[PATCH 3/7] drivers:input:tsc2007: add iio interface to read external ADC input, temperature and raw conversion values
From: H. Nikolaus Schaller
Date: Fri Nov 06 2015 - 10:17:44 EST
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 driver 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.
Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
---
drivers/input/touchscreen/tsc2007.c | 137 +++++++++++++++++++++++++++++++++++-
1 file changed, 135 insertions(+), 2 deletions(-)
diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
index 1a8a79d..4d3c995 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>
+#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);
@@ -340,6 +358,86 @@ 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? */
+ 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,
+};
+
#ifdef CONFIG_OF
static int tsc2007_get_pendown_state_gpio(struct device *dev)
{
@@ -473,15 +571,20 @@ 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)
@@ -489,10 +592,26 @@ 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));
@@ -566,6 +685,19 @@ 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 },
{ }
@@ -588,6 +720,7 @@ static struct i2c_driver tsc2007_driver = {
},
.id_table = tsc2007_idtable,
.probe = tsc2007_probe,
+ .remove = tsc2007_remove,
};
module_i2c_driver(tsc2007_driver);
--
2.5.1
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