Input: add wm97xx accelerated driver for Atmel microprocessors

This patch adds an accelerated driver for Atmel AVR32 AT32AP700X
microprocessors. It uses interrupts on the channel B in the AC97
controller. Thus, offloading the work queue in the wm97xx-ts driver.

The driver has been tested with Atmel AVR32 AT32AP7000 and Wolfson
WM9712 codec.

The driver can also be easily modified to support Atmel AT91 devices, as
AT91 and AVR32 share the same AC97C module.

[Fixed leak of atmel_wm97xx when probe fails. -- broonie]
[dtor@mail.ru: do not report ABS_PRESSURE events when not measuring pressure]
Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

3 files changed, 462 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index b01fd61d..82c388e 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -341,6 +341,21 @@ config TOUCHSCREEN_WM9713
 	  Say Y here to enable support for the Wolfson Microelectronics
 	  WM9713 touchscreen controller.
 
+config TOUCHSCREEN_WM97XX_ATMEL
+	tristate "WM97xx Atmel accelerated touch"
+	depends on TOUCHSCREEN_WM97XX && (AVR32 || ARCH_AT91)
+	help
+	  Say Y here for support for streaming mode with WM97xx touchscreens
+	  on Atmel AT91 or AVR32 systems with an AC97C module.
+
+	  Be aware that this will use channel B in the controller for
+	  streaming data, this must not conflict with other AC97C drivers.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called atmel-wm97xx.
+
 config TOUCHSCREEN_WM97XX_MAINSTONE
 	tristate "WM97xx Mainstone accelerated touch"
 	depends on TOUCHSCREEN_WM97XX && ARCH_PXA
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 6700f7b..bef7415 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -35,5 +35,6 @@ obj-$(CONFIG_TOUCHSCREEN_DA9034)	+= da9034-ts.o
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9705)	+= wm9705.o
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9712)	+= wm9712.o
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9713)	+= wm9713.o
+obj-$(CONFIG_TOUCHSCREEN_WM97XX_ATMEL)	+= atmel-wm97xx.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE)	+= mainstone-wm97xx.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX_ZYLONITE)	+= zylonite-wm97xx.o
diff --git a/drivers/input/touchscreen/atmel-wm97xx.c b/drivers/input/touchscreen/atmel-wm97xx.c
new file mode 100644
index 0000000..35377f5
--- /dev/null
+++ b/drivers/input/touchscreen/atmel-wm97xx.c
@@ -0,0 +1,446 @@
+/*
+ * Atmel AT91 and AVR32 continuous touch screen driver for Wolfson WM97xx AC97
+ * codecs.
+ *
+ * Copyright (C) 2008 - 2009 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+#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/wm97xx.h>
+#include <linux/timer.h>
+#include <linux/gpio.h>
+#include <linux/io.h>
+
+#define AC97C_ICA		0x10
+#define AC97C_CBRHR		0x30
+#define AC97C_CBSR		0x38
+#define AC97C_CBMR		0x3c
+#define AC97C_IER		0x54
+#define AC97C_IDR		0x58
+
+#define AC97C_RXRDY		(1 << 4)
+#define AC97C_OVRUN		(1 << 5)
+
+#define AC97C_CMR_SIZE_20	(0 << 16)
+#define AC97C_CMR_SIZE_18	(1 << 16)
+#define AC97C_CMR_SIZE_16	(2 << 16)
+#define AC97C_CMR_SIZE_10	(3 << 16)
+#define AC97C_CMR_CEM_LITTLE	(1 << 18)
+#define AC97C_CMR_CEM_BIG	(0 << 18)
+#define AC97C_CMR_CENA		(1 << 21)
+
+#define AC97C_INT_CBEVT		(1 << 4)
+
+#define AC97C_SR_CAEVT		(1 << 3)
+
+#define AC97C_CH_MASK(slot)						\
+	(0x7 << (3 * (slot - 3)))
+#define AC97C_CH_ASSIGN(slot, channel)					\
+	(AC97C_CHANNEL_##channel << (3 * (slot - 3)))
+#define AC97C_CHANNEL_NONE	0x0
+#define AC97C_CHANNEL_B		0x2
+
+#define ac97c_writel(chip, reg, val)			\
+	__raw_writel((val), (chip)->regs + AC97C_##reg)
+#define ac97c_readl(chip, reg)				\
+	__raw_readl((chip)->regs + AC97C_##reg)
+
+#ifdef CONFIG_CPU_AT32AP700X
+#define ATMEL_WM97XX_AC97C_IOMEM	(0xfff02800)
+#define ATMEL_WM97XX_AC97C_IRQ		(29)
+#define ATMEL_WM97XX_GPIO_DEFAULT	(32+16) /* Pin 16 on port B. */
+#else
+#error Unkown CPU, this driver only supports AT32AP700X CPUs.
