Re: [PATCH 3/3] input: touchscreen: ad7879: add device tree support
From: Michael Hennerich
Date: Tue Jan 26 2016 - 03:21:42 EST
On 01/26/2016 04:04 AM, Stefan Agner wrote:
Add device tree support for the I2C variant of AD7879 (AD7879-1). This
allows to specify the touchscreen controller as a I2C client node.
Most of the options available as platform data are also available as
device tree properties. Exporting the GPIO is currently not possible
through device tree.
Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
Hi Stefan,
Thanks for the patch -
There is something similar in our tree but I forgot to send it mainline
a long time ago.
https://github.com/analogdevicesinc/linux/commit/69b16d4b616a4bbe9001d3f67d3ff54f3deb85ce
There are some build issues can you have a look?
I also don't understand why "exporting the GPIO is not possible through
device tree"?
Can you explain?
Regards,
Michael
---
.../bindings/input/touchscreen/ad7879-i2c.txt | 47 ++++++++++++++++
drivers/input/touchscreen/ad7879-i2c.c | 63 +++++++++++++++++++++-
drivers/input/touchscreen/ad7879-spi.c | 3 +-
drivers/input/touchscreen/ad7879.c | 2 +-
drivers/input/touchscreen/ad7879.h | 1 +
5 files changed, 113 insertions(+), 3 deletions(-)
create mode 100644 Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
diff --git a/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt b/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
new file mode 100644
index 0000000..bf169a2
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
@@ -0,0 +1,47 @@
+* Analog Devices AD7879-1/AD7889-1 touchscreen interface (I2C)
+
+Required properties:
+- compatible: must be "adi,ad7879-1"
+- reg: i2c slave address
+- interrupt-parent: the phandle for the interrupt controller
+- interrupts: touch controller interrupt
+- resistance-plate-x : total resistance of X-plate (for pressure
+ calculation)
+- touchscreen-max-pressure : maximum reported pressure
+- touchscreen-swapped-x-y : X and Y axis are swapped (boolean)
+ Swapping is done after inverting the axis
+Optional properties:
+- first-conversion-delay : 0-12 in 128us steps (starting with 128us)
+ 13: 2.560ms
+ 14: 3.584ms
+ 15: 4.096ms
+- acquisition-time : 0: 2us
+ 1: 4us
+ 2: 8us
+ 3: 16us
+- median-filter-size : 0: disabled
+ 1: 4 measurements
+ 2: 8 measurements
+ 3: 16 measurements
+- averaging : 0: 2 middle values (1 if median disabled)
+ 1: 4 middle values
+ 2: 8 middle values
+ 3: 16 values
+- conversion-interval: : 0: convert one time only
+ 1-255: 515us + val * 35us (up to 9.440ms)
+
+Example:
+
+ ad7879@2c {
+ compatible = "adi,ad7879-1";
+ reg = <0x2c>;
+ interrupt-parent = <&gpio1>;
+ interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
+ resistance-plate-x = <120>;
+ touchscreen-max-pressure = <4096>;
+ first-conversion-delay = /bits/ 8 <3>;
+ acquisition-time = /bits/ 8 <1>;
+ median-filter-size = /bits/ 8 <2>;
+ averaging = /bits/ 8 <1>;
+ conversion-interval = /bits/ 8 <255>;
+ };
diff --git a/drivers/input/touchscreen/ad7879-i2c.c b/drivers/input/touchscreen/ad7879-i2c.c
index d66962c..08a2c9a 100644
--- a/drivers/input/touchscreen/ad7879-i2c.c
+++ b/drivers/input/touchscreen/ad7879-i2c.c
@@ -11,6 +11,7 @@
#include <linux/module.h>
#include <linux/types.h>
#include <linux/pm.h>
+#include <linux/input/ad7879.h>
#include "ad7879.h"
@@ -54,9 +55,50 @@ static const struct ad7879_bus_ops ad7879_i2c_bus_ops = {
.write = ad7879_i2c_write,
};
+static struct ad7879_platform_data *ad7879_parse_dt(struct device *dev)
+{
+ struct ad7879_platform_data *pdata;
+ struct device_node *np = dev->of_node;
+ int err;
+ u32 tmp;
+
+ if (!np)
+ return NULL;
+
+ pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+
+ if (!pdata)
