason it can't extend to touch pressure though, even if it's a boolean like this...
+ 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).
quoted hunk ↗ jump to hunk
+}; + +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);
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