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/*
* Generic PMC MSP71xx EXTENDED (EXD) GPIO handling. The extended gpio is
* a set of hardware registers that have no need for explicit locking as
* it is handled by unique method of writing individual set/clr bits.
*
* 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.
*
* @author Patrick Glass <patrickglass@gmail.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/gpio.h>
#include <linux/io.h>
#define MSP71XX_DATA_OFFSET(gpio) (2 * (gpio))
#define MSP71XX_READ_OFFSET(gpio) (MSP71XX_DATA_OFFSET(gpio) + 1)
#define MSP71XX_CFG_OUT_OFFSET(gpio) (MSP71XX_DATA_OFFSET(gpio) + 16)
#define MSP71XX_CFG_IN_OFFSET(gpio) (MSP71XX_CFG_OUT_OFFSET(gpio) + 1)
#define MSP71XX_EXD_GPIO_BASE 0x0BC000000L
#define to_msp71xx_exd_gpio_chip(c) \
container_of(c, struct msp71xx_exd_gpio_chip, chip)
/*
* struct msp71xx_exd_gpio_chip - container for gpio chip and registers
* @chip: chip structure for the specified gpio bank
* @reg: register for control and data of gpio pin
*/
struct msp71xx_exd_gpio_chip {
struct gpio_chip chip;
void __iomem *reg;
};
/*
* msp71xx_exd_gpio_get() - return the chip's gpio value
* @chip: chip structure which controls the specified gpio
* @offset: gpio whose value will be returned
*
* It will return 0 if gpio value is low and other if high.
*/
static int msp71xx_exd_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct msp71xx_exd_gpio_chip *msp71xx_chip =
to_msp71xx_exd_gpio_chip(chip);
const unsigned bit = MSP71XX_READ_OFFSET(offset);
return __raw_readl(msp71xx_chip->reg) & (1 << bit);
}
/*
* msp71xx_exd_gpio_set() - set the output value for the gpio
* @chip: chip structure who controls the specified gpio
* @offset: gpio whose value will be assigned
* @value: logic level to assign to the gpio initially
*
* This will set the gpio bit specified to the desired value. It will set the
* gpio pin low if value is 0 otherwise it will be high.
*/
static void msp71xx_exd_gpio_set(struct gpio_chip *chip,
unsigned offset, int value)
{
struct msp71xx_exd_gpio_chip *msp71xx_chip =
to_msp71xx_exd_gpio_chip(chip);
const unsigned bit = MSP71XX_DATA_OFFSET(offset);
__raw_writel(1 << (bit + (value ? 1 : 0)), msp71xx_chip->reg);
}
/*
* msp71xx_exd_direction_output() - declare the direction mode for a gpio
* @chip: chip structure which controls the specified gpio
* @offset: gpio whose value will be assigned
* @value: logic level to assign to the gpio initially
*
* This call will set the mode for the @gpio to output. It will set the
* gpio pin low if value is 0 otherwise it will be high.
*/
static int msp71xx_exd_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
struct msp71xx_exd_gpio_chip *msp71xx_chip =
to_msp71xx_exd_gpio_chip(chip);
msp71xx_exd_gpio_set(chip, offset, value);
__raw_writel(1 << MSP71XX_CFG_OUT_OFFSET(offset), msp71xx_chip->reg);
return 0;
}
/*
* msp71xx_exd_direction_input() - declare the direction mode for a gpio
* @chip: chip structure which controls the specified gpio
* @offset: gpio whose to which the value will be assigned
*
* This call will set the mode for the @gpio to input.
*/
static int msp71xx_exd_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct msp71xx_exd_gpio_chip *msp71xx_chip =
to_msp71xx_exd_gpio_chip(chip);
__raw_writel(1 << MSP71XX_CFG_IN_OFFSET(offset), msp71xx_chip->reg);
return 0;
}
#define MSP71XX_EXD_GPIO_BANK(name, exd_reg, base_gpio, num_gpio) \
{ \
.chip = { \
.label = name, \
.direction_input = msp71xx_exd_direction_input, \
.direction_output = msp71xx_exd_direction_output, \
.get = msp71xx_exd_gpio_get, \
.set = msp71xx_exd_gpio_set, \
.base = base_gpio, \
.ngpio = num_gpio, \
}, \
.reg = (void __iomem *)(MSP71XX_EXD_GPIO_BASE + exd_reg), \
}
/*
* struct msp71xx_exd_gpio_banks[] - container array of gpio banks
* @chip: chip structure for the specified gpio bank
* @reg: register for reading and writing the gpio pin value
*
* This array structure defines the extended gpio banks for the
* PMC MIPS Processor. We specify the bank name, the data/config
* register,the base starting gpio number, and the number of
* gpios exposed by the bank of gpios.
*/
static struct msp71xx_exd_gpio_chip msp71xx_exd_gpio_banks[] = {
MSP71XX_EXD_GPIO_BANK("GPIO_23_16", 0x188, 16, 8),
MSP71XX_EXD_GPIO_BANK("GPIO_27_24", 0x18C, 24, 4),
};
void __init msp71xx_init_gpio_extended(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(msp71xx_exd_gpio_banks); i++)
gpiochip_add(&msp71xx_exd_gpio_banks[i].chip);
}
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