Re: [PATCH v2 3/5] IIO: Ingenic JZ47xx: Add touchscreen mode.

Jonathan Cameron
2020-02-02T14:53:37Z

On Sun, 26 Jan 2020 17:12:34 +0100
Artur Rojek <contact@artur-rojek.eu> wrote:

> The SADC component in JZ47xx SoCs provides support for touchscreen
> operations (pen position and pen down pressure) in single-ended and
> differential modes.
>
> Of the known hardware to use this controller, GCW Zero and Anbernic RG-350
> utilize the touchscreen mode by having their joystick(s) attached to the
> X/Y positive/negative input pins.
> GCW Zero comes with a single joystick and is sufficiently handled with the
> currently implemented single-ended mode. Support for boards with two
> joysticks, where one is hooked up to Xn/Yn and the other to Xp/Yp channels
> will need to be provided in the future.
>
> The touchscreen component of SADC takes a significant time to stabilize
> after first receiving the clock and a delay of 50ms has been empirically
> proven to be a safe value before data sampling can begin.
>
> Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
> Tested-by: Paul Cercueil <paul@crapouillou.net>
Great. I guess it does all work without registering a pointless kfifo
based userspace interface :)

I'll pick this up once the dt issue in the next patch is resolved.

Thanks,

Jonathan

> ---
>
> Changes:
>
> v2: - improve description of the touchscreen mode,
> - get rid of the unneeded kfifo,
> - drop IIO_BUFFER_CB from Kconfig,
> - remove extended names from the touchscreen channels
>
> drivers/iio/adc/Kconfig | 1 +
> drivers/iio/adc/ingenic-adc.c | 110 +++++++++++++++++++++++++++++++++-
> 2 files changed, 109 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 5d8540b7b427..7381b91303c5 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -446,6 +446,7 @@ config INA2XX_ADC
> config INGENIC_ADC
> tristate "Ingenic JZ47xx SoCs ADC driver"
> depends on MIPS || COMPILE_TEST
> + select IIO_BUFFER
> help
> Say yes here to build support for the Ingenic JZ47xx SoCs ADC unit.
>
> diff --git a/drivers/iio/adc/ingenic-adc.c b/drivers/iio/adc/ingenic-adc.c
> index 7a24bc1dabe1..fcc29deeaf0b 100644
> --- a/drivers/iio/adc/ingenic-adc.c
> +++ b/drivers/iio/adc/ingenic-adc.c
> @@ -8,7 +8,10 @@
>
> #include <dt-bindings/iio/adc/ingenic,adc.h>
> #include <linux/clk.h>
> +#include <linux/iio/buffer.h>
> #include <linux/iio/iio.h>
> +#include <linux/iio/kfifo_buf.h>
Don't think you are using this any more..

