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 spinlock_t lock; 41 }; 42 43 static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio, 44 unsigned debounce) 45 { 46 struct men_z127_gpio *priv = gpiochip_get_data(gc); 47 struct device *dev = &priv->mdev->dev; 48 unsigned int rnd; 49 u32 db_en, db_cnt; 50 51 if (!MEN_Z127_DB_IN_RANGE(debounce)) { 52 dev_err(dev, "debounce value %u out of range", debounce); 53 return -EINVAL; 54 } 55 56 if (debounce > 0) { 57 /* round up or down depending on MSB-1 */ 58 rnd = fls(debounce) - 1; 59 60 if (rnd && (debounce & BIT(rnd - 1))) 61 debounce = round_up(debounce, MEN_Z127_DB_MIN_US); 62 else 63 debounce = round_down(debounce, MEN_Z127_DB_MIN_US); 64 65 if (debounce > MEN_Z127_DB_MAX_US) 66 debounce = MEN_Z127_DB_MAX_US; 67 68 /* 50us per register unit */ 69 debounce /= 50; 70 } 71 72 spin_lock(&priv->lock); 73 74 db_en = readl(priv->reg_base + MEN_Z127_DBER); 75 76 if (debounce == 0) { 77 db_en &= ~BIT(gpio); 78 db_cnt = 0; 79 } else { 80 db_en |= BIT(gpio); 81 db_cnt = debounce; 82 } 83 84 writel(db_en, priv->reg_base + MEN_Z127_DBER); 85 writel(db_cnt, priv->reg_base + GPIO_TO_DBCNT_REG(gpio)); 86 87 spin_unlock(&priv->lock); 88 89 return 0; 90 } 91 92 static int men_z127_request(struct gpio_chip *gc, unsigned gpio_pin) 93 { 94 struct men_z127_gpio *priv = gpiochip_get_data(gc); 95 u32 od_en; 96 97 if (gpio_pin >= gc->ngpio) 98 return -EINVAL; 99 100 spin_lock(&priv->lock); 101 od_en = readl(priv->reg_base + MEN_Z127_ODER); 102 103 if (gpiochip_line_is_open_drain(gc, gpio_pin)) 104 od_en |= BIT(gpio_pin); 105 else 106 od_en &= ~BIT(gpio_pin); 107 108 writel(od_en, priv->reg_base + MEN_Z127_ODER); 109 spin_unlock(&priv->lock); 110 111 return 0; 112 } 113 114 static int men_z127_probe(struct mcb_device *mdev, 115 const struct mcb_device_id *id) 116 { 117 struct men_z127_gpio *men_z127_gpio; 118 struct device *dev = &mdev->dev; 119 int ret; 120 121 men_z127_gpio = devm_kzalloc(dev, sizeof(struct men_z127_gpio), 122 GFP_KERNEL); 123 if (!men_z127_gpio) 124 return -ENOMEM; 125 126 men_z127_gpio->mem = mcb_request_mem(mdev, dev_name(dev)); 127 if (IS_ERR(men_z127_gpio->mem)) { 128 dev_err(dev, "failed to request device memory"); 129 return PTR_ERR(men_z127_gpio->mem); 130 } 131 132 men_z127_gpio->reg_base = ioremap(men_z127_gpio->mem->start, 133 resource_size(men_z127_gpio->mem)); 134 if (men_z127_gpio->reg_base == NULL) { 135 ret = -ENXIO; 136 goto err_release; 137 } 138 139 men_z127_gpio->mdev = mdev; 140 mcb_set_drvdata(mdev, men_z127_gpio); 141 142 ret = bgpio_init(&men_z127_gpio->gc, &mdev->dev, 4, 143 men_z127_gpio->reg_base + MEN_Z127_PSR, 144 men_z127_gpio->reg_base + MEN_Z127_CTRL, 145 NULL, 146 men_z127_gpio->reg_base + MEN_Z127_GPIODR, 147 NULL, 0); 148 if (ret) 149 goto err_unmap; 150 151 men_z127_gpio->gc.set_debounce = men_z127_debounce; 152 men_z127_gpio->gc.request = men_z127_request; 153 154 ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio); 155 if (ret) { 156 dev_err(dev, "failed to register MEN 16Z127 GPIO controller"); 157 goto err_unmap; 158 } 159 160 dev_info(dev, "MEN 16Z127 GPIO driver registered"); 161 162 return 0; 163 164 err_unmap: 165 iounmap(men_z127_gpio->reg_base); 166 err_release: 167 mcb_release_mem(men_z127_gpio->mem); 168 return ret; 169 } 170 171 static void men_z127_remove(struct mcb_device *mdev) 172 { 173 struct men_z127_gpio *men_z127_gpio = mcb_get_drvdata(mdev); 174 175 gpiochip_remove(&men_z127_gpio->gc); 176 iounmap(men_z127_gpio->reg_base); 177 mcb_release_mem(men_z127_gpio->mem); 178 } 179 180 static const struct mcb_device_id men_z127_ids[] = { 181 { .device = 0x7f }, 182 { } 183 }; 184 MODULE_DEVICE_TABLE(mcb, men_z127_ids); 185 186 static struct mcb_driver men_z127_driver = { 187 .driver = { 188 .name = "z127-gpio", 189 .owner = THIS_MODULE, 190 }, 191 .probe = men_z127_probe, 192 .remove = men_z127_remove, 193 .id_table = men_z127_ids, 194 }; 195 module_mcb_driver(men_z127_driver); 196 197 MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>"); 198 MODULE_DESCRIPTION("MEN 16z127 GPIO Controller"); 199 MODULE_LICENSE("GPL v2"); 200 MODULE_ALIAS("mcb:16z127"); 201