/*
* Generic PMC MSP71xx GPIO handling. These base gpio are controlled by two
* types of registers. The data register sets the output level when in output
* mode and when in input mode will contain the value at the input. The config
* register sets the various modes for each gpio.
*
* 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/spinlock.h>
#include <linux/io.h>
#define MSP71XX_CFG_OFFSET(gpio) (4 * (gpio))
#define CONF_MASK 0x0F
#define MSP71XX_GPIO_INPUT 0x01
#define MSP71XX_GPIO_OUTPUT 0x08
#define MSP71XX_GPIO_BASE 0x0B8400000L
#define to_msp71xx_gpio_chip(c) container_of(c, struct msp71xx_gpio_chip, chip)
static spinlock_t gpio_lock;
/*
* struct msp71xx_gpio_chip - container for gpio chip and registers
* @chip: chip structure for the specified gpio bank
* @data_reg: register for reading and writing the gpio pin value
* @config_reg: register to set the mode for the gpio pin bank
* @out_drive_reg: register to set the output drive mode for the gpio pin bank
*/
struct msp71xx_gpio_chip {
struct gpio_chip chip;
void __iomem *data_reg;
void __iomem *config_reg;
void __iomem *out_drive_reg;
};
/*
* msp71xx_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_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct msp71xx_gpio_chip *msp_chip = to_msp71xx_gpio_chip(chip);
return __raw_readl(msp_chip->data_reg) & (1 << offset);
}
/*
* msp71xx_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_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct msp71xx_gpio_chip *msp_chip = to_msp71xx_gpio_chip(chip);
unsigned long flags;
u32 data;
spin_lock_irqsave(&gpio_lock, flags);
data = __raw_readl(msp_chip->data_reg);
if (value)
data |= (1 << offset);
else
data &= ~(1 << offset);
__raw_writel(data, msp_chip->data_reg);
spin_unlock_irqrestore(&gpio_lock, flags);
}
/*
* msp71xx_set_gpio_mode() - declare the mode for a gpio
* @chip: chip structure which controls the specified gpio
* @offset: gpio whose value will be assigned
* @mode: desired configuration for the gpio (see datasheet)
*
* It will set the gpio pin config to the @mode value passed in.
*/
static int msp71xx_set_gpio_mode(struct gpio_chip *chip,
unsigned offset, int mode)
{
struct msp71xx_gpio_chip *msp_chip = to_msp71xx_gpio_chip(chip);
const unsigned bit_offset = MSP71XX_CFG_OFFSET(offset);
unsigned long flags;
u32 cfg;
spin_lock_irqsave(&gpio_lock, flags);
cfg = __raw_readl(msp_chip->config_reg);
cfg &= ~(CONF_MASK << bit_offset);
cfg |= (mode << bit_offset);
__raw_writel(cfg, msp_chip->config_reg);
spin_unlock_irqrestore(&gpio_lock, flags);
return 0;
}
/*
* msp71xx_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_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
msp71xx_gpio_set(chip, offset, value);
return msp71xx_set_gpio_mode(chip, offset, MSP71XX_GPIO_OUTPUT);
}
/*
* msp71xx_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_direction_input(struct gpio_chip *chip, unsigned offset)
{
return msp71xx_set_gpio_mode(chip, offset, MSP71XX_GPIO_INPUT);
}
/*
* msp71xx_set_output_drive() - declare the output drive for the gpio line
* @gpio: gpio pin whose output drive you wish to modify
* @value: zero for active drain 1 for open drain drive
*
* This call will set the output drive mode for the @gpio to output.
*/
int msp71xx_set_output_drive(unsigned gpio, int value)
{
unsigned long flags;
u32 data;
if (gpio > 15 || gpio < 0)
return -EINVAL;
spin_lock_irqsave(&gpio_lock, flags);
data = __raw_readl((void __iomem *)(MSP71XX_GPIO_BASE + 0x190));
if (value)
data |= (1 << gpio);
else
data &= ~(1 << gpio);
__raw_writel(data, (void __iomem *)(MSP71XX_GPIO_BASE + 0x190));
spin_unlock_irqrestore(&gpio_lock, flags);
return 0;
}
EXPORT_SYMBOL(msp71xx_set_output_drive);
#define MSP71XX_GPIO_BANK(name, dr, cr, base_gpio, num_gpio) \
{ \
.chip = { \
.label = name, \
.direction_input = msp71xx_direction_input, \
.direction_output = msp71xx_direction_output, \
.get = msp71xx_gpio_get, \
.set = msp71xx_gpio_set, \
.base = base_gpio, \
.ngpio = num_gpio \
}, \
.data_reg = (void __iomem *)(MSP71XX_GPIO_BASE + dr), \
.config_reg = (void __iomem *)(MSP71XX_GPIO_BASE + cr), \
.out_drive_reg = (void __iomem *)(MSP71XX_GPIO_BASE + 0x190), \
}
/*
* struct msp71xx_gpio_banks[] - container array of gpio banks
* @chip: chip structure for the specified gpio bank
* @data_reg: register for reading and writing the gpio pin value
* @config_reg: register to set the mode for the gpio pin bank
*
* This array structure defines the gpio banks for the PMC MIPS Processor.
* We specify the bank name, the data register, the config register, base
* starting gpio number, and the number of gpios exposed by the bank.
*/
static struct msp71xx_gpio_chip msp71xx_gpio_banks[] = {
MSP71XX_GPIO_BANK("GPIO_1_0", 0x170, 0x180, 0, 2),
MSP71XX_GPIO_BANK("GPIO_5_2", 0x174, 0x184, 2, 4),
MSP71XX_GPIO_BANK("GPIO_9_6", 0x178, 0x188, 6, 4),
MSP71XX_GPIO_BANK("GPIO_15_10", 0x17C, 0x18C, 10, 6),
};
void __init msp71xx_init_gpio(void)
{
int i;
spin_lock_init(&gpio_lock);
for (i = 0; i < ARRAY_SIZE(msp71xx_gpio_banks); i++)
gpiochip_add(&msp71xx_gpio_banks[i].chip);
}
