diff mbox

[v6,6/8] input: touchscreen: imx25 tcq driver

Message ID 1422540556-14828-7-git-send-email-mpa@pengutronix.de (mailing list archive)
State New, archived
Headers show

Commit Message

Markus Pargmann Jan. 29, 2015, 2:09 p.m. UTC
This is a driver for the imx25 ADC/TSC module. It controls the
touchscreen conversion queue and creates a touchscreen input device.
The driver currently only supports 4 wire touchscreens. The driver uses
a simple conversion queue of precharge, touch detection, X measurement,
Y measurement, precharge and another touch detection.

This driver uses the regmap from the parent to setup some touch specific
settings in the core driver and setup a idle configuration with touch
detection.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Denis Carikli <denis@eukrea.com>
Acked-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
---
 drivers/input/touchscreen/Kconfig         |   6 +
 drivers/input/touchscreen/Makefile        |   1 +
 drivers/input/touchscreen/fsl-imx25-tcq.c | 587 ++++++++++++++++++++++++++++++
 3 files changed, 594 insertions(+)
 create mode 100644 drivers/input/touchscreen/fsl-imx25-tcq.c

Comments

Varka Bhadram Jan. 29, 2015, 2:26 p.m. UTC | #1
Hi,

On Thursday 29 January 2015 07:39 PM, Markus Pargmann wrote:
> This is a driver for the imx25 ADC/TSC module. It controls the
> touchscreen conversion queue and creates a touchscreen input device.
> The driver currently only supports 4 wire touchscreens. The driver uses
> a simple conversion queue of precharge, touch detection, X measurement,
> Y measurement, precharge and another touch detection.
>
> This driver uses the regmap from the parent to setup some touch specific
> settings in the core driver and setup a idle configuration with touch
> detection.
>
> Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> Signed-off-by: Denis Carikli <denis@eukrea.com>
> Acked-by: Dmitry Torokhov <dtor@vmware.com>
> Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> ---
>   drivers/input/touchscreen/Kconfig         |   6 +
>   drivers/input/touchscreen/Makefile        |   1 +
>   drivers/input/touchscreen/fsl-imx25-tcq.c | 587 ++++++++++++++++++++++++++++++
>   3 files changed, 594 insertions(+)
>   create mode 100644 drivers/input/touchscreen/fsl-imx25-tcq.c
>
(...)

> +	ret = request_threaded_irq(priv->irq, mx25_tcq_irq, mx25_tcq_irq_thread,
> +				   IRQF_ONESHOT, pdev->name, priv);

We can use devres API for request_thread_irq()...

> +	if (ret) {
> +		dev_err(dev, "Failed requesting IRQ\n");
> +		goto err_clk_unprepare;
> +	}
> +
> +	ret = mx25_tcq_init(priv);
> +	if (ret) {
> +		dev_err(dev, "Failed to init tcq\n");
> +		goto error_free_irq;
> +	}
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	return 0;
> +
> +error_free_irq:
> +	free_irq(priv->irq, priv);

This is not required if we use devres API

> +err_clk_unprepare:
> +	clk_disable_unprepare(priv->clk);
> +	return ret;
> +}
> +
> +static int mx25_tcq_remove(struct platform_device *pdev)
> +{
> +	struct mx25_tcq_priv *priv = platform_get_drvdata(pdev);
> +
> +	free_irq(priv->irq, priv);

This also..
Dmitry Torokhov Jan. 30, 2015, 6:57 p.m. UTC | #2
On Thu, Jan 29, 2015 at 07:56:40PM +0530, Varka Bhadram wrote:
> Hi,
> 
> On Thursday 29 January 2015 07:39 PM, Markus Pargmann wrote:
> >This is a driver for the imx25 ADC/TSC module. It controls the
> >touchscreen conversion queue and creates a touchscreen input device.
> >The driver currently only supports 4 wire touchscreens. The driver uses
> >a simple conversion queue of precharge, touch detection, X measurement,
> >Y measurement, precharge and another touch detection.
> >
> >This driver uses the regmap from the parent to setup some touch specific
> >settings in the core driver and setup a idle configuration with touch
> >detection.
> >
> >Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> >Signed-off-by: Denis Carikli <denis@eukrea.com>
> >Acked-by: Dmitry Torokhov <dtor@vmware.com>
> >Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> >---
> >  drivers/input/touchscreen/Kconfig         |   6 +
> >  drivers/input/touchscreen/Makefile        |   1 +
> >  drivers/input/touchscreen/fsl-imx25-tcq.c | 587 ++++++++++++++++++++++++++++++
> >  3 files changed, 594 insertions(+)
> >  create mode 100644 drivers/input/touchscreen/fsl-imx25-tcq.c
> >
> (...)
> 
> >+	ret = request_threaded_irq(priv->irq, mx25_tcq_irq, mx25_tcq_irq_thread,
> >+				   IRQF_ONESHOT, pdev->name, priv);
> 
> We can use devres API for request_thread_irq()...
> 
> >+	if (ret) {
> >+		dev_err(dev, "Failed requesting IRQ\n");
> >+		goto err_clk_unprepare;
> >+	}
> >+
> >+	ret = mx25_tcq_init(priv);
> >+	if (ret) {
> >+		dev_err(dev, "Failed to init tcq\n");
> >+		goto error_free_irq;
> >+	}
> >+
> >+	platform_set_drvdata(pdev, priv);
> >+
> >+	return 0;
> >+
> >+error_free_irq:
> >+	free_irq(priv->irq, priv);
> 
> This is not required if we use devres API

