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a0386bba70
The value returned by an spi driver's remove function is mostly ignored. (Only an error message is printed if the value is non-zero that the error is ignored.) So change the prototype of the remove function to return no value. This way driver authors are not tempted to assume that passing an error to the upper layer is a good idea. All drivers are adapted accordingly. There is no intended change of behaviour, all callbacks were prepared to return 0 before. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Claudius Heine <ch@denx.de> Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com> Acked-by: Łukasz Stelmach <l.stelmach@samsung.com> Acked-by: Lee Jones <lee.jones@linaro.org> Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de Signed-off-by: Mark Brown <broonie@kernel.org>
201 lines
5.0 KiB
C
201 lines
5.0 KiB
C
/*
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* Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
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* Andrew F. Davis <afd@ti.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether expressed or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License version 2 for more details.
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*/
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#include <linux/bitmap.h>
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#include <linux/bitops.h>
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#include <linux/delay.h>
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#include <linux/gpio/consumer.h>
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#include <linux/gpio/driver.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/spi/spi.h>
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#define DEFAULT_NGPIO 8
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/**
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* struct pisosr_gpio - GPIO driver data
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* @chip: GPIO controller chip
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* @spi: SPI device pointer
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* @buffer: Buffer for device reads
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* @buffer_size: Size of buffer
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* @load_gpio: GPIO pin used to load input into device
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* @lock: Protects read sequences
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*/
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struct pisosr_gpio {
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struct gpio_chip chip;
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struct spi_device *spi;
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u8 *buffer;
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size_t buffer_size;
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struct gpio_desc *load_gpio;
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struct mutex lock;
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};
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static int pisosr_gpio_refresh(struct pisosr_gpio *gpio)
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{
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int ret;
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mutex_lock(&gpio->lock);
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if (gpio->load_gpio) {
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gpiod_set_value_cansleep(gpio->load_gpio, 1);
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udelay(1); /* registers load time (~10ns) */
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gpiod_set_value_cansleep(gpio->load_gpio, 0);
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udelay(1); /* registers recovery time (~5ns) */
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}
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ret = spi_read(gpio->spi, gpio->buffer, gpio->buffer_size);
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mutex_unlock(&gpio->lock);
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return ret;
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}
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static int pisosr_gpio_get_direction(struct gpio_chip *chip,
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unsigned offset)
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{
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/* This device always input */
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return GPIO_LINE_DIRECTION_IN;
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}
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static int pisosr_gpio_direction_input(struct gpio_chip *chip,
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unsigned offset)
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{
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/* This device always input */
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return 0;
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}
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static int pisosr_gpio_direction_output(struct gpio_chip *chip,
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unsigned offset, int value)
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{
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/* This device is input only */
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return -EINVAL;
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}
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static int pisosr_gpio_get(struct gpio_chip *chip, unsigned offset)
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{
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struct pisosr_gpio *gpio = gpiochip_get_data(chip);
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/* Refresh may not always be needed */
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pisosr_gpio_refresh(gpio);
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return (gpio->buffer[offset / 8] >> (offset % 8)) & 0x1;
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}
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static int pisosr_gpio_get_multiple(struct gpio_chip *chip,
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unsigned long *mask, unsigned long *bits)
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{
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struct pisosr_gpio *gpio = gpiochip_get_data(chip);
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unsigned long offset;
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unsigned long gpio_mask;
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unsigned long buffer_state;
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pisosr_gpio_refresh(gpio);
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bitmap_zero(bits, chip->ngpio);
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for_each_set_clump8(offset, gpio_mask, mask, chip->ngpio) {
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buffer_state = gpio->buffer[offset / 8] & gpio_mask;
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bitmap_set_value8(bits, buffer_state, offset);
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}
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return 0;
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}
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static const struct gpio_chip template_chip = {
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.label = "pisosr-gpio",
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.owner = THIS_MODULE,
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.get_direction = pisosr_gpio_get_direction,
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.direction_input = pisosr_gpio_direction_input,
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.direction_output = pisosr_gpio_direction_output,
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.get = pisosr_gpio_get,
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.get_multiple = pisosr_gpio_get_multiple,
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.base = -1,
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.ngpio = DEFAULT_NGPIO,
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.can_sleep = true,
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};
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static int pisosr_gpio_probe(struct spi_device *spi)
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{
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struct device *dev = &spi->dev;
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struct pisosr_gpio *gpio;
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int ret;
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gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
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if (!gpio)
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return -ENOMEM;
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spi_set_drvdata(spi, gpio);
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gpio->chip = template_chip;
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gpio->chip.parent = dev;
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of_property_read_u16(dev->of_node, "ngpios", &gpio->chip.ngpio);
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gpio->spi = spi;
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gpio->buffer_size = DIV_ROUND_UP(gpio->chip.ngpio, 8);
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gpio->buffer = devm_kzalloc(dev, gpio->buffer_size, GFP_KERNEL);
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if (!gpio->buffer)
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return -ENOMEM;
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gpio->load_gpio = devm_gpiod_get_optional(dev, "load", GPIOD_OUT_LOW);
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if (IS_ERR(gpio->load_gpio))
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return dev_err_probe(dev, PTR_ERR(gpio->load_gpio),
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"Unable to allocate load GPIO\n");
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mutex_init(&gpio->lock);
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ret = gpiochip_add_data(&gpio->chip, gpio);
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if (ret < 0) {
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dev_err(dev, "Unable to register gpiochip\n");
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return ret;
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}
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return 0;
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}
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static void pisosr_gpio_remove(struct spi_device *spi)
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{
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struct pisosr_gpio *gpio = spi_get_drvdata(spi);
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gpiochip_remove(&gpio->chip);
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mutex_destroy(&gpio->lock);
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}
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static const struct spi_device_id pisosr_gpio_id_table[] = {
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{ "pisosr-gpio", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(spi, pisosr_gpio_id_table);
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static const struct of_device_id pisosr_gpio_of_match_table[] = {
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{ .compatible = "pisosr-gpio", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, pisosr_gpio_of_match_table);
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static struct spi_driver pisosr_gpio_driver = {
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.driver = {
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.name = "pisosr-gpio",
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.of_match_table = pisosr_gpio_of_match_table,
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},
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.probe = pisosr_gpio_probe,
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.remove = pisosr_gpio_remove,
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.id_table = pisosr_gpio_id_table,
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};
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module_spi_driver(pisosr_gpio_driver);
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MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
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MODULE_DESCRIPTION("SPI Compatible PISO Shift Register GPIO Driver");
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MODULE_LICENSE("GPL v2");
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