173 lines
3.4 KiB
C
173 lines
3.4 KiB
C
// 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 void 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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gpiochip_remove(&mc->chip);
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mutex_destroy(&mc->lock);
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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 <info@mocean-labs.com>");
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MODULE_LICENSE("GPL v2");
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