+#endif
+
+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[] = {
+	{WM9705_ID2, 0, WM_READS(94), 94},
+	{WM9705_ID2, 1, WM_READS(188), 188},
+	{WM9705_ID2, 2, WM_READS(375), 375},
+	{WM9705_ID2, 3, WM_READS(750), 750},
+	{WM9712_ID2, 0, WM_READS(94), 94},
+	{WM9712_ID2, 1, WM_READS(188), 188},
+	{WM9712_ID2, 2, WM_READS(375), 375},
+	{WM9712_ID2, 3, WM_READS(750), 750},
+	{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 = 188;
+module_param(cont_rate, int, 0);
+MODULE_PARM_DESC(cont_rate, "Sampling rate in continuous mode (Hz)");
+
+/*
+ * Pen down detection.
+ *
+ * This driver can either poll or use an interrupt to indicate a pen down
+ * event. If the irq request fails then it will fall back to polling mode.
+ */
+static int pen_int = 1;
+module_param(pen_int, int, 0);
+MODULE_PARM_DESC(pen_int, "Pen down detection (1 = interrupt, 0 = polling)");
+
+/*
+ * 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");
+
+/*
+ * GPIO line number.
+ *
+ * Set to GPIO number where the signal from the WM97xx device is hooked up.
+ */
+static int atmel_gpio_line = ATMEL_WM97XX_GPIO_DEFAULT;
+module_param(atmel_gpio_line, int, 0);
+MODULE_PARM_DESC(atmel_gpio_line, "GPIO line number connected to WM97xx");
+
+struct atmel_wm97xx {
+	struct wm97xx		*wm;
+	struct timer_list	pen_timer;
+	void __iomem		*regs;
+	unsigned long		ac97c_irq;
+	unsigned long		gpio_pen;
+	unsigned long		gpio_irq;
+	unsigned short		x;
+	unsigned short		y;
+};
+
+static irqreturn_t atmel_wm97xx_channel_b_interrupt(int irq, void *dev_id)
+{
+	struct atmel_wm97xx *atmel_wm97xx = dev_id;
+	struct wm97xx *wm = atmel_wm97xx->wm;
+	int status = ac97c_readl(atmel_wm97xx, CBSR);
+	irqreturn_t retval = IRQ_NONE;
+
+	if (status & AC97C_OVRUN) {
+		dev_dbg(&wm->touch_dev->dev, "AC97C overrun\n");
+		ac97c_readl(atmel_wm97xx, CBRHR);
+		retval = IRQ_HANDLED;
+	} else if (status & AC97C_RXRDY) {
+		u16 data;
+		u16 value;
+		u16 source;
+		u16 pen_down;
+
+		data = ac97c_readl(atmel_wm97xx, CBRHR);
+		value = data & 0x0fff;
+		source = data & WM97XX_ADCSRC_MASK;
+		pen_down = (data & WM97XX_PEN_DOWN) >> 8;
+
+		if (source == WM97XX_ADCSEL_X)
+			atmel_wm97xx->x = value;
+		if (source == WM97XX_ADCSEL_Y)
+			atmel_wm97xx->y = value;
+
+		if (!pressure && source == WM97XX_ADCSEL_Y) {
+			input_report_abs(wm->input_dev, ABS_X, atmel_wm97xx->x);
+			input_report_abs(wm->input_dev, ABS_Y, atmel_wm97xx->y);
+			input_report_key(wm->input_dev, BTN_TOUCH, pen_down);
+			input_sync(wm->input_dev);
+		} else if (pressure && source == WM97XX_ADCSEL_PRES) {
+			input_report_abs(wm->input_dev, ABS_X, atmel_wm97xx->x);
+			input_report_abs(wm->input_dev, ABS_Y, atmel_wm97xx->y);
+			input_report_abs(wm->input_dev, ABS_PRESSURE, value);
+			input_report_key(wm->input_dev, BTN_TOUCH, value);
+			input_sync(wm->input_dev);
+		}
+
+		retval = IRQ_HANDLED;
+	}
+
+	return retval;
+}
+
+static void atmel_wm97xx_acc_pen_up(struct wm97xx *wm)
+{
+	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(wm->touch_dev);
+	struct input_dev *input_dev = wm->input_dev;
+	int pen_down = gpio_get_value(atmel_wm97xx->gpio_pen);
