[PATCH v4 3/3] input: touchscreen mc13xxx: Add mc34708 support

[Lukasz Majewski <lukma@denx.de>]

From: Sascha Hauer <s.hauer@pengutronix.de>

The mc34708 has a different bit to enable pen detection. This
adds the driver data and devtype necessary to probe the device
and to distinguish between the mc13783 and the mc34708.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

---
Changes for v4:
- Remove type from struct mc13xx_chip
- Add Acked-by from Dmitry

Changes for v3:
- Replace forward declaration of mc13xxx_driver_data with
  structure definition
- Rename mc13xxx_driver_data with mc13xxx_chip
- Move static struct mc13xxx_chip mc13783_chip and mc34708_chip
  closer to ID table
- Do not check mc13xxx device type

Changes for v2:
- Change nested if statements to a single one (with cr0 > ...)
- Replace hardcoded max resistance value (4080) with a generic driver data
  value.
- Introduce new include/linux/mfd/mc34708.h header file for mc34708 specific
  defines
- Define as driver data mask and value for accessing mc13xxx registers

Changes from the original patch:
- Simplify the mcXXXXX_set_pen_detection functions
- Fix checkpatch warnings
---
 drivers/input/touchscreen/mc13783_ts.c | 48 +++++++++++++++++++++++++++++++---
 1 file changed, 44 insertions(+), 4 deletions(-)

diff --git a/drivers/input/touchscreen/mc13783_ts.c b/drivers/input/touchscreen/mc13783_ts.c
index edd49e44e0c9..1dd8ed396225 100644
--- a/drivers/input/touchscreen/mc13783_ts.c
+++ b/drivers/input/touchscreen/mc13783_ts.c
@@ -10,6 +10,7 @@
  */
 #include <linux/platform_device.h>
 #include <linux/mfd/mc13783.h>
+#include <linux/mfd/mc34708.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/input.h>
@@ -30,6 +31,12 @@ MODULE_PARM_DESC(sample_tolerance,
 		"is supposed to be wrong and is discarded.  Set to 0 to "
 		"disable this check.");
 
+struct mc13xxx_chip {
+	int max_resistance;
+	u32 reg_mask;
+	u32 reg_value;
+};
+
 struct mc13783_ts_priv {
 	struct input_dev *idev;
 	struct mc13xxx *mc13xxx;
@@ -37,6 +44,7 @@ struct mc13783_ts_priv {
 	unsigned int sample[4];
 	u8 ato;
 	bool atox;
+	const struct mc13xxx_chip *chip;
 };
 
 static irqreturn_t mc13783_ts_handler(int irq, void *data)
@@ -93,6 +101,9 @@ static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
 
 	cr0 = (cr0 + cr1) / 2;
 
+	if (cr0 > priv->chip->max_resistance)
+		cr0 = 0;
+
 	if (!cr0 || !sample_tolerance ||
 			(x2 - x0 < sample_tolerance &&
 			 y2 - y0 < sample_tolerance)) {
@@ -102,14 +113,14 @@ static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
 			input_report_abs(idev, ABS_Y, y1);
 
 			dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
-					x1, y1, 0x1000 - cr0);
+				x1, y1, priv->chip->max_resistance - cr0);
 			schedule_delayed_work(&priv->work, HZ / 50);
 		} else {
 			dev_dbg(&idev->dev, "report release\n");
 		}
 
 		input_report_abs(idev, ABS_PRESSURE,
-				cr0 ? 0x1000 - cr0 : cr0);
+				 cr0 ? priv->chip->max_resistance - cr0 : 0);
 		input_report_key(idev, BTN_TOUCH, cr0);
 		input_sync(idev);
 	} else {
@@ -146,7 +157,8 @@ static int mc13783_ts_open(struct input_dev *dev)
 		goto out;
 
 	ret = mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
-			MC13XXX_ADC0_TSMOD_MASK, MC13XXX_ADC0_TSMOD0);
+			      priv->chip->reg_mask,
+			      priv->chip->reg_value);
 	if (ret)
 		mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
 out:
@@ -160,7 +172,7 @@ static void mc13783_ts_close(struct input_dev *dev)
 
 	mc13xxx_lock(priv->mc13xxx);
 	mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
-			MC13XXX_ADC0_TSMOD_MASK, 0);
+			priv->chip->reg_mask, 0);
 	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
 	mc13xxx_unlock(priv->mc13xxx);
 
@@ -172,6 +184,7 @@ static int __init mc13783_ts_probe(struct platform_device *pdev)
 	struct mc13783_ts_priv *priv;
 	struct mc13xxx_ts_platform_data *pdata = dev_get_platdata(&pdev->dev);
 	struct input_dev *idev;
+	const struct platform_device_id *id = platform_get_device_id(pdev);
 	int ret = -ENOMEM;
 
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
@@ -182,6 +195,7 @@ static int __init mc13783_ts_probe(struct platform_device *pdev)
 	INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
 	priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
 	priv->idev = idev;
+	priv->chip = (void *)id->driver_data;
 
 	if (pdata) {
 		priv->atox = pdata->atox;
@@ -228,7 +242,33 @@ static int mc13783_ts_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static struct mc13xxx_chip mc13783_chip = {
+	.max_resistance = 4096,
+	.reg_mask = MC13XXX_ADC0_TSMOD_MASK,
+	.reg_value = MC13XXX_ADC0_TSMOD0,
+};
+
+static struct mc13xxx_chip mc34708_chip = {
+	.max_resistance = 4080,
+	.reg_mask = MC34708_ADC0_TSMASK,
+	.reg_value = MC34708_ADC0_TSPENDETEN,
+};
+
+static const struct platform_device_id mc13xxx_ts_idtable[] = {
+	{
+		.name = "mc13783-ts",
+		.driver_data = (kernel_ulong_t)&mc13783_chip,
+	}, {
+		.name = "mc34708-ts",
+		.driver_data = (kernel_ulong_t)&mc34708_chip,
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(platform, mc13xxx_ts_idtable);
+
 static struct platform_driver mc13783_ts_driver = {
+	.id_table	= mc13xxx_ts_idtable,
 	.remove		= mc13783_ts_remove,
 	.driver		= {
 		.name	= MC13783_TS_NAME,
-- 
2.11.0