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// SPDX-License-Identifier: GPL-2.0-only
/*
* GPIO driver for Exar XR17V35X chip
*
* Copyright (C) 2015 Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
*/
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/gpio/driver.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#define EXAR_OFFSET_MPIOLVL_LO 0x90
#define EXAR_OFFSET_MPIOSEL_LO 0x93
#define EXAR_OFFSET_MPIOLVL_HI 0x96
#define EXAR_OFFSET_MPIOSEL_HI 0x99
/*
* The Device Configuration and UART Configuration Registers
* for each UART channel take 1KB of memory address space.
*/
#define EXAR_UART_CHANNEL_SIZE 0x400
#define DRIVER_NAME "gpio_exar"
static DEFINE_IDA(ida_index);
struct exar_gpio_chip {
struct gpio_chip gpio_chip;
struct regmap *regmap;
int index;
char name[20];
unsigned int first_pin;
/*
* The offset to the cascaded device's (if existing)
* Device Configuration Registers.
*/
unsigned int cascaded_offset;
};
static unsigned int
exar_offset_to_sel_addr(struct exar_gpio_chip *exar_gpio, unsigned int offset)
{
unsigned int pin = exar_gpio->first_pin + (offset % 16);
unsigned int cascaded = offset / 16;
unsigned int addr = pin / 8 ? EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
return addr + (cascaded ? exar_gpio->cascaded_offset : 0);
}
static unsigned int
exar_offset_to_lvl_addr(struct exar_gpio_chip *exar_gpio, unsigned int offset)
{
unsigned int pin = exar_gpio->first_pin + (offset % 16);
unsigned int cascaded = offset / 16;
unsigned int addr = pin / 8 ? EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
return addr + (cascaded ? exar_gpio->cascaded_offset : 0);
}
static unsigned int
exar_offset_to_bit(struct exar_gpio_chip *exar_gpio, unsigned int offset)
{
unsigned int pin = exar_gpio->first_pin + (offset % 16);
return pin % 8;
}
static int exar_get_direction(struct gpio_chip *chip, unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = exar_offset_to_sel_addr(exar_gpio, offset);
unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
if (regmap_test_bits(exar_gpio->regmap, addr, BIT(bit)))
return GPIO_LINE_DIRECTION_IN;
return GPIO_LINE_DIRECTION_OUT;
}
static int exar_get_value(struct gpio_chip *chip, unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = exar_offset_to_lvl_addr(exar_gpio, offset);
unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
return !!(regmap_test_bits(exar_gpio->regmap, addr, BIT(bit)));
}
static void exar_set_value(struct gpio_chip *chip, unsigned int offset,
int value)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = exar_offset_to_lvl_addr(exar_gpio, offset);
unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
if (value)
regmap_set_bits(exar_gpio->regmap, addr, BIT(bit));
else
regmap_clear_bits(exar_gpio->regmap, addr, BIT(bit));
}
static int exar_direction_output(struct gpio_chip *chip, unsigned int offset,
int value)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = exar_offset_to_sel_addr(exar_gpio, offset);
unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
exar_set_value(chip, offset, value);
regmap_clear_bits(exar_gpio->regmap, addr, BIT(bit));
return 0;
}
static int exar_direction_input(struct gpio_chip *chip, unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = exar_offset_to_sel_addr(exar_gpio, offset);
unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
regmap_set_bits(exar_gpio->regmap, addr, BIT(bit));
return 0;
}
static void exar_devm_ida_free(void *data)
{
struct exar_gpio_chip *exar_gpio = data;
ida_free(&ida_index, exar_gpio->index);
}
static const struct regmap_config exar_regmap_config = {
.name = "exar-gpio",
.reg_bits = 16,
.val_bits = 8,
.io_port = true,
};
static int gpio_exar_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct pci_dev *pcidev = to_pci_dev(dev->parent);
struct exar_gpio_chip *exar_gpio;
u32 first_pin, ngpios;
void __iomem *p;
int index, ret;
/*
* The UART driver must have mapped region 0 prior to registering this
* device - use it.
*/
p = pcim_iomap_table(pcidev)[0];
if (!p)
return -ENOMEM;
ret = device_property_read_u32(dev, "exar,first-pin", &first_pin);
if (ret)
return ret;
ret = device_property_read_u32(dev, "ngpios", &ngpios);
if (ret)
return ret;
exar_gpio = devm_kzalloc(dev, sizeof(*exar_gpio), GFP_KERNEL);
if (!exar_gpio)
return -ENOMEM;
/*
* If cascaded, secondary xr17v354 or xr17v358 have the same amount
* of MPIOs as their primaries and the last 4 bits of the primary's
* PCI Device ID is the number of its UART channels.
*/
if (pcidev->device & GENMASK(15, 12)) {
ngpios += ngpios;
exar_gpio->cascaded_offset = (pcidev->device & GENMASK(3, 0)) *
EXAR_UART_CHANNEL_SIZE;
}
/*
* We don't need to check the return values of mmio regmap operations (unless
* the regmap has a clock attached which is not the case here).
*/
exar_gpio->regmap = devm_regmap_init_mmio(dev, p, &exar_regmap_config);
if (IS_ERR(exar_gpio->regmap))
return PTR_ERR(exar_gpio->regmap);
index = ida_alloc(&ida_index, GFP_KERNEL);
if (index < 0)
return index;
ret = devm_add_action_or_reset(dev, exar_devm_ida_free, exar_gpio);
if (ret)
return ret;
sprintf(exar_gpio->name, "exar_gpio%d", index);
exar_gpio->gpio_chip.label = exar_gpio->name;
exar_gpio->gpio_chip.parent = dev;
exar_gpio->gpio_chip.direction_output = exar_direction_output;
exar_gpio->gpio_chip.direction_input = exar_direction_input;
exar_gpio->gpio_chip.get_direction = exar_get_direction;
exar_gpio->gpio_chip.get = exar_get_value;
exar_gpio->gpio_chip.set = exar_set_value;
exar_gpio->gpio_chip.base = -1;
exar_gpio->gpio_chip.ngpio = ngpios;
exar_gpio->index = index;
exar_gpio->first_pin = first_pin;
ret = devm_gpiochip_add_data(dev, &exar_gpio->gpio_chip, exar_gpio);
if (ret)
return ret;
return 0;
}
static struct platform_driver gpio_exar_driver = {
.probe = gpio_exar_probe,
.driver = {
.name = DRIVER_NAME,
},
};
module_platform_driver(gpio_exar_driver);
MODULE_ALIAS("platform:" DRIVER_NAME);
MODULE_DESCRIPTION("Exar GPIO driver");
MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>");
MODULE_LICENSE("GPL");
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