Date:	Sun, 28 Jun 2009 16:35:42 +0200
From:	Antonio Ospite <ospite@...denti.unina.it>
To:	Daniel Ribeiro <drwyrm@...il.com>
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	linux-input@...r.kernel.org,
	openezx-devel <openezx-devel@...ts.openezx.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Harald Welte <laforge@...monks.org>,
	Samuel Ortiz <sameo@...ux.intel.com>
Subject: Re: [PATCH] PCAP touchscreen driver (for 2.6.32)

Daniel, some trivial comments, I can do the changes if you want.

On Sat, 27 Jun 2009 14:02:18 -0300
Daniel Ribeiro <drwyrm@...il.com> wrote:

> Touchscreen driver for PCAP2 PMIC.
> 
> Signed-off-by: Daniel Ribeiro <drwyrm@...il.com>
> 
> ---
>  drivers/input/touchscreen/Kconfig   |    9 ++
>  drivers/input/touchscreen/Makefile  |    1 +
>  drivers/input/touchscreen/pcap_ts.c |  235 +++++++++++++++++++++++++++++++++++
>  3 files changed, 245 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index 72e2712..8e6fa8b 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -498,4 +498,13 @@ config TOUCHSCREEN_W90X900
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called w90p910_ts.
>  
> +config TOUCHSCREEN_PCAP
> +	tristate "Motorola PCAP touchscreen"
> +	depends on EZX_PCAP
> +	help
> +	  Say Y here if you have a Motorola EZX telephone and
> +	  want to support the built-in touchscreen.
> +
> +	  If unsure, say N.
> +
>  endif
> diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> index 3e1c5e0..4599bf7 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -40,3 +40,4 @@ obj-$(CONFIG_TOUCHSCREEN_WM97XX_ATMEL)	+= atmel-wm97xx.o
>  obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE)	+= mainstone-wm97xx.o
>  obj-$(CONFIG_TOUCHSCREEN_WM97XX_ZYLONITE)	+= zylonite-wm97xx.o
>  obj-$(CONFIG_TOUCHSCREEN_W90X900)	+= w90p910_ts.o
> +obj-$(CONFIG_TOUCHSCREEN_PCAP)		+= pcap_ts.o
> diff --git a/drivers/input/touchscreen/pcap_ts.c b/drivers/input/touchscreen/pcap_ts.c
> new file mode 100644
> index 0000000..7877fdf
> --- /dev/null
> +++ b/drivers/input/touchscreen/pcap_ts.c
> @@ -0,0 +1,235 @@
> +/*
> + * Driver for Motorola PCAP2 touchscreen as found in the EZX phone platform.
> + *
> + *  Copyright (C) 2006 Harald Welte <laforge@...nezx.org>
> + *  Copyright (C) 2009 Daniel Ribeiro <drwyrm@...il.com>
> + *
> + *  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/init.h>
> +#include <linux/fs.h>
> +#include <linux/string.h>
> +#include <linux/pm.h>
> +#include <linux/timer.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/input.h>
> +#include <linux/mfd/ezx-pcap.h>
> +
> +struct pcap_ts {
> +	struct pcap_chip *pcap;
> +	struct input_dev *input;
> +	struct delayed_work work;
> +	u16 x, y;
> +	u16 pressure;
> +	u8 read_state;
> +};
> +
> +#define SAMPLE_DELAY	20 /* msecs */
> +
> +#define X_AXIS_MIN	0
> +#define X_AXIS_MAX	1023
> +#define Y_AXIS_MAX	X_AXIS_MAX
> +#define Y_AXIS_MIN	X_AXIS_MIN
> +#define PRESSURE_MAX	X_AXIS_MAX
> +#define PRESSURE_MIN	X_AXIS_MIN
> +
> +static void pcap_ts_read_xy(void *data, u16 res[2])
> +{
> +	struct pcap_ts *pcap_ts = data;
> +
> +	switch (pcap_ts->read_state) {
> +	case PCAP_ADC_TS_M_PRESSURE:
> +		/* pressure reading is unreliable */
> +		if (res[0] > PRESSURE_MIN && res[0] < PRESSURE_MAX)
> +			pcap_ts->pressure = res[0];
> +		pcap_ts->read_state = PCAP_ADC_TS_M_XY;
> +		schedule_delayed_work(&pcap_ts->work, 0);
> +		break;
> +	case PCAP_ADC_TS_M_XY:
> +		pcap_ts->y = res[0];
> +		pcap_ts->x = res[1];
> +		if (pcap_ts->x <= X_AXIS_MIN || pcap_ts->x >= X_AXIS_MAX ||
> +		    pcap_ts->y <= Y_AXIS_MIN || pcap_ts->y >= Y_AXIS_MAX) {
> +			/* pen has been released */
> +			input_report_abs(pcap_ts->input, ABS_PRESSURE, 0);
> +			input_report_key(pcap_ts->input, BTN_TOUCH, 0);
> +
> +			pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
> +			schedule_delayed_work(&pcap_ts->work, 0);
> +		} else {
> +			/* pen is touching the screen*/
> +			input_report_abs(pcap_ts->input, ABS_X, pcap_ts->x);
> +			input_report_abs(pcap_ts->input, ABS_Y, pcap_ts->y);
> +			input_report_key(pcap_ts->input, BTN_TOUCH, 1);
> +			input_report_abs(pcap_ts->input, ABS_PRESSURE,
> +						pcap_ts->pressure);
> +
> +			/* switch back to pressure read mode */
> +			pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
> +			schedule_delayed_work(&pcap_ts->work,
> +					msecs_to_jiffies(SAMPLE_DELAY));
> +		}
> +		input_sync(pcap_ts->input);
> +		break;
> +	default:
> +		break;
> +	}
> +}
> +
> +static void pcap_ts_work(struct work_struct *work)
> +{
> +	struct delayed_work *dw = container_of(work, struct delayed_work, work);
> +	struct pcap_ts *pcap_ts = container_of(dw, struct pcap_ts, work);
> +	u8 ch[2];
> +
> +	pcap_set_ts_bits(pcap_ts->pcap,
> +			pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
> +
> +	if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY)
> +		return;
> +
> +	/* start adc conversion */
> +	ch[0] = PCAP_ADC_CH_TS_X1;
> +	ch[1] = PCAP_ADC_CH_TS_Y1;
> +	pcap_adc_async(pcap_ts->pcap, PCAP_ADC_BANK_1, 0, ch,
> +						pcap_ts_read_xy, pcap_ts);
> +}
> +
> +static irqreturn_t pcap_ts_event_touch(int pirq, void *data)
> +{
> +	struct pcap_ts *pcap_ts = data;
> +
> +	if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY) {
> +		pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
> +		schedule_delayed_work(&pcap_ts->work, 0);
> +	}
> +	return IRQ_HANDLED;
> +}
> +
> +static int __devinit pcap_ts_probe(struct platform_device *pdev)
> +{
> +	struct input_dev *input_dev;
> +	struct pcap_ts *pcap_ts;
> +	int err = -ENOMEM;
> +
> +	pcap_ts = kzalloc(sizeof(*pcap_ts), GFP_KERNEL);
> +	if (!pcap_ts)
> +		return err;
> +
> +	pcap_ts->pcap = platform_get_drvdata(pdev);
> +	platform_set_drvdata(pdev, pcap_ts);
> +
> +	input_dev = input_allocate_device();
> +	if (!pcap_ts || !input_dev)

