// SPDX-License-Identifier: GPL-2.0-only /* * GPIO driver for Exar XR17V35X chip * * Copyright (C) 2015 Sudip Mukherjee */ #include #include #include #include #include #include #include #include #include #include #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); unsigned int bit_value = value ? BIT(bit) : 0; /* * regmap_write_bits() forces value to be written when an external * pull up/down might otherwise indicate value was already set. */ regmap_write_bits(exar_gpio->regmap, addr, BIT(bit), bit_value); } 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 "); MODULE_LICENSE("GPL");