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

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This is an RFC for the new touchscreen properties.

Signed-off-by: Juergen Beisert <jbe@pengutronix.de>
Tested-by: Marek Vasut <marex@denx.de>
Acked-by: Marek Vasut <marex@denx.de>
Tested-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Jonathan 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
This commit is contained in:
Juergen Beisert 2013-09-23 15:36:00 +01:00 committed by Jonathan Cameron
parent cd6c558652
commit e9c88fb5cf
3 changed files with 71 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
View File

@ -1,7 +1,8 @@
* 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>;
};

4
arch/arm/boot/dts/imx28-evk.dts
View File

@ -183,6 +183,10 @@
lradc@80050000 {
status = "okay";
fsl,lradc-touchscreen-wires = <4>;
fsl,ave-ctrl = <4>;
fsl,ave-delay = <2>;
fsl,settling = <10>;
};
i2c0: i2c@80058000 {

57
drivers/staging/iio/adc/mxs-lradc.c
View File

@ -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);