[PATCH] ARM: pxa: magician: Add support for ADS7846 touchscreen

Petr Cvek [off-list ref] writes:

This patch adds support for ADS7846 touchscreen driver.

The basic functionality was tested, x_plate_ohms and y_plate_ohms were
physically measured. The value pressure_max was empirically set to match
the measured range, which is affected by x_plate_ohms and ADS samples.

+static struct platform_device vads7846_device = {
+	.name	= "reg-fixed-voltage",
+	.id	= 1,

Why "1" and not "-1" ?

 /*
+ * Touchscreen
+ */
+
+static struct ads7846_platform_data ads7846_pdata = {
+	.model		= 7846,
+	.x_plate_ohms	= 317,
+	.y_plate_ohms	= 500,
+	.pressure_max	= 1023,	/* with x plate ohms it will overflow 255 */
+	.debounce_max	= 3,	/* first readout is always bad */
+	.debounce_tol	= 30,
+	.debounce_rep	= 0,
+	.gpio_pendown	= GPIO115_MAGICIAN_nPEN_IRQ,
+	.keep_vref_on	= 1,	/* TODO can be off? */

Can you remove that TODO please ?
Either put it or not, and amend the commit message to explain the choice you
make and why you make it, either empirically or by measure.

+struct pxa2xx_spi_chip tsc2046_chip_info = {
+	.tx_threshold	= 1,
+	.rx_threshold	= 2,
+	.timeout	= 64,
+	/* NOTICE must be GPIO, incompatibility with hw PXA SPI framing */
+	.gpio_cs	= 14,

Hard encoded value of 14, I don't like it, a GPIO14_xxx would suit me better.

Cheers.

-- 
Robert