[deliverable/linux.git] / drivers / gpio / gpio-kempld.c

/*
 * Kontron PLD GPIO driver
 *
 * Copyright (c) 2010-2013 Kontron Europe GmbH
 * Author: Michael Brunner <michael.brunner@kontron.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License 2 as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/mfd/kempld.h>

#define KEMPLD_GPIO_MAX_NUM		16
#define KEMPLD_GPIO_MASK(x)		(1 << ((x) % 8))
#define KEMPLD_GPIO_DIR_NUM(x)		(0x40 + (x) / 8)
#define KEMPLD_GPIO_LVL_NUM(x)		(0x42 + (x) / 8)
#define KEMPLD_GPIO_EVT_LVL_EDGE	0x46
#define KEMPLD_GPIO_IEN			0x4A

struct kempld_gpio_data {
	struct gpio_chip		chip;
	struct kempld_device_data	*pld;
};

/*
 * Set or clear GPIO bit
 * kempld_get_mutex must be called prior to calling this function.
 */
static void kempld_gpio_bitop(struct kempld_device_data *pld,
			      u8 reg, u8 bit, u8 val)
{
	u8 status;

	status = kempld_read8(pld, reg);
	if (val)
		status |= (1 << bit);
	else
		status &= ~(1 << bit);
	kempld_write8(pld, reg, status);
}

static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit)
{
	u8 status;

	kempld_get_mutex(pld);
	status = kempld_read8(pld, reg);
	kempld_release_mutex(pld);

	return !!(status & (1 << bit));
}

static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct kempld_gpio_data *gpio
		= container_of(chip, struct kempld_gpio_data, chip);
	struct kempld_device_data *pld = gpio->pld;

	return kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset),
				   KEMPLD_GPIO_MASK(offset));
}

static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
	struct kempld_gpio_data *gpio
		= container_of(chip, struct kempld_gpio_data, chip);
	struct kempld_device_data *pld = gpio->pld;

	kempld_get_mutex(pld);
	kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset),
			  KEMPLD_GPIO_MASK(offset), value);
	kempld_release_mutex(pld);
}

static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
	struct kempld_gpio_data *gpio
		= container_of(chip, struct kempld_gpio_data, chip);
	struct kempld_device_data *pld = gpio->pld;

	kempld_get_mutex(pld);
	kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset),
			  KEMPLD_GPIO_MASK(offset), 0);
	kempld_release_mutex(pld);

	return 0;
}

static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
					int value)
{
	struct kempld_gpio_data *gpio
		= container_of(chip, struct kempld_gpio_data, chip);
	struct kempld_device_data *pld = gpio->pld;

	kempld_get_mutex(pld);
	kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset),
			  KEMPLD_GPIO_MASK(offset), value);
	kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset),
			  KEMPLD_GPIO_MASK(offset), 1);
	kempld_release_mutex(pld);

	return 0;
}

static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
	struct kempld_gpio_data *gpio
		= container_of(chip, struct kempld_gpio_data, chip);
	struct kempld_device_data *pld = gpio->pld;

	return kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset),
				   KEMPLD_GPIO_MASK(offset));
}

static int kempld_gpio_pincount(struct kempld_device_data *pld)
{
	u16 evt, evt_back;

	kempld_get_mutex(pld);

	/* Backup event register as it might be already initialized */
	evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
	/* Clear event register */
	kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000);
	/* Read back event register */
	evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
	/* Restore event register */
	kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back);

	kempld_release_mutex(pld);

	return evt ? __ffs(evt) : 16;
}

static int kempld_gpio_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct kempld_device_data *pld = dev_get_drvdata(dev->parent);
	struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
	struct kempld_gpio_data *gpio;
	struct gpio_chip *chip;
	int ret;

	if (pld->info.spec_major < 2) {
		dev_err(dev,
			"Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");
		return -ENODEV;
	}

	gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
	if (gpio == NULL)
		return -ENOMEM;

	gpio->pld = pld;

	platform_set_drvdata(pdev, gpio);