> +#include <linux/interrupt.h>
> #include <linux/io.h>
> #include <linux/iopoll.h>
> #include <linux/kernel.h>
> @@ -20,6 +23,8 @@
> #define JZ_ADC_REG_CFG 0x04
> #define JZ_ADC_REG_CTRL 0x08
> #define JZ_ADC_REG_STATUS 0x0c
> +#define JZ_ADC_REG_ADSAME 0x10
> +#define JZ_ADC_REG_ADWAIT 0x14
> #define JZ_ADC_REG_ADTCH 0x18
> #define JZ_ADC_REG_ADBDAT 0x1c
> #define JZ_ADC_REG_ADSDAT 0x20
> @@ -28,6 +33,9 @@
> #define JZ_ADC_REG_ENABLE_PD BIT(7)
> #define JZ_ADC_REG_CFG_AUX_MD (BIT(0) | BIT(1))
> #define JZ_ADC_REG_CFG_BAT_MD BIT(4)
> +#define JZ_ADC_REG_CFG_PULL_UP(n) ((n) << 16)
> +#define JZ_ADC_REG_CFG_SAMPLE_NUM(n) ((n) << 10)
> +#define JZ_ADC_REG_CFG_TOUCH_OPS_MASK (BIT(31) | GENMASK(23, 10))
> #define JZ_ADC_REG_ADCLK_CLKDIV_LSB 0
> #define JZ4725B_ADC_REG_ADCLK_CLKDIV10US_LSB 16
> #define JZ4770_ADC_REG_ADCLK_CLKDIV10US_LSB 8
> @@ -44,6 +52,14 @@
> #define JZ4770_ADC_BATTERY_VREF 6600
> #define JZ4770_ADC_BATTERY_VREF_BITS 12
>
> +#define JZ_ADC_IRQ_AUX BIT(0)
> +#define JZ_ADC_IRQ_BATTERY BIT(1)
> +#define JZ_ADC_IRQ_TOUCH BIT(2)
> +#define JZ_ADC_IRQ_PEN_DOWN BIT(3)
> +#define JZ_ADC_IRQ_PEN_UP BIT(4)
> +#define JZ_ADC_IRQ_PEN_DOWN_SLEEP BIT(5)
> +#define JZ_ADC_IRQ_SLEEP BIT(7)
> +
> struct ingenic_adc;
>
> struct ingenic_adc_soc_data {
> @@ -411,6 +427,28 @@ static const struct iio_info ingenic_adc_info = {
> };
>
> static const struct iio_chan_spec ingenic_channels[] = {
> + {
> + .type = IIO_POSITIONRELATIVE,
> + .indexed = 1,
> + .channel = INGENIC_ADC_TOUCH_XP,
> + .scan_index = 0,
> + .scan_type = {
> + .sign = 'u',
> + .realbits = 12,
> + .storagebits = 16
> + },
> + },
> + {
> + .type = IIO_POSITIONRELATIVE,
> + .indexed = 1,
> + .channel = INGENIC_ADC_TOUCH_YP,
> + .scan_index = 1,
> + .scan_type = {
> + .sign = 'u',
> + .realbits = 12,
> + .storagebits = 16
> + },
> + },
> {
> .extend_name = "aux",
> .type = IIO_VOLTAGE,
> @@ -418,6 +456,7 @@ static const struct iio_chan_spec ingenic_channels[] = {
> BIT(IIO_CHAN_INFO_SCALE),
> .indexed = 1,
> .channel = INGENIC_ADC_AUX,
> + .scan_index = -1
> },
> {
> .extend_name = "battery",
> @@ -428,6 +467,7 @@ static const struct iio_chan_spec ingenic_channels[] = {
> BIT(IIO_CHAN_INFO_SCALE),
> .indexed = 1,
> .channel = INGENIC_ADC_BATTERY,
> + .scan_index = -1
> },
> { /* Must always be last in the array. */
> .extend_name = "aux2",
> @@ -436,16 +476,69 @@ static const struct iio_chan_spec ingenic_channels[] = {
> BIT(IIO_CHAN_INFO_SCALE),
> .indexed = 1,
> .channel = INGENIC_ADC_AUX2,
> + .scan_index = -1
> },
> };
>
> +static int ingenic_adc_buffer_enable(struct iio_dev *iio_dev)
> +{
> + struct ingenic_adc *adc = iio_priv(iio_dev);
> +
> + clk_enable(adc->clk);
> + /* It takes significant time for the touchscreen hw to stabilize. */
> + msleep(50);
> + ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_TOUCH_OPS_MASK,
> + JZ_ADC_REG_CFG_SAMPLE_NUM(4) |
> + JZ_ADC_REG_CFG_PULL_UP(4));
> + writew(80, adc->base + JZ_ADC_REG_ADWAIT);
> + writew(2, adc->base + JZ_ADC_REG_ADSAME);
> + writeb((u8)~JZ_ADC_IRQ_TOUCH, adc->base + JZ_ADC_REG_CTRL);
> + writel(0, adc->base + JZ_ADC_REG_ADTCH);
> + ingenic_adc_enable(adc, 2, true);
> +
> + return 0;
> +}
> +
> +static int ingenic_adc_buffer_disable(struct iio_dev *iio_dev)
> +{
> + struct ingenic_adc *adc = iio_priv(iio_dev);
> +
> + ingenic_adc_enable(adc, 2, false);
> + writeb(0xff, adc->base + JZ_ADC_REG_CTRL);
> + writeb(0xff, adc->base + JZ_ADC_REG_STATUS);
> + ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_TOUCH_OPS_MASK, 0);
> + writew(0, adc->base + JZ_ADC_REG_ADSAME);
> + writew(0, adc->base + JZ_ADC_REG_ADWAIT);
> + clk_disable(adc->clk);
> +
> + return 0;
> +}
> +
> +static const struct iio_buffer_setup_ops ingenic_buffer_setup_ops = {
> + .postenable = &ingenic_adc_buffer_enable,
> + .predisable = &ingenic_adc_buffer_disable
> +};
> +
> +static irqreturn_t ingenic_adc_irq(int irq, void *data)
> +{
> + struct iio_dev *iio_dev = data;
> + struct ingenic_adc *adc = iio_priv(iio_dev);
> + u32 tdat;
> +
> + tdat = readl(adc->base + JZ_ADC_REG_ADTCH);
> + iio_push_to_buffers(iio_dev, &tdat);
> + writeb(JZ_ADC_IRQ_TOUCH, adc->base + JZ_ADC_REG_STATUS);
> +
> + return IRQ_HANDLED;
> +}
> +
> static int ingenic_adc_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> struct iio_dev *iio_dev;
> struct ingenic_adc *adc;
> const struct ingenic_adc_soc_data *soc_data;
> - int ret;
> + int irq, ret;
>
> soc_data = device_get_match_data(dev);
> if (!soc_data)
> @@ -460,6 +553,18 @@ static int ingenic_adc_probe(struct platform_device *pdev)
> mutex_init(&adc->aux_lock);
> adc->soc_data = soc_data;
>
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + dev_err(dev, "Failed to get irq: %d\n", irq);
> + return irq;
> + }
> + ret = devm_request_irq(dev, irq, ingenic_adc_irq, 0,
> + dev_name(dev), iio_dev);
> + if (ret < 0) {
> + dev_err(dev, "Failed to request irq: %d\n", ret);
> + return ret;
> + }
> +
> adc->base = devm_platform_ioremap_resource(pdev, 0);
> if (IS_ERR(adc->base))
> return PTR_ERR(adc->base);
> @@ -499,7 +604,8 @@ static int ingenic_adc_probe(struct platform_device *pdev)
>
> iio_dev->dev.parent = dev;
> iio_dev->name = "jz-adc";
> - iio_dev->modes = INDIO_DIRECT_MODE;
> + iio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
> + iio_dev->setup_ops = &ingenic_buffer_setup_ops;
> iio_dev->channels = ingenic_channels;
> iio_dev->num_channels = ARRAY_SIZE(ingenic_channels);
> /* Remove AUX2 from the list of supported channels. */