On Thu, May 19, 2016 at 02:34:00PM +0530, Vignesh R wrote: > There are rotary-encoders where GPIO lines reflect the actual position > of the rotary encoder dial. For example, if dial points to 9, then four > GPIO lines connected to the rotary encoder will read HLLH(1001b = 9). > Add support for such rotary-encoder. > The driver relies on rotary-encoder,absolute-encoder DT property to > detect such encoders. > Since, GPIO IRQs are not necessary to work with > such encoders, optional polling mode support is added using > input_poll_dev skeleton. This is can be used by enabling > CONFIG_INPUT_GPIO_ROTARY_ENCODER_POLL_MODE_SUPPORT. Does this really belong to a rotary encoder and not a new driver that simply translates gpio-encoded value into ABS* event? > > Signed-off-by: Vignesh R <vigneshr@xxxxxx> > --- > .../devicetree/bindings/input/rotary-encoder.txt | 4 + > Documentation/input/rotary-encoder.txt | 9 ++ > drivers/input/misc/Kconfig | 11 ++ > drivers/input/misc/rotary_encoder.c | 165 ++++++++++++++++----- > 4 files changed, 155 insertions(+), 34 deletions(-) > > diff --git a/Documentation/devicetree/bindings/input/rotary-encoder.txt b/Documentation/devicetree/bindings/input/rotary-encoder.txt > index 6c9f0c8a846c..9c928dbd1500 100644 > --- a/Documentation/devicetree/bindings/input/rotary-encoder.txt > +++ b/Documentation/devicetree/bindings/input/rotary-encoder.txt > @@ -12,6 +12,10 @@ Optional properties: > - rotary-encoder,relative-axis: register a relative axis rather than an > absolute one. Relative axis will only generate +1/-1 events on the input > device, hence no steps need to be passed. > +- rotary-encoder,absolute-encoder: support encoders where GPIO lines > + reflect the actual position of the rotary encoder dial. For example, > + if dial points to 9, then four GPIO lines read HLLH(1001b = 9). > + In this case, rotary-encoder,steps-per-period needed not be defined. > - rotary-encoder,rollover: Automatic rollove when the rotary value becomes > greater than the specified steps or smaller than 0. For absolute axis only. > - rotary-encoder,steps-per-period: Number of steps (stable states) per period. > diff --git a/Documentation/input/rotary-encoder.txt b/Documentation/input/rotary-encoder.txt > index 46a74f0c551a..dc76092f5618 100644 > --- a/Documentation/input/rotary-encoder.txt > +++ b/Documentation/input/rotary-encoder.txt > @@ -36,6 +36,15 @@ The phase diagram of these two outputs look like this: > |<>| > one step (quarter-period mode) > > + > +In some encoders, the value pointed by rotary encoders switch is directly > +reflected by status of the GPIOs connecting rotary encoder to CPU. For > +example, if rotary encoder dial points to 9, then the four GPIOs > +conncting rotary encoder will read HLLH(1001b = 9). Such encoders are > +supported by defining devictree binding "rotary-encoder,absolute-encoder". > +These encoders are also supported without need for event(IRQ) generation > +using Input subsytem's polling mode support. > + > For more information, please see > https://en.wikipedia.org/wiki/Rotary_encoder > > diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig > index 1f2337abcf2f..81805f9a534c 100644 > --- a/drivers/input/misc/Kconfig > +++ b/drivers/input/misc/Kconfig > @@ -566,6 +566,17 @@ config INPUT_GPIO_ROTARY_ENCODER > To compile this driver as a module, choose M here: the > module will be called rotary_encoder. > > +config INPUT_GPIO_ROTARY_ENCODER_POLL_MODE_SUPPORT > + bool "Polling mode support for rotary encoder" > + depends on INPUT_GPIO_ROTARY_ENCODER > + select INPUT_POLLDEV > + help > + Say Y here to enable polling mode support for rotary encoders > + connected to GPIO lines that do have interrupt capability and > + report rotary encoder position as absolute value over GPIO > + lines. Check file: Documentation/input/rotary-encoder.txt for > + more information. > + > config INPUT_RB532_BUTTON > tristate "Mikrotik Routerboard 532 button interface" > depends on MIKROTIK_RB532 > diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c > index c7fc8d4fb080..8f60289fb6cd 100644 > --- a/drivers/input/misc/rotary_encoder.c > +++ b/drivers/input/misc/rotary_encoder.c > @@ -25,24 +25,29 @@ > #include <linux/of.h> > #include <linux/pm.h> > #include <linux/property.h> > +#include <linux/input-polldev.h> > > #define DRV_NAME "rotary-encoder" > > struct rotary_encoder { > struct input_dev *input; > - > +#ifdef CONFIG_INPUT_GPIO_ROTARY_ENCODER_POLL_MODE_SUPPORT > + struct input_polled_dev *poll_dev; > +#endif > struct mutex access_mutex; > > u32 steps; > u32 axis; > bool relative_axis; > bool rollover; > + bool absolute_encoder; > > unsigned int pos; > > struct gpio_descs *gpios; > + struct device *dev; > > - unsigned int *irq; > + int *irq; > > bool armed; > signed char dir; /* 1 - clockwise, -1 - CCW */ > @@ -67,6 +72,21 @@ static unsigned int rotary_encoder_get_state(struct rotary_encoder *encoder) > return ret & 3; > } > > +static unsigned int rotary_encoder_get_gpios_state(struct rotary_encoder > + *encoder) > +{ > + int i; > + unsigned int ret = 0; > + > + for (i = 0; i < encoder->gpios->ndescs; ++i) { > + int val = gpiod_get_value_cansleep(encoder->gpios->desc[i]); > + > + ret = ret << 1 | val; > + } > + > + return ret; > +} > + > static void rotary_encoder_report_event(struct rotary_encoder *encoder) > { > if (encoder->relative_axis) { > @@ -178,6 +198,72 @@ out: > return IRQ_HANDLED; > } > > +static void rotary_encoder_setup_input_params(struct rotary_encoder *encoder) > +{ > + struct input_dev *input = encoder->input; > + struct platform_device *pdev = to_platform_device(encoder->dev); > + > + input->name = pdev->name; > + input->id.bustype = BUS_HOST; > + input->dev.parent = encoder->dev; > + > + if (encoder->relative_axis) > + input_set_capability(input, EV_REL, encoder->axis); > + else > + input_set_abs_params(input, > + encoder->axis, 0, encoder->steps, 0, 1); > +} > + > +static irqreturn_t rotary_absolute_encoder_irq(int irq, void *dev_id) > +{ > + struct rotary_encoder *encoder = dev_id; > + unsigned int state; > + > + mutex_lock(&encoder->access_mutex); > + > + state = rotary_encoder_get_gpios_state(encoder); > + if (state != encoder->last_stable) { > + input_report_abs(encoder->input, encoder->axis, state); > + input_sync(encoder->input); > + encoder->last_stable = state; > + } > + > + mutex_lock(&encoder->access_mutex); > + > + return IRQ_HANDLED; > +} > + > +#ifdef CONFIG_INPUT_GPIO_ROTARY_ENCODER_POLL_MODE_SUPPORT > +static void rotary_encoder_poll_gpios(struct input_polled_dev *poll_dev) > +{ > + struct rotary_encoder *encoder = poll_dev->private; > + unsigned int state = rotary_encoder_get_gpios_state(encoder); > + > + if (state != encoder->last_stable) { > + input_report_abs(encoder->input, encoder->axis, state); > + input_sync(encoder->input); > + encoder->last_stable = state; > + } > +} > + > +static int rotary_encoder_register_poll_device(struct rotary_encoder > + *encoder) > +{ > + struct input_polled_dev *poll_dev = > + devm_input_allocate_polled_device(encoder->dev); > + > + if (!poll_dev) > + return -ENOMEM; > + poll_dev->private = encoder; > + poll_dev->poll = rotary_encoder_poll_gpios; > + encoder->input = poll_dev->input; > + rotary_encoder_setup_input_params(encoder); > + encoder->poll_dev = poll_dev; > + > + return input_register_polled_device(poll_dev); > +} > +#endif > + > static int rotary_encoder_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > @@ -227,38 +313,32 @@ static int rotary_encoder_probe(struct platform_device *pdev) > return -EINVAL; > } > > - input = devm_input_allocate_device(dev); > - if (!input) > - return -ENOMEM; > - > - encoder->input = input; > - > - input->name = pdev->name; > - input->id.bustype = BUS_HOST; > - input->dev.parent = dev; > - > - if (encoder->relative_axis) > - input_set_capability(input, EV_REL, encoder->axis); > - else > - input_set_abs_params(input, > - encoder->axis, 0, encoder->steps, 0, 1); > - > - switch (steps_per_period >> (encoder->gpios->ndescs - 2)) { > - case 4: > - handler = &rotary_encoder_quarter_period_irq; > - encoder->last_stable = rotary_encoder_get_state(encoder); > - break; > - case 2: > - handler = &rotary_encoder_half_period_irq; > - encoder->last_stable = rotary_encoder_get_state(encoder); > - break; > - case 1: > - handler = &rotary_encoder_irq; > - break; > - default: > - dev_err(dev, "'%d' is not a valid steps-per-period value\n", > - steps_per_period); > - return -EINVAL; > + encoder->dev = dev; > + encoder->absolute_encoder = > + device_property_read_bool(dev, > + "rotary-encoder,absolute-encoder"); > + if (encoder->absolute_encoder) { > + handler = rotary_absolute_encoder_irq; > + } else { > + switch (steps_per_period >> (encoder->gpios->ndescs - 2)) { > + case 4: > + handler = &rotary_encoder_quarter_period_irq; > + encoder->last_stable = > + rotary_encoder_get_state(encoder); > + break; > + case 2: > + handler = &rotary_encoder_half_period_irq; > + encoder->last_stable = > + rotary_encoder_get_state(encoder); > + break; > + case 1: > + handler = &rotary_encoder_irq; > + break; > + default: > + dev_err(dev, "'%d' is not a valid steps-per-period value\n", > + steps_per_period); > + return -EINVAL; > + } > } > > encoder->irq = > @@ -271,6 +351,18 @@ static int rotary_encoder_probe(struct platform_device *pdev) > for (i = 0; i < encoder->gpios->ndescs; ++i) { > encoder->irq[i] = gpiod_to_irq(encoder->gpios->desc[i]); > > +#ifdef CONFIG_INPUT_GPIO_ROTARY_ENCODER_POLL_MODE_SUPPORT > + if (encoder->irq[i] < 0 && encoder->absolute_encoder) { > + dev_info(dev, "Using poll mode\n"); > + err = rotary_encoder_register_poll_device(encoder); > + if (err) { > + dev_err(dev, "failed to register poll dev\n"); > + return err; > + } > + platform_set_drvdata(pdev, encoder); > + return 0; > + } > +#endif > err = devm_request_threaded_irq(dev, encoder->irq[i], > NULL, handler, > IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | > @@ -283,6 +375,11 @@ static int rotary_encoder_probe(struct platform_device *pdev) > } > } > > + input = devm_input_allocate_device(dev); > + if (!input) > + return -ENOMEM; > + encoder->input = input; > + rotary_encoder_setup_input_params(encoder); > err = input_register_device(input); > if (err) { > dev_err(dev, "failed to register input device\n"); > -- > 2.8.2 > -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
