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