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! -- Regards Vignesh -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
