diff options
Diffstat (limited to 'drivers/gpio/gpio-mc33880.c')
| -rw-r--r-- | drivers/gpio/gpio-mc33880.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-mc33880.c b/drivers/gpio/gpio-mc33880.c new file mode 100644 index 000000000..a431604c9 --- /dev/null +++ b/drivers/gpio/gpio-mc33880.c @@ -0,0 +1,189 @@ +/* + * 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 = container_of(chip, struct mc33880, 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.dev = &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(&mc->chip); + 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, + .owner = THIS_MODULE, + }, + .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"); + |