On Mon, Aug 29, 2016 at 09:50:28AM +0530, Vignesh R wrote: > > > On Thursday 25 August 2016 10:26 PM, Dmitry Torokhov wrote: > > 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. > > > > Ok. > > >> + } > >> + } > >> + > >> + 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; > > > > ? > > Oops, you are right. > > > > >> + > >> + 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? > > > > Sorry, I overlooked flat param when I copied this line from > rotary-encoder.c. > > >> + > >> + 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. > > Thanks a lot! Applied, thank you. DTS change should go through some other tree though. -- 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