Yes it does - you do not really want to stop clocks in the middle of
servicing interrupt.

Thanks.
Markus Pargmann Feb. 2, 2015, 4:05 p.m. UTC | #3
Hi,

On Fri, Jan 30, 2015 at 10:57:21AM -0800, Dmitry Torokhov wrote:
> On Thu, Jan 29, 2015 at 07:56:40PM +0530, Varka Bhadram wrote:
> > Hi,
> > 
> > On Thursday 29 January 2015 07:39 PM, Markus Pargmann wrote:
> > >This is a driver for the imx25 ADC/TSC module. It controls the
> > >touchscreen conversion queue and creates a touchscreen input device.
> > >The driver currently only supports 4 wire touchscreens. The driver uses
> > >a simple conversion queue of precharge, touch detection, X measurement,
> > >Y measurement, precharge and another touch detection.
> > >
> > >This driver uses the regmap from the parent to setup some touch specific
> > >settings in the core driver and setup a idle configuration with touch
> > >detection.
> > >
> > >Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> > >Signed-off-by: Denis Carikli <denis@eukrea.com>
> > >Acked-by: Dmitry Torokhov <dtor@vmware.com>
> > >Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> > >---
> > >  drivers/input/touchscreen/Kconfig         |   6 +
> > >  drivers/input/touchscreen/Makefile        |   1 +
> > >  drivers/input/touchscreen/fsl-imx25-tcq.c | 587 ++++++++++++++++++++++++++++++
> > >  3 files changed, 594 insertions(+)
> > >  create mode 100644 drivers/input/touchscreen/fsl-imx25-tcq.c
> > >
> > (...)
> > 
> > >+	ret = request_threaded_irq(priv->irq, mx25_tcq_irq, mx25_tcq_irq_thread,
> > >+				   IRQF_ONESHOT, pdev->name, priv);
> > 
> > We can use devres API for request_thread_irq()...
> > 
> > >+	if (ret) {
> > >+		dev_err(dev, "Failed requesting IRQ\n");
> > >+		goto err_clk_unprepare;
> > >+	}
> > >+
> > >+	ret = mx25_tcq_init(priv);
> > >+	if (ret) {
> > >+		dev_err(dev, "Failed to init tcq\n");
> > >+		goto error_free_irq;
> > >+	}
> > >+
> > >+	platform_set_drvdata(pdev, priv);
> > >+
> > >+	return 0;
> > >+
> > >+error_free_irq:
> > >+	free_irq(priv->irq, priv);
> > 
> > This is not required if we use devres API
> 
> Yes it does - you do not really want to stop clocks in the middle of
> servicing interrupt.

Thanks, I missed the clocks. I will not use devm here then.

For the gcq (ADC) driver, it would still works to use devm_request_irq as the
interrupt can only trigger when the user requested an ADC conversion. So as
soon as the device is unregistered from the IIO subsystem, there should
not be any interrupts. However I would like to keep free_irq in the gcq
driver as well. Unexpected interrupts wouldn't be a problem and
especially if the driver is extended for continous conversion in the
future, this may be better.

