cregit-Linux how code gets into the kernel

Release 4.11 drivers/input/misc/gpio_decoder.c

/*
 * 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 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) { dev_err(decoder->dev, "Error reading gpio %d: %d\n", desc_to_gpio(gpios->desc[i]), val); return val; } val = !!val; ret = (ret << 1) | val; } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Vignesh R111100.00%1100.00%
Total111100.00%1100.00%


static void gpio_decoder_poll_gpios(struct input_polled_dev *poll_dev) { struct gpio_decoder *decoder = poll_dev->private; int state; state = gpio_decoder_get_gpios_state(decoder); if (state >= 0 && state != decoder->last_stable) { input_report_abs(poll_dev->input, decoder->axis, state); input_sync(poll_dev->input); decoder->last_stable = state; } }

Contributors

PersonTokensPropCommitsCommitProp
Vignesh R70100.00%1100.00%
Total70100.00%1100.00%


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 = (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, 0); err = input_register_polled_device(poll_dev); if (err) { dev_err(dev, "failed to register polled device\n"); return err; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Vignesh R268100.00%1100.00%
Total268100.00%1100.00%

#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@ti.com>"); MODULE_LICENSE("GPL v2");

Overall Contributors

PersonTokensPropCommitsCommitProp
Vignesh R580100.00%1100.00%
Total580100.00%1100.00%
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.