1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * GPIO driver for Exar XR17V35X chip 4 * 5 * Copyright (C) 2015 Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> 6 */ 7 8 #include <linux/bitops.h> 9 #include <linux/device.h> 10 #include <linux/gpio/driver.h> 11 #include <linux/idr.h> 12 #include <linux/init.h> 13 #include <linux/kernel.h> 14 #include <linux/module.h> 15 #include <linux/pci.h> 16 #include <linux/platform_device.h> 17 #include <linux/regmap.h> 18 19 #define EXAR_OFFSET_MPIOLVL_LO 0x90 20 #define EXAR_OFFSET_MPIOSEL_LO 0x93 21 #define EXAR_OFFSET_MPIOLVL_HI 0x96 22 #define EXAR_OFFSET_MPIOSEL_HI 0x99 23 24 /* 25 * The Device Configuration and UART Configuration Registers 26 * for each UART channel take 1KB of memory address space. 27 */ 28 #define EXAR_UART_CHANNEL_SIZE 0x400 29 30 #define DRIVER_NAME "gpio_exar" 31 32 static DEFINE_IDA(ida_index); 33 34 struct exar_gpio_chip { 35 struct gpio_chip gpio_chip; 36 struct regmap *regmap; 37 int index; 38 char name[20]; 39 unsigned int first_pin; 40 /* 41 * The offset to the cascaded device's (if existing) 42 * Device Configuration Registers. 43 */ 44 unsigned int cascaded_offset; 45 }; 46 47 static unsigned int 48 exar_offset_to_sel_addr(struct exar_gpio_chip *exar_gpio, unsigned int offset) 49 { 50 unsigned int pin = exar_gpio->first_pin + (offset % 16); 51 unsigned int cascaded = offset / 16; 52 unsigned int addr = pin / 8 ? EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO; 53 54 return addr + (cascaded ? exar_gpio->cascaded_offset : 0); 55 } 56 57 static unsigned int 58 exar_offset_to_lvl_addr(struct exar_gpio_chip *exar_gpio, unsigned int offset) 59 { 60 unsigned int pin = exar_gpio->first_pin + (offset % 16); 61 unsigned int cascaded = offset / 16; 62 unsigned int addr = pin / 8 ? EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO; 63 64 return addr + (cascaded ? exar_gpio->cascaded_offset : 0); 65 } 66 67 static unsigned int 68 exar_offset_to_bit(struct exar_gpio_chip *exar_gpio, unsigned int offset) 69 { 70 unsigned int pin = exar_gpio->first_pin + (offset % 16); 71 72 return pin % 8; 73 } 74 75 static int exar_get_direction(struct gpio_chip *chip, unsigned int offset) 76 { 77 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 78 unsigned int addr = exar_offset_to_sel_addr(exar_gpio, offset); 79 unsigned int bit = exar_offset_to_bit(exar_gpio, offset); 80 81 if (regmap_test_bits(exar_gpio->regmap, addr, BIT(bit))) 82 return GPIO_LINE_DIRECTION_IN; 83 84 return GPIO_LINE_DIRECTION_OUT; 85 } 86 87 static int exar_get_value(struct gpio_chip *chip, unsigned int offset) 88 { 89 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 90 unsigned int addr = exar_offset_to_lvl_addr(exar_gpio, offset); 91 unsigned int bit = exar_offset_to_bit(exar_gpio, offset); 92 93 return !!(regmap_test_bits(exar_gpio->regmap, addr, BIT(bit))); 94 } 95 96 static void exar_set_value(struct gpio_chip *chip, unsigned int offset, 97 int value) 98 { 99 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 100 unsigned int addr = exar_offset_to_lvl_addr(exar_gpio, offset); 101 unsigned int bit = exar_offset_to_bit(exar_gpio, offset); 102 103 if (value) 104 regmap_set_bits(exar_gpio->regmap, addr, BIT(bit)); 105 else 106 regmap_clear_bits(exar_gpio->regmap, addr, BIT(bit)); 107 } 108 109 static int exar_direction_output(struct gpio_chip *chip, unsigned int offset, 110 int value) 111 { 112 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 113 unsigned int addr = exar_offset_to_sel_addr(exar_gpio, offset); 114 unsigned int bit = exar_offset_to_bit(exar_gpio, offset); 115 116 exar_set_value(chip, offset, value); 117 regmap_clear_bits(exar_gpio->regmap, addr, BIT(bit)); 118 119 return 0; 120 } 121 122 static int exar_direction_input(struct gpio_chip *chip, unsigned int offset) 123 { 124 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 125 unsigned int addr = exar_offset_to_sel_addr(exar_gpio, offset); 126 unsigned int bit = exar_offset_to_bit(exar_gpio, offset); 127 128 regmap_set_bits(exar_gpio->regmap, addr, BIT(bit)); 129 130 return 0; 131 } 132 133 static void exar_devm_ida_free(void *data) 134 { 135 struct exar_gpio_chip *exar_gpio = data; 136 137 ida_free(&ida_index, exar_gpio->index); 138 } 139 140 static const struct regmap_config exar_regmap_config = { 141 .name = "exar-gpio", 142 .reg_bits = 16, 143 .val_bits = 8, 144 .io_port = true, 145 }; 146 147 static int gpio_exar_probe(struct platform_device *pdev) 148 { 149 struct device *dev = &pdev->dev; 150 struct pci_dev *pcidev = to_pci_dev(dev->parent); 151 struct exar_gpio_chip *exar_gpio; 152 u32 first_pin, ngpios; 153 void __iomem *p; 154 int index, ret; 155 156 /* 157 * The UART driver must have mapped region 0 prior to registering this 158 * device - use it. 159 */ 160 p = pcim_iomap_table(pcidev)[0]; 161 if (!p) 162 return -ENOMEM; 163 164 ret = device_property_read_u32(dev, "exar,first-pin", &first_pin); 165 if (ret) 166 return ret; 167 168 ret = device_property_read_u32(dev, "ngpios", &ngpios); 169 if (ret) 170 return ret; 171 172 exar_gpio = devm_kzalloc(dev, sizeof(*exar_gpio), GFP_KERNEL); 173 if (!exar_gpio) 174 return -ENOMEM; 175 176 /* 177 * If cascaded, secondary xr17v354 or xr17v358 have the same amount 178 * of MPIOs as their primaries and the last 4 bits of the primary's 179 * PCI Device ID is the number of its UART channels. 180 */ 181 if (pcidev->device & GENMASK(15, 12)) { 182 ngpios += ngpios; 183 exar_gpio->cascaded_offset = (pcidev->device & GENMASK(3, 0)) * 184 EXAR_UART_CHANNEL_SIZE; 185 } 186 187 /* 188 * We don't need to check the return values of mmio regmap operations (unless 189 * the regmap has a clock attached which is not the case here). 190 */ 191 exar_gpio->regmap = devm_regmap_init_mmio(dev, p, &exar_regmap_config); 192 if (IS_ERR(exar_gpio->regmap)) 193 return PTR_ERR(exar_gpio->regmap); 194 195 index = ida_alloc(&ida_index, GFP_KERNEL); 196 if (index < 0) 197 return index; 198 199 ret = devm_add_action_or_reset(dev, exar_devm_ida_free, exar_gpio); 200 if (ret) 201 return ret; 202 203 sprintf(exar_gpio->name, "exar_gpio%d", index); 204 exar_gpio->gpio_chip.label = exar_gpio->name; 205 exar_gpio->gpio_chip.parent = dev; 206 exar_gpio->gpio_chip.direction_output = exar_direction_output; 207 exar_gpio->gpio_chip.direction_input = exar_direction_input; 208 exar_gpio->gpio_chip.get_direction = exar_get_direction; 209 exar_gpio->gpio_chip.get = exar_get_value; 210 exar_gpio->gpio_chip.set = exar_set_value; 211 exar_gpio->gpio_chip.base = -1; 212 exar_gpio->gpio_chip.ngpio = ngpios; 213 exar_gpio->index = index; 214 exar_gpio->first_pin = first_pin; 215 216 ret = devm_gpiochip_add_data(dev, &exar_gpio->gpio_chip, exar_gpio); 217 if (ret) 218 return ret; 219 220 return 0; 221 } 222 223 static struct platform_driver gpio_exar_driver = { 224 .probe = gpio_exar_probe, 225 .driver = { 226 .name = DRIVER_NAME, 227 }, 228 }; 229 230 module_platform_driver(gpio_exar_driver); 231 232 MODULE_ALIAS("platform:" DRIVER_NAME); 233 MODULE_DESCRIPTION("Exar GPIO driver"); 234 MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>"); 235 MODULE_LICENSE("GPL"); 236