1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Turris Mox Moxtet GPIO expander 4 * 5 * Copyright (C) 2018 Marek Behún <kabel@kernel.org> 6 */ 7 8 #include <linux/bitops.h> 9 #include <linux/gpio/driver.h> 10 #include <linux/moxtet.h> 11 #include <linux/module.h> 12 13 #define MOXTET_GPIO_NGPIOS 12 14 #define MOXTET_GPIO_INPUTS 4 15 16 struct moxtet_gpio_desc { 17 u16 in_mask; 18 u16 out_mask; 19 }; 20 21 static const struct moxtet_gpio_desc descs[] = { 22 [TURRIS_MOX_MODULE_SFP] = { 23 .in_mask = GENMASK(2, 0), 24 .out_mask = GENMASK(5, 4), 25 }, 26 }; 27 28 struct moxtet_gpio_chip { 29 struct device *dev; 30 struct gpio_chip gpio_chip; 31 const struct moxtet_gpio_desc *desc; 32 }; 33 34 static int moxtet_gpio_get_value(struct gpio_chip *gc, unsigned int offset) 35 { 36 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); 37 int ret; 38 39 if (chip->desc->in_mask & BIT(offset)) { 40 ret = moxtet_device_read(chip->dev); 41 } else if (chip->desc->out_mask & BIT(offset)) { 42 ret = moxtet_device_written(chip->dev); 43 if (ret >= 0) 44 ret <<= MOXTET_GPIO_INPUTS; 45 } else { 46 return -EINVAL; 47 } 48 49 if (ret < 0) 50 return ret; 51 52 return !!(ret & BIT(offset)); 53 } 54 55 static void moxtet_gpio_set_value(struct gpio_chip *gc, unsigned int offset, 56 int val) 57 { 58 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); 59 int state; 60 61 state = moxtet_device_written(chip->dev); 62 if (state < 0) 63 return; 64 65 offset -= MOXTET_GPIO_INPUTS; 66 67 if (val) 68 state |= BIT(offset); 69 else 70 state &= ~BIT(offset); 71 72 moxtet_device_write(chip->dev, state); 73 } 74 75 static int moxtet_gpio_get_direction(struct gpio_chip *gc, unsigned int offset) 76 { 77 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); 78 79 /* All lines are hard wired to be either input or output, not both. */ 80 if (chip->desc->in_mask & BIT(offset)) 81 return GPIO_LINE_DIRECTION_IN; 82 else if (chip->desc->out_mask & BIT(offset)) 83 return GPIO_LINE_DIRECTION_OUT; 84 else 85 return -EINVAL; 86 } 87 88 static int moxtet_gpio_direction_input(struct gpio_chip *gc, 89 unsigned int offset) 90 { 91 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); 92 93 if (chip->desc->in_mask & BIT(offset)) 94 return 0; 95 else if (chip->desc->out_mask & BIT(offset)) 96 return -ENOTSUPP; 97 else 98 return -EINVAL; 99 } 100 101 static int moxtet_gpio_direction_output(struct gpio_chip *gc, 102 unsigned int offset, int val) 103 { 104 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); 105 106 if (chip->desc->out_mask & BIT(offset)) 107 moxtet_gpio_set_value(gc, offset, val); 108 else if (chip->desc->in_mask & BIT(offset)) 109 return -ENOTSUPP; 110 else 111 return -EINVAL; 112 113 return 0; 114 } 115 116 static int moxtet_gpio_probe(struct device *dev) 117 { 118 struct moxtet_gpio_chip *chip; 119 struct device_node *nc = dev->of_node; 120 int id; 121 122 id = to_moxtet_device(dev)->id; 123 124 if (id >= ARRAY_SIZE(descs)) { 125 dev_err(dev, "%pOF Moxtet device id 0x%x is not supported by gpio-moxtet driver\n", 126 nc, id); 127 return -ENOTSUPP; 128 } 129 130 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); 131 if (!chip) 132 return -ENOMEM; 133 134 chip->dev = dev; 135 chip->gpio_chip.parent = dev; 136 chip->desc = &descs[id]; 137 138 dev_set_drvdata(dev, chip); 139 140 chip->gpio_chip.label = dev_name(dev); 141 chip->gpio_chip.get_direction = moxtet_gpio_get_direction; 142 chip->gpio_chip.direction_input = moxtet_gpio_direction_input; 143 chip->gpio_chip.direction_output = moxtet_gpio_direction_output; 144 chip->gpio_chip.get = moxtet_gpio_get_value; 145 chip->gpio_chip.set = moxtet_gpio_set_value; 146 chip->gpio_chip.base = -1; 147 148 chip->gpio_chip.ngpio = MOXTET_GPIO_NGPIOS; 149 150 chip->gpio_chip.can_sleep = true; 151 chip->gpio_chip.owner = THIS_MODULE; 152 153 return devm_gpiochip_add_data(dev, &chip->gpio_chip, chip); 154 } 155 156 static const struct of_device_id moxtet_gpio_dt_ids[] = { 157 { .compatible = "cznic,moxtet-gpio", }, 158 {}, 159 }; 160 MODULE_DEVICE_TABLE(of, moxtet_gpio_dt_ids); 161 162 static const enum turris_mox_module_id moxtet_gpio_module_table[] = { 163 TURRIS_MOX_MODULE_SFP, 164 0, 165 }; 166 167 static struct moxtet_driver moxtet_gpio_driver = { 168 .driver = { 169 .name = "moxtet-gpio", 170 .of_match_table = moxtet_gpio_dt_ids, 171 .probe = moxtet_gpio_probe, 172 }, 173 .id_table = moxtet_gpio_module_table, 174 }; 175 module_moxtet_driver(moxtet_gpio_driver); 176 177 MODULE_AUTHOR("Marek Behun <kabel@kernel.org>"); 178 MODULE_DESCRIPTION("Turris Mox Moxtet GPIO expander"); 179 MODULE_LICENSE("GPL v2"); 180