[linux-2.6-block.git] / drivers / gpio / gpio-spear-spics.c

/*
 * SPEAr platform SPI chipselect abstraction over gpiolib
 *
 * Copyright (C) 2012 ST Microelectronics
 * Shiraz Hashim <shiraz.linux.kernel@gmail.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/err.h>
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/types.h>

/* maximum chipselects */
#define NUM_OF_GPIO	4

/*
 * Provision is available on some SPEAr SoCs to control ARM PL022 spi cs
 * through system registers. This register lies outside spi (pl022)
 * address space into system registers.
 *
 * It provides control for spi chip select lines so that any chipselect
 * (out of 4 possible chipselects in pl022) can be made low to select
 * the particular slave.
 */

/**
 * struct spear_spics - represents spi chip select control
 * @base: base address
 * @perip_cfg: configuration register
 * @sw_enable_bit: bit to enable s/w control over chipselects
 * @cs_value_bit: bit to program high or low chipselect
 * @cs_enable_mask: mask to select bits required to select chipselect
 * @cs_enable_shift: bit pos of cs_enable_mask
 * @use_count: use count of a spi controller cs lines
 * @last_off: stores last offset caller of set_value()
 * @chip: gpio_chip abstraction
 */
struct spear_spics {
	void __iomem		*base;
	u32			perip_cfg;
	u32			sw_enable_bit;
	u32			cs_value_bit;
	u32			cs_enable_mask;
	u32			cs_enable_shift;
	unsigned long		use_count;
	int			last_off;
	struct gpio_chip	chip;
};

/* gpio framework specific routines */
static int spics_get_value(struct gpio_chip *chip, unsigned offset)
{
	return -ENXIO;
}

static void spics_set_value(struct gpio_chip *chip, unsigned offset, int value)
{
	struct spear_spics *spics = gpiochip_get_data(chip);
	u32 tmp;

	/* select chip select from register */
	tmp = readl_relaxed(spics->base + spics->perip_cfg);
	if (spics->last_off != offset) {
		spics->last_off = offset;
		tmp &= ~(spics->cs_enable_mask << spics->cs_enable_shift);
		tmp |= offset << spics->cs_enable_shift;
	}

	/* toggle chip select line */
	tmp &= ~(0x1 << spics->cs_value_bit);
	tmp |= value << spics->cs_value_bit;
	writel_relaxed(tmp, spics->base + spics->perip_cfg);
}

static int spics_direction_input(struct gpio_chip *chip, unsigned offset)
{
	return -ENXIO;
}

static int spics_direction_output(struct gpio_chip *chip, unsigned offset,
		int value)
{
	spics_set_value(chip, offset, value);
	return 0;
}

static int spics_request(struct gpio_chip *chip, unsigned offset)
{
	struct spear_spics *spics = gpiochip_get_data(chip);
	u32 tmp;

	if (!spics->use_count++) {
		tmp = readl_relaxed(spics->base + spics->perip_cfg);
		tmp |= 0x1 << spics->sw_enable_bit;
		tmp |= 0x1 << spics->cs_value_bit;
		writel_relaxed(tmp, spics->base + spics->perip_cfg);
	}

	return 0;
}

static void spics_free(struct gpio_chip *chip, unsigned offset)
{
	struct spear_spics *spics = gpiochip_get_data(chip);
	u32 tmp;

	if (!--spics->use_count) {
		tmp = readl_relaxed(spics->base + spics->perip_cfg);
		tmp &= ~(0x1 << spics->sw_enable_bit);
		writel_relaxed(tmp, spics->base + spics->perip_cfg);
	}
}

static int spics_gpio_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct spear_spics *spics;
	int ret;

	spics = devm_kzalloc(&pdev->dev, sizeof(*spics), GFP_KERNEL);
	if (!spics)
		return -ENOMEM;

	spics->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(spics->base))
		return PTR_ERR(spics->base);

	if (of_property_read_u32(np, "st-spics,peripcfg-reg",
				&spics->perip_cfg))
		goto err_dt_data;
	if (of_property_read_u32(np, "st-spics,sw-enable-bit",
				&spics->sw_enable_bit))
		goto err_dt_data;
	if (of_property_read_u32(np, "st-spics,cs-value-bit",
				&spics->cs_value_bit))
		goto err_dt_data;
	if (of_property_read_u32(np, "st-spics,cs-enable-mask",
				&spics->cs_enable_mask))
		goto err_dt_data;
	if (of_property_read_u32(np, "st-spics,cs-enable-shift",
				&spics->cs_enable_shift))
		goto err_dt_data;

	platform_set_drvdata(pdev, spics);

