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99ea2626 DD |
1 | /* |
2 | * Linux GPIOlib driver for the VIA VX855 integrated southbridge GPIO | |
3 | * | |
4 | * Copyright (C) 2009 VIA Technologies, Inc. | |
5 | * Copyright (C) 2010 One Laptop per Child | |
6 | * Author: Harald Welte <HaraldWelte@viatech.com> | |
7 | * All rights reserved. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License as | |
11 | * published by the Free Software Foundation; either version 2 of | |
12 | * the License, or (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program; if not, write to the Free Software | |
21 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, | |
22 | * MA 02111-1307 USA | |
23 | * | |
24 | */ | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | #include <linux/module.h> | |
28 | #include <linux/gpio.h> | |
c5e7043e | 29 | #include <linux/slab.h> |
99ea2626 DD |
30 | #include <linux/device.h> |
31 | #include <linux/platform_device.h> | |
32 | #include <linux/pci.h> | |
33 | #include <linux/io.h> | |
34 | ||
35 | #define MODULE_NAME "vx855_gpio" | |
36 | ||
37 | /* The VX855 south bridge has the following GPIO pins: | |
38 | * GPI 0...13 General Purpose Input | |
39 | * GPO 0...12 General Purpose Output | |
40 | * GPIO 0...14 General Purpose I/O (Open-Drain) | |
41 | */ | |
42 | ||
43 | #define NR_VX855_GPI 14 | |
44 | #define NR_VX855_GPO 13 | |
45 | #define NR_VX855_GPIO 15 | |
46 | ||
47 | #define NR_VX855_GPInO (NR_VX855_GPI + NR_VX855_GPO) | |
48 | #define NR_VX855_GP (NR_VX855_GPI + NR_VX855_GPO + NR_VX855_GPIO) | |
49 | ||
50 | struct vx855_gpio { | |
51 | struct gpio_chip gpio; | |
52 | spinlock_t lock; | |
53 | u32 io_gpi; | |
54 | u32 io_gpo; | |
99ea2626 DD |
55 | }; |
56 | ||
57 | /* resolve a GPIx into the corresponding bit position */ | |
58 | static inline u_int32_t gpi_i_bit(int i) | |
59 | { | |
60 | if (i < 10) | |
61 | return 1 << i; | |
62 | else | |
63 | return 1 << (i + 14); | |
64 | } | |
65 | ||
66 | static inline u_int32_t gpo_o_bit(int i) | |
67 | { | |
68 | if (i < 11) | |
69 | return 1 << i; | |
70 | else | |
71 | return 1 << (i + 14); | |
72 | } | |
73 | ||
74 | static inline u_int32_t gpio_i_bit(int i) | |
75 | { | |
76 | if (i < 14) | |
77 | return 1 << (i + 10); | |
78 | else | |
79 | return 1 << (i + 14); | |
80 | } | |
81 | ||
82 | static inline u_int32_t gpio_o_bit(int i) | |
83 | { | |
84 | if (i < 14) | |
85 | return 1 << (i + 11); | |
86 | else | |
87 | return 1 << (i + 13); | |
88 | } | |
89 | ||
90 | /* Mapping betwee numeric GPIO ID and the actual GPIO hardware numbering: | |
91 | * 0..13 GPI 0..13 | |
92 | * 14..26 GPO 0..12 | |
93 | * 27..41 GPIO 0..14 | |
94 | */ | |
95 | ||
96 | static int vx855gpio_direction_input(struct gpio_chip *gpio, | |
97 | unsigned int nr) | |
98 | { | |
99 | struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio); | |
100 | unsigned long flags; | |
101 | u_int32_t reg_out; | |
102 | ||
103 | /* Real GPI bits are always in input direction */ | |
104 | if (nr < NR_VX855_GPI) | |
105 | return 0; | |
106 | ||
107 | /* Real GPO bits cannot be put in output direction */ | |
108 | if (nr < NR_VX855_GPInO) | |
109 | return -EINVAL; | |