Best regards,

Markus
Dmitry Torokhov Feb. 2, 2015, 5:51 p.m. UTC | #4
On Mon, Feb 02, 2015 at 05:05:39PM +0100, Markus Pargmann wrote:
> Hi,
> 
> On Fri, Jan 30, 2015 at 10:57:21AM -0800, Dmitry Torokhov wrote:
> > On Thu, Jan 29, 2015 at 07:56:40PM +0530, Varka Bhadram wrote:
> > > Hi,
> > > 
> > > On Thursday 29 January 2015 07:39 PM, Markus Pargmann wrote:
> > > >This is a driver for the imx25 ADC/TSC module. It controls the
> > > >touchscreen conversion queue and creates a touchscreen input device.
> > > >The driver currently only supports 4 wire touchscreens. The driver uses
> > > >a simple conversion queue of precharge, touch detection, X measurement,
> > > >Y measurement, precharge and another touch detection.
> > > >
> > > >This driver uses the regmap from the parent to setup some touch specific
> > > >settings in the core driver and setup a idle configuration with touch
> > > >detection.
> > > >
> > > >Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> > > >Signed-off-by: Denis Carikli <denis@eukrea.com>
> > > >Acked-by: Dmitry Torokhov <dtor@vmware.com>
> > > >Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> > > >---
> > > >  drivers/input/touchscreen/Kconfig         |   6 +
> > > >  drivers/input/touchscreen/Makefile        |   1 +
> > > >  drivers/input/touchscreen/fsl-imx25-tcq.c | 587 ++++++++++++++++++++++++++++++
> > > >  3 files changed, 594 insertions(+)
> > > >  create mode 100644 drivers/input/touchscreen/fsl-imx25-tcq.c
> > > >
> > > (...)
> > > 
> > > >+	ret = request_threaded_irq(priv->irq, mx25_tcq_irq, mx25_tcq_irq_thread,
> > > >+				   IRQF_ONESHOT, pdev->name, priv);
> > > 
> > > We can use devres API for request_thread_irq()...
> > > 
> > > >+	if (ret) {
> > > >+		dev_err(dev, "Failed requesting IRQ\n");
> > > >+		goto err_clk_unprepare;
> > > >+	}
> > > >+
> > > >+	ret = mx25_tcq_init(priv);
> > > >+	if (ret) {
> > > >+		dev_err(dev, "Failed to init tcq\n");
> > > >+		goto error_free_irq;
> > > >+	}
> > > >+
> > > >+	platform_set_drvdata(pdev, priv);
> > > >+
> > > >+	return 0;
> > > >+
> > > >+error_free_irq:
> > > >+	free_irq(priv->irq, priv);
> > > 
> > > This is not required if we use devres API
> > 
> > Yes it does - you do not really want to stop clocks in the middle of
> > servicing interrupt.
> 
> Thanks, I missed the clocks. I will not use devm here then.

Actually, you still can if you move clock enabling/disabling and
mx25_tcq_init() into input_dev->open() and ->close() callbacks. Close
will be called during input device un-registration which happens (given
your current sequence) after freeing irq by devm.

By the way, I used my old @vmware address by accident. Can you please
replace the original acked by with:

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Thanks.
Markus Pargmann Feb. 26, 2015, 2:30 p.m. UTC | #5
Hi,

On Mon, Feb 02, 2015 at 09:51:34AM -0800, Dmitry Torokhov wrote:
> On Mon, Feb 02, 2015 at 05:05:39PM +0100, Markus Pargmann wrote:
> > Hi,
> > 
> > On Fri, Jan 30, 2015 at 10:57:21AM -0800, Dmitry Torokhov wrote:
> > > On Thu, Jan 29, 2015 at 07:56:40PM +0530, Varka Bhadram wrote:
> > > > Hi,
> > > > 
> > > > On Thursday 29 January 2015 07:39 PM, Markus Pargmann wrote:
> > > > >This is a driver for the imx25 ADC/TSC module. It controls the
> > > > >touchscreen conversion queue and creates a touchscreen input device.
> > > > >The driver currently only supports 4 wire touchscreens. The driver uses
> > > > >a simple conversion queue of precharge, touch detection, X measurement,
> > > > >Y measurement, precharge and another touch detection.
> > > > >
> > > > >This driver uses the regmap from the parent to setup some touch specific
> > > > >settings in the core driver and setup a idle configuration with touch
> > > > >detection.
> > > > >
> > > > >Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> > > > >Signed-off-by: Denis Carikli <denis@eukrea.com>
> > > > >Acked-by: Dmitry Torokhov <dtor@vmware.com>
> > > > >Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> > > > >---
> > > > >  drivers/input/touchscreen/Kconfig         |   6 +
> > > > >  drivers/input/touchscreen/Makefile        |   1 +
> > > > >  drivers/input/touchscreen/fsl-imx25-tcq.c | 587 ++++++++++++++++++++++++++++++
> > > > >  3 files changed, 594 insertions(+)
> > > > >  create mode 100644 drivers/input/touchscreen/fsl-imx25-tcq.c
> > > > >
> > > > (...)
> > > > 
> > > > >+	ret = request_threaded_irq(priv->irq, mx25_tcq_irq, mx25_tcq_irq_thread,
> > > > >+				   IRQF_ONESHOT, pdev->name, priv);
> > > > 
> > > > We can use devres API for request_thread_irq()...
> > > > 
> > > > >+	if (ret) {
> > > > >+		dev_err(dev, "Failed requesting IRQ\n");
> > > > >+		goto err_clk_unprepare;
> > > > >+	}
> > > > >+
> > > > >+	ret = mx25_tcq_init(priv);
> > > > >+	if (ret) {
> > > > >+		dev_err(dev, "Failed to init tcq\n");
> > > > >+		goto error_free_irq;
> > > > >+	}
> > > > >+
> > > > >+	platform_set_drvdata(pdev, priv);
> > > > >+
> > > > >+	return 0;
> > > > >+
> > > > >+error_free_irq:
> > > > >+	free_irq(priv->irq, priv);
> > > > 
> > > > This is not required if we use devres API
> > > 
> > > Yes it does - you do not really want to stop clocks in the middle of
> > > servicing interrupt.
> > 
> > Thanks, I missed the clocks. I will not use devm here then.
> 
> Actually, you still can if you move clock enabling/disabling and
> mx25_tcq_init() into input_dev->open() and ->close() callbacks. Close
> will be called during input device un-registration which happens (given
> your current sequence) after freeing irq by devm.

