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Message-ID: <53CC368E.9060506@gmx.de> Date: Sun, 20 Jul 2014 23:37:18 +0200 From: Hartmut Knaack <knaack.h@....de> To: Jonathan Cameron <jic23@...nel.org>, Arnd Bergmann <arnd@...db.de>, linux-arm-kernel@...ts.infradead.org CC: Chanwoo Choi <cw00.choi@...sung.com>, ch.naveen@...sung.com, mark.rutland@....com, devicetree@...r.kernel.org, kgene.kim@...sung.com, pawel.moll@....com, ijc+devicetree@...lion.org.uk, linux-iio@...r.kernel.org, t.figa@...sung.com, rdunlap@...radead.org, linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org, kyungmin.park@...sung.com, robh+dt@...nel.org, galak@...eaurora.org, heiko.stuebner@...com, Ben Dooks <ben-linux@...ff.org> Subject: Re: [PATCH 2/2] iio: exynos-adc: add experimental touchscreen support Jonathan Cameron schrieb: > On 18/07/14 20:29, Arnd Bergmann wrote: >> This adds support for the touchscreen on Samsung s3c64xx. >> The driver is completely untested but shows roughly how >> it could be done, following the example of the at91 driver. >> > Hi Arnd, > >> Open questions include: >> >> - compared to the old plat-samsung/adc driver, there is >> no support for prioritizing ts over other clients, nor >> for oversampling. From my reading of the code, the >> priorities didn't actually have any effect at all, but >> the oversampling might be needed. Maybe the original >> authors have some insight. >> >> - I simply register the input device from the adc driver >> itself, as the at91 code does. The driver also supports >> sub-nodes, but I don't understand how they are meant >> to be used, so using those might be better. > So, the alternative you are (I think) referring to is to use > the buffered in kernel client interface. That way a separate > touch screen driver can use the output channels provided by IIO > in much the same way you might use a regulator or similar. > Note that whilst this is similar to the simple polled interface > used for things like the iio_hwmon driver, the data flow is > quite different (clearly the polled interfce would be > inappropriate here). > > Whilst we've discussed it in the past for touch screen drivers > like this, usually the hardware isn't generic enough to be > of any real use if not being used as a touch screen. As such > it's often simpler to just have the support directly in the > driver (as you've observed the at91 driver does this). > > Whilst the interface has been there a while, it's not really had > all that much use. The original target was the simpler case > of 3D accelerometer where we have a generic iio to input > bridge driver. Time constraints meant that I haven't yet actually > formally submitted the input side of this. Whilst there are lots > of other things that can use this interface, right now nothing > actually does so. > >> - The new exynos_read_s3c64xx_ts() function is intentionally >> very similar to the existing exynos_read_raw() functions. >> It should probably be changed, either by merging the two >> into one, or by simplifying the exynos_read_s3c64xx_ts() >> function. This depends a bit on the answers to the questions >> above. > I'd be tempted to not bother keeping them that similar. It's > not a generic IIO channel so simplify it where possible. >> - We probably need to add support for platform_data as well, >> I've skipped this so far. >> >> - Is anybody able to debug this driver on real hardware? >> While it's possible that it actually works, it's more >> likely that I made a few subtle mistakes. >> >> Signed-off-by: Arnd Bergmann <arnd@...db.de> > Looks pretty good to me. A few symantic bits and pieces and > one bug spotted. Short and sweet. >> diff --git a/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt b/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt >> index e1b74828f413..4329bf3c3326 100644 >> --- a/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt >> +++ b/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt >> @@ -41,6 +41,10 @@ Required properties: >> and compatible ADC block) >> - vdd-supply VDD input supply. >> >> +Optional properties: >> +- has-touchscreen: If present, indicates that a touchscreen is >> + connected an usable. >> + >> Note: child nodes can be added for auto probing from device tree. >> >> Example: adding device info in dtsi file >> diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c >> index 5f95638513d2..cf1d9f3e2492 100644 >> --- a/drivers/iio/adc/exynos_adc.c >> +++ b/drivers/iio/adc/exynos_adc.c >> @@ -34,6 +34,7 @@ >> #include <linux/regulator/consumer.h> >> #include <linux/of_platform.h> >> #include <linux/err.h> >> +#include <linux/input.h> > Might want to make the input side optional at compile time... > I supose the existing parts are unlikely to be used much in headless > devices, but you never know. Maybe we just leave this until someone > shouts they want to be able to avoid compiling it in. >> #include <linux/iio/iio.h> >> #include <linux/iio/machine.h> >> @@ -103,6 +104,7 @@ >> >> /* Bit definitions common for ADC_V1 and ADC_V2 */ >> #define ADC_CON_EN_START (1u << 0) >> +#define ADC_DATX_PRESSED (1u << 15) >> #define ADC_DATX_MASK 0xFFF >> >> #define EXYNOS_ADC_TIMEOUT (msecs_to_jiffies(100)) >> @@ -110,16 +112,20 @@ >> struct exynos_adc { >> struct exynos_adc_data *data; >> struct device *dev; >> + struct input_dev *input; >> void __iomem *regs; >> void __iomem *enable_reg; >> struct clk *clk; >> struct clk *sclk; >> unsigned int irq; >> + unsigned int tsirq; >> struct regulator *vdd; >> >> struct completion completion; >> >> + bool read_ts; >> u32 value; >> + u32 value2; > As I state further down, I'd rather keep a little > clear of the naming used in IIO for bits that aren't > going through IIO (less confusing!). Maybe just > have > u32 x, y; >> unsigned int version; >> }; >> >> @@ -390,12 +396,61 @@ static int exynos_read_raw(struct iio_dev *indio_dev, >> return ret; >> } >> >> +static int exynos_read_s3c64xx_ts(struct iio_dev *indio_dev, >> + struct iio_chan_spec const *chan, >> + int *val, >> + int *val2, >> + long mask) >> +{ >> + struct exynos_adc *info = iio_priv(indio_dev); >> + unsigned long timeout; >> + int ret; >> + >> + if (mask != IIO_CHAN_INFO_RAW) >> + return -EINVAL; >> + >> + mutex_lock(&indio_dev->mlock); >> + info->read_ts = 1; Since info->read_ts is of type bool, use true/false. >> + >> + reinit_completion(&info->completion); >> + >> + writel(ADC_S3C2410_TSC_PULL_UP_DISABLE | ADC_TSC_AUTOPST, >> + ADC_V1_TSC(info->regs)); >> + >> + /* Select the ts channel to be used and Trigger conversion */ >> + info->data->start_conv(info, 0); > 0 is a rather magic value. A define perhaps? >> + >> + timeout = wait_for_completion_timeout >> + (&info->completion, EXYNOS_ADC_TIMEOUT); >> + if (timeout == 0) { >> + dev_warn(&indio_dev->dev, "Conversion timed out! Resetting\n"); >> + if (info->data->init_hw) >> + info->data->init_hw(info); >> + ret = -ETIMEDOUT; >> + } else { >> + *val = info->value; >> + *val2 = info->value2; > This is definitely abuse as those two values are not intended for > different values. If you want to do this please use different naming > and don't try to fiddle it into the IIO read raw framework. > As you've suggested above, better to simplify this code and drop the > bits cloned from the other handler. >> + ret = IIO_VAL_INT; >> + } >> + >> + info->read_ts = 0; >> + mutex_unlock(&indio_dev->mlock); >> + >> + return ret; >> +} >> + >> static irqreturn_t exynos_adc_isr(int irq, void *dev_id) >> { >> struct exynos_adc *info = (struct exynos_adc *)dev_id; >> >> /* Read value */ >> - info->value = readl(ADC_V1_DATX(info->regs)) & ADC_DATX_MASK; >> + if (info->read_ts) { >> + info->value = readl(ADC_V1_DATX(info->regs)) & ADC_DATX_MASK; >> + info->value2 = readl(ADC_V1_DATY(info->regs)) & ADC_DATX_MASK; > ADC_DATY_MASK would be more obviously correct. > >> + writel(ADC_TSC_WAIT4INT | ADC_S3C2443_TSC_UD_SEN, ADC_V1_TSC(info->regs)); > Perhaps the above is cryptic enough to warrant a comment? >> + } else { >> + info->value = readl(ADC_V1_DATX(info->regs)) & ADC_DATX_MASK; >> + } >> >> /* clear irq */ >> if (info->data->clear_irq) >> @@ -406,6 +461,46 @@ static irqreturn_t exynos_adc_isr(int irq, void *dev_id) >> return IRQ_HANDLED; >> } >> >> +/* >> + * Here we (ab)use a threaded interrupt handler to stay running >> + * for as long as the touchscreen remains pressed, we report >> + * a new event with the latest data and then sleep until the >> + * next timer tick. This mirrors the behavior of the old >> + * driver, with much less code. >> + */ >> +static irqreturn_t exynos_ts_isr(int irq, void *dev_id) >> +{ >> + struct exynos_adc *info = dev_id; >> + struct iio_dev *dev = dev_get_drvdata(info->dev); >> + u32 x, y; >> + bool pressed; >> + int ret; >> + >> + do { >> + ret =exynos_read_s3c64xx_ts(dev, NULL, &x, &y, IIO_CHAN_INFO_RAW); > = exynos >> + if (ret == -ETIMEDOUT) >> + break; >> + >> + pressed = x & y & ADC_DATX_PRESSED; >> + if (!pressed) >> + break; >> + >> + input_report_abs(info->input, ABS_X, x & ADC_DATX_MASK); >> + input_report_abs(info->input, ABS_Y, y & ADC_DATX_MASK); >> + input_report_key(info->input, BTN_TOUCH, 1); >> + input_sync(info->input); >> + >> + msleep(1); >> + } while (1); >> + >> + input_report_key(info->input, BTN_TOUCH, 0); >> + input_sync(info->input); >> + >> + writel(0, ADC_V1_CLRINTPNDNUP(info->regs)); >> + >> + return IRQ_HANDLED; >> +} >> + >> static int exynos_adc_reg_access(struct iio_dev *indio_dev, >> unsigned reg, unsigned writeval, >> unsigned *readval) >> @@ -457,12 +552,57 @@ static int exynos_adc_remove_devices(struct device *dev, void *c) >> return 0; >> } >> >> +static int exynos_adc_ts_init(struct exynos_adc *info) >> +{ >> + int ret; >> + >> + info->input = input_allocate_device(); >> + if (!info->input) >> + return -ENOMEM; >> + >> + info->input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); >> + info->input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); >> + >> + input_set_abs_params(info->input, ABS_X, 0, 0x3FF, 0, 0); >> + input_set_abs_params(info->input, ABS_Y, 0, 0x3FF, 0, 0); >> + >> + /* data from s3c2410_ts driver */ >> + info->input->name = "S3C24xx TouchScreen"; >> + info->input->id.bustype = BUS_HOST; >> + info->input->id.vendor = 0xDEAD; >> + info->input->id.product = 0xBEEF; >> + info->input->id.version = 0x0200; >> + >> + ret = input_register_device(info->input); >> + if (ret) { >> + input_free_device(info->input); >> + goto err; Just return ret, without goto (and get rid of label err). >> + } >> + >> + if (info->tsirq > 0) >> + ret = request_threaded_irq(info->irq, NULL, exynos_ts_isr, >> + 0, "touchscreen", info); > info->tsirq > (that had me really confused for a moment ;) > Also, perhaps a more specific name. touchscreen_updown or similar as the > main interrupt is also used during touchscreen operation. >> + if (ret < 0) { >> + dev_err(info->dev, "failed requesting touchsccreen irq, irq = %d\n", >> + info->irq); >> + goto err_input; >> + } >> + >> + return 0; >> + Probably better to get rid of the labels and move the code up, as it is only used once. >> +err_input: >> + input_unregister_device(info->input); >> +err: >> + return ret; >> +} >> + >> static int exynos_adc_probe(struct platform_device *pdev) >> { >> struct exynos_adc *info = NULL; >> struct device_node *np = pdev->dev.of_node; >> struct iio_dev *indio_dev = NULL; >> struct resource *mem; >> + bool has_ts; >> int ret = -ENODEV; >> int irq; >> >> @@ -498,8 +638,14 @@ static int exynos_adc_probe(struct platform_device *pdev) >> dev_err(&pdev->dev, "no irq resource?\n"); >> return irq; >> } >> - >> info->irq = irq; >> + >> + irq = platform_get_irq(pdev, 1); >> + if (irq == -EPROBE_DEFER) >> + return irq; What about other possible error codes? >> + >> + info->tsirq = irq; >> + >> info->dev = &pdev->dev; >> >> init_completion(&info->completion); >> @@ -565,6 +711,12 @@ static int exynos_adc_probe(struct platform_device *pdev) >> if (info->data->init_hw) >> info->data->init_hw(info); >> >> + has_ts = of_property_read_bool(pdev->dev.of_node, "has-touchscreen"); >> + if (has_ts) >> + ret = exynos_adc_ts_init(info); >> + if (ret) >> + goto err_iio; >> + >> ret = of_platform_populate(np, exynos_adc_match, NULL, &indio_dev->dev); >> if (ret < 0) { >> dev_err(&pdev->dev, "failed adding child nodes\n"); >> @@ -576,6 +728,11 @@ static int exynos_adc_probe(struct platform_device *pdev) >> err_of_populate: >> device_for_each_child(&indio_dev->dev, NULL, >> exynos_adc_remove_devices); >> + if (has_ts) { >> + input_unregister_device(info->input); >> + free_irq(info->tsirq, info); >> + } >> +err_iio: >> iio_device_unregister(indio_dev); >> err_irq: >> free_irq(info->irq, info); >> @@ -595,9 +752,12 @@ static int exynos_adc_remove(struct platform_device *pdev) >> struct iio_dev *indio_dev = platform_get_drvdata(pdev); >> struct exynos_adc *info = iio_priv(indio_dev); >> >> + input_free_device(info->input); >> device_for_each_child(&indio_dev->dev, NULL, >> exynos_adc_remove_devices); >> iio_device_unregister(indio_dev); >> + if (info->tsirq > 0) >> + free_irq(info->tsirq, info); >> free_irq(info->irq, info); >> if (info->data->exit_hw) >> info->data->exit_hw(info); >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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