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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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4eec8772e4
There is a custom loop that repeats parts of gpiod_get_array_value_cansleep(). Use that in conjunction with bitmap API to make code shorter and easier to follow. With this done, add an upper check for amount of GPIOs given based on the driver's code. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://patch.msgid.link/20251113154616.3107676-4-andriy.shevchenko@linux.intel.com Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
126 lines
3.2 KiB
C
126 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
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*
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* A generic driver to read multiple gpio lines and translate the
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* encoded numeric value into an input event.
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*/
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#include <linux/bitmap.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/gpio/consumer.h>
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#include <linux/input.h>
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#include <linux/kernel.h>
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#include <linux/minmax.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/property.h>
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struct gpio_decoder {
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struct gpio_descs *input_gpios;
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struct device *dev;
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u32 axis;
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u32 last_stable;
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};
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static int gpio_decoder_get_gpios_state(struct gpio_decoder *decoder)
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{
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struct gpio_descs *gpios = decoder->input_gpios;
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DECLARE_BITMAP(values, 32);
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unsigned int size;
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int err;
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size = min(gpios->ndescs, 32U);
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err = gpiod_get_array_value_cansleep(size, gpios->desc, gpios->info, values);
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if (err) {
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dev_err(decoder->dev, "Error reading GPIO: %d\n", err);
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return err;
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}
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return bitmap_read(values, 0, size);
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}
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static void gpio_decoder_poll_gpios(struct input_dev *input)
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{
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struct gpio_decoder *decoder = input_get_drvdata(input);
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int state;
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state = gpio_decoder_get_gpios_state(decoder);
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if (state >= 0 && state != decoder->last_stable) {
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input_report_abs(input, decoder->axis, state);
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input_sync(input);
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decoder->last_stable = state;
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}
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}
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static int gpio_decoder_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct gpio_decoder *decoder;
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struct input_dev *input;
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u32 max;
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int err;
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decoder = devm_kzalloc(dev, sizeof(*decoder), GFP_KERNEL);
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if (!decoder)
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return -ENOMEM;
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decoder->dev = dev;
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device_property_read_u32(dev, "linux,axis", &decoder->axis);
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decoder->input_gpios = devm_gpiod_get_array(dev, NULL, GPIOD_IN);
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if (IS_ERR(decoder->input_gpios))
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return dev_err_probe(dev, PTR_ERR(decoder->input_gpios),
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"unable to acquire input gpios\n");
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if (decoder->input_gpios->ndescs < 2)
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return dev_err_probe(dev, -EINVAL, "not enough gpios found\n");
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if (decoder->input_gpios->ndescs > 31)
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return dev_err_probe(dev, -EINVAL, "too many gpios found\n");
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if (device_property_read_u32(dev, "decoder-max-value", &max))
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max = (1U << decoder->input_gpios->ndescs) - 1;
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input = devm_input_allocate_device(dev);
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if (!input)
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return -ENOMEM;
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input_set_drvdata(input, decoder);
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input->name = pdev->name;
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input->id.bustype = BUS_HOST;
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input_set_abs_params(input, decoder->axis, 0, max, 0, 0);
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err = input_setup_polling(input, gpio_decoder_poll_gpios);
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if (err)
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return dev_err_probe(dev, err, "failed to set up polling\n");
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err = input_register_device(input);
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if (err)
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return dev_err_probe(dev, err, "failed to register input device\n");
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return 0;
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}
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static const struct of_device_id gpio_decoder_of_match[] = {
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{ .compatible = "gpio-decoder", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, gpio_decoder_of_match);
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static struct platform_driver gpio_decoder_driver = {
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.probe = gpio_decoder_probe,
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.driver = {
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.name = "gpio-decoder",
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.of_match_table = gpio_decoder_of_match,
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}
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};
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module_platform_driver(gpio_decoder_driver);
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MODULE_DESCRIPTION("GPIO decoder input driver");
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MODULE_AUTHOR("Vignesh R <vigneshr@ti.com>");
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MODULE_LICENSE("GPL v2");
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