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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * GPIO driver for Exar XR17V35X chip
4 *
5 * Copyright (C) 2015 Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
6 */
7
8#include <linux/bitops.h>
9#include <linux/device.h>
10#include <linux/gpio/driver.h>
11#include <linux/idr.h>
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/pci.h>
16#include <linux/platform_device.h>
17#include <linux/regmap.h>
18
19#define EXAR_OFFSET_MPIOLVL_LO 0x90
20#define EXAR_OFFSET_MPIOSEL_LO 0x93
21#define EXAR_OFFSET_MPIOLVL_HI 0x96
22#define EXAR_OFFSET_MPIOSEL_HI 0x99
23
24#define DRIVER_NAME "gpio_exar"
25
26static DEFINE_IDA(ida_index);
27
28struct exar_gpio_chip {
29 struct gpio_chip gpio_chip;
30 struct regmap *regmap;
31 int index;
32 char name[20];
33 unsigned int first_pin;
34};
35
36static unsigned int
37exar_offset_to_sel_addr(struct exar_gpio_chip *exar_gpio, unsigned int offset)
38{
39 return (offset + exar_gpio->first_pin) / 8 ? EXAR_OFFSET_MPIOSEL_HI
40 : EXAR_OFFSET_MPIOSEL_LO;
41}
42
43static unsigned int
44exar_offset_to_lvl_addr(struct exar_gpio_chip *exar_gpio, unsigned int offset)
45{
46 return (offset + exar_gpio->first_pin) / 8 ? EXAR_OFFSET_MPIOLVL_HI
47 : EXAR_OFFSET_MPIOLVL_LO;
48}
49
50static unsigned int
51exar_offset_to_bit(struct exar_gpio_chip *exar_gpio, unsigned int offset)
52{
53 return (offset + exar_gpio->first_pin) % 8;
54}
55
56static int exar_get_direction(struct gpio_chip *chip, unsigned int offset)
57{
58 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
59 unsigned int addr = exar_offset_to_sel_addr(exar_gpio, offset);
60 unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
61
62 if (regmap_test_bits(exar_gpio->regmap, addr, BIT(bit)))
63 return GPIO_LINE_DIRECTION_IN;
64
65 return GPIO_LINE_DIRECTION_OUT;
66}
67
68static int exar_get_value(struct gpio_chip *chip, unsigned int offset)
69{
70 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
71 unsigned int addr = exar_offset_to_lvl_addr(exar_gpio, offset);
72 unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
73
74 return !!(regmap_test_bits(exar_gpio->regmap, addr, BIT(bit)));
75}
76
77static void exar_set_value(struct gpio_chip *chip, unsigned int offset,
78 int value)
79{
80 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
81 unsigned int addr = exar_offset_to_lvl_addr(exar_gpio, offset);
82 unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
83
84 if (value)
85 regmap_set_bits(exar_gpio->regmap, addr, BIT(bit));
86 else
87 regmap_clear_bits(exar_gpio->regmap, addr, BIT(bit));
88}
89
90static int exar_direction_output(struct gpio_chip *chip, unsigned int offset,
91 int value)
92{
93 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
94 unsigned int addr = exar_offset_to_sel_addr(exar_gpio, offset);
95 unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
96
97 exar_set_value(chip, offset, value);
98 regmap_clear_bits(exar_gpio->regmap, addr, BIT(bit));
99
100 return 0;
101}
102
103static int exar_direction_input(struct gpio_chip *chip, unsigned int offset)
104{
105 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
106 unsigned int addr = exar_offset_to_sel_addr(exar_gpio, offset);
107 unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
108
109 regmap_set_bits(exar_gpio->regmap, addr, BIT(bit));
110
111 return 0;
112}
113
114static void exar_devm_ida_free(void *data)
115{
116 struct exar_gpio_chip *exar_gpio = data;
117
118 ida_free(&ida_index, exar_gpio->index);
119}
120
121static const struct regmap_config exar_regmap_config = {
122 .name = "exar-gpio",
123 .reg_bits = 16,
124 .val_bits = 8,
125};
126
127static int gpio_exar_probe(struct platform_device *pdev)
128{
129 struct device *dev = &pdev->dev;
130 struct pci_dev *pcidev = to_pci_dev(dev->parent);
131 struct exar_gpio_chip *exar_gpio;
132 u32 first_pin, ngpios;
133 void __iomem *p;
134 int index, ret;
135
136 /*
137 * The UART driver must have mapped region 0 prior to registering this
138 * device - use it.
139 */
140 p = pcim_iomap_table(pcidev)[0];
141 if (!p)
142 return -ENOMEM;
143
144 ret = device_property_read_u32(dev, "exar,first-pin", &first_pin);
145 if (ret)
146 return ret;
147
148 ret = device_property_read_u32(dev, "ngpios", &ngpios);
149 if (ret)
150 return ret;
151
152 exar_gpio = devm_kzalloc(dev, sizeof(*exar_gpio), GFP_KERNEL);
153 if (!exar_gpio)
154 return -ENOMEM;
155
156 /*
157 * We don't need to check the return values of mmio regmap operations (unless
158 * the regmap has a clock attached which is not the case here).
159 */
160 exar_gpio->regmap = devm_regmap_init_mmio(dev, p, &exar_regmap_config);
161 if (IS_ERR(exar_gpio->regmap))
162 return PTR_ERR(exar_gpio->regmap);
163
164 index = ida_alloc(&ida_index, GFP_KERNEL);
165 if (index < 0)
166 return index;
167
168 ret = devm_add_action_or_reset(dev, exar_devm_ida_free, exar_gpio);
169 if (ret)
170 return ret;
171
172 sprintf(exar_gpio->name, "exar_gpio%d", index);
173 exar_gpio->gpio_chip.label = exar_gpio->name;
174 exar_gpio->gpio_chip.parent = dev;
175 exar_gpio->gpio_chip.direction_output = exar_direction_output;
176 exar_gpio->gpio_chip.direction_input = exar_direction_input;
177 exar_gpio->gpio_chip.get_direction = exar_get_direction;
178 exar_gpio->gpio_chip.get = exar_get_value;
179 exar_gpio->gpio_chip.set = exar_set_value;
180 exar_gpio->gpio_chip.base = -1;
181 exar_gpio->gpio_chip.ngpio = ngpios;
182 exar_gpio->index = index;
183 exar_gpio->first_pin = first_pin;
184
185 ret = devm_gpiochip_add_data(dev, &exar_gpio->gpio_chip, exar_gpio);
186 if (ret)
187 return ret;
188
189 platform_set_drvdata(pdev, exar_gpio);
190
191 return 0;
192}
193
194static struct platform_driver gpio_exar_driver = {
195 .probe = gpio_exar_probe,
196 .driver = {
197 .name = DRIVER_NAME,
198 },
199};
200
201module_platform_driver(gpio_exar_driver);
202
203MODULE_ALIAS("platform:" DRIVER_NAME);
204MODULE_DESCRIPTION("Exar GPIO driver");
205MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>");
206MODULE_LICENSE("GPL");