+
+	if (pen_down != 0) {
+		mod_timer(&atmel_wm97xx->pen_timer,
+			  jiffies + msecs_to_jiffies(1));
+	} else {
+		if (pressure)
+			input_report_abs(input_dev, ABS_PRESSURE, 0);
+		input_report_key(input_dev, BTN_TOUCH, 0);
+		input_sync(input_dev);
+	}
+}
+
+static void atmel_wm97xx_pen_timer(unsigned long data)
+{
+	atmel_wm97xx_acc_pen_up((struct wm97xx *)data);
+}
+
+static int atmel_wm97xx_acc_startup(struct wm97xx *wm)
+{
+	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(wm->touch_dev);
+	int idx = 0;
+
+	if (wm->ac97 == NULL)
+		return -ENODEV;
+
+	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->touch_dev->dev, "atmel accelerated touchscreen driver, "
+			"%d samples/sec\n", cinfo[sp_idx].speed);
+
+	if (pen_int) {
+		unsigned long reg;
+
+		wm->pen_irq = atmel_wm97xx->gpio_irq;
+
+		switch (wm->id) {
+		case WM9712_ID2: /* Fall through. */
+		case WM9713_ID2:
+			/*
+			 * Use GPIO 13 (PEN_DOWN) to assert GPIO line 3
+			 * (PENDOWN).
+			 */
+			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_3, WM97XX_GPIO_OUT,
+					WM97XX_GPIO_POL_HIGH,
+					WM97XX_GPIO_NOTSTICKY,
+					WM97XX_GPIO_NOWAKE);
+		case WM9705_ID2: /* Fall through. */
+			/*
+			 * Enable touch data slot in AC97 controller channel B.
+			 */
+			reg = ac97c_readl(atmel_wm97xx, ICA);
+			reg &= ~AC97C_CH_MASK(wm->acc_slot);
+			reg |= AC97C_CH_ASSIGN(wm->acc_slot, B);
+			ac97c_writel(atmel_wm97xx, ICA, reg);
+
+			/*
+			 * Enable channel and interrupt for RXRDY and OVERRUN.
+			 */
+			ac97c_writel(atmel_wm97xx, CBMR, AC97C_CMR_CENA
+					| AC97C_CMR_CEM_BIG
+					| AC97C_CMR_SIZE_16
+					| AC97C_OVRUN
+					| AC97C_RXRDY);
+			/* Dummy read to empty RXRHR. */
+			ac97c_readl(atmel_wm97xx, CBRHR);
+			/*
+			 * Enable interrupt for channel B in the AC97
+			 * controller.
+			 */
+			ac97c_writel(atmel_wm97xx, IER, AC97C_INT_CBEVT);
+			break;
+		default:
+			dev_err(&wm->touch_dev->dev, "pen down irq not "
+					"supported on this device\n");
+			pen_int = 0;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static void atmel_wm97xx_acc_shutdown(struct wm97xx *wm)
+{
+	if (pen_int) {
+		struct atmel_wm97xx *atmel_wm97xx =
+			platform_get_drvdata(wm->touch_dev);
+		unsigned long ica;
+
+		switch (wm->id & 0xffff) {
+		case WM9705_ID2: /* Fall through. */
+		case WM9712_ID2: /* Fall through. */
+		case WM9713_ID2:
+			/* Disable slot and turn off channel B interrupts. */
+			ica = ac97c_readl(atmel_wm97xx, ICA);
+			ica &= ~AC97C_CH_MASK(wm->acc_slot);
+			ac97c_writel(atmel_wm97xx, ICA, ica);
+			ac97c_writel(atmel_wm97xx, IDR, AC97C_INT_CBEVT);
+			ac97c_writel(atmel_wm97xx, CBMR, 0);
+			wm->pen_irq = 0;
+			break;
+		default:
+			dev_err(&wm->touch_dev->dev, "unknown codec\n");
+			break;
+		}
+	}
+}
+
+static void atmel_wm97xx_irq_enable(struct wm97xx *wm, int enable)
+{
+	/* Intentionally left empty. */
+}
+
+static struct wm97xx_mach_ops atmel_mach_ops = {
+	.acc_enabled	= 1,
+	.acc_pen_up	= atmel_wm97xx_acc_pen_up,
+	.acc_startup	= atmel_wm97xx_acc_startup,
+	.acc_shutdown	= atmel_wm97xx_acc_shutdown,
