1/*
  2 * MOXA ART SoCs GPIO driver.
  3 *
  4 * Copyright (C) 2013 Jonas Jensen
  5 *
  6 * Jonas Jensen <jonas.jensen@gmail.com>
  7 *
  8 * This file is licensed under the terms of the GNU General Public
  9 * License version 2.  This program is licensed "as is" without any
 10 * warranty of any kind, whether express or implied.
 11 */
 12
 13#include <linux/err.h>
 14#include <linux/init.h>
 15#include <linux/irq.h>
 16#include <linux/io.h>
 17#include <linux/gpio.h>
 18#include <linux/platform_device.h>
 19#include <linux/module.h>
 20#include <linux/of_address.h>
 21#include <linux/of_gpio.h>
 22#include <linux/pinctrl/consumer.h>
 23#include <linux/delay.h>
 24#include <linux/timer.h>
 25#include <linux/bitops.h>
 26
 27#define GPIO_DATA_OUT		0x00
 28#define GPIO_DATA_IN		0x04
 29#define GPIO_PIN_DIRECTION	0x08
 30
 31struct moxart_gpio_chip {
 32	struct gpio_chip gpio;
 33	void __iomem *base;
 34};
 35
 36static inline struct moxart_gpio_chip *to_moxart_gpio(struct gpio_chip *chip)
 37{
 38	return container_of(chip, struct moxart_gpio_chip, gpio);
 39}
 40
 41static int moxart_gpio_request(struct gpio_chip *chip, unsigned offset)
 42{
 43	return pinctrl_request_gpio(offset);
 44}
 45
 46static void moxart_gpio_free(struct gpio_chip *chip, unsigned offset)
 47{
 48	pinctrl_free_gpio(offset);
 49}
 50
 51static void moxart_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 52{
 53	struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
 54	void __iomem *ioaddr = gc->base + GPIO_DATA_OUT;
 55	u32 reg = readl(ioaddr);
 56
 57	if (value)
 58		reg = reg | BIT(offset);
 59	else
 60		reg = reg & ~BIT(offset);
 61
 62	writel(reg, ioaddr);
 63}
 64
 65static int moxart_gpio_get(struct gpio_chip *chip, unsigned offset)
 66{
 67	struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
 68	u32 ret = readl(gc->base + GPIO_PIN_DIRECTION);
 69
 70	if (ret & BIT(offset))
 71		return !!(readl(gc->base + GPIO_DATA_OUT) & BIT(offset));
 72	else
 73		return !!(readl(gc->base + GPIO_DATA_IN) & BIT(offset));
 74}
 75
 76static int moxart_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 77{
 78	struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
 79	void __iomem *ioaddr = gc->base + GPIO_PIN_DIRECTION;
 80
 81	writel(readl(ioaddr) & ~BIT(offset), ioaddr);
 82	return 0;
 83}
 84
 85static int moxart_gpio_direction_output(struct gpio_chip *chip,
 86					unsigned offset, int value)
 87{
 88	struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
 89	void __iomem *ioaddr = gc->base + GPIO_PIN_DIRECTION;
 90
 91	moxart_gpio_set(chip, offset, value);
 92	writel(readl(ioaddr) | BIT(offset), ioaddr);
 93	return 0;
 94}
 95
 96static struct gpio_chip moxart_template_chip = {
 97	.label			= "moxart-gpio",
 98	.request		= moxart_gpio_request,
 99	.free			= moxart_gpio_free,
100	.direction_input	= moxart_gpio_direction_input,
101	.direction_output	= moxart_gpio_direction_output,
102	.set			= moxart_gpio_set,
103	.get			= moxart_gpio_get,
104	.ngpio			= 32,
105	.owner			= THIS_MODULE,
106};
107
108static int moxart_gpio_probe(struct platform_device *pdev)
109{
110	struct device *dev = &pdev->dev;
111	struct resource *res;
112	struct moxart_gpio_chip *mgc;
113	int ret;
114
115	mgc = devm_kzalloc(dev, sizeof(*mgc), GFP_KERNEL);
116	if (!mgc) {
117		dev_err(dev, "can't allocate GPIO chip container\n");
118		return -ENOMEM;
119	}
120	mgc->gpio = moxart_template_chip;
121
122	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
123	mgc->base = devm_ioremap_resource(dev, res);
124	if (IS_ERR(mgc->base))
125		return PTR_ERR(mgc->base);
126
127	mgc->gpio.dev = dev;
128
129	ret = gpiochip_add(&mgc->gpio);
130	if (ret) {
131		dev_err(dev, "%s: gpiochip_add failed\n",
132			dev->of_node->full_name);
133		return ret;
134	}
135
136	return 0;
137}
138
139static const struct of_device_id moxart_gpio_match[] = {
140	{ .compatible = "moxa,moxart-gpio" },
141	{ }
142};
143
144static struct platform_driver moxart_gpio_driver = {
145	.driver	= {
146		.name		= "moxart-gpio",
147		.owner		= THIS_MODULE,
148		.of_match_table	= moxart_gpio_match,
149	},
150	.probe	= moxart_gpio_probe,
151};
152module_platform_driver(moxart_gpio_driver);
153
154MODULE_DESCRIPTION("MOXART GPIO chip driver");
155MODULE_LICENSE("GPL");
156MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");