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 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, ®, &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