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- /*
- * MC33880 high-side/low-side switch GPIO driver
- * Copyright (c) 2009 Intel Corporation
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
- /* Supports:
- * Freescale MC33880 high-side/low-side switch
- */
- #include <linux/init.h>
- #include <linux/mutex.h>
- #include <linux/spi/spi.h>
- #include <linux/spi/mc33880.h>
- #include <linux/gpio.h>
- #include <linux/slab.h>
- #include <linux/module.h>
- #define DRIVER_NAME "mc33880"
- /*
- * Pin configurations, see MAX7301 datasheet page 6
- */
- #define PIN_CONFIG_MASK 0x03
- #define PIN_CONFIG_IN_PULLUP 0x03
- #define PIN_CONFIG_IN_WO_PULLUP 0x02
- #define PIN_CONFIG_OUT 0x01
- #define PIN_NUMBER 8
- /*
- * Some registers must be read back to modify.
- * To save time we cache them here in memory
- */
- struct mc33880 {
- struct mutex lock; /* protect from simultaneous accesses */
- u8 port_config;
- struct gpio_chip chip;
- struct spi_device *spi;
- };
- static int mc33880_write_config(struct mc33880 *mc)
- {
- return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));
- }
- static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value)
- {
- if (value)
- mc->port_config |= 1 << offset;
- else
- mc->port_config &= ~(1 << offset);
- return mc33880_write_config(mc);
- }
- static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value)
- {
- struct mc33880 *mc = gpiochip_get_data(chip);
- mutex_lock(&mc->lock);
- __mc33880_set(mc, offset, value);
- mutex_unlock(&mc->lock);
- }
- static int mc33880_probe(struct spi_device *spi)
- {
- struct mc33880 *mc;
- struct mc33880_platform_data *pdata;
- int ret;
- pdata = dev_get_platdata(&spi->dev);
- if (!pdata || !pdata->base) {
- dev_dbg(&spi->dev, "incorrect or missing platform data\n");
- return -EINVAL;
- }
- /*
- * bits_per_word cannot be configured in platform data
- */
- spi->bits_per_word = 8;
- ret = spi_setup(spi);
- if (ret < 0)
- return ret;
- mc = devm_kzalloc(&spi->dev, sizeof(struct mc33880), GFP_KERNEL);
- if (!mc)
- return -ENOMEM;
- mutex_init(&mc->lock);
- spi_set_drvdata(spi, mc);
- mc->spi = spi;
- mc->chip.label = DRIVER_NAME,
- mc->chip.set = mc33880_set;
- mc->chip.base = pdata->base;
- mc->chip.ngpio = PIN_NUMBER;
- mc->chip.can_sleep = true;
- mc->chip.parent = &spi->dev;
- mc->chip.owner = THIS_MODULE;
- mc->port_config = 0x00;
- /* write twice, because during initialisation the first setting
- * is just for testing SPI communication, and the second is the
- * "real" configuration
- */
- ret = mc33880_write_config(mc);
- mc->port_config = 0x00;
- if (!ret)
- ret = mc33880_write_config(mc);
- if (ret) {
- dev_err(&spi->dev, "Failed writing to " DRIVER_NAME ": %d\n",
- ret);
- goto exit_destroy;
- }
- ret = gpiochip_add_data(&mc->chip, mc);
- if (ret)
- goto exit_destroy;
- return ret;
- exit_destroy:
- mutex_destroy(&mc->lock);
- return ret;
- }
- static int mc33880_remove(struct spi_device *spi)
- {
- struct mc33880 *mc;
- mc = spi_get_drvdata(spi);
- if (!mc)
- return -ENODEV;
- gpiochip_remove(&mc->chip);
- mutex_destroy(&mc->lock);
- return 0;
- }
- static struct spi_driver mc33880_driver = {
- .driver = {
- .name = DRIVER_NAME,
- },
- .probe = mc33880_probe,
- .remove = mc33880_remove,
- };
- static int __init mc33880_init(void)
- {
- return spi_register_driver(&mc33880_driver);
- }
- /* register after spi postcore initcall and before
- * subsys initcalls that may rely on these GPIOs
- */
- subsys_initcall(mc33880_init);
- static void __exit mc33880_exit(void)
- {
- spi_unregister_driver(&mc33880_driver);
- }
- module_exit(mc33880_exit);
- MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
- MODULE_LICENSE("GPL v2");
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