Thank you. I now moved that code into open() and close(), replaced the
irq_request() with devm_irq_request. mx25_tcq_remove() is gone now.

> 
> By the way, I used my old @vmware address by accident. Can you please
> replace the original acked by with:
> 
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Replaced it.

Thanks,

Markus
diff mbox

Patch

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 58917525126e..f1534a0cd23f 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -748,6 +748,12 @@  config TOUCHSCREEN_USB_COMPOSITE
 	  To compile this driver as a module, choose M here: the
 	  module will be called usbtouchscreen.
 
+config TOUCHSCREEN_MX25
+	tristate "Freescale i.MX25 touchscreen input driver"
+	depends on MFD_MX25_TSADC
+	help
+	  Enable support for touchscreen connected to your i.MX25.
+
 config TOUCHSCREEN_MC13783
 	tristate "Freescale MC13783 touchscreen input driver"
 	depends on MFD_MC13XXX
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 0242fea2102a..bbb55a69c33c 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -41,6 +41,7 @@  obj-$(CONFIG_TOUCHSCREEN_INEXIO)	+= inexio.o
 obj-$(CONFIG_TOUCHSCREEN_INTEL_MID)	+= intel-mid-touch.o
 obj-$(CONFIG_TOUCHSCREEN_LPC32XX)	+= lpc32xx_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MAX11801)	+= max11801_ts.o
+obj-$(CONFIG_TOUCHSCREEN_MX25)		+= fsl-imx25-tcq.o
 obj-$(CONFIG_TOUCHSCREEN_MC13783)	+= mc13783_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MCS5000)	+= mcs5000_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MIGOR)		+= migor_ts.o
diff --git a/drivers/input/touchscreen/fsl-imx25-tcq.c b/drivers/input/touchscreen/fsl-imx25-tcq.c
new file mode 100644
index 000000000000..2eb3bd00d56c
--- /dev/null
+++ b/drivers/input/touchscreen/fsl-imx25-tcq.c
@@ -0,0 +1,587 @@ 
+/*
+ * Copyright 2014 Markus Pargmann, Pengutronix <mpa@pengutronix.de>
+ * Based on driver from 2011:
+ *   Juergen Beisert, Pengutronix <kernel@pengutronix.de>
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * This is the driver for the imx25 TCQ (Touchscreen Conversion Queue)
+ * connected to the imx25 ADC.
+ */
+
+#include <linux/clk.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/imx25-tsadc.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+static const char mx25_tcq_name[] = "mx25-tcq";
+
+enum mx25_tcq_mode {
+	MX25_TS_4WIRE,
+};
+
+struct mx25_tcq_priv {
+	struct regmap *regs;
+	struct regmap *core_regs;
+	struct input_dev *idev;
+	enum mx25_tcq_mode mode;
+	unsigned int pen_threshold;
+	unsigned int sample_count;
+	unsigned int expected_samples;
+	unsigned int pen_debounce;
+	unsigned int settling_time;
+	struct clk *clk;
+	int irq;
+};
+
+static struct regmap_config mx25_tcq_regconfig = {
+	.fast_io = true,
+	.max_register = 0x5c,
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static struct of_device_id mx25_tcq_ids[] = {
+	{ .compatible = "fsl,imx25-tcq", },
+	{ /* Sentinel */ }
+};
+
+#define TSC_4WIRE_PRE_INDEX 0
+#define TSC_4WIRE_X_INDEX 1
+#define TSC_4WIRE_Y_INDEX 2
+#define TSC_4WIRE_POST_INDEX 3
+#define TSC_4WIRE_LEAVE 4
+
+#define MX25_TSC_DEF_THRESHOLD 80
+#define TSC_MAX_SAMPLES 16
+
+#define MX25_TSC_REPEAT_WAIT 14
+
+enum mx25_adc_configurations {
+	MX25_CFG_PRECHARGE = 0,
+	MX25_CFG_TOUCH_DETECT,
+	MX25_CFG_X_MEASUREMENT,
+	MX25_CFG_Y_MEASUREMENT,
+};
+
+#define MX25_PRECHARGE_VALUE (\
+			MX25_ADCQ_CFG_YPLL_OFF | \
+			MX25_ADCQ_CFG_XNUR_OFF | \
