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176 lines
3.5 KiB
176 lines
3.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* MC33880 high-side/low-side switch GPIO driver |
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* Copyright (c) 2009 Intel Corporation |
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*/ |
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/* Supports: |
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* Freescale MC33880 high-side/low-side switch |
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*/ |
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#include <linux/init.h> |
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#include <linux/mutex.h> |
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#include <linux/spi/spi.h> |
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#include <linux/spi/mc33880.h> |
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#include <linux/gpio/driver.h> |
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#include <linux/slab.h> |
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#include <linux/module.h> |
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#define DRIVER_NAME "mc33880" |
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/* |
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* Pin configurations, see MAX7301 datasheet page 6 |
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*/ |
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#define PIN_CONFIG_MASK 0x03 |
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#define PIN_CONFIG_IN_PULLUP 0x03 |
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#define PIN_CONFIG_IN_WO_PULLUP 0x02 |
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#define PIN_CONFIG_OUT 0x01 |
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#define PIN_NUMBER 8 |
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/* |
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* Some registers must be read back to modify. |
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* To save time we cache them here in memory |
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*/ |
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struct mc33880 { |
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struct mutex lock; /* protect from simultaneous accesses */ |
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u8 port_config; |
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struct gpio_chip chip; |
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struct spi_device *spi; |
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}; |
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static int mc33880_write_config(struct mc33880 *mc) |
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{ |
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return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config)); |
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} |
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static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value) |
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{ |
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if (value) |
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mc->port_config |= 1 << offset; |
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else |
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mc->port_config &= ~(1 << offset); |
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return mc33880_write_config(mc); |
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} |
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static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value) |
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{ |
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struct mc33880 *mc = gpiochip_get_data(chip); |
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mutex_lock(&mc->lock); |
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__mc33880_set(mc, offset, value); |
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mutex_unlock(&mc->lock); |
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} |
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static int mc33880_probe(struct spi_device *spi) |
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{ |
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struct mc33880 *mc; |
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struct mc33880_platform_data *pdata; |
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int ret; |
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pdata = dev_get_platdata(&spi->dev); |
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if (!pdata || !pdata->base) { |
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dev_dbg(&spi->dev, "incorrect or missing platform data\n"); |
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return -EINVAL; |
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} |
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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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mc = devm_kzalloc(&spi->dev, sizeof(struct mc33880), GFP_KERNEL); |
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if (!mc) |
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return -ENOMEM; |
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mutex_init(&mc->lock); |
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spi_set_drvdata(spi, mc); |
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mc->spi = spi; |
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mc->chip.label = DRIVER_NAME, |
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mc->chip.set = mc33880_set; |
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mc->chip.base = pdata->base; |
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mc->chip.ngpio = PIN_NUMBER; |
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mc->chip.can_sleep = true; |
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mc->chip.parent = &spi->dev; |
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mc->chip.owner = THIS_MODULE; |
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mc->port_config = 0x00; |
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/* write twice, because during initialisation the first setting |
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* is just for testing SPI communication, and the second is the |
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* "real" configuration |
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*/ |
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ret = mc33880_write_config(mc); |
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mc->port_config = 0x00; |
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if (!ret) |
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ret = mc33880_write_config(mc); |
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if (ret) { |
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dev_err(&spi->dev, "Failed writing to " DRIVER_NAME ": %d\n", |
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ret); |
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goto exit_destroy; |
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} |
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ret = gpiochip_add_data(&mc->chip, mc); |
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if (ret) |
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goto exit_destroy; |
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return ret; |
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exit_destroy: |
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mutex_destroy(&mc->lock); |
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return ret; |
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} |
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static int mc33880_remove(struct spi_device *spi) |
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{ |
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struct mc33880 *mc; |
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mc = spi_get_drvdata(spi); |
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if (!mc) |
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return -ENODEV; |
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gpiochip_remove(&mc->chip); |
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mutex_destroy(&mc->lock); |
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return 0; |
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} |
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static struct spi_driver mc33880_driver = { |
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.driver = { |
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.name = DRIVER_NAME, |
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}, |
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.probe = mc33880_probe, |
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.remove = mc33880_remove, |
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}; |
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static int __init mc33880_init(void) |
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{ |
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return spi_register_driver(&mc33880_driver); |
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} |
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/* register after spi postcore initcall and before |
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* subsys initcalls that may rely on these GPIOs |
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*/ |
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subsys_initcall(mc33880_init); |
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static void __exit mc33880_exit(void) |
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{ |
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spi_unregister_driver(&mc33880_driver); |
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} |
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module_exit(mc33880_exit); |
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MODULE_AUTHOR("Mocean Laboratories <[email protected]>"); |
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MODULE_LICENSE("GPL v2"); |
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