mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 11:19:37 +00:00
![abdoulaye berthe](/assets/img/avatar_default.png)
Signed-off-by: abdoulaye berthe <berthe.ab@gmail.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
246 lines
5.9 KiB
C
246 lines
5.9 KiB
C
/**
|
|
* Copyright (C) 2006 Juergen Beisert, Pengutronix
|
|
* Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
|
|
* Copyright (C) 2009 Wolfram Sang, Pengutronix
|
|
*
|
|
* 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.
|
|
*
|
|
* The Maxim MAX7300/1 device is an I2C/SPI driven GPIO expander. There are
|
|
* 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more
|
|
* details
|
|
* Note:
|
|
* - DIN must be stable at the rising edge of clock.
|
|
* - when writing:
|
|
* - always clock in 16 clocks at once
|
|
* - at DIN: D15 first, D0 last
|
|
* - D0..D7 = databyte, D8..D14 = commandbyte
|
|
* - D15 = low -> write command
|
|
* - when reading
|
|
* - always clock in 16 clocks at once
|
|
* - at DIN: D15 first, D0 last
|
|
* - D0..D7 = dummy, D8..D14 = register address
|
|
* - D15 = high -> read command
|
|
* - raise CS and assert it again
|
|
* - always clock in 16 clocks at once
|
|
* - at DOUT: D15 first, D0 last
|
|
* - D0..D7 contains the data from the first cycle
|
|
*
|
|
* The driver exports a standard gpiochip interface
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/spi/max7301.h>
|
|
#include <linux/gpio.h>
|
|
#include <linux/slab.h>
|
|
|
|
/*
|
|
* 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 28
|
|
|
|
static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
|
|
{
|
|
struct max7301 *ts = container_of(chip, struct max7301, chip);
|
|
u8 *config;
|
|
u8 offset_bits, pin_config;
|
|
int ret;
|
|
|
|
/* First 4 pins are unused in the controller */
|
|
offset += 4;
|
|
offset_bits = (offset & 3) << 1;
|
|
|
|
config = &ts->port_config[offset >> 2];
|
|
|
|
if (ts->input_pullup_active & BIT(offset))
|
|
pin_config = PIN_CONFIG_IN_PULLUP;
|
|
else
|
|
pin_config = PIN_CONFIG_IN_WO_PULLUP;
|
|
|
|
mutex_lock(&ts->lock);
|
|
|
|
*config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
|
|
| (pin_config << offset_bits);
|
|
|
|
ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
|
|
|
|
mutex_unlock(&ts->lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int __max7301_set(struct max7301 *ts, unsigned offset, int value)
|
|
{
|
|
if (value) {
|
|
ts->out_level |= 1 << offset;
|
|
return ts->write(ts->dev, 0x20 + offset, 0x01);
|
|
} else {
|
|
ts->out_level &= ~(1 << offset);
|
|
return ts->write(ts->dev, 0x20 + offset, 0x00);
|
|
}
|
|
}
|
|
|
|
static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,
|
|
int value)
|
|
{
|
|
struct max7301 *ts = container_of(chip, struct max7301, chip);
|
|
u8 *config;
|
|
u8 offset_bits;
|
|
int ret;
|
|
|
|
/* First 4 pins are unused in the controller */
|
|
offset += 4;
|
|
offset_bits = (offset & 3) << 1;
|
|
|
|
config = &ts->port_config[offset >> 2];
|
|
|
|
mutex_lock(&ts->lock);
|
|
|
|
*config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
|
|
| (PIN_CONFIG_OUT << offset_bits);
|
|
|
|
ret = __max7301_set(ts, offset, value);
|
|
|
|
if (!ret)
|
|
ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
|
|
|
|
