Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Sat, 7 Mar 2020 13:12:29 +0000
From:   Jonathan Cameron <jic23@kernel.org>
To:     Paul Cercueil <paul@crapouillou.net>
Cc:     Artur Rojek <contact@artur-rojek.eu>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Heiko Stuebner <heiko@sntech.de>, linux-input@vger.kernel.org,
        devicetree@vger.kernel.org, linux-iio@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 3/5] IIO: Ingenic JZ47xx: Add touchscreen mode.
Message-ID: <20200307131229.571c20c5@archlinux>
In-Reply-To: <1583585920.3.0@crapouillou.net>
References: <20200301150920.55993-1-contact@artur-rojek.eu>
        <20200301150920.55993-3-contact@artur-rojek.eu>
        <20200307124740.708ae2f3@archlinux>
        <1583585920.3.0@crapouillou.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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

> Hi Jonathan,
>=20
>=20
> Le sam., mars 7, 2020 at 12:47, Jonathan Cameron=20
> <jic23@jic23.retrosnub.co.uk> a =C3=A9crit :
> > On Sun,  1 Mar 2020 16:09:18 +0100
> > Artur Rojek <contact@artur-rojek.eu> wrote:
> >  =20
> >>  The SADC component in JZ47xx SoCs provides support for touchscreen
> >>  operations (pen position and pen down pressure) in single-ended and
> >>  differential modes.
> >>=20
> >>  Of the known hardware to use this controller, GCW Zero and Anbernic=20
> >> RG-350
> >>  utilize the touchscreen mode by having their joystick(s) attached=20
> >> to the
> >>  X/Y positive/negative input pins.
> >>  GCW Zero comes with a single joystick and is sufficiently handled=20
> >> 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=20
> >> channels
> >>  will need to be provided in the future.
> >>=20
> >>  The touchscreen component of SADC takes a significant time to=20
> >> stabilize
> >>  after first receiving the clock and a delay of 50ms has been=20
> >> empirically
> >>  proven to be a safe value before data sampling can begin.
> >>=20
> >>  Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
> >>  Tested-by: Paul Cercueil <paul@crapouillou.net> =20
> >=20
> > This relies on the use of an irq that wasn't previously used.  Was=20
> > that
> > always hooked up?  If not we need to still work as before when it
> > isn't provided.
> >=20
> > Otherwise this looks fine to me. =20
>=20
> All the boards that probe the ingenic-adc driver have the interrupt=20
> 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


>=20
> Cheers,
> -Paul
>=20
> >  =20
> >>  ---
> >>=20
> >>   Changes:
> >>=20
> >>   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
> >>=20
> >>   v3: remove unneeded `linux/iio/kfifo_buf.h` include
> >>=20
> >>   drivers/iio/adc/Kconfig       |   1 +
> >>   drivers/iio/adc/ingenic-adc.c | 109=20
> >> +++++++++++++++++++++++++++++++++-
> >>   2 files changed, 108 insertions(+), 2 deletions(-)
> >>=20
> >>  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=20
> >> unit.
