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, ®, &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 int offset,int value)64 static int logicvc_gpio_set(struct gpio_chip *chip, unsigned int offset,
65 int value)
66 {
67 struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
68 unsigned int reg, bit;
69
70 logicvc_gpio_offset(logicvc, offset, ®, &bit);
71
72 return 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 return logicvc_gpio_set(chip, offset, value);
80 }
81
82 static struct regmap_config logicvc_gpio_regmap_config = {
83 .reg_bits = 32,
84 .val_bits = 32,
85 .reg_stride = 4,
86 .name = "logicvc-gpio",
87 };
88
logicvc_gpio_probe(struct platform_device * pdev)89 static int logicvc_gpio_probe(struct platform_device *pdev)
90 {
91 struct device *dev = &pdev->dev;
92 struct device_node *of_node = dev->of_node;
93 struct logicvc_gpio *logicvc;
94 int ret;
95
96 logicvc = devm_kzalloc(dev, sizeof(*logicvc), GFP_KERNEL);
97 if (!logicvc)
98 return -ENOMEM;
99
100 /* Try to get regmap from parent first. */
101 logicvc->regmap = syscon_node_to_regmap(of_node->parent);
102
103 /* Grab our own regmap if that fails. */
104 if (IS_ERR(logicvc->regmap)) {
105 struct resource res;
106 void __iomem *base;
107
108 ret = of_address_to_resource(of_node, 0, &res);
109 if (ret) {
110 dev_err(dev, "Failed to get resource from address\n");
111 return ret;
112 }
113
114 base = devm_ioremap_resource(dev, &res);
115 if (IS_ERR(base))
116 return PTR_ERR(base);
117
118 logicvc_gpio_regmap_config.max_register = resource_size(&res) -
119 logicvc_gpio_regmap_config.reg_stride;
120
121 logicvc->regmap =
122 devm_regmap_init_mmio(dev, base,
123 &logicvc_gpio_regmap_config);
124 if (IS_ERR(logicvc->regmap)) {
125 dev_err(dev, "Failed to create regmap for I/O\n");
126 return PTR_ERR(logicvc->regmap);
127 }
128 }
129
130 logicvc->chip.parent = dev;
131 logicvc->chip.owner = THIS_MODULE;
132 logicvc->chip.label = dev_name(dev);
133 logicvc->chip.base = -1;
134 logicvc->chip.ngpio = LOGICVC_CTRL_GPIO_BITS +
135 LOGICVC_POWER_CTRL_GPIO_BITS;
136 logicvc->chip.get = logicvc_gpio_get;
137 logicvc->chip.set_rv = logicvc_gpio_set;
138 logicvc->chip.direction_output = logicvc_gpio_direction_output;
139
140 return devm_gpiochip_add_data(dev, &logicvc->chip, logicvc);
141 }
142
143 static const struct of_device_id logicivc_gpio_of_table[] = {
144 {
145 .compatible = "xylon,logicvc-3.02.a-gpio",
146 },
147 { }
148 };
149
150 MODULE_DEVICE_TABLE(of, logicivc_gpio_of_table);
151
152 static struct platform_driver logicvc_gpio_driver = {
153 .driver = {
154 .name = "gpio-logicvc",
155 .of_match_table = logicivc_gpio_of_table,
156 },
157 .probe = logicvc_gpio_probe,
158 };
159
160 module_platform_driver(logicvc_gpio_driver);
161
162 MODULE_AUTHOR("Paul Kocialkowski <paul.kocialkowski@bootlin.com>");
163 MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver");
164 MODULE_LICENSE("GPL");
165