1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Copyright (C) 2019 Bootlin
  4 * Author: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
  5 */
  6
  7#include <linux/err.h>
  8#include <linux/gpio/driver.h>
  9#include <linux/module.h>
 10#include <linux/of.h>
 11#include <linux/of_device.h>
 12#include <linux/of_address.h>
 13#include <linux/platform_device.h>
 14#include <linux/regmap.h>
 15#include <linux/mfd/syscon.h>
 16
 17#define LOGICVC_CTRL_REG		0x40
 18#define LOGICVC_CTRL_GPIO_SHIFT		11
 19#define LOGICVC_CTRL_GPIO_BITS		5
 20
 21#define LOGICVC_POWER_CTRL_REG		0x78
 22#define LOGICVC_POWER_CTRL_GPIO_SHIFT	0
 23#define LOGICVC_POWER_CTRL_GPIO_BITS	4
 24
 25struct logicvc_gpio {
 26	struct gpio_chip chip;
 27	struct regmap *regmap;
 28};
 29
 30static void logicvc_gpio_offset(struct logicvc_gpio *logicvc, unsigned offset,
 31				unsigned int *reg, unsigned int *bit)
 32{
 33	if (offset >= LOGICVC_CTRL_GPIO_BITS) {
 34		*reg = LOGICVC_POWER_CTRL_REG;
 35
 36		/* To the (virtual) power ctrl offset. */
 37		offset -= LOGICVC_CTRL_GPIO_BITS;
 38		/* To the actual bit offset in reg. */
 39		offset += LOGICVC_POWER_CTRL_GPIO_SHIFT;
 40	} else {
 41		*reg = LOGICVC_CTRL_REG;
 42
 43		/* To the actual bit offset in reg. */
 44		offset += LOGICVC_CTRL_GPIO_SHIFT;
 45	}
 46
 47	*bit = BIT(offset);
 48}
 49
 50static int logicvc_gpio_get(struct gpio_chip *chip, unsigned offset)
 51{
 52	struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
 53	unsigned int reg, bit, value;
 54	int ret;
 55
 56	logicvc_gpio_offset(logicvc, offset, &reg, &bit);
 57
 58	ret = regmap_read(logicvc->regmap, reg, &value);
 59	if (ret)
 60		return ret;
 61
 62	return !!(value & bit);
 63}
 64
 65static void logicvc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 66{
 67	struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
 68	unsigned int reg, bit;
 69
 70	logicvc_gpio_offset(logicvc, offset, &reg, &bit);
 71
 72	regmap_update_bits(logicvc->regmap, reg, bit, value ? bit : 0);
 73}
 74
 75static int logicvc_gpio_direction_output(struct gpio_chip *chip,
 76					 unsigned offset, int value)
 77{
 78	/* Pins are always configured as output, so just set the value. */
 79	logicvc_gpio_set(chip, offset, value);
 80
 81	return 0;
 82}
 83
 84static struct regmap_config logicvc_gpio_regmap_config = {
 85	.reg_bits	= 32,
 86	.val_bits	= 32,
 87	.reg_stride	= 4,
 88	.name		= "logicvc-gpio",
 89};
 90
 91static int logicvc_gpio_probe(struct platform_device *pdev)
 92{
 93	struct device *dev = &pdev->dev;
 94	struct device_node *of_node = dev->of_node;
 95	struct logicvc_gpio *logicvc;
 96	int ret;
 97
 98	logicvc = devm_kzalloc(dev, sizeof(*logicvc), GFP_KERNEL);
 99	if (!logicvc)
100		return -ENOMEM;
101
102	/* Try to get regmap from parent first. */
103	logicvc->regmap = syscon_node_to_regmap(of_node->parent);
104
105	/* Grab our own regmap if that fails. */
106	if (IS_ERR(logicvc->regmap)) {
107		struct resource res;
108		void __iomem *base;
109
110		ret = of_address_to_resource(of_node, 0, &res);
111		if (ret) {
112			dev_err(dev, "Failed to get resource from address\n");
113			return ret;
114		}
115
116		base = devm_ioremap_resource(dev, &res);
117		if (IS_ERR(base))
118			return PTR_ERR(base);
119
120		logicvc_gpio_regmap_config.max_register = resource_size(&res) -
121			logicvc_gpio_regmap_config.reg_stride;
122
123		logicvc->regmap =
124			devm_regmap_init_mmio(dev, base,
125					      &logicvc_gpio_regmap_config);
126		if (IS_ERR(logicvc->regmap)) {
127			dev_err(dev, "Failed to create regmap for I/O\n");
128			return PTR_ERR(logicvc->regmap);
129		}
130	}
131
132	logicvc->chip.parent = dev;
133	logicvc->chip.owner = THIS_MODULE;
134	logicvc->chip.label = dev_name(dev);
135	logicvc->chip.base = -1;
136	logicvc->chip.ngpio = LOGICVC_CTRL_GPIO_BITS +
137			      LOGICVC_POWER_CTRL_GPIO_BITS;
138	logicvc->chip.get = logicvc_gpio_get;
139	logicvc->chip.set = logicvc_gpio_set;
140	logicvc->chip.direction_output = logicvc_gpio_direction_output;
141
142	platform_set_drvdata(pdev, logicvc);
143
144	return devm_gpiochip_add_data(dev, &logicvc->chip, logicvc);
145}
146
147static const struct of_device_id logicivc_gpio_of_table[] = {
148	{
149		.compatible	= "xylon,logicvc-3.02.a-gpio",
150	},
151	{ }
152};
153
154MODULE_DEVICE_TABLE(of, logicivc_gpio_of_table);
155
156static struct platform_driver logicvc_gpio_driver = {
157	.driver	= {
158		.name		= "gpio-logicvc",
159		.of_match_table	= logicivc_gpio_of_table,
160	},
161	.probe	= logicvc_gpio_probe,
162};
163
164module_platform_driver(logicvc_gpio_driver);
165
166MODULE_AUTHOR("Paul Kocialkowski <paul.kocialkowski@bootlin.com>");
167MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver");
168MODULE_LICENSE("GPL");