[PATCH 7/7] Staging/iio/adc/touchscreen/MXS: provide devicetree adaption
Jonathan Cameron
jic23 at kernel.org
Sat Sep 21 08:42:37 EDT 2013
The device tree list has moved, so I've changed the cc.
Few comments inline. Basically I'd go for longer more
descriptive names when the abreviation isn't a really
well known common one.
Note I'm not all that familiar with device tree conventions
so may be barking up the wrong tree ;)
On 09/19/13 13:22, Juergen Beisert wrote:
> This is an RFC for the new touchscreen properties.
>
> Signed-off-by: Juergen Beisert <jbe at pengutronix.de>
> CC: linux-arm-kernel at lists.infradead.org
> CC: devel at driverdev.osuosl.org
> CC: Marek Vasut <marex at denx.de>
> CC: Fabio Estevam <fabio.estevam at freescale.com>
> CC: Jonathan Cameron <jic23 at cam.ac.uk>
> CC: devicetree-discuss at lists.ozlabs.org
> ---
> .../bindings/staging/iio/adc/mxs-lradc.txt | 36 ++++++++++++--
> drivers/staging/iio/adc/mxs-lradc.c | 57 ++++++++++++++--------
> 2 files changed, 67 insertions(+), 26 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> index 4688205..ee05dc3 100644
> --- a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> +++ b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> @@ -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.
Do we want that lradc prefix on these other properties?
> + 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
This naming seems less than informative, what about fsl,average_num_samples of average_count
(ave isn't all that obvious an abrevaition of average).
> +- 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,average_intersample_delay (I assume any limit of device tree property names is longer than that?)
> +- 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 at 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 at 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>;
> };
> diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
> index 122475f..ffcb0dd 100644
> --- a/drivers/staging/iio/adc/mxs-lradc.c
> +++ b/drivers/staging/iio/adc/mxs-lradc.c
> @@ -1225,10 +1225,45 @@ 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;
> }
> @@ -1244,7 +1279,6 @@ 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;
>
> @@ -1267,25 +1301,6 @@ 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);
>
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