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 #include <linux/bitops.h> 8 #include <linux/device.h> 9 #include <linux/gpio/driver.h> 10 #include <linux/init.h> 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/pci.h> 14 #include <linux/platform_device.h> 15 16 #define EXAR_OFFSET_MPIOLVL_LO 0x90 17 #define EXAR_OFFSET_MPIOSEL_LO 0x93 18 #define EXAR_OFFSET_MPIOLVL_HI 0x96 19 #define EXAR_OFFSET_MPIOSEL_HI 0x99 20 21 #define DRIVER_NAME "gpio_exar" 22 23 static DEFINE_IDA(ida_index); 24 25 struct exar_gpio_chip { 26 struct gpio_chip gpio_chip; 27 struct mutex lock; 28 int index; 29 void __iomem *regs; 30 char name[20]; 31 unsigned int first_pin; 32 }; 33 34 static void exar_update(struct gpio_chip *chip, unsigned int reg, int val, 35 unsigned int offset) 36 { 37 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 38 int temp; 39 40 mutex_lock(&exar_gpio->lock); 41 temp = readb(exar_gpio->regs + reg); 42 temp &= ~BIT(offset); 43 if (val) 44 temp |= BIT(offset); 45 writeb(temp, exar_gpio->regs + reg); 46 mutex_unlock(&exar_gpio->lock); 47 } 48 49 static int exar_set_direction(struct gpio_chip *chip, int direction, 50 unsigned int offset) 51 { 52 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 53 unsigned int addr = (offset + exar_gpio->first_pin) / 8 ? 54 EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO; 55 unsigned int bit = (offset + exar_gpio->first_pin) % 8; 56 57 exar_update(chip, addr, direction, bit); 58 return 0; 59 } 60 61 static int exar_get(struct gpio_chip *chip, unsigned int reg) 62 { 63 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 64 int value; 65 66 mutex_lock(&exar_gpio->lock); 67 value = readb(exar_gpio->regs + reg); 68 mutex_unlock(&exar_gpio->lock); 69 70 return value; 71 } 72 73 static int exar_get_direction(struct gpio_chip *chip, unsigned int offset) 74 { 75 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 76 unsigned int addr = (offset + exar_gpio->first_pin) / 8 ? 77 EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO; 78 unsigned int bit = (offset + exar_gpio->first_pin) % 8; 79 80 return !!(exar_get(chip, addr) & BIT(bit)); 81 } 82 83 static int exar_get_value(struct gpio_chip *chip, unsigned int offset) 84 { 85 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 86 unsigned int addr = (offset + exar_gpio->first_pin) / 8 ? 87 EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO; 88 unsigned int bit = (offset + exar_gpio->first_pin) % 8; 89 90 return !!(exar_get(chip, addr) & BIT(bit)); 91 } 92 93 static void exar_set_value(struct gpio_chip *chip, unsigned int offset, 94 int value) 95 { 96 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); 97 unsigned int addr = (offset + exar_gpio->first_pin) / 8 ? 98 EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO; 99 unsigned int bit = (offset + exar_gpio->first_pin) % 8; 100 101 exar_update(chip, addr, value, bit); 102 } 103 104 static int exar_direction_output(struct gpio_chip *chip, unsigned int offset, 105 int value) 106 { 107 exar_set_value(chip, offset, value); 108 return exar_set_direction(chip, 0, offset); 109 } 110 111 static int exar_direction_input(struct gpio_chip *chip, unsigned int offset) 112 { 113 return exar_set_direction(chip, 1, offset); 114 } 115 116 static int gpio_exar_probe(struct platform_device *pdev) 117 { 118 struct pci_dev *pcidev = to_pci_dev(pdev->dev.parent); 119 struct exar_gpio_chip *exar_gpio; 120 u32 first_pin, ngpios; 121 void __iomem *p; 122 int index, ret; 123 124 /* 125 * The UART driver must have mapped region 0 prior to registering this 126 * device - use it. 127 */ 128 p = pcim_iomap_table(pcidev)[0]; 129 if (!p) 130 return -ENOMEM; 131 132 ret = device_property_read_u32(&pdev->dev, "exar,first-pin", 133 &first_pin); 134 if (ret) 135 return ret; 136 137 ret = device_property_read_u32(&pdev->dev, "ngpios", &ngpios); 138 if (ret) 139 return ret; 140 141 exar_gpio = devm_kzalloc(&pdev->dev, sizeof(*exar_gpio), GFP_KERNEL); 142 if (!exar_gpio) 143 return -ENOMEM; 144 145 mutex_init(&exar_gpio->lock); 146 147 index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL); 148 if (index < 0) 149 goto err_destroy; 150 151 sprintf(exar_gpio->name, "exar_gpio%d", index); 152 exar_gpio->gpio_chip.label = exar_gpio->name; 153 exar_gpio->gpio_chip.parent = &pdev->dev; 154 exar_gpio->gpio_chip.direction_output = exar_direction_output; 155 exar_gpio->gpio_chip.direction_input = exar_direction_input; 156 exar_gpio->gpio_chip.get_direction = exar_get_direction; 157 exar_gpio->gpio_chip.get = exar_get_value; 158 exar_gpio->gpio_chip.set = exar_set_value; 159 exar_gpio->gpio_chip.base = -1; 160 exar_gpio->gpio_chip.ngpio = ngpios; 161 exar_gpio->regs = p; 162 exar_gpio->index = index; 163 exar_gpio->first_pin = first_pin; 164 165 ret = devm_gpiochip_add_data(&pdev->dev, 166 &exar_gpio->gpio_chip, exar_gpio); 167 if (ret) 168 goto err_destroy; 169 170 platform_set_drvdata(pdev, exar_gpio); 171 172 return 0; 173 174 err_destroy: 175 ida_simple_remove(&ida_index, index); 176 mutex_destroy(&exar_gpio->lock); 177 return ret; 178 } 179 180 static int gpio_exar_remove(struct platform_device *pdev) 181 { 182 struct exar_gpio_chip *exar_gpio = platform_get_drvdata(pdev); 183 184 ida_simple_remove(&ida_index, exar_gpio->index); 185 mutex_destroy(&exar_gpio->lock); 186 187 return 0; 188 } 189 190 static struct platform_driver gpio_exar_driver = { 191 .probe = gpio_exar_probe, 192 .remove = gpio_exar_remove, 193 .driver = { 194 .name = DRIVER_NAME, 195 }, 196 }; 197 198 module_platform_driver(gpio_exar_driver); 199 200 MODULE_ALIAS("platform:" DRIVER_NAME); 201 MODULE_DESCRIPTION("Exar GPIO driver"); 202 MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>"); 203 MODULE_LICENSE("GPL"); 204