	chip = &gpio->chip;
	chip->label = "gpio-kempld";
	chip->owner = THIS_MODULE;
	chip->dev = dev;
	chip->can_sleep = 1;
	if (pdata && pdata->gpio_base)
		chip->base = pdata->gpio_base;
	else
		chip->base = -1;
	chip->direction_input = kempld_gpio_direction_input;
	chip->direction_output = kempld_gpio_direction_output;
	chip->get_direction = kempld_gpio_get_direction;
	chip->get = kempld_gpio_get;
	chip->set = kempld_gpio_set;
	chip->ngpio = kempld_gpio_pincount(pld);
	if (chip->ngpio == 0) {
		dev_err(dev, "No GPIO pins detected\n");
		return -ENODEV;
	}

	ret = gpiochip_add(chip);
	if (ret) {
		dev_err(dev, "Could not register GPIO chip\n");
		return ret;
	}

	dev_info(dev, "GPIO functionality initialized with %d pins\n",
		 chip->ngpio);

	return 0;
}

static int kempld_gpio_remove(struct platform_device *pdev)
{
	struct kempld_gpio_data *gpio = platform_get_drvdata(pdev);

	return gpiochip_remove(&gpio->chip);
}

static struct platform_driver kempld_gpio_driver = {
	.driver = {
		.name = "kempld-gpio",
		.owner = THIS_MODULE,
	},
	.probe		= kempld_gpio_probe,
	.remove		= kempld_gpio_remove,
};

module_platform_driver(kempld_gpio_driver);

