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, ®, &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, ®, &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