+			MX25_ADCQ_CFG_XPUL_HIGH | \
+			MX25_ADCQ_CFG_REFP_INT | \
+			MX25_ADCQ_CFG_IN_XP | \
+			MX25_ADCQ_CFG_REFN_NGND2 | \
+			MX25_ADCQ_CFG_IGS)
+
+#define MX25_TOUCH_DETECT_VALUE (\
+			MX25_ADCQ_CFG_YNLR | \
+			MX25_ADCQ_CFG_YPLL_OFF | \
+			MX25_ADCQ_CFG_XNUR_OFF | \
+			MX25_ADCQ_CFG_XPUL_OFF | \
+			MX25_ADCQ_CFG_REFP_INT | \
+			MX25_ADCQ_CFG_IN_XP | \
+			MX25_ADCQ_CFG_REFN_NGND2 | \
+			MX25_ADCQ_CFG_PENIACK)
+
+static void imx25_setup_queue_cfgs(struct mx25_tcq_priv *priv,
+				   unsigned int settling_time)
+{
+	u32 precharge_cfg =
+			MX25_PRECHARGE_VALUE |
+			MX25_ADCQ_CFG_SETTLING_TIME(settling_time);
+	u32 touch_detect_cfg =
+			MX25_TOUCH_DETECT_VALUE |
+			MX25_ADCQ_CFG_NOS(1) |
+			MX25_ADCQ_CFG_SETTLING_TIME(settling_time);
+
+	regmap_write(priv->core_regs, MX25_TSC_TICR, precharge_cfg);
+
+	/* PRECHARGE */
+	regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_PRECHARGE),
+		     precharge_cfg);
+
+	/* TOUCH_DETECT */
+	regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_TOUCH_DETECT),
+		     touch_detect_cfg);
+
+	/* X Measurement */
+	regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_X_MEASUREMENT),
+		     MX25_ADCQ_CFG_YPLL_OFF |
+		     MX25_ADCQ_CFG_XNUR_LOW |
+		     MX25_ADCQ_CFG_XPUL_HIGH |
+		     MX25_ADCQ_CFG_REFP_XP |
+		     MX25_ADCQ_CFG_IN_YP |
+		     MX25_ADCQ_CFG_REFN_XN |
+		     MX25_ADCQ_CFG_NOS(priv->sample_count) |
+		     MX25_ADCQ_CFG_SETTLING_TIME(settling_time));
+
+	/* Y Measurement */
+	regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_Y_MEASUREMENT),
+		     MX25_ADCQ_CFG_YNLR |
+		     MX25_ADCQ_CFG_YPLL_HIGH |
+		     MX25_ADCQ_CFG_XNUR_OFF |
+		     MX25_ADCQ_CFG_XPUL_OFF |
+		     MX25_ADCQ_CFG_REFP_YP |
+		     MX25_ADCQ_CFG_IN_XP |
+		     MX25_ADCQ_CFG_REFN_YN |
+		     MX25_ADCQ_CFG_NOS(priv->sample_count) |
+		     MX25_ADCQ_CFG_SETTLING_TIME(settling_time));
+
+	/* Enable the touch detection right now */
+	regmap_write(priv->core_regs, MX25_TSC_TICR, touch_detect_cfg |
+		     MX25_ADCQ_CFG_IGS);
+}
+
+static int imx25_setup_queue_4wire(struct mx25_tcq_priv *priv,
+				   unsigned settling_time, int *items)
+{
+	imx25_setup_queue_cfgs(priv, settling_time);
+
+	/* Setup the conversion queue */
+	regmap_write(priv->regs, MX25_ADCQ_ITEM_7_0,
+		     MX25_ADCQ_ITEM(0, MX25_CFG_PRECHARGE) |
+		     MX25_ADCQ_ITEM(1, MX25_CFG_TOUCH_DETECT) |
+		     MX25_ADCQ_ITEM(2, MX25_CFG_X_MEASUREMENT) |
+		     MX25_ADCQ_ITEM(3, MX25_CFG_Y_MEASUREMENT) |
+		     MX25_ADCQ_ITEM(4, MX25_CFG_PRECHARGE) |
+		     MX25_ADCQ_ITEM(5, MX25_CFG_TOUCH_DETECT));
+
+	/* We measure X/Y with 'sample_count' number of samples and execute a
+	 * touch detection twice, with 1 sample each */
+	priv->expected_samples = priv->sample_count * 2 + 2;
+	*items = 6;
+
+	return 0;
+}
+
+static void mx25_tcq_disable_touch_irq(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_PDMSK,
+			   MX25_ADCQ_CR_PDMSK);
+}
+
+static void mx25_tcq_enable_touch_irq(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_PDMSK, 0);
+}
+
+static void mx25_tcq_disable_fifo_irq(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_FDRY_IRQ,
+			   MX25_ADCQ_MR_FDRY_IRQ);
+}
+
+static void mx25_tcq_enable_fifo_irq(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_FDRY_IRQ, 0);
+}
+
+static void mx25_tcq_force_queue_start(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+			   MX25_ADCQ_CR_FQS,
+			   MX25_ADCQ_CR_FQS);
+}
