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/*
* 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 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 = gc->parent;
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_set_single_ended(struct gpio_chip *gc,
unsigned offset,
enum single_ended_mode mode)
{
struct men_z127_gpio *priv = gpiochip_get_data(gc);
u32 od_en;
if (mode != LINE_MODE_OPEN_DRAIN &&
mode != LINE_MODE_PUSH_PULL)
return -ENOTSUPP;
spin_lock(&gc->bgpio_lock);
od_en = readl(priv->reg_base + MEN_Z127_ODER);
if (mode == LINE_MODE_OPEN_DRAIN)
od_en |= BIT(offset);
else
/* Implicitly LINE_MODE_PUSH_PULL */
od_en &= ~BIT(offset);
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;
}
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.set_single_ended = men_z127_set_single_ended;
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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