xref: /openbmc/linux/drivers/gpio/gpio-logicvc.c (revision 8020619a)
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_address.h>
12 #include <linux/platform_device.h>
13 #include <linux/regmap.h>
14 #include <linux/mfd/syscon.h>
15 
16 #define LOGICVC_CTRL_REG		0x40
17 #define LOGICVC_CTRL_GPIO_SHIFT		11
18 #define LOGICVC_CTRL_GPIO_BITS		5
19 
20 #define LOGICVC_POWER_CTRL_REG		0x78
21 #define LOGICVC_POWER_CTRL_GPIO_SHIFT	0
22 #define LOGICVC_POWER_CTRL_GPIO_BITS	4
23 
24 struct logicvc_gpio {
25 	struct gpio_chip chip;
26 	struct regmap *regmap;
27 };
28 
logicvc_gpio_offset(struct logicvc_gpio * logicvc,unsigned offset,unsigned int * reg,unsigned int * bit)29 static void logicvc_gpio_offset(struct logicvc_gpio *logicvc, unsigned offset,
30 				unsigned int *reg, unsigned int *bit)
31 {
32 	if (offset >= LOGICVC_CTRL_GPIO_BITS) {
33 		*reg = LOGICVC_POWER_CTRL_REG;
34 
35 		/* To the (virtual) power ctrl offset. */
36 		offset -= LOGICVC_CTRL_GPIO_BITS;
37 		/* To the actual bit offset in reg. */
38 		offset += LOGICVC_POWER_CTRL_GPIO_SHIFT;
39 	} else {
40 		*reg = LOGICVC_CTRL_REG;
41 
42 		/* To the actual bit offset in reg. */
43 		offset += LOGICVC_CTRL_GPIO_SHIFT;
44 	}
45 
46 	*bit = BIT(offset);
47 }
48 
logicvc_gpio_get(struct gpio_chip * chip,unsigned offset)49 static int logicvc_gpio_get(struct gpio_chip *chip, unsigned offset)
50 {
51 	struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
52 	unsigned int reg, bit, value;
53 	int ret;
54 
55 	logicvc_gpio_offset(logicvc, offset, &reg, &bit);
56 
57 	ret = regmap_read(logicvc->regmap, reg, &value);
58 	if (ret)
59 		return ret;
60 
61 	return !!(value & bit);
62 }
63 
logicvc_gpio_set(struct gpio_chip * chip,unsigned offset,int value)64 static void logicvc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
65 {
66 	struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
67 	unsigned int reg, bit;
68 
69 	logicvc_gpio_offset(logicvc, offset, &reg, &bit);
70 
71 	regmap_update_bits(logicvc->regmap, reg, bit, value ? bit : 0);
72 }
73 
logicvc_gpio_direction_output(struct gpio_chip * chip,unsigned offset,int value)74 static int logicvc_gpio_direction_output(struct gpio_chip *chip,
75 					 unsigned offset, int value)
76 {
77 	/* Pins are always configured as output, so just set the value. */
78 	logicvc_gpio_set(chip, offset, value);
79 
80 	return 0;
81 }
82 
83 static struct regmap_config logicvc_gpio_regmap_config = {
84 	.reg_bits	= 32,
85 	.val_bits	= 32,
86 	.reg_stride	= 4,
87 	.name		= "logicvc-gpio",
88 };
89 
logicvc_gpio_probe(struct platform_device * pdev)90 static int logicvc_gpio_probe(struct platform_device *pdev)
91 {
92 	struct device *dev = &pdev->dev;
93 	struct device_node *of_node = dev->of_node;
94 	struct logicvc_gpio *logicvc;
95 	int ret;
96 
97 	logicvc = devm_kzalloc(dev, sizeof(*logicvc), GFP_KERNEL);
98 	if (!logicvc)
99 		return -ENOMEM;
100 
101 	/* Try to get regmap from parent first. */
102 	logicvc->regmap = syscon_node_to_regmap(of_node->parent);
103 
104 	/* Grab our own regmap if that fails. */
105 	if (IS_ERR(logicvc->regmap)) {
106 		struct resource res;
107 		void __iomem *base;
108 
109 		ret = of_address_to_resource(of_node, 0, &res);
110 		if (ret) {
111 			dev_err(dev, "Failed to get resource from address\n");
112 			return ret;
113 		}
114 
115 		base = devm_ioremap_resource(dev, &res);
116 		if (IS_ERR(base))
117 			return PTR_ERR(base);
118 
119 		logicvc_gpio_regmap_config.max_register = resource_size(&res) -
120 			logicvc_gpio_regmap_config.reg_stride;
121 
122 		logicvc->regmap =
123 			devm_regmap_init_mmio(dev, base,
124 					      &logicvc_gpio_regmap_config);
125 		if (IS_ERR(logicvc->regmap)) {
126 			dev_err(dev, "Failed to create regmap for I/O\n");
127 			return PTR_ERR(logicvc->regmap);
128 		}
129 	}
130 
131 	logicvc->chip.parent = dev;
132 	logicvc->chip.owner = THIS_MODULE;
133 	logicvc->chip.label = dev_name(dev);
134 	logicvc->chip.base = -1;
135 	logicvc->chip.ngpio = LOGICVC_CTRL_GPIO_BITS +
136 			      LOGICVC_POWER_CTRL_GPIO_BITS;
137 	logicvc->chip.get = logicvc_gpio_get;
138 	logicvc->chip.set = logicvc_gpio_set;
139 	logicvc->chip.direction_output = logicvc_gpio_direction_output;
140 
141 	return devm_gpiochip_add_data(dev, &logicvc->chip, logicvc);
142 }
143 
144 static const struct of_device_id logicivc_gpio_of_table[] = {
145 	{
146 		.compatible	= "xylon,logicvc-3.02.a-gpio",
147 	},
148 	{ }
149 };
150 
151 MODULE_DEVICE_TABLE(of, logicivc_gpio_of_table);
152 
153 static struct platform_driver logicvc_gpio_driver = {
154 	.driver	= {
155 		.name		= "gpio-logicvc",
156 		.of_match_table	= logicivc_gpio_of_table,
157 	},
158 	.probe	= logicvc_gpio_probe,
159 };
160 
161 module_platform_driver(logicvc_gpio_driver);
162 
163 MODULE_AUTHOR("Paul Kocialkowski <paul.kocialkowski@bootlin.com>");
164 MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver");
165 MODULE_LICENSE("GPL");
166