+
+static void mx25_tcq_force_queue_stop(struct mx25_tcq_priv *priv)
+{
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+			   MX25_ADCQ_CR_FQS, 0);
+}
+
+static void mx25_tcq_fifo_reset(struct mx25_tcq_priv *priv)
+{
+	u32 tcqcr;
+
+	regmap_read(priv->regs, MX25_ADCQ_CR, &tcqcr);
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FRST,
+			   MX25_ADCQ_CR_FRST);
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FRST, 0);
+	regmap_write(priv->regs, MX25_ADCQ_CR, tcqcr);
+}
+
+static void mx25_tcq_re_enable_touch_detection(struct mx25_tcq_priv *priv)
+{
+	/* stop the queue from looping */
+	mx25_tcq_force_queue_stop(priv);
+
+	/* for a clean touch detection, preload the X plane */
+	regmap_write(priv->core_regs, MX25_TSC_TICR, MX25_PRECHARGE_VALUE);
+
+	/* waste some time now to pre-load the X plate to high voltage */
+	mx25_tcq_fifo_reset(priv);
+
+	/* re-enable the detection right now */
+	regmap_write(priv->core_regs, MX25_TSC_TICR,
+		     MX25_TOUCH_DETECT_VALUE | MX25_ADCQ_CFG_IGS);
+
+	regmap_update_bits(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_PD,
+			   MX25_ADCQ_SR_PD);
+
+	/* enable the pen down event to be a source for the interrupt */
+	regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_PD_IRQ, 0);
+
+	/* lets fire the next IRQ if someone touches the touchscreen */
+	mx25_tcq_enable_touch_irq(priv);
+}
+
+static int mx25_tcq_create_event_for_4wire(struct mx25_tcq_priv *priv,
+					   u32 *sample_buf,
+					   unsigned int samples)
+{
+	unsigned int x_pos = 0;
+	unsigned int y_pos = 0;
+	unsigned int touch_pre = 0;
+	unsigned int touch_post = 0;
+	unsigned int i;
+	int ret = 0;
+
+	for (i = 0; i < samples; i++) {
+		unsigned int index = MX25_ADCQ_FIFO_ID(sample_buf[i]);
+		unsigned int val = MX25_ADCQ_FIFO_DATA(sample_buf[i]);
+
+		switch (index) {
+		case 1:
+			touch_pre = val;
+			break;
+		case 2:
+			x_pos = val;
+			break;
+		case 3:
+			y_pos = val;
+			break;
+		case 5:
+			touch_post = val;
+			break;
+		default:
+			ret = -EINVAL;
+			break;
+		}
+	}
+
+	if (ret == 0 && samples != 0) {
+		/*
+		 * only if both touch measures are below a threshold,
+		 * the position is valid
+		 */
+		if (touch_pre < priv->pen_threshold &&
+		    touch_post < priv->pen_threshold) {
+			/* valid samples, generate a report */
+			x_pos /= priv->sample_count;
+			y_pos /= priv->sample_count;
+			input_report_abs(priv->idev, ABS_X, x_pos);
+			input_report_abs(priv->idev, ABS_Y, y_pos);
+			input_report_key(priv->idev, BTN_TOUCH, 1);
+			input_sync(priv->idev);
+
+			/* get next sample */
+			mx25_tcq_enable_fifo_irq(priv);
+		} else if (touch_pre >= priv->pen_threshold &&
+			   touch_post >= priv->pen_threshold) {
+			/*
+			 * if both samples are invalid,
+			 * generate a release report
+			 */
+			input_report_key(priv->idev, BTN_TOUCH, 0);
+			input_sync(priv->idev);
+			mx25_tcq_re_enable_touch_detection(priv);
+		} else {
+			/*
+			 * if only one of both touch measurements are
+			 * below the threshold, still some bouncing
+			 * happens. Take additional samples in this
+			 * case to be sure
+			 */
+			mx25_tcq_enable_fifo_irq(priv);
+		}
+	}
+
+	return ret;
+}
+
+static irqreturn_t mx25_tcq_irq_thread(int irq, void *dev_id)
+{
+	struct mx25_tcq_priv *priv = dev_id;
+	u32 sample_buf[TSC_MAX_SAMPLES];
+	unsigned int samples = 0;
+
+	/* read all samples */
+	while (1) {
+		u32 stats;
+
+		regmap_read(priv->regs, MX25_ADCQ_SR, &stats);