+	.irq_enable	= atmel_wm97xx_irq_enable,
+	.irq_gpio	= WM97XX_GPIO_3,
+};
+
+static int __init atmel_wm97xx_probe(struct platform_device *pdev)
+{
+	struct wm97xx *wm = platform_get_drvdata(pdev);
+	struct atmel_wm97xx *atmel_wm97xx;
+	int ret;
+
+	atmel_wm97xx = kzalloc(sizeof(struct atmel_wm97xx), GFP_KERNEL);
+	if (!atmel_wm97xx) {
+		dev_dbg(&pdev->dev, "out of memory\n");
+		return -ENOMEM;
+	}
+
+	atmel_wm97xx->wm	= wm;
+	atmel_wm97xx->regs	= (void *)ATMEL_WM97XX_AC97C_IOMEM;
+	atmel_wm97xx->ac97c_irq	= ATMEL_WM97XX_AC97C_IRQ;
+	atmel_wm97xx->gpio_pen	= atmel_gpio_line;
+	atmel_wm97xx->gpio_irq	= gpio_to_irq(atmel_wm97xx->gpio_pen);
+
+	setup_timer(&atmel_wm97xx->pen_timer, atmel_wm97xx_pen_timer,
+			(unsigned long)wm);
+
+	ret = request_irq(atmel_wm97xx->ac97c_irq,
+			  atmel_wm97xx_channel_b_interrupt,
+			  IRQF_SHARED, "atmel-wm97xx-ch-b", atmel_wm97xx);
+	if (ret) {
+		dev_dbg(&pdev->dev, "could not request ac97c irq\n");
+		goto err;
+	}
+
+	platform_set_drvdata(pdev, atmel_wm97xx);
+
+	ret = wm97xx_register_mach_ops(wm, &atmel_mach_ops);
+	if (ret)
+		goto err_irq;
+
+	return ret;
+
+err_irq:
+	free_irq(atmel_wm97xx->ac97c_irq, atmel_wm97xx);
+err:
+	platform_set_drvdata(pdev, NULL);
+	kfree(atmel_wm97xx);
+	return ret;
+}
+
+static int __exit atmel_wm97xx_remove(struct platform_device *pdev)
+{
+	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(pdev);
+	struct wm97xx *wm = atmel_wm97xx->wm;
+
+	ac97c_writel(atmel_wm97xx, IDR, AC97C_INT_CBEVT);
+	free_irq(atmel_wm97xx->ac97c_irq, atmel_wm97xx);
+	del_timer_sync(&atmel_wm97xx->pen_timer);
+	wm97xx_unregister_mach_ops(wm);
+	platform_set_drvdata(pdev, NULL);
+	kfree(atmel_wm97xx);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int atmel_wm97xx_suspend(struct platform_device *pdev, pm_message_t msg)
+{
+	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(pdev);
+
+	ac97c_writel(atmel_wm97xx, IDR, AC97C_INT_CBEVT);
+	disable_irq(atmel_wm97xx->gpio_irq);
+	del_timer_sync(&atmel_wm97xx->pen_timer);
+
+	return 0;
+}
+
+static int atmel_wm97xx_resume(struct platform_device *pdev)
+{
+	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(pdev);
+	struct wm97xx *wm = atmel_wm97xx->wm;
+
+	if (wm->input_dev->users) {
+		enable_irq(atmel_wm97xx->gpio_irq);
+		ac97c_writel(atmel_wm97xx, IER, AC97C_INT_CBEVT);
+	}
+
+	return 0;
+}
+#else
+#define atmel_wm97xx_suspend	NULL
+#define atmel_wm97xx_resume	NULL
+#endif
+
+static struct platform_driver atmel_wm97xx_driver = {
+	.remove		= __exit_p(atmel_wm97xx_remove),
+	.driver		= {
+		.name = "wm97xx-touch",
+	},
+	.suspend	= atmel_wm97xx_suspend,
+	.resume		= atmel_wm97xx_resume,
+};
+
+static int __init atmel_wm97xx_init(void)
+{
+	return platform_driver_probe(&atmel_wm97xx_driver, atmel_wm97xx_probe);
+}
+module_init(atmel_wm97xx_init);
+
+static void __exit atmel_wm97xx_exit(void)
+{
+	platform_driver_unregister(&atmel_wm97xx_driver);
+}
+module_exit(atmel_wm97xx_exit);
+
+MODULE_AUTHOR("Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>");
+MODULE_DESCRIPTION("wm97xx continuous touch driver for Atmel AT91 and AVR32");
+MODULE_LICENSE("GPL");