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 
25 struct logicvc_gpio {
26 	struct gpio_chip chip;
27 	struct regmap *regmap;
28 };
29 
logicvc_gpio_offset(struct logicvc_gpio * logicvc,unsigned offset,unsigned int * reg,unsigned int * bit)30 static 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 
logicvc_gpio_get(struct gpio_chip * chip,unsigned offset)50 static 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 
logicvc_gpio_set(struct gpio_chip * chip,unsigned offset,int value)65 static 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 
logicvc_gpio_direction_output(struct gpio_chip * chip,unsigned offset,int value)75 static 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 
84 static 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 
logicvc_gpio_probe(struct platform_device * pdev)91 static 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 
147 static const struct of_device_id logicivc_gpio_of_table[] = {
148 	{
149 		.compatible	= "xylon,logicvc-3.02.a-gpio",
150 	},
151 	{ }
152 };
153 
154 MODULE_DEVICE_TABLE(of, logicivc_gpio_of_table);
155 
156 static 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 
164 module_platform_driver(logicvc_gpio_driver);
165 
166 MODULE_AUTHOR("Paul Kocialkowski <paul.kocialkowski@bootlin.com>");
167 MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver");
168 MODULE_LICENSE("GPL");
169