+		if (stats & MX25_ADCQ_SR_EMPT)
+			break;
+
+		if (samples < TSC_MAX_SAMPLES) {
+			regmap_read(priv->regs, MX25_ADCQ_FIFO,
+				    &sample_buf[samples]);
+			++samples;
+		} else {
+			u32 discarded;
+			/* discard samples */
+			regmap_read(priv->regs, MX25_ADCQ_FIFO, &discarded);
+		}
+	}
+
+	mx25_tcq_create_event_for_4wire(priv, sample_buf, samples);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mx25_tcq_irq(int irq, void *dev_id)
+{
+	struct mx25_tcq_priv *priv = dev_id;
+	u32 stat;
+	int ret = IRQ_HANDLED;
+
+	regmap_read(priv->regs, MX25_ADCQ_SR, &stat);
+
+	if (stat & (MX25_ADCQ_SR_FRR | MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR))
+		mx25_tcq_fifo_reset(priv);
+
+	if (stat & MX25_ADCQ_SR_PD) {
+		mx25_tcq_disable_touch_irq(priv);
+		mx25_tcq_force_queue_start(priv);
+		mx25_tcq_enable_fifo_irq(priv);
+	}
+
+	if (stat & MX25_ADCQ_SR_FDRY) {
+		mx25_tcq_disable_fifo_irq(priv);
+		ret = IRQ_WAKE_THREAD;
+	}
+
+	regmap_update_bits(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_FRR |
+			   MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR |
+			   MX25_ADCQ_SR_PD | MX25_ADCQ_SR_EOQ,
+			   MX25_ADCQ_SR_FRR | MX25_ADCQ_SR_FUR |
+			   MX25_ADCQ_SR_FOR | MX25_ADCQ_SR_PD |
+			   MX25_ADCQ_SR_EOQ);
+
+	return ret;
+}
+
+/* configure the statemachine for a 4-wire touchscreen */
+static int mx25_tcq_init(struct mx25_tcq_priv *priv)
+{
+	u32 tgcr;
+	unsigned int ipg_div;
+	unsigned int adc_period;
+	unsigned int debounce_cnt;
+	unsigned int settling_time;
+	int itemct;
+	int ret;
+
+	regmap_read(priv->core_regs, MX25_TSC_TGCR, &tgcr);
+	ipg_div = max_t(unsigned int, 4, MX25_TGCR_GET_ADCCLK(tgcr));
+	adc_period = clk_get_rate(priv->clk) / (ipg_div * 2 + 2);
+	debounce_cnt = DIV_ROUND_UP(priv->pen_debounce, adc_period * 8) - 1;
+	settling_time = DIV_ROUND_UP(priv->settling_time, adc_period);
+
+	/* Reset */
+	regmap_write(priv->regs, MX25_ADCQ_CR,
+		     MX25_ADCQ_CR_QRST | MX25_ADCQ_CR_FRST);
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+			   MX25_ADCQ_CR_QRST | MX25_ADCQ_CR_FRST, 0);
+
+	/* up to 128 * 8 ADC clocks are possible */
+	if (debounce_cnt > 127)
+		debounce_cnt = 127;
+
+	ret = imx25_setup_queue_4wire(priv, settling_time, &itemct);
+	if (ret)
+		return ret;
+
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+			   MX25_ADCQ_CR_LITEMID_MASK | MX25_ADCQ_CR_WMRK_MASK,
+			   MX25_ADCQ_CR_LITEMID(itemct - 1) |
+			   MX25_ADCQ_CR_WMRK(priv->expected_samples - 1));
+
+	/* setup debounce count */
+	regmap_update_bits(priv->core_regs, MX25_TSC_TGCR,
+			   MX25_TGCR_PDBTIME_MASK,
+			   MX25_TGCR_PDBTIME(debounce_cnt));
+
+	/* enable debounce */
+	regmap_update_bits(priv->core_regs, MX25_TSC_TGCR, MX25_TGCR_PDBEN,
+			   MX25_TGCR_PDBEN);
+	regmap_update_bits(priv->core_regs, MX25_TSC_TGCR, MX25_TGCR_PDEN,
+			   MX25_TGCR_PDEN);
+
+	/* enable the engine on demand */
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_QSM_MASK,
+			   MX25_ADCQ_CR_QSM_FQS);
+
+	/* Enable repeat and repeat wait */
+	regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+			   MX25_ADCQ_CR_RPT | MX25_ADCQ_CR_RWAIT_MASK,
+			   MX25_ADCQ_CR_RPT |
+			   MX25_ADCQ_CR_RWAIT(MX25_TSC_REPEAT_WAIT));
+
+	mx25_tcq_re_enable_touch_detection(priv);
+
+	return 0;
+}
+
+static int mx25_tcq_parse_dt(struct platform_device *pdev,
+			     struct mx25_tcq_priv *priv)
+{
+	struct device_node *np = pdev->dev.of_node;
