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 mcb_device *mdev; 39 struct resource *mem; 40 }; 41 42 static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio, 43 unsigned debounce) 44 { 45 struct men_z127_gpio *priv = gpiochip_get_data(gc); 46 struct device *dev = &priv->mdev->dev; 47 unsigned int rnd; 48 u32 db_en, db_cnt; 49 50 if (!MEN_Z127_DB_IN_RANGE(debounce)) { 51 dev_err(dev, "debounce value %u out of range", debounce); 52 return -EINVAL; 53 } 54 55 if (debounce > 0) { 56 /* round up or down depending on MSB-1 */ 57 rnd = fls(debounce) - 1; 58 59 if (rnd && (debounce & BIT(rnd - 1))) 60 debounce = round_up(debounce, MEN_Z127_DB_MIN_US); 61 else 62 debounce = round_down(debounce, MEN_Z127_DB_MIN_US); 63 64 if (debounce > MEN_Z127_DB_MAX_US) 65 debounce = MEN_Z127_DB_MAX_US; 66 67 /* 50us per register unit */ 68 debounce /= 50; 69 } 70 71 spin_lock(&gc->bgpio_lock); 72 73 db_en = readl(priv->reg_base + MEN_Z127_DBER); 74 75 if (debounce == 0) { 76 db_en &= ~BIT(gpio); 77 db_cnt = 0; 78 } else { 79 db_en |= BIT(gpio); 80 db_cnt = debounce; 81 } 82 83 writel(db_en, priv->reg_base + MEN_Z127_DBER); 84 writel(db_cnt, priv->reg_base + GPIO_TO_DBCNT_REG(gpio)); 85 86 spin_unlock(&gc->bgpio_lock); 87 88 return 0; 89 } 90 91 static int men_z127_request(struct gpio_chip *gc, unsigned gpio_pin) 92 { 93 struct men_z127_gpio *priv = gpiochip_get_data(gc); 94 u32 od_en; 95 96 if (gpio_pin >= gc->ngpio) 97 return -EINVAL; 98 99 spin_lock(&gc->bgpio_lock); 100 od_en = readl(priv->reg_base + MEN_Z127_ODER); 101 102 if (gpiochip_line_is_open_drain(gc, gpio_pin)) 103 od_en |= BIT(gpio_pin); 104 else 105 od_en &= ~BIT(gpio_pin); 106 107 writel(od_en, priv->reg_base + MEN_Z127_ODER); 108 spin_unlock(&gc->bgpio_lock); 109 110 return 0; 111 } 112 113 static int men_z127_probe(struct mcb_device *mdev, 114 const struct mcb_device_id *id) 115 { 116 struct men_z127_gpio *men_z127_gpio; 117 struct device *dev = &mdev->dev; 118 int ret; 119 120 men_z127_gpio = devm_kzalloc(dev, sizeof(struct men_z127_gpio), 121 GFP_KERNEL); 122 if (!men_z127_gpio) 123 return -ENOMEM; 124 125 men_z127_gpio->mem = mcb_request_mem(mdev, dev_name(dev)); 126 if (IS_ERR(men_z127_gpio->mem)) { 127 dev_err(dev, "failed to request device memory"); 128 return PTR_ERR(men_z127_gpio->mem); 129 } 130 131 men_z127_gpio->reg_base = ioremap(men_z127_gpio->mem->start, 132 resource_size(men_z127_gpio->mem)); 133 if (men_z127_gpio->reg_base == NULL) { 134 ret = -ENXIO; 135 goto err_release; 136 } 137 138 men_z127_gpio->mdev = mdev; 139 mcb_set_drvdata(mdev, men_z127_gpio); 140 141 ret = bgpio_init(&men_z127_gpio->gc, &mdev->dev, 4, 142 men_z127_gpio->reg_base + MEN_Z127_PSR, 143 men_z127_gpio->reg_base + MEN_Z127_CTRL, 144 NULL, 145 men_z127_gpio->reg_base + MEN_Z127_GPIODR, 146 NULL, 0); 147 if (ret) 148 goto err_unmap; 149 150 men_z127_gpio->gc.set_debounce = men_z127_debounce; 151 men_z127_gpio->gc.request = men_z127_request; 152 153 ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio); 154 if (ret) { 155 dev_err(dev, "failed to register MEN 16Z127 GPIO controller"); 156 goto err_unmap; 157 } 158 159 dev_info(dev, "MEN 16Z127 GPIO driver registered"); 160 161 return 0; 162 163 err_unmap: 164 iounmap(men_z127_gpio->reg_base); 165 err_release: 166 mcb_release_mem(men_z127_gpio->mem); 167 return ret; 168 } 169 170 static void men_z127_remove(struct mcb_device *mdev) 171 { 172 struct men_z127_gpio *men_z127_gpio = mcb_get_drvdata(mdev); 173 174 gpiochip_remove(&men_z127_gpio->gc); 175 iounmap(men_z127_gpio->reg_base); 176 mcb_release_mem(men_z127_gpio->mem); 177 } 178 179 static const struct mcb_device_id men_z127_ids[] = { 180 { .device = 0x7f }, 181 { } 182 }; 183 MODULE_DEVICE_TABLE(mcb, men_z127_ids); 184 185 static struct mcb_driver men_z127_driver = { 186 .driver = { 187 .name = "z127-gpio", 188 .owner = THIS_MODULE, 189 }, 190 .probe = men_z127_probe, 191 .remove = men_z127_remove, 192 .id_table = men_z127_ids, 193 }; 194 module_mcb_driver(men_z127_driver); 195 196 MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>"); 197 MODULE_DESCRIPTION("MEN 16z127 GPIO Controller"); 198 MODULE_LICENSE("GPL v2"); 199 MODULE_ALIAS("mcb:16z127"); 200