diff options
Diffstat (limited to 'drivers/gpio/gpio-menz127.c')
| -rw-r--r-- | drivers/gpio/gpio-menz127.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-menz127.c b/drivers/gpio/gpio-menz127.c new file mode 100644 index 000000000..c5c9599a3 --- /dev/null +++ b/drivers/gpio/gpio-menz127.c @@ -0,0 +1,199 @@ +/* + * MEN 16Z127 GPIO driver + * + * Copyright (C) 2016 MEN Mikroelektronik GmbH (www.men.de) + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; version 2 of the License. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/io.h> +#include <linux/err.h> +#include <linux/mcb.h> +#include <linux/bitops.h> +#include <linux/gpio/driver.h> + +#define MEN_Z127_CTRL 0x00 +#define MEN_Z127_PSR 0x04 +#define MEN_Z127_IRQR 0x08 +#define MEN_Z127_GPIODR 0x0c +#define MEN_Z127_IER1 0x10 +#define MEN_Z127_IER2 0x14 +#define MEN_Z127_DBER 0x18 +#define MEN_Z127_ODER 0x1C +#define GPIO_TO_DBCNT_REG(gpio) ((gpio * 4) + 0x80) + +#define MEN_Z127_DB_MIN_US 50 +/* 16 bit compare register. Each bit represents 50us */ +#define MEN_Z127_DB_MAX_US (0xffff * MEN_Z127_DB_MIN_US) +#define MEN_Z127_DB_IN_RANGE(db) ((db >= MEN_Z127_DB_MIN_US) && \ + (db <= MEN_Z127_DB_MAX_US)) + +struct men_z127_gpio { + struct gpio_chip gc; + void __iomem *reg_base; + struct mcb_device *mdev; + struct resource *mem; +}; + +static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio, + unsigned debounce) +{ + struct men_z127_gpio *priv = gpiochip_get_data(gc); + struct device *dev = &priv->mdev->dev; + unsigned int rnd; + u32 db_en, db_cnt; + + if (!MEN_Z127_DB_IN_RANGE(debounce)) { + dev_err(dev, "debounce value %u out of range", debounce); + return -EINVAL; + } + + if (debounce > 0) { + /* round up or down depending on MSB-1 */ + rnd = fls(debounce) - 1; + + if (rnd && (debounce & BIT(rnd - 1))) + debounce = round_up(debounce, MEN_Z127_DB_MIN_US); + else + debounce = round_down(debounce, MEN_Z127_DB_MIN_US); + + if (debounce > MEN_Z127_DB_MAX_US) + debounce = MEN_Z127_DB_MAX_US; + + /* 50us per register unit */ + debounce /= 50; + } + + spin_lock(&gc->bgpio_lock); + + db_en = readl(priv->reg_base + MEN_Z127_DBER); + + if (debounce == 0) { + db_en &= ~BIT(gpio); + db_cnt = 0; + } else { + db_en |= BIT(gpio); + db_cnt = debounce; + } + + writel(db_en, priv->reg_base + MEN_Z127_DBER); + writel(db_cnt, priv->reg_base + GPIO_TO_DBCNT_REG(gpio)); + + spin_unlock(&gc->bgpio_lock); + + return 0; +} + +static int men_z127_request(struct gpio_chip *gc, unsigned gpio_pin) +{ + struct men_z127_gpio *priv = gpiochip_get_data(gc); + u32 od_en; + + if (gpio_pin >= gc->ngpio) + return -EINVAL; + + spin_lock(&gc->bgpio_lock); + od_en = readl(priv->reg_base + MEN_Z127_ODER); + + if (gpiochip_line_is_open_drain(gc, gpio_pin)) + od_en |= BIT(gpio_pin); + else + od_en &= ~BIT(gpio_pin); + + writel(od_en, priv->reg_base + MEN_Z127_ODER); + spin_unlock(&gc->bgpio_lock); + + return 0; +} + +static int men_z127_probe(struct mcb_device *mdev, + const struct mcb_device_id *id) +{ + struct men_z127_gpio *men_z127_gpio; + struct device *dev = &mdev->dev; + int ret; + + men_z127_gpio = devm_kzalloc(dev, sizeof(struct men_z127_gpio), + GFP_KERNEL); + if (!men_z127_gpio) + return -ENOMEM; + + men_z127_gpio->mem = mcb_request_mem(mdev, dev_name(dev)); + if (IS_ERR(men_z127_gpio->mem)) { + dev_err(dev, "failed to request device memory"); + return PTR_ERR(men_z127_gpio->mem); + } + + men_z127_gpio->reg_base = ioremap(men_z127_gpio->mem->start, + resource_size(men_z127_gpio->mem)); + if (men_z127_gpio->reg_base == NULL) { + ret = -ENXIO; + goto err_release; + } + + men_z127_gpio->mdev = mdev; + mcb_set_drvdata(mdev, men_z127_gpio); + + ret = bgpio_init(&men_z127_gpio->gc, &mdev->dev, 4, + men_z127_gpio->reg_base + MEN_Z127_PSR, + men_z127_gpio->reg_base + MEN_Z127_CTRL, + NULL, + men_z127_gpio->reg_base + MEN_Z127_GPIODR, + NULL, 0); + if (ret) + goto err_unmap; + + men_z127_gpio->gc.set_debounce = men_z127_debounce; + men_z127_gpio->gc.request = men_z127_request; + + ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio); + if (ret) { + dev_err(dev, "failed to register MEN 16Z127 GPIO controller"); + goto err_unmap; + } + + dev_info(dev, "MEN 16Z127 GPIO driver registered"); + + return 0; + +err_unmap: + iounmap(men_z127_gpio->reg_base); +err_release: + mcb_release_mem(men_z127_gpio->mem); + return ret; +} + +static void men_z127_remove(struct mcb_device *mdev) +{ + struct men_z127_gpio *men_z127_gpio = mcb_get_drvdata(mdev); + + gpiochip_remove(&men_z127_gpio->gc); + iounmap(men_z127_gpio->reg_base); + mcb_release_mem(men_z127_gpio->mem); +} + +static const struct mcb_device_id men_z127_ids[] = { + { .device = 0x7f }, + { } +}; +MODULE_DEVICE_TABLE(mcb, men_z127_ids); + +static struct mcb_driver men_z127_driver = { + .driver = { + .name = "z127-gpio", + .owner = THIS_MODULE, + }, + .probe = men_z127_probe, + .remove = men_z127_remove, + .id_table = men_z127_ids, +}; +module_mcb_driver(men_z127_driver); + +MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>"); +MODULE_DESCRIPTION("MEN 16z127 GPIO Controller"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("mcb:16z127"); |