1 /* 2 * MEN 16Z127 GPIO driver 3 * 4 * Copyright (C) 2016 MEN Mikroelektronik GmbH (www.men.de) 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License as published by the Free 8 * Software Foundation; version 2 of the License. 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/io.h> 14 #include <linux/err.h> 15 #include <linux/mcb.h> 16 #include <linux/bitops.h> 17 #include <linux/gpio/driver.h> 18 19 #define MEN_Z127_CTRL 0x00 20 #define MEN_Z127_PSR 0x04 21 #define MEN_Z127_IRQR 0x08 22 #define MEN_Z127_GPIODR 0x0c 23 #define MEN_Z127_IER1 0x10 24 #define MEN_Z127_IER2 0x14 25 #define MEN_Z127_DBER 0x18 26 #define MEN_Z127_ODER 0x1C 27 #define GPIO_TO_DBCNT_REG(gpio) ((gpio * 4) + 0x80) 28 29 #define MEN_Z127_DB_MIN_US 50 30 /* 16 bit compare register. Each bit represents 50us */ 31 #define MEN_Z127_DB_MAX_US (0xffff * MEN_Z127_DB_MIN_US) 32 #define MEN_Z127_DB_IN_RANGE(db) ((db >= MEN_Z127_DB_MIN_US) && \ 33 (db <= MEN_Z127_DB_MAX_US)) 34 35 struct men_z127_gpio { 36 struct gpio_chip gc; 37 void __iomem *reg_base; 38 struct resource *mem; 39 }; 40 41 static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio, 42 unsigned debounce) 43 { 44 struct men_z127_gpio *priv = gpiochip_get_data(gc); 45 struct device *dev = gc->parent; 46 unsigned int rnd; 47 u32 db_en, db_cnt; 48 49 if (!MEN_Z127_DB_IN_RANGE(debounce)) { 50 dev_err(dev, "debounce value %u out of range", debounce); 51 return -EINVAL; 52 } 53 54 if (debounce > 0) { 55 /* round up or down depending on MSB-1 */ 56 rnd = fls(debounce) - 1; 57 58 if (rnd && (debounce & BIT(rnd - 1))) 59 debounce = round_up(debounce, MEN_Z127_DB_MIN_US); 60 else 61 debounce = round_down(debounce, MEN_Z127_DB_MIN_US); 62 63 if (debounce > MEN_Z127_DB_MAX_US) 64 debounce = MEN_Z127_DB_MAX_US; 65 66 /* 50us per register unit */ 67 debounce /= 50; 68 } 69 70 spin_lock(&gc->bgpio_lock); 71 72 db_en = readl(priv->reg_base + MEN_Z127_DBER); 73 74 if (debounce == 0) { 75 db_en &= ~BIT(gpio); 76 db_cnt = 0; 77 } else { 78 db_en |= BIT(gpio); 79 db_cnt = debounce; 80 } 81 82 writel(db_en, priv->reg_base + MEN_Z127_DBER); 83 writel(db_cnt, priv->reg_base + GPIO_TO_DBCNT_REG(gpio)); 84 85 spin_unlock(&gc->bgpio_lock); 86 87 return 0; 88 } 89 90 static int men_z127_set_single_ended(struct gpio_chip *gc, 91 unsigned offset, 92 enum pin_config_param param) 93 { 94 struct men_z127_gpio *priv = gpiochip_get_data(gc); 95 u32 od_en; 96 97 spin_lock(&gc->bgpio_lock); 98 od_en = readl(priv->reg_base + MEN_Z127_ODER); 99 100 if (param == PIN_CONFIG_DRIVE_OPEN_DRAIN) 101 od_en |= BIT(offset); 102 else 103 /* Implicitly PIN_CONFIG_DRIVE_PUSH_PULL */ 104 od_en &= ~BIT(offset); 105 106 writel(od_en, priv->reg_base + MEN_Z127_ODER); 107 spin_unlock(&gc->bgpio_lock); 108 109 return 0; 110 } 111 112 static int