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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126// SPDX-License-Identifier: GPL-2.0-only/* * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/ * * A generic driver to read multiple gpio lines and translate the * encoded numeric value into an input event. */
#include <linux/bitmap.h>#include <linux/dev_printk.h>#include <linux/device/devres.h>#include <linux/err.h>#include <linux/gpio/consumer.h>#include <linux/input.h>#include <linux/minmax.h>#include <linux/module.h>#include <linux/platform_device.h>#include <linux/property.h>#include <linux/types.h>
struct gpio_decoder { struct gpio_descs *input_gpios; struct device *dev; u32 axis; u32 last_stable;};
static int gpio_decoder_get_gpios_state(struct gpio_decoder *decoder){ struct gpio_descs *gpios = decoder->input_gpios; DECLARE_BITMAP(values, 32); unsigned int size; int err;
size = min(gpios->ndescs, 32U); err = gpiod_get_array_value_cansleep(size, gpios->desc, gpios->info, values); if (err) { dev_err(decoder->dev, "Error reading GPIO: %d\n", err); return err; }
return bitmap_read(values, 0, size);}
static void gpio_decoder_poll_gpios(struct input_dev *input){ struct gpio_decoder *decoder = input_get_drvdata(input); int state;
state = gpio_decoder_get_gpios_state(decoder); if (state >= 0 && state != decoder->last_stable) { input_report_abs(input, decoder->axis, state); input_sync(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_dev *input; u32 max; int err;
decoder = devm_kzalloc(dev, sizeof(*decoder), GFP_KERNEL); if (!decoder) return -ENOMEM;
decoder->dev = dev; 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)) return dev_err_probe(dev, PTR_ERR(decoder->input_gpios), "unable to acquire input gpios\n");
if (decoder->input_gpios->ndescs < 2) return dev_err_probe(dev, -EINVAL, "not enough gpios found\n");
if (decoder->input_gpios->ndescs > 31) return dev_err_probe(dev, -EINVAL, "too many gpios found\n");
if (device_property_read_u32(dev, "decoder-max-value", &max)) max = BIT(decoder->input_gpios->ndescs) - 1;
input = devm_input_allocate_device(dev); if (!input) return -ENOMEM;
input_set_drvdata(input, decoder);
input->name = pdev->name; input->id.bustype = BUS_HOST; input_set_abs_params(input, decoder->axis, 0, max, 0, 0);
err = input_setup_polling(input, gpio_decoder_poll_gpios); if (err) return dev_err_probe(dev, err, "failed to set up polling\n");
err = input_register_device(input); if (err) return dev_err_probe(dev, err, "failed to register input device\n");
return 0;}
static const struct of_device_id gpio_decoder_of_match[] = { { .compatible = "gpio-decoder", }, { }};MODULE_DEVICE_TABLE(of, gpio_decoder_of_match);
static struct platform_driver gpio_decoder_driver = { .probe = gpio_decoder_probe, .driver = { .name = "gpio-decoder", .of_match_table = gpio_decoder_of_match, }};module_platform_driver(gpio_decoder_driver);
MODULE_DESCRIPTION("GPIO decoder input driver");MODULE_AUTHOR("Vignesh R <vigneshr@ti.com>");MODULE_LICENSE("GPL v2");