On 12/18/2013 07:39 PM, Dmitry Torokhov wrote:

Hi Roger,

On Wed, Dec 18, 2013 at 02:51:12PM +0530, Roger Quadros wrote:

quoted

Provide device tree support and binding information.
Change platform data parameters from x/y_max to x/y_size..

I'd rather keep them as they were.

OK.

quoted

Signed-off-by: Roger Quadros <redacted>
Acked-by: Mugunthan V N <redacted>
---
 .../bindings/input/touchscreen/pixcir_i2c_ts.txt   | 26 ++++++++
 drivers/input/touchscreen/pixcir_i2c_ts.c          | 77 ++++++++++++++++++++--
 include/linux/input/pixcir_ts.h                    |  5 +-
 3 files changed, 101 insertions(+), 7 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt

diff --git a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt
new file mode 100644
index 0000000..c0b0b270
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt

@@ -0,0 +1,26 @@
+* Pixcir I2C touchscreen controllers
+
+Required properties:
+- compatible: must be "pixcir,pixcir_ts"
+- reg: I2C address of the chip
+- interrupts: interrupt to which the chip is connected
+- attb-gpio: GPIO connected to the ATTB line of the chip
+- x-size: horizontal resolution of touchscreen
+- y-size: vertical resolution of touchscreen
+
+Example:
+
+	i2c@00000000 {
+		/* ... */
+
+		pixcir_ts@5c {
+			compatible = "pixcir,pixcir_ts";
+			reg = <0x5c>;
+			interrupts = <2 0>;
+			attb-gpio = <&gpf 2 0 2>;
+			x-size = <800>;
+			y-size = <600>;
+		};
+
+		/* ... */
+	};

diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c
index 6cc6b36..3a447c9 100644
--- a/drivers/input/touchscreen/pixcir_i2c_ts.c
+++ b/drivers/input/touchscreen/pixcir_i2c_ts.c

@@ -24,6 +24,10 @@
 #include <linux/i2c.h>
 #include <linux/input.h>
 #include <linux/input/pixcir_ts.h>
+#include <linux/gpio.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/of_device.h>
 
 struct pixcir_i2c_ts_data {
 	struct i2c_client *client;

@@ -125,15 +129,65 @@ static int pixcir_i2c_ts_resume(struct device *dev)
 static SIMPLE_DEV_PM_OPS(pixcir_dev_pm_ops,
 			 pixcir_i2c_ts_suspend, pixcir_i2c_ts_resume);
 
+#if defined(CONFIG_OF)

#ifdef is preferred for simple conditions.

quoted

+static const struct of_device_id pixcir_of_match[];
+
+static struct pixcir_ts_platform_data *pixcir_parse_dt(struct device *dev)
+{
+	struct pixcir_ts_platform_data *pdata;
+	struct device_node *np = dev->of_node;
+	const struct of_device_id *match;
+
+	match = of_match_device(of_match_ptr(pixcir_of_match), dev);
+	if (!match)
+		return ERR_PTR(-EINVAL);

Why do you need an explicit match here?

Right, it is not needed here for this patch but used later in patch 6
to get chip specific data. I'll fix this while re-arranging the patches.

quoted

+
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	pdata->gpio_attb = of_get_named_gpio(np, "attb-gpio", 0);
+	if (!gpio_is_valid(pdata->gpio_attb))
+		dev_err(dev, "Failed to get ATTB GPIO\n");
+
+	if (of_property_read_u32(np, "x-size", &pdata->x_size)) {
+		dev_err(dev, "Failed to get x-size property\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (of_property_read_u32(np, "y-size", &pdata->y_size)) {
+		dev_err(dev, "Failed to get y-size property\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	dev_dbg(dev, "%s: x %d, y %d, gpio %d\n", __func__,
+				pdata->x_size, pdata->y_size, pdata->gpio_attb);
+
+	return pdata;
+}
+#else
+static struct pixcir_ts_platform_data *pixcir_parse_dt(struct device *dev)
+{
+	return NULL;

This should be

	return ERR_PTR(-EINVAL);

since you test it with IS_ERR() later.