> >>=20
> >>  diff --git a/drivers/iio/adc/ingenic-adc.c=20
> >> 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 @@
> >>=20
> >>   #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
> >>=20
> >>  +#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;
> >>=20
> >>   struct ingenic_adc_soc_data {
> >>  @@ -411,6 +426,28 @@ static const struct iio_info ingenic_adc_info=20
> >> =3D {
> >>   };
> >>=20
> >>   static const struct iio_chan_spec ingenic_channels[] =3D {
> >>  +	{
> >>  +		.type =3D IIO_POSITIONRELATIVE,
> >>  +		.indexed =3D 1,
> >>  +		.channel =3D INGENIC_ADC_TOUCH_XP,
> >>  +		.scan_index =3D 0,
> >>  +		.scan_type =3D {
> >>  +			.sign =3D 'u',
> >>  +			.realbits =3D 12,
> >>  +			.storagebits =3D 16
> >>  +		},
> >>  +	},
> >>  +	{
> >>  +		.type =3D IIO_POSITIONRELATIVE,
> >>  +		.indexed =3D 1,
> >>  +		.channel =3D INGENIC_ADC_TOUCH_YP,
> >>  +		.scan_index =3D 1,
> >>  +		.scan_type =3D {
> >>  +			.sign =3D 'u',
> >>  +			.realbits =3D 12,
> >>  +			.storagebits =3D 16
> >>  +		},
> >>  +	},
> >>   	{
> >>   		.extend_name =3D "aux",
> >>   		.type =3D IIO_VOLTAGE,
> >>  @@ -418,6 +455,7 @@ static const struct iio_chan_spec=20
> >> ingenic_channels[] =3D {
> >>   				      BIT(IIO_CHAN_INFO_SCALE),
> >>   		.indexed =3D 1,
> >>   		.channel =3D INGENIC_ADC_AUX,
> >>  +		.scan_index =3D -1
> >>   	},
> >>   	{
> >>   		.extend_name =3D "battery",
> >>  @@ -428,6 +466,7 @@ static const struct iio_chan_spec=20
> >> ingenic_channels[] =3D {
> >>   						BIT(IIO_CHAN_INFO_SCALE),
> >>   		.indexed =3D 1,
> >>   		.channel =3D INGENIC_ADC_BATTERY,
> >>  +		.scan_index =3D -1
> >>   	},
> >>   	{ /* Must always be last in the array. */
> >>   		.extend_name =3D "aux2",
> >>  @@ -436,16 +475,69 @@ static const struct iio_chan_spec=20
> >> ingenic_channels[] =3D {
> >>   				      BIT(IIO_CHAN_INFO_SCALE),
> >>   		.indexed =3D 1,
> >>   		.channel =3D INGENIC_ADC_AUX2,
> >>  +		.scan_index =3D -1
> >>   	},
> >>   };
> >>=20
> >>  +static int ingenic_adc_buffer_enable(struct iio_dev *iio_dev)
> >>  +{
> >>  +	struct ingenic_adc *adc =3D iio_priv(iio_dev);
> >>  +
> >>  +	clk_enable(adc->clk);
> >>  +	/* It takes significant time for the touchscreen hw to stabilize.=20
> >> */
> >>  +	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 =3D 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=20
> >> =3D {
> >>  +	.postenable =3D &ingenic_adc_buffer_enable,
> >>  +	.predisable =3D &ingenic_adc_buffer_disable
> >>  +};
> >>  +
> >>  +static irqreturn_t ingenic_adc_irq(int irq, void *data)
> >>  +{
> >>  +	struct iio_dev *iio_dev =3D data;
> >>  +	struct ingenic_adc *adc =3D iio_priv(iio_dev);
> >>  +	u32 tdat;
> >>  +
> >>  +	tdat =3D 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 =3D &pdev->dev;
> >>   	struct iio_dev *iio_dev;
> >>   	struct ingenic_adc *adc;
> >>   	const struct ingenic_adc_soc_data *soc_data;
> >>  -	int ret;
> >>  +	int irq, ret;
> >>=20
> >>   	soc_data =3D device_get_match_data(dev);
> >>   	if (!soc_data)
> >>  @@ -460,6 +552,18 @@ static int ingenic_adc_probe(struct=20
> >> platform_device *pdev)
> >>   	mutex_init(&adc->aux_lock);
> >>   	adc->soc_data =3D soc_data;
> >>=20
> >>  +	irq =3D platform_get_irq(pdev, 0); =20
> >=20
> > Do we need a fallback path if there is no irq provided?  We can't=20
> > break existing
> > supported devices that don't specify one.
> >  =20
> >>  +	if (irq < 0) {
> >>  +		dev_err(dev, "Failed to get irq: %d\n", irq);
> >>  +		return irq;
> >>  +	}
> >>  +	ret =3D 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 =3D 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=20
> >> platform_device *pdev)
> >>=20
> >>   	iio_dev->dev.parent =3D dev;
> >>   	iio_dev->name =3D "jz-adc";
> >>  -	iio_dev->modes =3D INDIO_DIRECT_MODE;
> >>  +	iio_dev->modes =3D INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
> >>  +	iio_dev->setup_ops =3D &ingenic_buffer_setup_ops;
> >>   	iio_dev->channels =3D ingenic_channels;
> >>   	iio_dev->num_channels =3D ARRAY_SIZE(ingenic_channels);
> >>   	/* Remove AUX2 from the list of supported channels. */ =20
> >  =20
>=20
>=20