Commit | Line | Data |
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6596e59e SM |
1 | /* |
2 | * GPIO driver for Exar XR17V35X chip | |
3 | * | |
4 | * Copyright (C) 2015 Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | */ | |
10 | #include <linux/bitops.h> | |
11 | #include <linux/device.h> | |
12 | #include <linux/gpio/driver.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/pci.h> | |
17 | #include <linux/platform_device.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 | ||
26 | static DEFINE_IDA(ida_index); | |
27 | ||
28 | struct exar_gpio_chip { | |
29 | struct gpio_chip gpio_chip; | |
30 | struct mutex lock; | |
31 | int index; | |
32 | void __iomem *regs; | |
33 | char name[20]; | |
34 | }; | |
35 | ||
36 | static void exar_update(struct gpio_chip *chip, unsigned int reg, int val, | |
37 | unsigned int offset) | |
38 | { | |
39 | struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); | |
40 | int temp; | |
41 | ||
42 | mutex_lock(&exar_gpio->lock); | |
43 | temp = readb(exar_gpio->regs + reg); | |
44 | temp &= ~BIT(offset); | |
45 | if (val) | |
46 | temp |= BIT(offset); | |
47 | writeb(temp, exar_gpio->regs + reg); | |
48 | mutex_unlock(&exar_gpio->lock); | |
49 | } | |
50 | ||
51 | static int exar_set_direction(struct gpio_chip *chip, int direction, | |
52 | unsigned int offset) | |
53 | { | |
54 | unsigned int bank = offset / 8; | |
55 | unsigned int addr; | |
56 | ||
57 | addr = bank ? EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO; | |
58 | exar_update(chip, addr, direction, offset % 8); | |
59 | return 0; | |
60 | } | |
61 | ||
62 | static int exar_direction_output(struct gpio_chip *chip, unsigned int offset, | |
63 | int value) | |
64 | { | |
65 | return exar_set_direction(chip, 0, offset); | |
66 | } | |
67 | ||
68 | static int exar_direction_input(struct gpio_chip *chip, unsigned int offset) | |
69 | { | |
70 | return exar_set_direction(chip, 1, offset); | |
71 | } | |
72 | ||
73 | static int exar_get(struct gpio_chip *chip, unsigned int reg) | |
74 | { | |
75 | struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip); | |
76 | int value; | |
77 | ||
78 | mutex_lock(&exar_gpio->lock); | |
79 | value = readb(exar_gpio->regs + reg); | |
80 | mutex_unlock(&exar_gpio->lock); | |
81 | ||
82 | return !!value; | |
83 | } | |
84 | ||
85 | static int exar_get_direction(struct gpio_chip *chip, unsigned int offset) | |
86 | { | |
87 | unsigned int bank = offset / 8; | |
88 | unsigned int addr; | |
89 | int val; | |
90 | ||
91 | addr = bank ? EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO; | |
92 | val = exar_get(chip, addr) >> (offset % 8); | |
93 | ||
94 | return !!val; | |
95 | } | |
96 | ||
97 | static int exar_get_value(struct gpio_chip *chip, unsigned int offset) | |
98 | { | |
99 | unsigned int bank = offset / 8; | |
100 | unsigned int addr; | |
101 | int val; | |
102 | ||
103 | addr = bank ? EXAR_OFFSET_MPIOLVL_LO : EXAR_OFFSET_MPIOLVL_HI; | |
104 | val = exar_get(chip, addr) >> (offset % 8); | |
105 | ||
106 | return !!val; | |
107 | } | |
108 | ||
109 | static void exar_set_value(struct gpio_chip *chip, unsigned int offset, | |
110 | int value) | |
111 | { | |
112 | unsigned int bank = offset / 8; | |
113 | unsigned int addr; | |
114 | ||
115 | addr = bank ? EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO; | |
116 | exar_update(chip, addr, value, offset % 8); | |
117 | } | |
118 | ||
119 | static int gpio_exar_probe(struct platform_device *pdev) | |
120 | { | |
121 | struct pci_dev *pcidev = platform_get_drvdata(pdev); | |
122 | struct exar_gpio_chip *exar_gpio; | |
123 | void __iomem *p; | |
124 | int index, ret; | |
125 | ||
126 | if (pcidev->vendor != PCI_VENDOR_ID_EXAR) | |
127 | return -ENODEV; | |
128 | ||
129 | /* | |
130 | * Map the pci device to get the register addresses. | |
131 | * We will need to read and write those registers to control | |
132 | * the GPIO pins. | |
133 | * Using managed functions will save us from unmaping on exit. | |
134 | * As the device is enabled using managed functions by the | |
135 | * UART driver we can also use managed functions here. | |
136 | */ | |
137 | p = pcim_iomap(pcidev, 0, 0); | |
138 | if (!p) | |
139 | return -ENOMEM; | |
140 | ||
141 | exar_gpio = devm_kzalloc(&pcidev->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 | ||
149 | sprintf(exar_gpio->name, "exar_gpio%d", index); | |
150 | exar_gpio->gpio_chip.label = exar_gpio->name; | |
151 | exar_gpio->gpio_chip.parent = &pcidev->dev; | |
152 | exar_gpio->gpio_chip.direction_output = exar_direction_output; | |
153 | exar_gpio->gpio_chip.direction_input = exar_direction_input; | |
154 | exar_gpio->gpio_chip.get_direction = exar_get_direction; | |
155 | exar_gpio->gpio_chip.get = exar_get_value; | |
156 | exar_gpio->gpio_chip.set = exar_set_value; | |
157 | exar_gpio->gpio_chip.base = -1; | |
158 | exar_gpio->gpio_chip.ngpio = 16; | |
159 | exar_gpio->regs = p; | |
160 | exar_gpio->index = index; | |
161 | ||
162 | ret = devm_gpiochip_add_data(&pcidev->dev, | |
163 | &exar_gpio->gpio_chip, exar_gpio); | |
164 | if (ret) | |
165 | goto err_destroy; | |
166 | ||
167 | platform_set_drvdata(pdev, exar_gpio); | |
168 | ||
169 | return 0; | |
170 | ||
171 | err_destroy: | |
172 | ida_simple_remove(&ida_index, index); | |
173 | mutex_destroy(&exar_gpio->lock); | |
174 | return ret; | |
175 | } | |
176 | ||
177 | static int gpio_exar_remove(struct platform_device *pdev) | |
178 | { | |
179 | struct exar_gpio_chip *exar_gpio = platform_get_drvdata(pdev); | |
180 | ||
181 | ida_simple_remove(&ida_index, exar_gpio->index); | |
182 | mutex_destroy(&exar_gpio->lock); | |
183 | ||
184 | return 0; | |
185 | } | |
186 | ||
187 | static struct platform_driver gpio_exar_driver = { | |
188 | .probe = gpio_exar_probe, | |
189 | .remove = gpio_exar_remove, | |
190 | .driver = { | |
191 | .name = DRIVER_NAME, | |
192 | }, | |
193 | }; | |
194 | ||
195 | module_platform_driver(gpio_exar_driver); | |
196 | ||
197 | MODULE_ALIAS("platform:" DRIVER_NAME); | |
198 | MODULE_DESCRIPTION("Exar GPIO driver"); | |
199 | MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>"); | |
200 | MODULE_LICENSE("GPL"); |