--- /dev/null
+/*
+ * 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;
+ spinlock_t lock;
+};
+
+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(&priv->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(&priv->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(&priv->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(&priv->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");
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