OK.

quoted

+}
+#endif
+
 static int pixcir_i2c_ts_probe(struct i2c_client *client,
 					 const struct i2c_device_id *id)
 {
 	const struct pixcir_ts_platform_data *pdata = client->dev.platform_data;
+	struct device *dev = &client->dev;
+	struct device_node *np = dev->of_node;
 	struct pixcir_i2c_ts_data *tsdata;
 	struct input_dev *input;
 	int error;
 
-	if (!pdata) {
+	if (np) {
+		pdata = pixcir_parse_dt(dev);
+		if (IS_ERR(pdata))
+			return PTR_ERR(pdata);

We should be favoring kernel-provided platform data if it is pesent even
if there is dt-data available. This way user can override firmware,m if
needed.

OK. But how can the user override kernel provided platform data? Can't device
tree overlays be used to patch DT data in the same fashion.

I've not tried either so I don't know which one is more user friendly.

quoted

+
+	} else if (!pdata) {
 		dev_err(&client->dev, "platform data not defined\n");
 		return -EINVAL;
 	}

@@ -157,10 +211,14 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
 	__set_bit(EV_KEY, input->evbit);
 	__set_bit(EV_ABS, input->evbit);
 	__set_bit(BTN_TOUCH, input->keybit);
-	input_set_abs_params(input, ABS_X, 0, pdata->x_max, 0, 0);
-	input_set_abs_params(input, ABS_Y, 0, pdata->y_max, 0, 0);
-	input_set_abs_params(input, ABS_MT_POSITION_X, 0, pdata->x_max, 0, 0);
-	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, pdata->y_max, 0, 0);
+	input_set_abs_params(input, ABS_X,
+					0, pdata->x_size - 1, 0, 0);
+	input_set_abs_params(input, ABS_Y,
+					0, pdata->y_size - 1, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_X,
+					0, pdata->x_size - 1, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_Y,
+					0, pdata->y_size - 1, 0, 0);
 
 	input_set_drvdata(input, tsdata);
 

@@ -211,11 +269,20 @@ static const struct i2c_device_id pixcir_i2c_ts_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, pixcir_i2c_ts_id);
 
+#if defined(CONFIG_OF)
+static const struct of_device_id pixcir_of_match[] = {
+	{ .compatible = "pixcir,pixcir_ts", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pixcir_of_match);
+#endif

#ifdef is preferred for simple conditions.

OK.

quoted

+
 static struct i2c_driver pixcir_i2c_ts_driver = {
 	.driver = {
 		.owner	= THIS_MODULE,
 		.name	= "pixcir_ts",
 		.pm	= &pixcir_dev_pm_ops,
+		.of_match_table = of_match_ptr(pixcir_of_match),
 	},
 	.probe		= pixcir_i2c_ts_probe,
 	.remove		= pixcir_i2c_ts_remove,

diff --git a/include/linux/input/pixcir_ts.h b/include/linux/input/pixcir_ts.h
index 7163d91..b34ff7e 100644
--- a/include/linux/input/pixcir_ts.h
+++ b/include/linux/input/pixcir_ts.h

@@ -3,8 +3,9 @@
 
 struct pixcir_ts_platform_data {
 	int (*attb_read_val)(void);
-	int x_max;
-	int y_max;
+	unsigned int x_size;	/* X axis resolution */
+	unsigned int y_size;	/* Y axis resolution */
+	int gpio_attb;		/* GPIO connected to ATTB line */
 };

OK, it looks like the series were split awkwardly: you are defining data
that is used by follow-up patches and its purpose is unclear when
reviewing patch-by-patch. I'd recommend rearranging so that DT support
patch is the very last in the series.

Got it.

quoted

 
 #endif
-- 
1.8.3.2

cheers,
-roger