Input: add accelerated touchscreen support for Marvell Zylonite

This patch implements accelerated touchscreen support for the Marvell
Zylonite development platform, supporting pen down interrupts and
continuous mode data transfers.

Signed-off-by: Mark Brown <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/touchscreen/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called mainstone-wm97xx.
 
+config TOUCHSCREEN_WM97XX_ZYLONITE
+	tristate "Zylonite accelerated touch"
+	depends on TOUCHSCREEN_WM97XX && MACH_ZYLONITE
+	select TOUCHSCREEN_WM9713
+	help
+	  Say Y here for support for streaming mode with the touchscreen
+	  on Zylonite systems.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called zylonite-wm97xx.
+
 config TOUCHSCREEN_USB_COMPOSITE
 	tristate "USB Touchscreen Driver"
 	depends on USB_ARCH_HAS_HCD

drivers/input/touchscreen/Makefile

···
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9712)	+= wm9712.o
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9713)	+= wm9713.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE)	+= mainstone-wm97xx.o
+obj-$(CONFIG_TOUCHSCREEN_WM97XX_ZYLONITE)	+= zylonite-wm97xx.o

drivers/input/touchscreen/zylonite-wm97xx.c

···
+/*
+ * zylonite-wm97xx.c  --  Zylonite Continuous Touch screen driver
+ *
+ * Copyright 2004, 2007, 2008 Wolfson Microelectronics PLC.
+ * Author: Mark Brown <[e-mail]>
+ * Parts Copyright : Ian Molton <[e-mail]>
+ *                   Andrew Zabolotny <[e-mail]>
+ *
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under  the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ *
+ * Notes:
+ *     This is a wm97xx extended touch driver supporting interrupt driven
+ *     and continuous operation on Marvell Zylonite development systems
+ *     (which have a WM9713 on board).
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/wm97xx.h>
+
+#include <mach/hardware.h>
+#include <mach/mfp.h>
+#include <mach/regs-ac97.h>
+
+struct continuous {
+	u16 id;    /* codec id */
+	u8 code;   /* continuous code */
+	u8 reads;  /* number of coord reads per read cycle */
+	u32 speed; /* number of coords per second */
+};
+
+#define WM_READS(sp) ((sp / HZ) + 1)
+
+static const struct continuous cinfo[] = {
+	{ WM9713_ID2, 0, WM_READS(94),  94  },
+	{ WM9713_ID2, 1, WM_READS(120), 120 },
+	{ WM9713_ID2, 2, WM_READS(154), 154 },
+	{ WM9713_ID2, 3, WM_READS(188), 188 },
+};
+
+/* continuous speed index */
+static int sp_idx;
+
+/*
+ * Pen sampling frequency (Hz) in continuous mode.
+ */
+static int cont_rate = 200;
+module_param(cont_rate, int, 0);
+MODULE_PARM_DESC(cont_rate, "Sampling rate in continuous mode (Hz)");
+
+/*
+ * Pressure readback.
+ *
+ * Set to 1 to read back pen down pressure
+ */
+static int pressure;
+module_param(pressure, int, 0);
+MODULE_PARM_DESC(pressure, "Pressure readback (1 = pressure, 0 = no pressure)");
+
+/*
+ * AC97 touch data slot.
+ *
+ * Touch screen readback data ac97 slot
+ */
+static int ac97_touch_slot = 5;
+module_param(ac97_touch_slot, int, 0);
+MODULE_PARM_DESC(ac97_touch_slot, "Touch screen data slot AC97 number");
+
+
+/* flush AC97 slot 5 FIFO machines */
+static void wm97xx_acc_pen_up(struct wm97xx *wm)
+{
+	int i;
+
+	msleep(1);
+
+	for (i = 0; i < 16; i++)
+		MODR;
+}
+
+static int wm97xx_acc_pen_down(struct wm97xx *wm)
+{
+	u16 x, y, p = 0x100 | WM97XX_ADCSEL_PRES;
+	int reads = 0;
+	static u16 last, tries;
+
+	/* When the AC97 queue has been drained we need to allow time