+	u32 wires;
+	int ret;
+
+	/* Setup defaults */
+	priv->pen_threshold = 500;
+	priv->sample_count = 3;
+	priv->pen_debounce = 1000000;
+	priv->settling_time = 250000;
+
+	ret = of_property_read_u32(np, "fsl,wires", &wires);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to find fsl,wires properties\n");
+		return ret;
+	}
+
+	if (wires == 4) {
+		priv->mode = MX25_TS_4WIRE;
+	} else {
+		dev_err(&pdev->dev, "%u-wire mode not supported\n", wires);
+		return -EINVAL;
+	}
+
+	/* These are optional, we don't care about the return values */
+	of_property_read_u32(np, "fsl,pen-threshold", &priv->pen_threshold);
+	of_property_read_u32(np, "fsl,settling-time", &priv->settling_time);
+	of_property_read_u32(np, "fsl,pen-debounce", &priv->pen_debounce);
+
+	return 0;
+}
+
+static int mx25_tcq_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct input_dev *idev;
+	struct mx25_tcq_priv *priv;
+	struct mx25_tsadc *tsadc = dev_get_drvdata(pdev->dev.parent);
+	struct resource *res;
+	void __iomem *mem;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mem = devm_ioremap_resource(dev, res);
+	if (!mem)
+		return -ENOMEM;
+
+	ret = mx25_tcq_parse_dt(pdev, priv);
+	if (ret)
+		return ret;
+
+	priv->regs = devm_regmap_init_mmio(dev, mem, &mx25_tcq_regconfig);
+	if (IS_ERR(priv->regs)) {
+		dev_err(dev, "Failed to initialize regmap\n");
+		return PTR_ERR(priv->regs);
+	}
+
+	priv->irq = platform_get_irq(pdev, 0);
+	if (priv->irq <= 0) {
+		dev_err(dev, "Failed to get IRQ\n");
+		return priv->irq;
+	}
+
+	idev = devm_input_allocate_device(dev);
+	if (!idev) {
+		dev_err(dev, "Failed to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	idev->name = mx25_tcq_name;
+	idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+	idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+	input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
+	input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
+
+	idev->id.bustype = BUS_HOST;
+
+	ret = input_register_device(idev);
+	if (ret) {
+		dev_err(dev, "Failed to register input device\n");
+		return ret;
+	}
+
+	priv->idev = idev;
+
+	priv->core_regs = tsadc->regs;
+	if (!priv->core_regs)
+		return -EINVAL;
+
+	priv->clk = tsadc->clk;
+	if (!priv->clk)
+		return -EINVAL;
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable ipg clock\n");
+		return ret;
+	}
+
+	ret = request_threaded_irq(priv->irq, mx25_tcq_irq, mx25_tcq_irq_thread,
+				   IRQF_ONESHOT, pdev->name, priv);
+	if (ret) {
+		dev_err(dev, "Failed requesting IRQ\n");
+		goto err_clk_unprepare;
+	}
+
+	ret = mx25_tcq_init(priv);
+	if (ret) {
+		dev_err(dev, "Failed to init tcq\n");
+		goto error_free_irq;
+	}
+
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+
+error_free_irq:
+	free_irq(priv->irq, priv);
+err_clk_unprepare:
+	clk_disable_unprepare(priv->clk);
+	return ret;
+}
+
+static int mx25_tcq_remove(struct platform_device *pdev)
+{
+	struct mx25_tcq_priv *priv = platform_get_drvdata(pdev);
+
+	free_irq(priv->irq, priv);
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static struct platform_driver mx25_tcq_driver = {
+	.driver		= {
+		.name	= "mx25-tcq",
+		.of_match_table = mx25_tcq_ids,
+	},
+	.probe		= mx25_tcq_probe,
+	.remove		= mx25_tcq_remove,
+};
+module_platform_driver(mx25_tcq_driver);
+
+MODULE_DESCRIPTION("TS input driver for Freescale mx25");
+MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
+MODULE_LICENSE("GPL v2");