	spics->chip.ngpio = NUM_OF_GPIO;
	spics->chip.base = -1;
	spics->chip.request = spics_request;
	spics->chip.free = spics_free;
	spics->chip.direction_input = spics_direction_input;
	spics->chip.direction_output = spics_direction_output;
	spics->chip.get = spics_get_value;
	spics->chip.set = spics_set_value;
	spics->chip.label = dev_name(&pdev->dev);
	spics->chip.parent = &pdev->dev;
	spics->chip.owner = THIS_MODULE;
	spics->last_off = -1;

	ret = devm_gpiochip_add_data(&pdev->dev, &spics->chip, spics);
	if (ret) {
		dev_err(&pdev->dev, "unable to add gpio chip\n");
		return ret;
	}

	dev_info(&pdev->dev, "spear spics registered\n");
	return 0;

err_dt_data:
	dev_err(&pdev->dev, "DT probe failed\n");
	return -EINVAL;
}

static const struct of_device_id spics_gpio_of_match[] = {
	{ .compatible = "st,spear-spics-gpio" },
	{}
};

static struct platform_driver spics_gpio_driver = {
	.probe = spics_gpio_probe,
	.driver = {
		.name = "spear-spics-gpio",
		.of_match_table = spics_gpio_of_match,
	},
};

