On Wed, Aug 24, 2016 at 01:28:58PM +0530, Vignesh R wrote: > Add a driver to read group of GPIO lines and provide its status as a > numerical value as input event to the system. This will help in > interfacing devices, that can be connected over GPIOs, that provide > input to the system by driving GPIO lines connected to them like a > rotary dial or a switch. > > For example, a rotary switch can be connected to four GPIO lines. The > status of the GPIO lines reflect the actual position of the rotary > switch dial. For example, if dial points to 9, then the four GPIO lines > connected to the switch will read HLLH(0b'1001 = 9). This value > can be reported as an ABS_* event to the input subsystem. > > Signed-off-by: Vignesh R <vigneshr@xxxxxx> > Acked-by: Rob Herring <robh@xxxxxxxxxx> > --- > > v3: Fix comments by Andrew and Dmitry > Link to v2: https://lkml.org/lkml/2016/8/23/79 > > .../devicetree/bindings/input/gpio-decoder.txt | 23 ++++ > drivers/input/misc/Kconfig | 12 ++ > drivers/input/misc/Makefile | 1 + > drivers/input/misc/gpio_decoder.c | 134 +++++++++++++++++++++ > 4 files changed, 170 insertions(+) > create mode 100644 Documentation/devicetree/bindings/input/gpio-decoder.txt > create mode 100644 drivers/input/misc/gpio_decoder.c > > diff --git a/Documentation/devicetree/bindings/input/gpio-decoder.txt b/Documentation/devicetree/bindings/input/gpio-decoder.txt > new file mode 100644 > index 000000000000..14a77fb96cf0 > --- /dev/null > +++ b/Documentation/devicetree/bindings/input/gpio-decoder.txt > @@ -0,0 +1,23 @@ > +* GPIO Decoder DT bindings > + > +Required Properties: > +- compatible: should be "gpio-decoder" > +- gpios: a spec of gpios (at least two) to be decoded to a number with > + first entry representing the MSB. > + > +Optional Properties: > +- decoder-max-value: Maximum possible value that can be reported by > + the gpios. > +- linux,axis: the input subsystem axis to map to (ABS_X/ABS_Y). > + Defaults to 0 (ABS_X). > + > +Example: > + gpio-decoder0 { > + compatible = "gpio-decoder"; > + gpios = <&pca9536 3 GPIO_ACTIVE_HIGH>, > + <&pca9536 2 GPIO_ACTIVE_HIGH>, > + <&pca9536 1 GPIO_ACTIVE_HIGH>, > + <&pca9536 0 GPIO_ACTIVE_HIGH>; > + linux,axis = <0>; /* ABS_X */ > + decoder-max-value = <9>; > + }; > diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig > index efb0ca871327..7cdb89397d18 100644 > --- a/drivers/input/misc/Kconfig > +++ b/drivers/input/misc/Kconfig > @@ -292,6 +292,18 @@ config INPUT_GPIO_TILT_POLLED > To compile this driver as a module, choose M here: the > module will be called gpio_tilt_polled. > > +config INPUT_GPIO_DECODER > + tristate "Polled GPIO Decoder Input driver" > + depends on GPIOLIB || COMPILE_TEST > + select INPUT_POLLDEV > + help > + Say Y here if you want driver to read status of multiple GPIO > + lines and report the encoded value as an absolute integer to > + input subsystem. > + > + To compile this driver as a module, choose M here: the module > + will be called gpio_decoder. > + > config INPUT_IXP4XX_BEEPER > tristate "IXP4XX Beeper support" > depends on ARCH_IXP4XX > diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile > index 6a1e5e20fc1c..0b6d025f0487 100644 > --- a/drivers/input/misc/Makefile > +++ b/drivers/input/misc/Makefile > @@ -35,6 +35,7 @@ obj-$(CONFIG_INPUT_DRV2667_HAPTICS) += drv2667.o > obj-$(CONFIG_INPUT_GP2A) += gp2ap002a00f.o > obj-$(CONFIG_INPUT_GPIO_BEEPER) += gpio-beeper.o > obj-$(CONFIG_INPUT_GPIO_TILT_POLLED) += gpio_tilt_polled.o > +obj-$(CONFIG_INPUT_GPIO_DECODER) += gpio_decoder.o > obj-$(CONFIG_INPUT_HISI_POWERKEY) += hisi_powerkey.o > obj-$(CONFIG_HP_SDC_RTC) += hp_sdc_rtc.o > obj-$(CONFIG_INPUT_IMS_PCU) += ims-pcu.o > diff --git a/drivers/input/misc/gpio_decoder.c b/drivers/input/misc/gpio_decoder.c > new file mode 100644 > index 000000000000..1c2191d4b143 > --- /dev/null > +++ b/drivers/input/misc/gpio_decoder.c > @@ -0,0 +1,134 @@ > +/* > + * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/ > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License as > + * published by the Free Software Foundation version 2. > + * > + * This program is distributed "as is" WITHOUT ANY WARRANTY of any > + * kind, whether express or implied; without even the implied warranty > + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * A generic driver to read multiple gpio lines and translate the > + * encoded numeric value into an input event. > + */ > + > +#include <linux/device.h> > +#include <linux/gpio/consumer.h> > +#include <linux/input.h> > +#include <linux/input-polldev.