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/*
* Xilinx Zynq GPIO device driver
*
* Copyright (C) 2015 DAVE Embedded Systems <devel@dave.eu>
*
* Most of code taken from linux kernel driver (linux/drivers/gpio/gpio-zynq.c)
* Copyright (C) 2009 - 2014 Xilinx, Inc.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/gpio.h>
#include <asm/io.h>
#include <asm/errno.h>
/**
* zynq_gpio_get_bank_pin - Get the bank number and pin number within that bank
* for a given pin in the GPIO device
* @pin_num: gpio pin number within the device
* @bank_num: an output parameter used to return the bank number of the gpio
* pin
* @bank_pin_num: an output parameter used to return pin number within a bank
* for the given gpio pin
*
* Returns the bank number and pin offset within the bank.
*/
static inline void zynq_gpio_get_bank_pin(unsigned int pin_num,
unsigned int *bank_num,
unsigned int *bank_pin_num)
{
switch (pin_num) {
case ZYNQ_GPIO_BANK0_PIN_MIN ... ZYNQ_GPIO_BANK0_PIN_MAX:
*bank_num = 0;
*bank_pin_num = pin_num;
break;
case ZYNQ_GPIO_BANK1_PIN_MIN ... ZYNQ_GPIO_BANK1_PIN_MAX:
*bank_num = 1;
*bank_pin_num = pin_num - ZYNQ_GPIO_BANK1_PIN_MIN;
break;
case ZYNQ_GPIO_BANK2_PIN_MIN ... ZYNQ_GPIO_BANK2_PIN_MAX:
*bank_num = 2;
*bank_pin_num = pin_num - ZYNQ_GPIO_BANK2_PIN_MIN;
break;
case ZYNQ_GPIO_BANK3_PIN_MIN ... ZYNQ_GPIO_BANK3_PIN_MAX:
*bank_num = 3;
*bank_pin_num = pin_num - ZYNQ_GPIO_BANK3_PIN_MIN;
break;
default:
printf("invalid GPIO pin number: %u\n", pin_num);
*bank_num = 0;
*bank_pin_num = 0;
break;
}
}
int gpio_is_valid(unsigned gpio)
{
return (gpio >= 0) && (gpio < ZYNQ_GPIO_NR_GPIOS);
}
static int check_gpio(unsigned gpio)
{
if (!gpio_is_valid(gpio)) {
printf("ERROR : check_gpio: invalid GPIO %d\n", gpio);
return -1;
}
return 0;
}
/**
* gpio_get_value - Get the state of the specified pin of GPIO device
* @gpio: gpio pin number within the device
*
* This function reads the state of the specified pin of the GPIO device.
*
* Return: 0 if the pin is low, 1 if pin is high.
*/
int gpio_get_value(unsigned gpio)
{
u32 data;
unsigned int bank_num, bank_pin_num;
if (check_gpio(gpio) < 0)
return -1;
zynq_gpio_get_bank_pin(gpio, &bank_num, &bank_pin_num);
data = readl(ZYNQ_GPIO_BASE_ADDRESS +
ZYNQ_GPIO_DATA_RO_OFFSET(bank_num));
return (data >> bank_pin_num) & 1;
}
/**
* gpio_set_value - Modify the value of the pin with specified value
* @gpio: gpio pin number within the device
* @value: value used to modify the value of the specified pin
*
* This function calculates the register offset (i.e to lower 16 bits or
* upper 16 bits) based on the given pin number and sets the value of a
* gpio pin to the specified value. The value is either 0 or non-zero.
*/
int gpio_set_value(unsigned gpio, int value)
{
unsigned int reg_offset, bank_num, bank_pin_num;
if (check_gpio(gpio) < 0)
return -1;
zynq_gpio_get_bank_pin(gpio, &bank_num, &bank_pin_num);
if (bank_pin_num >= ZYNQ_GPIO_MID_PIN_NUM) {
/* only 16 data bits in bit maskable reg */
bank_pin_num -= ZYNQ_GPIO_MID_PIN_NUM;
reg_offset = ZYNQ_GPIO_DATA_MSW_OFFSET(bank_num);
} else {
reg_offset = ZYNQ_GPIO_DATA_LSW_OFFSET(bank_num);
}
/*
* get the 32 bit value to be written to the mask/data register where
* the upper 16 bits is the mask and lower 16 bits is the data
*/
value = !!value;
value = ~(1 << (bank_pin_num + ZYNQ_GPIO_MID_PIN_NUM)) &
((value << bank_pin_num) | ZYNQ_GPIO_UPPER_MASK);
writel(value, ZYNQ_GPIO_BASE_ADDRESS + reg_offset);
return 0;
}
/**
* gpio_direction_input - Set the direction of the specified GPIO pin as input
* @gpio: gpio pin number within the device
*
* This function uses the read-modify-write sequence to set the direction of
* the gpio pin as input.
*
* Return: -1 if invalid gpio specified, 0 if successul
*/
int gpio_direction_input(unsigned gpio)
{
u32 reg;
unsigned int bank_num, bank_pin_num;
if (check_gpio(gpio) < 0)
return -1;
zynq_gpio_get_bank_pin(gpio, &bank_num, &bank_pin_num);
/* bank 0 pins 7 and 8 are special and cannot be used as inputs */
if (bank_num == 0 && (bank_pin_num == 7 || bank_pin_num == 8))
return -1;
/* clear the bit in direction mode reg to set the pin as input */
reg = readl(ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
reg &= ~BIT(bank_pin_num);
writel(reg, ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
return 0;
}
/**
* gpio_direction_output - Set the direction of the specified GPIO pin as output
* @gpio: gpio pin number within the device
* @value: value to be written to specified pin
*
* This function sets the direction of specified GPIO pin as output, configures
* the Output Enable register for the pin and uses zynq_gpio_set to set
* the value of the pin to the value specified.
*
* Return: 0 always
*/
int gpio_direction_output(unsigned gpio, int value)
{
u32 reg;
unsigned int bank_num, bank_pin_num;
if (check_gpio(gpio) < 0)
return -1;
zynq_gpio_get_bank_pin(gpio, &bank_num, &bank_pin_num);
/* set the GPIO pin as output */
reg = readl(ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
reg |= BIT(bank_pin_num);
writel(reg, ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
/* configure the output enable reg for the pin */
reg = readl(ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_OUTEN_OFFSET(bank_num));
reg |= BIT(bank_pin_num);
writel(reg, ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_OUTEN_OFFSET(bank_num));
/* set the state of the pin */
gpio_set_value(gpio, value);
return 0;
}
/**
* Request a gpio before using it.
*
* NOTE: Argument 'label' is unused.
*/
int gpio_request(unsigned gpio, const char *label)
{
if (check_gpio(gpio) < 0)
return -1;
return 0;
}
/**
* Reset and free the gpio after using it.
*/
int gpio_free(unsigned gpio)
{
return 0;
}
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