Commit e9c88fb5 authored by Juergen Beisert's avatar Juergen Beisert Committed by Jonathan Cameron
Browse files

Staging/iio/adc/touchscreen/MXS: provide devicetree adaption 



This is an RFC for the new touchscreen properties.

Signed-off-by: default avatarJuergen Beisert <jbe@pengutronix.de>
Tested-by: default avatarMarek Vasut <marex@denx.de>
Acked-by: default avatarMarek Vasut <marex@denx.de>
Tested-by: default avatarLothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
CC: linux-arm-kernel@lists.infradead.org
CC: linux-input@vger.kernel.org
CC: devel@driverdev.osuosl.org
CC: Marek Vasut <marex@denx.de>
CC: Fabio Estevam <fabio.estevam@freescale.com>
CC: devicetree@vger.kernel.org
parent cd6c5586

Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt

+31 −5
Original line number Diff line number Diff line 
* Freescale i.MX28 LRADC device driver



Required properties:

- compatible: Should be "fsl,imx28-lradc"

- compatible: Should be "fsl,imx23-lradc" for i.MX23 SoC and "fsl,imx28-lradc"

              for i.MX28 SoC

- reg: Address and length of the register set for the device

- interrupts: Should contain the LRADC interrupts
@@ -9,13 +10,38 @@ Optional properties: 
- fsl,lradc-touchscreen-wires: Number of wires used to connect the touchscreen

                               to LRADC. Valid value is either 4 or 5. If this

                               property is not present, then the touchscreen is

                               disabled.

                               disabled. 5 wires is valid for i.MX28 SoC only.

- fsl,ave-ctrl: number of samples per direction to calculate an average value.

                Allowed value is 1 ... 31, default is 4

- fsl,ave-delay: delay between consecutive samples. Allowed value is

                 1 ... 2047. It is used if 'fsl,ave-ctrl' > 1, counts at

                 2 kHz and its default is 2 (= 1 ms)

- fsl,settling: delay between plate switch to next sample. Allowed value is

                1 ... 2047. It counts at 2 kHz and its default is

                10 (= 5 ms)



Examples:

Example for i.MX23 SoC:



	lradc@80050000 {

		compatible = "fsl,imx23-lradc";

		reg = <0x80050000 0x2000>;

		interrupts = <36 37 38 39 40 41 42 43 44>;

		status = "okay";

		fsl,lradc-touchscreen-wires = <4>;

		fsl,ave-ctrl = <4>;

		fsl,ave-delay = <2>;

		fsl,settling = <10>;

	};



Example for i.MX28 SoC:



	lradc@80050000 {

		compatible = "fsl,imx28-lradc";

		reg = <0x80050000 0x2000>;

		interrupts = <10 14 15 16 17 18 19

				20 21 22 23 24 25>;

		interrupts = <10 14 15 16 17 18 19 20 21 22 23 24 25>;

		status = "okay";

		fsl,lradc-touchscreen-wires = <5>;

		fsl,ave-ctrl = <4>;

		fsl,ave-delay = <2>;

		fsl,settling = <10>;

	};

arch/arm/boot/dts/imx28-evk.dts

+4 −0
Original line number Diff line number Diff line
@@ -183,6 +183,10 @@ saif1: saif@80046000 { 


			lradc@80050000 {

				status = "okay";

				fsl,lradc-touchscreen-wires = <4>;

				fsl,ave-ctrl = <4>;

				fsl,ave-delay = <2>;

				fsl,settling = <10>;

			};



			i2c0: i2c@80058000 {

drivers/staging/iio/adc/mxs-lradc.c

+36 −21
Original line number Diff line number Diff line
@@ -1224,10 +1224,45 @@ MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids); 
static int mxs_lradc_probe_touchscreen(struct mxs_lradc *lradc,

						struct device_node *lradc_node)

{

	/* TODO retrieve from device tree */

	int ret;

	u32 ts_wires = 0, adapt;



	ret = of_property_read_u32(lradc_node, "fsl,lradc-touchscreen-wires",

				&ts_wires);

	if (ret)

		return -ENODEV; /* touchscreen feature disabled */



	switch (ts_wires) {

	case 4:

		lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE;

		break;

	case 5:

		if (lradc->soc == IMX28_LRADC) {

			lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE;

			break;

		}

		/* fall through an error message for i.MX23 */

	default:

		dev_err(lradc->dev,

			"Unsupported number of touchscreen wires (%d)\n",

			ts_wires);

		return -EINVAL;

	}



	lradc->over_sample_cnt = 4;

	ret = of_property_read_u32(lradc_node, "fsl,ave-ctrl", &adapt);

	if (ret == 0)

		lradc->over_sample_cnt = adapt;



	lradc->over_sample_delay = 2;

	ret = of_property_read_u32(lradc_node, "fsl,ave-delay", &adapt);

	if (ret == 0)

		lradc->over_sample_delay = adapt;



	lradc->settling_delay = 10;

	ret = of_property_read_u32(lradc_node, "fsl,settling", &adapt);

	if (ret == 0)

		lradc->settling_delay = adapt;



	return 0;

}
@@ -1243,7 +1278,6 @@ static int mxs_lradc_probe(struct platform_device *pdev) 
	struct mxs_lradc *lradc;

	struct iio_dev *iio;

	struct resource *iores;

	uint32_t ts_wires = 0;

	int ret = 0, touch_ret;

	int i;
@@ -1277,25 +1311,6 @@ static int mxs_lradc_probe(struct platform_device *pdev) 


	touch_ret = mxs_lradc_probe_touchscreen(lradc, node);



	/* Check if touchscreen is enabled in DT. */

	ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",

				&ts_wires);

	if (ret)

		dev_info(dev, "Touchscreen not enabled.\n");

	else if (ts_wires == 4)

		lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE;

	else if (ts_wires == 5)

		lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE;

	else

		dev_warn(dev, "Unsupported number of touchscreen wires (%d)\n",

				ts_wires);



	if ((lradc->soc == IMX23_LRADC) && (ts_wires == 5)) {

		dev_warn(dev, "No support for 5 wire touches on i.MX23\n");

		dev_warn(dev, "Falling back to 4 wire\n");

		ts_wires = 4;

	}



	/* Grab all IRQ sources */

	for (i = 0; i < of_cfg->irq_count; i++) {

		lradc->irq[i] = platform_get_irq(pdev, i);