tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#include <linux/bitops.h>
8#include <linux/device.h>
9#include <linux/gpio/driver.h>
10#include <linux/init.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/pci.h>
14#include <linux/platform_device.h>
15
16#define EXAR_OFFSET_MPIOLVL_LO 0x90
17#define EXAR_OFFSET_MPIOSEL_LO 0x93
18#define EXAR_OFFSET_MPIOLVL_HI 0x96
19#define EXAR_OFFSET_MPIOSEL_HI 0x99
20
21#define DRIVER_NAME "gpio_exar"
22
23static DEFINE_IDA(ida_index);
24
25struct exar_gpio_chip {
26 struct gpio_chip gpio_chip;
27 struct mutex lock;
28 int index;
29 void __iomem *regs;
30 char name[20];
31 unsigned int first_pin;
32};
33
34static void exar_update(struct gpio_chip *chip, unsigned int reg, int val,
35 unsigned int offset)
36{
37 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
38 int temp;
39
40 mutex_lock(&exar_gpio->lock);
41 temp = readb(exar_gpio->regs + reg);
42 temp &= ~BIT(offset);
43 if (val)
44 temp |= BIT(offset);
45 writeb(temp, exar_gpio->regs + reg);
46 mutex_unlock(&exar_gpio->lock);
47}
48
49static int exar_set_direction(struct gpio_chip *chip, int direction,
50 unsigned int offset)
51{
52 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
53 unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
54 EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
55 unsigned int bit = (offset + exar_gpio->first_pin) % 8;
56
57 exar_update(chip, addr, direction, bit);
58 return 0;
59}
60
61static int exar_get(struct gpio_chip *chip, unsigned int reg)
62{
63 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
64 int value;
65
66 mutex_lock(&exar_gpio->lock);
67 value = readb(exar_gpio->regs + reg);
68 mutex_unlock(&exar_gpio->lock);
69
70 return value;
71}
72
73static int exar_get_direction(struct gpio_chip *chip, unsigned int offset)
74{
75 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
76 unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
77 EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
78 unsigned int bit = (offset + exar_gpio->first_pin) % 8;
79
80 return !!(exar_get(chip, addr) & BIT(bit));
81}
82
83static int exar_get_value(struct gpio_chip *chip, unsigned int offset)
84{
85 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
86 unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
87 EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
88 unsigned int bit = (offset + exar_gpio->first_pin) % 8;
89
90 return !!(exar_get(chip, addr) & BIT(bit));
91}
92
93static void exar_set_value(struct gpio_chip *chip, unsigned int offset,
94 int value)
95{
96 struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
97 unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
98 EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
99 unsigned int bit = (offset + exar_gpio->first_pin) % 8;
100
101 exar_update(chip, addr, value, bit);
102}
103
104static int exar_direction_output(struct gpio_chip *chip, unsigned int offset,
105 int value)
106{
107 exar_set_value(chip, offset, value);
108 return exar_set_direction(chip, 0, offset);
109}
110
111static int exar_direction_input(struct gpio_chip *chip, unsigned int offset)
112{
113 return exar_set_direction(chip, 1, offset);
114}
115
116static int gpio_exar_probe(struct platform_device *pdev)
117{
118 struct pci_dev *pcidev = to_pci_dev(pdev->dev.parent);
119 struct exar_gpio_chip *exar_gpio;
120 u32 first_pin, ngpios;
121 void __iomem *p;
122 int index, ret;
123
124 /*
125 * The UART driver must have mapped region 0 prior to registering this
126 * device - use it.
127 */
128 p = pcim_iomap_table(pcidev)[0];
129 if (!p)
130 return -ENOMEM;
131
132 ret = device_property_read_u32(&pdev->dev, "exar,first-pin",
133 &first_pin);
134 if (ret)
135 return ret;
136
137 ret = device_property_read_u32(&pdev->dev, "ngpios", &ngpios);
138 if (ret)
139 return ret;
140
141 exar_gpio = devm_kzalloc(&pdev->dev, sizeof(*exar_gpio), GFP_KERNEL);
142 if (!exar_gpio)
143 return -ENOMEM;
144
145 mutex_init(&exar_gpio->lock);
146
147 index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL);
148 if (index < 0)
149 goto err_destroy;
150
151 sprintf(exar_gpio->name, "exar_gpio%d", index);
152 exar_gpio->gpio_chip.label = exar_gpio->name;
153 exar_gpio->gpio_chip.parent = &pdev->dev;
154 exar_gpio->gpio_chip.direction_output = exar_direction_output;
155 exar_gpio->gpio_chip.direction_input = exar_direction_input;
156 exar_gpio->gpio_chip.get_direction = exar_get_direction;
157 exar_gpio->gpio_chip.get = exar_get_value;
158 exar_gpio->gpio_chip.set = exar_set_value;
159 exar_gpio->gpio_chip.base = -1;
160 exar_gpio->gpio_chip.ngpio = ngpios;
161 exar_gpio->regs = p;
162 exar_gpio->index = index;
163 exar_gpio->first_pin = first_pin;
164
165 ret = devm_gpiochip_add_data(&pdev->dev,
166 &exar_gpio->gpio_chip, exar_gpio);
167 if (ret)
168 goto err_destroy;
169
170 platform_set_drvdata(pdev, exar_gpio);
171
172 return 0;
173
174err_destroy:
175 ida_simple_remove(&ida_index, index);
176 mutex_destroy(&exar_gpio->lock);
177 return ret;
178}
179
180static int gpio_exar_remove(struct platform_device *pdev)
181{
182 struct exar_gpio_chip *exar_gpio = platform_get_drvdata(pdev);
183
184 ida_simple_remove(&ida_index, exar_gpio->index);
185 mutex_destroy(&exar_gpio->lock);
186
187 return 0;
188}
189
190static struct platform_driver gpio_exar_driver = {
191 .probe = gpio_exar_probe,
192 .remove = gpio_exar_remove,
193 .driver = {
194 .name = DRIVER_NAME,
195 },
196};
197
198module_platform_driver(gpio_exar_driver);
199
200MODULE_ALIAS("platform:" DRIVER_NAME);
201MODULE_DESCRIPTION("Exar GPIO driver");
202MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>");
203MODULE_LICENSE("GPL");