mutex_unlock(&ts->lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int max7301_get(struct gpio_chip *chip, unsigned offset)
|
|
{
|
|
struct max7301 *ts = container_of(chip, struct max7301, chip);
|
|
int config, level = -EINVAL;
|
|
|
|
/* First 4 pins are unused in the controller */
|
|
offset += 4;
|
|
|
|
mutex_lock(&ts->lock);
|
|
|
|
config = (ts->port_config[offset >> 2] >> ((offset & 3) << 1))
|
|
& PIN_CONFIG_MASK;
|
|
|
|
switch (config) {
|
|
case PIN_CONFIG_OUT:
|
|
/* Output: return cached level */
|
|
level = !!(ts->out_level & (1 << offset));
|
|
break;
|
|
case PIN_CONFIG_IN_WO_PULLUP:
|
|
case PIN_CONFIG_IN_PULLUP:
|
|
/* Input: read out */
|
|
level = ts->read(ts->dev, 0x20 + offset) & 0x01;
|
|
}
|
|
mutex_unlock(&ts->lock);
|
|
|
|
return level;
|
|
}
|
|
|
|
static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
|
|
{
|
|
struct max7301 *ts = container_of(chip, struct max7301, chip);
|
|
|
|
/* First 4 pins are unused in the controller */
|
|
offset += 4;
|
|
|
|
mutex_lock(&ts->lock);
|
|
|
|
__max7301_set(ts, offset, value);
|
|
|
|
mutex_unlock(&ts->lock);
|
|
}
|
|
|
|
int __max730x_probe(struct max7301 *ts)
|
|
{
|
|
struct device *dev = ts->dev;
|
|
struct max7301_platform_data *pdata;
|
|
int i, ret;
|
|
|
|
pdata = dev_get_platdata(dev);
|
|
|
|
mutex_init(&ts->lock);
|
|
dev_set_drvdata(dev, ts);
|
|
|
|
/* Power up the chip and disable IRQ output */
|
|
ts->write(dev, 0x04, 0x01);
|
|
|
|
if (pdata) {
|
|
ts->input_pullup_active = pdata->input_pullup_active;
|
|
ts->chip.base = pdata->base;
|
|
} else {
|
|
ts->chip.base = -1;
|
|
}
|
|
ts->chip.label = dev->driver->name;
|
|
|
|
ts->chip.direction_input = max7301_direction_input;
|
|
ts->chip.get = max7301_get;
|
|
ts->chip.direction_output = max7301_direction_output;
|
|
ts->chip.set = max7301_set;
|
|
|
|
ts->chip.ngpio = PIN_NUMBER;
|
|
ts->chip.can_sleep = true;
|
|
ts->chip.dev = dev;
|
|
ts->chip.owner = THIS_MODULE;
|
|
|
|
/*
|
|
* initialize pullups according to platform data and cache the
|
|
* register values for later use.
|
|
*/
|
|
for (i = 1; i < 8; i++) {
|
|
int j;
|
|
/*
|
|
* initialize port_config with "0xAA", which means
|
|
* input with internal pullup disabled. This is needed
|
|
* to avoid writing zeros (in the inner for loop),
|
|
* which is not allowed according to the datasheet.
|
|
*/
|
|
ts->port_config[i] = 0xAA;
|
|
for (j = 0; j < 4; j++) {
|
|
int offset = (i - 1) * 4 + j;
|
|
ret = max7301_direction_input(&ts->chip, offset);
|
|
if (ret)
|
|
goto exit_destroy;
|
|
}
|
|
}
|
|
|
|
ret = gpiochip_add(&ts->chip);
|
|
if (ret)
|
|
goto exit_destroy;
|
|
|
|
return ret;
|
|
|
|
exit_destroy:
|
|
mutex_destroy(&ts->lock);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__max730x_probe);
|
|
|
|
int __max730x_remove(struct device *dev)
|
|
{
|
|
struct max7301 *ts = dev_get_drvdata(dev);
|
|
|
|
if (ts == NULL)
|
|
return -ENODEV;
|
|
|
|
/* Power down the chip and disable IRQ output */
|
|
ts->write(dev, 0x04, 0x00);
|
|
gpiochip_remove(&ts->chip);
|
|
mutex_destroy(&ts->lock);
|
|
kfree(ts);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__max730x_remove);
|
|
|
|
MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
|
|
MODULE_LICENSE("GPL v2");
|
|
MODULE_DESCRIPTION("MAX730x GPIO-Expanders, generic parts");
|