Re: [PATCH v3 3/5] IIO: Ingenic JZ47xx: Add touchscreen mode.

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On Sat, 07 Mar 2020 13:58:40 +0100
Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote:

> Hi Jonathan,
> 
> 
> Le sam., mars 7, 2020 at 12:47, Jonathan Cameron 
> <jic23@xxxxxxxxxxxxxxxxxxxxx> a écrit :
> > On Sun,  1 Mar 2020 16:09:18 +0100
> > Artur Rojek <contact@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
> >>  Tested-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>  
> > 
> > This relies on the use of an irq that wasn't previously used.  Was 
> > that
> > always hooked up?  If not we need to still work as before when it
> > isn't provided.
> > 
> > Otherwise this looks fine to me.  
> 
> All the boards that probe the ingenic-adc driver have the interrupt 
> provided from devicetree, yes.
Great :)

No problem then.  Perhaps add a note to the patch description to say
that so no one else wonders in future.

Thanks,

Jonathan


> 
> Cheers,
> -Paul
> 
> >   
> >>  ---
> >> 
> >>   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
> >> 
> >>   v3: remove unneeded `linux/iio/kfifo_buf.h` include
> >> 
> >>   drivers/iio/adc/Kconfig       |   1 +
> >>   drivers/iio/adc/ingenic-adc.c | 109 
> >> +++++++++++++++++++++++++++++++++-
> >>   2 files changed, 108 insertions(+), 2 deletions(-)
> >> 
> >>  diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> >>  index 82e33082958c..d3fd4b6e2d47 100644
> >>  --- a/drivers/iio/adc/Kconfig
> >>  +++ b/drivers/iio/adc/Kconfig
> >>  @@ -453,6 +453,7 @@ 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..0dafc8d5d0d8 100644
> >>  --- a/drivers/iio/adc/ingenic-adc.c
> >>  +++ b/drivers/iio/adc/ingenic-adc.c
> >>  @@ -8,7 +8,9 @@
> >> 
> >>   #include <dt-bindings/iio/adc/ingenic,adc.h>
> >>   #include <linux/clk.h>
> >>  +#include <linux/iio/buffer.h>
> >>   #include <linux/iio/iio.h>
> >>  +#include <linux/interrupt.h>
> >>   #include <linux/io.h>
> >>   #include <linux/iopoll.h>
> >>   #include <linux/kernel.h>
> >>  @@ -20,6 +22,8 @@
> >>   #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 +32,9 @@
> >>   #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 +51,14 @@
> >>   #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 +426,28 @@ 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 +455,7 @@ 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 +466,7 @@ 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 +475,69 @@ 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 +552,18 @@ 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);  
> > 
> > Do we need a fallback path if there is no irq provided?  We can't 
> > break existing
> > supported devices that don't specify one.
> >   
> >>  +	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 +603,8 @@ 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. */  
> >   
> 
> 





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