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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>
203 lines
5 KiB
C
203 lines
5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver
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*
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* Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
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* Copyright (C) 2010 Miguel Gaio <miguel.gaio@efixo.com>
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*/
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#include <linux/bitops.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/property.h>
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#include <linux/slab.h>
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#include <linux/spi/spi.h>
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#define GEN_74X164_NUMBER_GPIOS 8
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struct gen_74x164_chip {
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struct gpio_chip gpio_chip;
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struct mutex lock;
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struct gpio_desc *gpiod_oe;
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u32 registers;
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/*
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* Since the registers are chained, every byte sent will make
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* the previous byte shift to the next register in the
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* chain. Thus, the first byte sent will end up in the last
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* register at the end of the transfer. So, to have a logical
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* numbering, store the bytes in reverse order.
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*/
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u8 buffer[];
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};
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static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
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{
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return spi_write(to_spi_device(chip->gpio_chip.parent), chip->buffer,
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chip->registers);
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}
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static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
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{
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struct gen_74x164_chip *chip = gpiochip_get_data(gc);
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u8 bank = chip->registers - 1 - offset / 8;
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u8 pin = offset % 8;
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int ret;
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mutex_lock(&chip->lock);
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ret = (chip->buffer[bank] >> pin) & 0x1;
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mutex_unlock(&chip->lock);
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return ret;
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}
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static void gen_74x164_set_value(struct gpio_chip *gc,
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unsigned offset, int val)
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{
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struct gen_74x164_chip *chip = gpiochip_get_data(gc);
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u8 bank = chip->registers - 1 - offset / 8;
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u8 pin = offset % 8;
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mutex_lock(&chip->lock);
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if (val)
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chip->buffer[bank] |= (1 << pin);
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else
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chip->buffer[bank] &= ~(1 << pin);
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__gen_74x164_write_config(chip);
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mutex_unlock(&chip->lock);
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}
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static void gen_74x164_set_multiple(struct gpio_chip *gc, unsigned long *mask,
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unsigned long *bits)
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{
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struct gen_74x164_chip *chip = gpiochip_get_data(gc);
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unsigned long offset;
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unsigned long bankmask;
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size_t bank;
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unsigned long bitmask;
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mutex_lock(&chip->lock);
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for_each_set_clump8(offset, bankmask, mask, chip->registers * 8) {
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bank = chip->registers - 1 - offset / 8;
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bitmask = bitmap_get_value8(bits, offset) & bankmask;
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chip->buffer[bank] &= ~bankmask;
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chip->buffer[bank] |= bitmask;
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}
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__gen_74x164_write_config(chip);
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mutex_unlock(&chip->lock);
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}
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static int gen_74x164_direction_output(struct gpio_chip *gc,
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unsigned offset, int val)
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{
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gen_74x164_set_value(gc, offset, val);
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return 0;
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}
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static int gen_74x164_probe(struct spi_device *spi)
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{
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struct gen_74x164_chip *chip;
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u32 nregs;
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int ret;
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/*
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* bits_per_word cannot be configured in platform data
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*/
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spi->bits_per_word = 8;
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ret = spi_setup(spi);
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if (ret < 0)
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return ret;
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ret = device_property_read_u32(&spi->dev, "registers-number", &nregs);
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if (ret) {
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dev_err(&spi->dev, "Missing 'registers-number' property.\n");
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return -EINVAL;
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}
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chip = devm_kzalloc(&spi->dev, sizeof(*chip) + nregs, GFP_KERNEL);
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if (!chip)
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return -ENOMEM;
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chip->gpiod_oe = devm_gpiod_get_optional(&spi->dev, "enable",
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GPIOD_OUT_LOW);
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if (IS_ERR(chip->gpiod_oe))
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return PTR_ERR(chip->gpiod_oe);
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gpiod_set_value_cansleep(chip->gpiod_oe, 1);
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spi_set_drvdata(spi, chip);
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chip->gpio_chip.label = spi->modalias;
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chip->gpio_chip.direction_output = gen_74x164_direction_output;
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chip->gpio_chip.get = gen_74x164_get_value;
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chip->gpio_chip.set = gen_74x164_set_value;
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chip->gpio_chip.set_multiple = gen_74x164_set_multiple;
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chip->gpio_chip.base = -1;
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chip->registers = nregs;
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chip->gpio_chip.ngpio = GEN_74X164_NUMBER_GPIOS * chip->registers;
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chip->gpio_chip.can_sleep = true;
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chip->gpio_chip.parent = &spi->dev;
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chip->gpio_chip.owner = THIS_MODULE;
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mutex_init(&chip->lock);
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ret = __gen_74x164_write_config(chip);
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if (ret) {
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dev_err(&spi->dev, "Failed writing: %d\n", ret);
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goto exit_destroy;
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}
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ret = gpiochip_add_data(&chip->gpio_chip, chip);
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if (!ret)
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return 0;
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exit_destroy:
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mutex_destroy(&chip->lock);
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return ret;
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}
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static void gen_74x164_remove(struct spi_device *spi)
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{
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struct gen_74x164_chip *chip = spi_get_drvdata(spi);
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gpiod_set_value_cansleep(chip->gpiod_oe, 0);
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gpiochip_remove(&chip->gpio_chip);
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mutex_destroy(&chip->lock);
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}
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static const struct spi_device_id gen_74x164_spi_ids[] = {
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{ .name = "74hc595" },
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{ .name = "74lvc594" },
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{},
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};
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MODULE_DEVICE_TABLE(spi, gen_74x164_spi_ids);
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static const struct of_device_id gen_74x164_dt_ids[] = {
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{ .compatible = "fairchild,74hc595" },
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{ .compatible = "nxp,74lvc594" },
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{},
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};
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MODULE_DEVICE_TABLE(of, gen_74x164_dt_ids);
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static struct spi_driver gen_74x164_driver = {
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.driver = {
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.name = "74x164",
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.of_match_table = gen_74x164_dt_ids,
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},
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.probe = gen_74x164_probe,
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.remove = gen_74x164_remove,
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.id_table = gen_74x164_spi_ids,
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};
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module_spi_driver(gen_74x164_driver);
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MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
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MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
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MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
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MODULE_LICENSE("GPL v2");
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