105 lines
2.3 KiB
C
105 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (C) 2006 Juergen Beisert, Pengutronix
|
|
* Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
|
|
* Copyright (C) 2009 Wolfram Sang, Pengutronix
|
|
*
|
|
* Check max730x.c for further details.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/spi/spi.h>
|
|
#include <linux/spi/max7301.h>
|
|
|
|
/* A write to the MAX7301 means one message with one transfer */
|
|
static int max7301_spi_write(struct device *dev, unsigned int reg,
|
|
unsigned int val)
|
|
{
|
|
struct spi_device *spi = to_spi_device(dev);
|
|
u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);
|
|
|
|
return spi_write_then_read(spi, &word, sizeof(word), NULL, 0);
|
|
}
|
|
|
|
/* A read from the MAX7301 means two transfers; here, one message each */
|
|
|
|
static int max7301_spi_read(struct device *dev, unsigned int reg)
|
|
{
|
|
int ret;
|
|
u16 word;
|
|
struct spi_device *spi = to_spi_device(dev);
|
|
|
|
word = 0x8000 | (reg << 8);
|
|
ret = spi_write_then_read(spi, &word, sizeof(word), &word,
|
|
sizeof(word));
|
|
if (ret)
|
|
return ret;
|
|
return word & 0xff;
|
|
}
|
|
|
|
static int max7301_probe(struct spi_device *spi)
|
|
{
|
|
struct max7301 *ts;
|
|
int ret;
|
|
|
|
/* bits_per_word cannot be configured in platform data */
|
|
spi->bits_per_word = 16;
|
|
ret = spi_setup(spi);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL);
|
|
if (!ts)
|
|
return -ENOMEM;
|
|
|
|
ts->read = max7301_spi_read;
|
|
ts->write = max7301_spi_write;
|
|
ts->dev = &spi->dev;
|
|
|
|
ret = __max730x_probe(ts);
|
|
return ret;
|
|
}
|
|
|
|
static int max7301_remove(struct spi_device *spi)
|
|
{
|
|
return __max730x_remove(&spi->dev);
|
|
}
|
|
|
|
static const struct spi_device_id max7301_id[] = {
|
|
{ "max7301", 0 },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(spi, max7301_id);
|
|
|
|
static struct spi_driver max7301_driver = {
|
|
.driver = {
|
|
.name = "max7301",
|
|
},
|
|
.probe = max7301_probe,
|
|
.remove = max7301_remove,
|
|
.id_table = max7301_id,
|
|
};
|
|
|
|
static int __init max7301_init(void)
|
|
{
|
|
return spi_register_driver(&max7301_driver);
|
|
}
|
|
/* register after spi postcore initcall and before
|
|
* subsys initcalls that may rely on these GPIOs
|
|
*/
|
|
subsys_initcall(max7301_init);
|
|
|
|
static void __exit max7301_exit(void)
|
|
{
|
|
spi_unregister_driver(&max7301_driver);
|
|
}
|
|
module_exit(max7301_exit);
|
|
|
|
MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
|
|
MODULE_LICENSE("GPL v2");
|
|
MODULE_DESCRIPTION("MAX7301 GPIO-Expander");
|