+ return ERR_PTR(-ENOMEM);
+
+ err = of_property_read_u32(np, "resistance-plate-x", &tmp);
+ if (err) {
+ dev_err(dev, "failed to get resistance-plate-x property\n");
+ return ERR_PTR(err);
+ }
+ pdata->x_plate_ohms = (u16)tmp;
+
+ err = of_property_read_u32(np, "touchscreen-max-pressure", &tmp);
+ if (err) {
+ dev_err(dev, "failed to get touchscreen-max-pressure property\n");
+ return ERR_PTR(err);
+ }
+ pdata->pressure_min = (u16)tmp;
+
+ of_property_read_u8(np, "first-conversion-delay", &pdata->first_conversion_delay);
+ of_property_read_u8(np, "acquisition-time", &pdata->acquisition_time);
+ of_property_read_u8(np, "median-filter-size", &pdata->median);
+ of_property_read_u8(np, "averaging", &pdata->averaging);
+ of_property_read_u8(np, "conversion-interval", &pdata->pen_down_acc_interval);
+
+ pdata->swap_xy = of_property_read_bool(np, "touchscreen-swapped-x-y");
+
+ return pdata;
+}
+
static int ad7879_i2c_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
+ struct ad7879_platform_data *pdata;
struct ad7879 *ts;
if (!i2c_check_functionality(client->adapter,
@@ -65,7 +107,17 @@ static int ad7879_i2c_probe(struct i2c_client *client,
return -EIO;
}
- ts = ad7879_probe(&client->dev, AD7879_DEVID, client->irq,
+ pdata = dev_get_platdata(&client->dev);
+
+ if (!pdata && IS_ENABLED(CONFIG_OF))
+ pdata = ad7879_parse_dt(&client->dev);
+
+ if (IS_ERR_OR_NULL(pdata)) {
+ dev_err(&client->dev, "Need platform data\n");
+ return PTR_ERR(pdata);
+ }
+
+ ts = ad7879_probe(&client->dev, AD7879_DEVID, client->irq, pdata,
&ad7879_i2c_bus_ops);
if (IS_ERR(ts))
return PTR_ERR(ts);
@@ -91,10 +143,19 @@ static const struct i2c_device_id ad7879_id[] = {
};
MODULE_DEVICE_TABLE(i2c, ad7879_id);
+#ifdef CONFIG_OF
+static const struct of_device_id ad7879_dt_ids[] = {
+ { .compatible = "adi,ad7879-1", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
+#endif
+
static struct i2c_driver ad7879_i2c_driver = {
.driver = {
.name = "ad7879",
.pm = &ad7879_pm_ops,
+ .of_match_table = of_match_ptr(ad7879_dt_ids),
},
.probe = ad7879_i2c_probe,
.remove = ad7879_i2c_remove,
diff --git a/drivers/input/touchscreen/ad7879-spi.c b/drivers/input/touchscreen/ad7879-spi.c
index 48033c2..8ebe604 100644
--- a/drivers/input/touchscreen/ad7879-spi.c
+++ b/drivers/input/touchscreen/ad7879-spi.c
@@ -128,7 +128,8 @@ static int ad7879_spi_probe(struct spi_device *spi)
return err;
}
- ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, &ad7879_spi_bus_ops);
+ ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, pdata,
+ dev_get_platdata(&spi->dev), &ad7879_spi_bus_ops);
if (IS_ERR(ts))
return PTR_ERR(ts);
diff --git a/drivers/input/touchscreen/ad7879.c b/drivers/input/touchscreen/ad7879.c
index e290e7b..e763c77 100644
--- a/drivers/input/touchscreen/ad7879.c
+++ b/drivers/input/touchscreen/ad7879.c
@@ -486,9 +486,9 @@ static inline void ad7879_gpio_remove(struct ad7879 *ts)
#endif
struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned int irq,
+ struct ad7879_platform_data *pdata,
const struct ad7879_bus_ops *bops)
{
- struct ad7879_platform_data *pdata = dev_get_platdata(dev);
struct ad7879 *ts;
struct input_dev *input_dev;
int err;
diff --git a/drivers/input/touchscreen/ad7879.h b/drivers/input/touchscreen/ad7879.h
index 6fd13c4..fa363a0 100644
--- a/drivers/input/touchscreen/ad7879.h
+++ b/drivers/input/touchscreen/ad7879.h
@@ -24,6 +24,7 @@ struct ad7879_bus_ops {
extern const struct dev_pm_ops ad7879_pm_ops;
struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned irq,
+ struct ad7879_platform_data *pdata,
const struct ad7879_bus_ops *bops);
void ad7879_remove(struct ad7879 *);
--
Greetings,
Michael
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