MODULE_DESCRIPTION("KEM PLD GPIO Driver");
MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:gpio-kempld");
Commit	Line	Data
d22fcde0 GR	1	/*
	2	* Kontron PLD GPIO driver
	3	*
	4	* Copyright (c) 2010-2013 Kontron Europe GmbH
	5	* Author: Michael Brunner <michael.brunner@kontron.com>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License 2 as published
	9	* by the Free Software Foundation.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*/
	16
	17	#include <linux/init.h>
	18	#include <linux/kernel.h>
	19	#include <linux/module.h>
	20	#include <linux/bitops.h>
	21	#include <linux/errno.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/gpio.h>
	24	#include <linux/mfd/kempld.h>
	25
	26	#define KEMPLD_GPIO_MAX_NUM 16
	27	#define KEMPLD_GPIO_MASK(x) (1 << ((x) % 8))
	28	#define KEMPLD_GPIO_DIR_NUM(x) (0x40 + (x) / 8)
	29	#define KEMPLD_GPIO_LVL_NUM(x) (0x42 + (x) / 8)
	30	#define KEMPLD_GPIO_EVT_LVL_EDGE 0x46
	31	#define KEMPLD_GPIO_IEN 0x4A
	32
	33	struct kempld_gpio_data {
	34	struct gpio_chip chip;
	35	struct kempld_device_data *pld;
	36	};
	37
	38	/*
	39	* Set or clear GPIO bit
	40	* kempld_get_mutex must be called prior to calling this function.
	41	*/
	42	static void kempld_gpio_bitop(struct kempld_device_data *pld,
	43	u8 reg, u8 bit, u8 val)
	44	{
	45	u8 status;
	46
	47	status = kempld_read8(pld, reg);
	48	if (val)
	49	status \|= (1 << bit);
	50	else
	51	status &= ~(1 << bit);
	52	kempld_write8(pld, reg, status);
	53	}
	54
	55	static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit)
	56	{
	57	u8 status;
	58
	59	kempld_get_mutex(pld);
	60	status = kempld_read8(pld, reg);
	61	kempld_release_mutex(pld);
	62
	63	return !!(status & (1 << bit));
	64	}
65
66	static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset)
67	{
68	struct kempld_gpio_data *gpio
69	= container_of(chip, struct kempld_gpio_data, chip);
70	struct kempld_device_data *pld = gpio->pld;
71
72	return kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset),
73	KEMPLD_GPIO_MASK(offset));
74	}
75
76	static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
77	{
78	struct kempld_gpio_data *gpio
79	= container_of(chip, struct kempld_gpio_data, chip);
80	struct kempld_device_data *pld = gpio->pld;
81
82	kempld_get_mutex(pld);
83	kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset),
84	KEMPLD_GPIO_MASK(offset), value);
85	kempld_release_mutex(pld);
86	}
87
88	static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
89	{
90	struct kempld_gpio_data *gpio
91	= container_of(chip, struct kempld_gpio_data, chip);
92	struct kempld_device_data *pld = gpio->pld;
93
94	kempld_get_mutex(pld);
95	kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset),
96	KEMPLD_GPIO_MASK(offset), 0);
97	kempld_release_mutex(pld);
98
99	return 0;
100	}
101
102	static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
103	int value)
104	{
105	struct kempld_gpio_data *gpio
106	= container_of(chip, struct kempld_gpio_data, chip);
107	struct kempld_device_data *pld = gpio->pld;
108
109	kempld_get_mutex(pld);
110	kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset),
111	KEMPLD_GPIO_MASK(offset), value);
112	kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset),
113	KEMPLD_GPIO_MASK(offset), 1);
114	kempld_release_mutex(pld);
115
116	return 0;
117	}
118
119	static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
120	{
121	struct kempld_gpio_data *gpio
122	= container_of(chip, struct kempld_gpio_data, chip);
123	struct kempld_device_data *pld = gpio->pld;
124
125	return kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset),
126	KEMPLD_GPIO_MASK(offset));
127	}
128
129	static int kempld_gpio_pincount(struct kempld_device_data *pld)
130	{
131	u16 evt, evt_back;
132
133	kempld_get_mutex(pld);
134
135	/* Backup event register as it might be already initialized */
136	evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
137	/* Clear event register */
138	kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000);
139	/* Read back event register */
140	evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
141	/* Restore event register */
142	kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back);
143
144	kempld_release_mutex(pld);
145
146	return evt ? __ffs(evt) : 16;
147	}
148
149	static int kempld_gpio_probe(struct platform_device *pdev)
150	{
151	struct device *dev = &pdev->dev;
152	struct kempld_device_data *pld = dev_get_drvdata(dev->parent);
e56aee18	153	struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
d22fcde0 GR	154	struct kempld_gpio_data *gpio;
	155	struct gpio_chip *chip;
	156	int ret;
	157
	158	if (pld->info.spec_major < 2) {
	159	dev_err(dev,
	160	"Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");
	161	return -ENODEV;
	162	}
	163
	164	gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
	165	if (gpio == NULL)
	166	return -ENOMEM;
	167
	168	gpio->pld = pld;
	169
	170	platform_set_drvdata(pdev, gpio);
	171
	172	chip = &gpio->chip;
	173	chip->label = "gpio-kempld";
	174	chip->owner = THIS_MODULE;
	175	chip->dev = dev;
	176	chip->can_sleep = 1;
	177	if (pdata && pdata->gpio_base)
	178	chip->base = pdata->gpio_base;
	179	else
	180	chip->base = -1;
	181	chip->direction_input = kempld_gpio_direction_input;
	182	chip->direction_output = kempld_gpio_direction_output;
	183	chip->get_direction = kempld_gpio_get_direction;
	184	chip->get = kempld_gpio_get;
	185	chip->set = kempld_gpio_set;
	186	chip->ngpio = kempld_gpio_pincount(pld);
	187	if (chip->ngpio == 0) {
	188	dev_err(dev, "No GPIO pins detected\n");
	189	return -ENODEV;
	190	}
	191
	192	ret = gpiochip_add(chip);
	193	if (ret) {
	194	dev_err(dev, "Could not register GPIO chip\n");
	195	return ret;
	196	}
	197
	198	dev_info(dev, "GPIO functionality initialized with %d pins\n",
	199	chip->ngpio);
	200
	201	return 0;
	202	}
	203
	204	static int kempld_gpio_remove(struct platform_device *pdev)
	205	{
	206	struct kempld_gpio_data *gpio = platform_get_drvdata(pdev);
	207
	208	return gpiochip_remove(&gpio->chip);
	209	}
	210
	211	static struct platform_driver kempld_gpio_driver = {
	212	.driver = {
81e9df2c	213	.name = "kempld-gpio",
d22fcde0 GR	214	.owner = THIS_MODULE,
	215	},
	216	.probe = kempld_gpio_probe,
	217	.remove = kempld_gpio_remove,
	218	};
	219
	220	module_platform_driver(kempld_gpio_driver);
	221
	222	MODULE_DESCRIPTION("KEM PLD GPIO Driver");
	223	MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
	224	MODULE_LICENSE("GPL");
	225	MODULE_ALIAS("platform:gpio-kempld");