Can pcap_ts be ever NULL here? This test can be simplified.

> +		goto fail;
> +
> +	INIT_DELAYED_WORK(&pcap_ts->work, pcap_ts_work);
> +
> +	pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
> +
> +	pcap_ts->input = input_dev;
> +
> +	input_dev->name = "pcap-touchscreen";
> +	input_dev->phys = "pcap_ts/input0";
> +	input_dev->id.bustype = BUS_HOST;
> +	input_dev->id.vendor = 0x0001;
> +	input_dev->id.product = 0x0002;
> +	input_dev->id.version = 0x0100;
> +	input_dev->dev.parent = &pdev->dev;
> +
> +	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
> +	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
> +	input_set_abs_params(input_dev, ABS_X, X_AXIS_MIN, X_AXIS_MAX, 0, 0);
> +	input_set_abs_params(input_dev, ABS_Y, Y_AXIS_MIN, Y_AXIS_MAX, 0, 0);
> +	input_set_abs_params(input_dev, ABS_PRESSURE, PRESSURE_MIN,
> +			     PRESSURE_MAX, 0, 0);
> +
> +	err = request_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS),
> +			pcap_ts_event_touch, 0, "Touch Screen", pcap_ts);
> +	if (err)
> +		goto fail;
> +
> +	err = input_register_device(pcap_ts->input);
> +	if (err)
> +		goto fail_touch;
> +
> +	schedule_delayed_work(&pcap_ts->work, 0);
> +
> +	return 0;
> +
> +fail_touch:
> +	free_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS), pcap_ts);
> +fail:
> +	input_free_device(input_dev);
> +	kfree(pcap_ts);
> +
> +	return err;
> +}
> +
> +static int __devexit pcap_ts_remove(struct platform_device *pdev)
> +{
> +	struct pcap_ts *pcap_ts = platform_get_drvdata(pdev);
> +
> +	free_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS), pcap_ts);
> +
> +	input_unregister_device(pcap_ts->input);
> +	cancel_delayed_work_sync(&pcap_ts->work);
> +	kfree(pcap_ts);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int pcap_ts_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> +	struct pcap_ts *pcap_ts = platform_get_drvdata(pdev);
> +
> +	pcap_set_ts_bits(pcap_ts->pcap, PCAP_ADC_TS_REF_LOWPWR);
> +	return 0;
> +}
> +
> +static int pcap_ts_resume(struct platform_device *pdev)
> +{
> +	struct pcap_ts *pcap_ts = platform_get_drvdata(pdev);
> +
> +	pcap_set_ts_bits(pcap_ts->pcap,
> +				pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
> +	return 0;
> +}
> +#endif
> +

define the suspend/resume callbacks as NULL in a #else here and remove
the #ifdef CONFIG_PM below? That seems to be the most used style.

> +static struct platform_driver pcap_ts_driver = {
> +	.probe		= pcap_ts_probe,
> +	.remove		= __devexit_p(pcap_ts_remove),
> +#ifdef CONFIG_PM
> +	.suspend	= pcap_ts_suspend,
> +	.resume		= pcap_ts_resume,
> +#endif
> +	.driver		= {
> +		.name	= "pcap-ts",
> +		.owner	= THIS_MODULE,
> +	},
> +};
> +
> +static int __init pcap_ts_init(void)
> +{
> +	return platform_driver_register(&pcap_ts_driver);
> +}
> +
> +static void __exit pcap_ts_exit(void)
> +{
> +	platform_driver_unregister(&pcap_ts_driver);
> +}
> +
> +module_init(pcap_ts_init);
> +module_exit(pcap_ts_exit);
> +
> +MODULE_DESCRIPTION("Motorola PCAP2 touchscreen driver");
> +MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
> +MODULE_LICENSE("GPL");
> -- 
> tg: (8892412..) ezx/pcap_ts (depends on: ezx/local/pcap)
> 
> -- 
> Daniel Ribeiro


-- 
A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
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Antonio Ospite
http://ao2.it

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