/*
* GPIO controller in LSI ZEVIO SoCs.
*
* Author: Fabian Vogt <fabian@ritter-vogt.de>
*
* 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.
*/
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/io.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/slab.h>
#include <linux/gpio.h>
/*
* Memory layout:
* This chip has four gpio sections, each controls 8 GPIOs.
* Bit 0 in section 0 is GPIO 0, bit 2 in section 1 is GPIO 10.
* Disclaimer: Reverse engineered!
* For more information refer to:
* http://hackspire.unsads.com/wiki/index.php/Memory-mapped_I/O_ports#90000000_-_General_Purpose_I.2FO_.28GPIO.29
*
* 0x00-0x3F: Section 0
* +0x00: Masked interrupt status (read-only)
* +0x04: R: Interrupt status W: Reset interrupt status
* +0x08: R: Interrupt mask W: Mask interrupt
* +0x0C: W: Unmask interrupt (write-only)
* +0x10: Direction: I/O=1/0
* +0x14: Output
* +0x18: Input (read-only)
* +0x20: R: Level interrupt W: Set as level interrupt
* 0x40-0x7F: Section 1
* 0x80-0xBF: Section 2
* 0xC0-0xFF: Section 3
*/
#define ZEVIO_GPIO_SECTION_SIZE 0x40
/* Offsets to various registers */
#define ZEVIO_GPIO_INT_MASKED_STATUS 0x00
#define ZEVIO_GPIO_INT_STATUS 0x04
#define ZEVIO_GPIO_INT_UNMASK 0x08
#define ZEVIO_GPIO_INT_MASK 0x0C
#define ZEVIO_GPIO_DIRECTION 0x10
#define ZEVIO_GPIO_OUTPUT 0x14
#define ZEVIO_GPIO_INPUT 0x18
#define ZEVIO_GPIO_INT_STICKY 0x20
#define to_zevio_gpio(chip) container_of(to_of_mm_gpio_chip(chip), \
struct zevio_gpio, chip)
/* Bit number of GPIO in its section */
#define ZEVIO_GPIO_BIT(gpio) (gpio&7)
struct zevio_gpio {
spinlock_t lock;
struct of_mm_gpio_chip chip;
};
static inline u32 zevio_gpio_port_get(struct zevio_gpio *c, unsigned pin,
unsigned port_offset)
{
unsigned section_offset = ((pin >> 3) & 3)*ZEVIO_GPIO_SECTION_SIZE;
return readl(IOMEM(c->chip.regs + section_offset + port_offset));
}
static inline void zevio_gpio_port_set(struct zevio_gpio *c, unsigned pin,
unsigned port_offset, u32 val)
{
unsigned section_offset = ((pin >> 3) & 3)*ZEVIO_GPIO_SECTION_SIZE;
writel(val, IOMEM(c->chip.regs + section_offset + port_offset));
}
/* Functions for struct gpio_chip */
static int zevio_gpio_get(struct gpio_chip *chip, unsigned pin)
{
struct zevio_gpio *controller = to_zevio_gpio(chip);
u32 val, dir;
spin_lock(&controller->lock);
dir = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION);
if (dir & BIT(ZEVIO_GPIO_BIT(pin)))
val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_INPUT);
else
val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT);
spin_unlock(&controller->lock);
return (val >> ZEVIO_GPIO_BIT(pin)) & 0x1;
}
static void zevio_gpio_set(struct gpio_chip *chip, unsigned pin, int value)
{
struct zevio_gpio *controller = to_zevio_gpio(chip);
u32 val;
spin_lock(&controller->lock);
val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT);
if (value)
val |= BIT(ZEVIO_GPIO_BIT(pin));
else
val &= ~BIT(ZEVIO_GPIO_BIT(pin));
zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_OUTPUT, val);
spin_unlock(&controller->lock);
}
static int zevio_gpio_direction_input(struct gpio_chip *chip, unsigned pin)
{
struct zevio_gpio *controller = to_zevio_gpio(chip);
u32 val;
spin_lock(&controller->lock);
val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION);
val |= BIT(ZEVIO_GPIO_BIT(pin));
zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_DIRECTION, val);
spin_unlock(&controller->lock);
return 0;
}
static int zevio_gpio_direction_output(struct gpio_chip *chip,
unsigned pin, int value)
{
struct zevio_gpio *controller = to_zevio_gpio(chip);
u32 val;
spin_lock(&controller->lock);
val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT);
if (value)
val |= BIT(ZEVIO_GPIO_BIT(pin));
else
val &= ~BIT(ZEVIO_GPIO_BIT(pin));
zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_OUTPUT, val);
val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION);
val &= ~BIT(ZEVIO_GPIO_BIT(pin));
zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_DIRECTION, val);
spin_unlock(&controller->lock);
return 0;
}
static int zevio_gpio_to_irq(struct gpio_chip *chip, unsigned pin)
{
/*
* TODO: Implement IRQs.
* Not implemented yet due to weird lockups
*/
return -ENXIO;
}
static struct gpio_chip zevio_gpio_chip = {
.direction_input = zevio_gpio_direction_input,
.direction_output = zevio_gpio_direction_output,
.set = zevio_gpio_set,
.get = zevio_gpio_get,
.to_irq = zevio_gpio_to_irq,
.base = 0,
.owner = THIS_MODULE,
.ngpio = 32,
.of_gpio_n_cells = 2,
};
/* Initialization */
static int zevio_gpio_probe(struct platform_device *pdev)
{
struct zevio_gpio *controller;
int status, i;
controller = devm_kzalloc(&pdev->dev, sizeof(*controller), GFP_KERNEL);
if (!controller)
return -ENOMEM;
platform_set_drvdata(pdev, controller);
/* Copy our reference */
controller->chip.gc = zevio_gpio_chip;
controller->chip.gc.parent = &pdev->dev;
status = of_mm_gpiochip_add(pdev->dev.of_node, &(controller->chip));
if (status) {
dev_err(&pdev->dev, "failed to add gpiochip: %d\n", status);
return status;
}
spin_lock_init(&controller->lock);
/* Disable interrupts, they only cause errors */
for (i = 0; i < controller->chip.gc.ngpio; i += 8)
zevio_gpio_port_set(controller, i, ZEVIO_GPIO_INT_MASK, 0xFF);
dev_dbg(controller->chip.gc.parent, "ZEVIO GPIO controller set up!\n");
return 0;
}
static int zevio_gpio_remove(struct platform_device *pdev)
{
struct zevio_gpio *controller = platform_get_drvdata(pdev);
of_mm_gpiochip_remove(&controller->chip);
return 0;
}
static const struct of_device_id zevio_gpio_of_match[] = {
{ .compatible = "lsi,zevio-gpio", },
{ },
};
MODULE_DEVICE_TABLE(of, zevio_gpio_of_match);
static struct platform_driver zevio_gpio_driver = {
.driver = {
.name = "gpio-zevio",
.of_match_table = zevio_gpio_of_match,
},
.probe = zevio_gpio_probe,
.remove = zevio_gpio_remove,
};
module_platform_driver(zevio_gpio_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Fabian Vogt <fabian@ritter-vogt.de>");
MODULE_DESCRIPTION("LSI ZEVIO SoC GPIO driver");