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > + > +struct gpio_decoder { > + struct input_polled_dev *poll_dev; > + struct gpio_descs *input_gpios; > + struct device *dev; > + u32 axis; > + u32 last_stable; > +}; > + > +static unsigned int gpio_decoder_get_gpios_state(struct gpio_decoder > + *decoder) > +{ > + struct gpio_descs *gpios = decoder->input_gpios; > + unsigned int ret = 0; > + int i, val; > + > + for (i = 0; i < gpios->ndescs; i++) { > + val = gpiod_get_value_cansleep(gpios->desc[i]); > + if (val >= 0) { > + ret = (ret << 1) | !!val; > + } else { > + dev_err(decoder->dev, "Error reading gpio\n"); > + break; I think if we fail reading any one of gpio lines we should skip reporting the event. > + } > + } > + > + return ret; > +} > + > +static void gpio_decoder_poll_gpios(struct input_polled_dev *poll_dev) > +{ > + struct gpio_decoder *decoder = poll_dev->private; > + unsigned int state = gpio_decoder_get_gpios_state(decoder); > + > + if (state != decoder->last_stable) { > + input_report_abs(poll_dev->input, decoder->axis, state); > + input_sync(poll_dev->input); > + decoder->last_stable = state; > + } > +} > + > +static int gpio_decoder_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct gpio_decoder *decoder; > + struct input_polled_dev *poll_dev; > + u32 max; > + int err; > + > + decoder = devm_kzalloc(dev, sizeof(struct gpio_decoder), GFP_KERNEL); > + if (!decoder) > + return -ENOMEM; > + > + device_property_read_u32(dev, "linux,axis", &decoder->axis); > + decoder->input_gpios = devm_gpiod_get_array(dev, NULL, GPIOD_IN); > + if (IS_ERR(decoder->input_gpios)) { > + dev_err(dev, "unable to acquire input gpios\n"); > + return PTR_ERR(decoder->input_gpios); > + } > + if (decoder->input_gpios->ndescs < 2) { > + dev_err(dev, "not enough gpios found\n"); > + return -EINVAL; > + } > + > + if (device_property_read_u32(dev, "decoder-max-value", &max)) > + max = BIT(decoder->input_gpios->ndescs); Shouldn't this be max = (1U << decoder->input_gpios->ndescs) - 1; ? > + > + decoder->dev = dev; > + poll_dev = devm_input_allocate_polled_device(decoder->dev); > + if (!poll_dev) > + return -ENOMEM; > + > + poll_dev->private = decoder; > + poll_dev->poll = gpio_decoder_poll_gpios; > + decoder->poll_dev = poll_dev; > + > + poll_dev->input->name = pdev->name; > + poll_dev->input->id.bustype = BUS_HOST; > + input_set_abs_params(poll_dev->input, decoder->axis, 0, max, 0, 1); Why do you need flat == 1? Do you actually use joydev for this device? > + > + err = input_register_polled_device(poll_dev); > + if (err) { > + dev_err(dev, "failed to register polled device\n"); > + return err; > + } > + platform_set_drvdata(pdev, decoder); > + > + return 0; > +} > + > +#ifdef CONFIG_OF > +static const struct of_device_id gpio_decoder_of_match[] = { > + { .compatible = "gpio-decoder", }, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, gpio_decoder_of_match); > +#endif > + > +static struct platform_driver gpio_decoder_driver = { > + .probe = gpio_decoder_probe, > + .driver = { > + .name = "gpio-decoder", > + .of_match_table = of_match_ptr(gpio_decoder_of_match), > + } > +}; > +module_platform_driver(gpio_decoder_driver); > + > +MODULE_DESCRIPTION("GPIO decoder input driver"); > +MODULE_AUTHOR("Vignesh R <vigneshr@xxxxxx>"); > +MODULE_LICENSE("GPL v2"); > -- > 2.9.2 > No need to resubmit, I can adjust on my side. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