+	 * to buffer up samples otherwise we end up spinning polling
+	 * for samples.  The controller can't have a suitably low
+	 * threashold set to use the notifications it gives.
+	 */
+	msleep(1);
+
+	if (tries > 5) {
+		tries = 0;
+		return RC_PENUP;
+	}
+
+	x = MODR;
+	if (x == last) {
+		tries++;
+		return RC_AGAIN;
+	}
+	last = x;
+	do {
+		if (reads)
+			x = MODR;
+		y = MODR;
+		if (pressure)
+			p = MODR;
+
+		/* are samples valid */
+		if ((x & WM97XX_ADCSRC_MASK) != WM97XX_ADCSEL_X ||
+		    (y & WM97XX_ADCSRC_MASK) != WM97XX_ADCSEL_Y ||
+		    (p & WM97XX_ADCSRC_MASK) != WM97XX_ADCSEL_PRES)
+			goto up;
+
+		/* coordinate is good */
+		tries = 0;
+		input_report_abs(wm->input_dev, ABS_X, x & 0xfff);
+		input_report_abs(wm->input_dev, ABS_Y, y & 0xfff);
+		input_report_abs(wm->input_dev, ABS_PRESSURE, p & 0xfff);
+		input_report_key(wm->input_dev, BTN_TOUCH, (p != 0));
+		input_sync(wm->input_dev);
+		reads++;
+	} while (reads < cinfo[sp_idx].reads);
+up:
+	return RC_PENDOWN | RC_AGAIN;
+}
+
+static int wm97xx_acc_startup(struct wm97xx *wm)
+{
+	int idx;
+
+	/* check we have a codec */
+	if (wm->ac97 == NULL)
+		return -ENODEV;
+
+	/* Go you big red fire engine */
+	for (idx = 0; idx < ARRAY_SIZE(cinfo); idx++) {
+		if (wm->id != cinfo[idx].id)
+			continue;
+		sp_idx = idx;
+		if (cont_rate <= cinfo[idx].speed)
+			break;
+	}
+	wm->acc_rate = cinfo[sp_idx].code;
+	wm->acc_slot = ac97_touch_slot;
+	dev_info(wm->dev,
+		 "zylonite accelerated touchscreen driver, %d samples/sec\n",
+		 cinfo[sp_idx].speed);
+
+	return 0;
+}
+
+static void wm97xx_irq_enable(struct wm97xx *wm, int enable)
+{
+	if (enable)
+		enable_irq(wm->pen_irq);
+	else
+		disable_irq_nosync(wm->pen_irq);
+}
+
+static struct wm97xx_mach_ops zylonite_mach_ops = {
+	.acc_enabled	= 1,
+	.acc_pen_up	= wm97xx_acc_pen_up,
+	.acc_pen_down	= wm97xx_acc_pen_down,
+	.acc_startup	= wm97xx_acc_startup,
+	.irq_enable	= wm97xx_irq_enable,
+	.irq_gpio	= WM97XX_GPIO_2,
+};
+
+static int zylonite_wm97xx_probe(struct platform_device *pdev)
+{
+	struct wm97xx *wm = platform_get_drvdata(pdev);
+	int gpio_touch_irq;
+
+	if (cpu_is_pxa320())
+		gpio_touch_irq = mfp_to_gpio(MFP_PIN_GPIO15);
+	else
+		gpio_touch_irq = mfp_to_gpio(MFP_PIN_GPIO26);
+
+	wm->pen_irq = IRQ_GPIO(gpio_touch_irq);
+	set_irq_type(IRQ_GPIO(gpio_touch_irq), IRQ_TYPE_EDGE_BOTH);
+
+	wm97xx_config_gpio(wm, WM97XX_GPIO_13, WM97XX_GPIO_IN,
+			   WM97XX_GPIO_POL_HIGH,
+			   WM97XX_GPIO_STICKY,
+			   WM97XX_GPIO_WAKE);
+	wm97xx_config_gpio(wm, WM97XX_GPIO_2, WM97XX_GPIO_OUT,
+			   WM97XX_GPIO_POL_HIGH,
+			   WM97XX_GPIO_NOTSTICKY,
+			   WM97XX_GPIO_NOWAKE);
+
+	return wm97xx_register_mach_ops(wm, &zylonite_mach_ops);
+}
+
+static int zylonite_wm97xx_remove(struct platform_device *pdev)
+{
+	struct wm97xx *wm = platform_get_drvdata(pdev);
+
+	wm97xx_unregister_mach_ops(wm);
+
+	return 0;
+}
+
+static struct platform_driver zylonite_wm97xx_driver = {
+	.probe	= zylonite_wm97xx_probe,
+	.remove	= zylonite_wm97xx_remove,
+	.driver	= {
+		.name	= "wm97xx-touch",
+	},
+};
+
+static int __init zylonite_wm97xx_init(void)
+{
+	return platform_driver_register(&zylonite_wm97xx_driver);
+}
+
+static void __exit zylonite_wm97xx_exit(void)
+{
+	platform_driver_unregister(&zylonite_wm97xx_driver);
+}
+
+module_init(zylonite_wm97xx_init);
+module_exit(zylonite_wm97xx_exit);
+
+/* Module information */
+MODULE_AUTHOR("Mark Brown <[e-mail]>");
+MODULE_DESCRIPTION("wm97xx continuous touch driver for Zylonite");
+MODULE_LICENSE("GPL");