static int __init spics_gpio_init(void)
{
	return platform_driver_register(&spics_gpio_driver);
}
subsys_initcall(spics_gpio_init);
Commit	Line	Data
b53bc281 SH	1	/*
	2	* SPEAr platform SPI chipselect abstraction over gpiolib
	3	*
	4	* Copyright (C) 2012 ST Microelectronics
9cc23682	5	* Shiraz Hashim <shiraz.linux.kernel@gmail.com>
b53bc281 SH	6	*
	7	* This file is licensed under the terms of the GNU General Public
	8	* License version 2. This program is licensed "as is" without any
	9	* warranty of any kind, whether express or implied.
	10	*/
	11
	12	#include <linux/err.h>
9fc18cc5	13	#include <linux/gpio/driver.h>
b53bc281	14	#include <linux/io.h>
b29c5dda	15	#include <linux/init.h>
b53bc281 SH	16	#include <linux/of.h>
	17	#include <linux/platform_device.h>
	18	#include <linux/types.h>
	19
	20	/* maximum chipselects */
	21	#define NUM_OF_GPIO 4
	22
	23	/*
	24	* Provision is available on some SPEAr SoCs to control ARM PL022 spi cs
	25	* through system registers. This register lies outside spi (pl022)
	26	* address space into system registers.
	27	*
	28	* It provides control for spi chip select lines so that any chipselect
	29	* (out of 4 possible chipselects in pl022) can be made low to select
	30	* the particular slave.
	31	*/
	32
	33	/**
	34	* struct spear_spics - represents spi chip select control
	35	* @base: base address
	36	* @perip_cfg: configuration register
	37	* @sw_enable_bit: bit to enable s/w control over chipselects
	38	* @cs_value_bit: bit to program high or low chipselect
	39	* @cs_enable_mask: mask to select bits required to select chipselect
	40	* @cs_enable_shift: bit pos of cs_enable_mask
	41	* @use_count: use count of a spi controller cs lines
	42	* @last_off: stores last offset caller of set_value()
	43	* @chip: gpio_chip abstraction
	44	*/
	45	struct spear_spics {
	46	void __iomem *base;
	47	u32 perip_cfg;
	48	u32 sw_enable_bit;
	49	u32 cs_value_bit;
	50	u32 cs_enable_mask;
	51	u32 cs_enable_shift;
	52	unsigned long use_count;
	53	int last_off;
	54	struct gpio_chip chip;
	55	};
	56
	57	/* gpio framework specific routines */
	58	static int spics_get_value(struct gpio_chip *chip, unsigned offset)
	59	{
	60	return -ENXIO;
	61	}
	62
	63	static void spics_set_value(struct gpio_chip *chip, unsigned offset, int value)
	64	{
c0ad184a	65	struct spear_spics *spics = gpiochip_get_data(chip);
b53bc281 SH	66	u32 tmp;
	67
	68	/* select chip select from register */
	69	tmp = readl_relaxed(spics->base + spics->perip_cfg);
	70	if (spics->last_off != offset) {
	71	spics->last_off = offset;
	72	tmp &= ~(spics->cs_enable_mask << spics->cs_enable_shift);
	73	tmp \|= offset << spics->cs_enable_shift;
	74	}
	75
	76	/* toggle chip select line */
	77	tmp &= ~(0x1 << spics->cs_value_bit);
	78	tmp \|= value << spics->cs_value_bit;
	79	writel_relaxed(tmp, spics->base + spics->perip_cfg);
	80	}
	81
	82	static int spics_direction_input(struct gpio_chip *chip, unsigned offset)
	83	{
	84	return -ENXIO;
	85	}
	86
	87	static int spics_direction_output(struct gpio_chip *chip, unsigned offset,
	88	int value)
	89	{
	90	spics_set_value(chip, offset, value);
	91	return 0;
	92	}
	93
	94	static int spics_request(struct gpio_chip *chip, unsigned offset)
	95	{
c0ad184a	96	struct spear_spics *spics = gpiochip_get_data(chip);
b53bc281 SH	97	u32 tmp;
	98
	99	if (!spics->use_count++) {
	100	tmp = readl_relaxed(spics->base + spics->perip_cfg);
	101	tmp \|= 0x1 << spics->sw_enable_bit;
	102	tmp \|= 0x1 << spics->cs_value_bit;
	103	writel_relaxed(tmp, spics->base + spics->perip_cfg);
	104	}
	105
	106	return 0;
	107	}
	108
	109	static void spics_free(struct gpio_chip *chip, unsigned offset)
	110	{
c0ad184a	111	struct spear_spics *spics = gpiochip_get_data(chip);
b53bc281 SH	112	u32 tmp;
	113
	114	if (!--spics->use_count) {
	115	tmp = readl_relaxed(spics->base + spics->perip_cfg);
	116	tmp &= ~(0x1 << spics->sw_enable_bit);
	117	writel_relaxed(tmp, spics->base + spics->perip_cfg);
	118	}
	119	}
	120
	121	static int spics_gpio_probe(struct platform_device *pdev)
	122	{
	123	struct device_node *np = pdev->dev.of_node;
	124	struct spear_spics *spics;
b53bc281 SH	125	int ret;
b53bc281 SH	126
b53bc281	127	spics = devm_kzalloc(&pdev->dev, sizeof(*spics), GFP_KERNEL);
48b9750c	128	if (!spics)
b53bc281	129	return -ENOMEM;
b53bc281	130
7290f152	131	spics->base = devm_platform_ioremap_resource(pdev, 0);
641d0342 TR	132	if (IS_ERR(spics->base))
641d0342 TR	133	return PTR_ERR(spics->base);
b53bc281 SH	134
	135	if (of_property_read_u32(np, "st-spics,peripcfg-reg",
	136	&spics->perip_cfg))
	137	goto err_dt_data;
	138	if (of_property_read_u32(np, "st-spics,sw-enable-bit",
	139	&spics->sw_enable_bit))
	140	goto err_dt_data;
	141	if (of_property_read_u32(np, "st-spics,cs-value-bit",
	142	&spics->cs_value_bit))
	143	goto err_dt_data;
	144	if (of_property_read_u32(np, "st-spics,cs-enable-mask",
	145	&spics->cs_enable_mask))
	146	goto err_dt_data;
	147	if (of_property_read_u32(np, "st-spics,cs-enable-shift",
	148	&spics->cs_enable_shift))
	149	goto err_dt_data;
	150
	151	platform_set_drvdata(pdev, spics);
	152
	153	spics->chip.ngpio = NUM_OF_GPIO;
	154	spics->chip.base = -1;
	155	spics->chip.request = spics_request;
	156	spics->chip.free = spics_free;
	157	spics->chip.direction_input = spics_direction_input;
	158	spics->chip.direction_output = spics_direction_output;
	159	spics->chip.get = spics_get_value;
	160	spics->chip.set = spics_set_value;
	161	spics->chip.label = dev_name(&pdev->dev);
58383c78	162	spics->chip.parent = &pdev->dev;
b53bc281 SH	163	spics->chip.owner = THIS_MODULE;
	164	spics->last_off = -1;
	165
3d297bb0	166	ret = devm_gpiochip_add_data(&pdev->dev, &spics->chip, spics);
b53bc281 SH	167	if (ret) {
	168	dev_err(&pdev->dev, "unable to add gpio chip\n");
	169	return ret;
	170	}
	171
	172	dev_info(&pdev->dev, "spear spics registered\n");
	173	return 0;
	174
	175	err_dt_data:
	176	dev_err(&pdev->dev, "DT probe failed\n");
	177	return -EINVAL;
	178	}
	179
	180	static const struct of_device_id spics_gpio_of_match[] = {
	181	{ .compatible = "st,spear-spics-gpio" },
	182	{}
	183	};
b53bc281 SH	184
	185	static struct platform_driver spics_gpio_driver = {
	186	.probe = spics_gpio_probe,
	187	.driver = {
b53bc281 SH	188	.name = "spear-spics-gpio",
	189	.of_match_table = spics_gpio_of_match,
	190	},
	191	};
	192
	193	static int __init spics_gpio_init(void)
	194	{
	195	return platform_driver_register(&spics_gpio_driver);
	196	}
	197	subsys_initcall(spics_gpio_init);