men_z127_set_config(struct gpio_chip *gc, unsigned offset, 113 unsigned long config) 114 { 115 enum pin_config_param param = pinconf_to_config_param(config); 116 117 switch (param) { 118 case PIN_CONFIG_DRIVE_OPEN_DRAIN: 119 case PIN_CONFIG_DRIVE_PUSH_PULL: 120 return men_z127_set_single_ended(gc, offset, param); 121 122 case PIN_CONFIG_INPUT_DEBOUNCE: 123 return men_z127_debounce(gc, offset, 124 pinconf_to_config_argument(config)); 125 126 default: 127 break; 128 } 129 130 return -ENOTSUPP; 131 } 132 133 static int men_z127_probe(struct mcb_device *mdev, 134 const struct mcb_device_id *id) 135 { 136 struct men_z127_gpio *men_z127_gpio; 137 struct device *dev = &mdev->dev; 138 int ret; 139 140 men_z127_gpio = devm_kzalloc(dev, sizeof(struct men_z127_gpio), 141 GFP_KERNEL); 142 if (!men_z127_gpio) 143 return -ENOMEM; 144 145 men_z127_gpio->mem = mcb_request_mem(mdev, dev_name(dev)); 146 if (IS_ERR(men_z127_gpio->mem)) { 147 dev_err(dev, "failed to request device memory"); 148 return PTR_ERR(men_z127_gpio->mem); 149 } 150 151 men_z127_gpio->reg_base = ioremap(men_z127_gpio->mem->start, 152 resource_size(men_z127_gpio->mem)); 153 if (men_z127_gpio->reg_base == NULL) { 154 ret = -ENXIO; 155 goto err_release; 156 } 157 158 mcb_set_drvdata(mdev, men_z127_gpio); 159 160 ret = bgpio_init(&men_z127_gpio->gc, &mdev->dev, 4, 161 men_z127_gpio->reg_base + MEN_Z127_PSR, 162 men_z127_gpio->reg_base + MEN_Z127_CTRL, 163 NULL, 164 men_z127_gpio->reg_base + MEN_Z127_GPIODR, 165 NULL, 0); 166 if (ret) 167 goto err_unmap; 168 169 men_z127_gpio->gc.set_config = men_z127_set_config; 170 171 ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio); 172 if (ret) { 173 dev_err(dev, "failed to register MEN 16Z127 GPIO controller"); 174 goto err_unmap; 175 } 176 177 dev_info(dev, "MEN 16Z127 GPIO driver registered"); 178 179 return 0; 180 181 err_unmap: 182 iounmap(men_z127_gpio->reg_base); 183 err_release: 184 mcb_release_mem(men_z127_gpio->mem); 185 return ret; 186 } 187 188 static void men_z127_remove(struct mcb_device *mdev) 189 { 190 struct men_z127_gpio *men_z127_gpio = mcb_get_drvdata(mdev); 191 192 gpiochip_remove(&men_z127_gpio->gc); 193 iounmap(men_z127_gpio->reg_base); 194 mcb_release_mem(men_z127_gpio->mem); 195 } 196 197 static const struct mcb_device_id men_z127_ids[] = { 198 { .device = 0x7f }, 199 { } 200 }; 201 MODULE_DEVICE_TABLE(mcb, men_z127_ids); 202 203 static struct mcb_driver men_z127_driver = { 204 .driver = { 205 .name = "z127-gpio", 206 }, 207 .probe = men_z127_probe, 208 .remove = men_z127_remove, 209 .id_table = men_z127_ids, 210 }; 211 module_mcb_driver(men_z127_driver); 212 213 MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>"); 214 MODULE_DESCRIPTION("MEN 16z127 GPIO Controller"); 215 MODULE_LICENSE("GPL v2"); 216 MODULE_ALIAS("mcb:16z127"); 217