110 | ||
111 | /* Open Drain GPIO have to be set to one */ | |
112 | spin_lock_irqsave(&vg->lock, flags); | |
113 | reg_out = inl(vg->io_gpo); | |
114 | reg_out |= gpio_o_bit(nr - NR_VX855_GPInO); | |
115 | outl(reg_out, vg->io_gpo); | |
116 | spin_unlock_irqrestore(&vg->lock, flags); | |
117 | ||
118 | return 0; | |
119 | } | |
120 | ||
121 | static int vx855gpio_get(struct gpio_chip *gpio, unsigned int nr) | |
122 | { | |
123 | struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio); | |
124 | u_int32_t reg_in; | |
125 | int ret = 0; | |
126 | ||
127 | if (nr < NR_VX855_GPI) { | |
128 | reg_in = inl(vg->io_gpi); | |
129 | if (reg_in & gpi_i_bit(nr)) | |
130 | ret = 1; | |
131 | } else if (nr < NR_VX855_GPInO) { | |
132 | /* GPO don't have an input bit, we need to read it | |
133 | * back from the output register */ | |
134 | reg_in = inl(vg->io_gpo); | |
135 | if (reg_in & gpo_o_bit(nr - NR_VX855_GPI)) | |
136 | ret = 1; | |
137 | } else { | |
138 | reg_in = inl(vg->io_gpi); | |
139 | if (reg_in & gpio_i_bit(nr - NR_VX855_GPInO)) | |
140 | ret = 1; | |
141 | } | |
142 | ||
143 | return ret; | |
144 | } | |
145 | ||
146 | static void vx855gpio_set(struct gpio_chip *gpio, unsigned int nr, | |
147 | int val) | |
148 | { | |
149 | struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio); | |
150 | unsigned long flags; | |
151 | u_int32_t reg_out; | |
152 | ||
153 | /* True GPI cannot be switched to output mode */ | |
154 | if (nr < NR_VX855_GPI) | |
155 | return; | |
156 | ||
157 | spin_lock_irqsave(&vg->lock, flags); | |
158 | reg_out = inl(vg->io_gpo); | |
159 | if (nr < NR_VX855_GPInO) { | |
160 | if (val) | |
161 | reg_out |= gpo_o_bit(nr - NR_VX855_GPI); | |
162 | else | |
163 | reg_out &= ~gpo_o_bit(nr - NR_VX855_GPI); | |
164 | } else { | |
165 | if (val) | |
166 | reg_out |= gpio_o_bit(nr - NR_VX855_GPInO); | |
167 | else | |
168 | reg_out &= ~gpio_o_bit(nr - NR_VX855_GPInO); | |
169 | } | |
170 | outl(reg_out, vg->io_gpo); | |
171 | spin_unlock_irqrestore(&vg->lock, flags); | |
172 | } | |
173 | ||
174 | static int vx855gpio_direction_output(struct gpio_chip *gpio, | |
175 | unsigned int nr, int val) | |
176 | { | |
177 | /* True GPI cannot be switched to output mode */ | |
178 | if (nr < NR_VX855_GPI) | |
179 | return -EINVAL; | |
180 | ||
181 | /* True GPO don't need to be switched to output mode, | |
182 | * and GPIO are open-drain, i.e. also need no switching, | |
183 | * so all we do is set the level */ | |
184 | vx855gpio_set(gpio, nr, val); | |
185 | ||
186 | return 0; | |
187 | } | |
188 | ||
189 | static const char *vx855gpio_names[NR_VX855_GP] = { | |
190 | "VX855_GPI0", "VX855_GPI1", "VX855_GPI2", "VX855_GPI3", "VX855_GPI4", | |
191 | "VX855_GPI5", "VX855_GPI6", "VX855_GPI7", "VX855_GPI8", "VX855_GPI9", | |
192 | "VX855_GPI10", "VX855_GPI11", "VX855_GPI12", "VX855_GPI13", | |
193 | "VX855_GPO0", "VX855_GPO1", "VX855_GPO2", "VX855_GPO3", "VX855_GPO4", | |
194 | "VX855_GPO5", "VX855_GPO6", "VX855_GPO7", "VX855_GPO8", "VX855_GPO9", | |
195 | "VX855_GPO10", "VX855_GPO11", "VX855_GPO12", | |
196 | "VX855_GPIO0", "VX855_GPIO1", "VX855_GPIO2", "VX855_GPIO3", | |
197 | "VX855_GPIO4", "VX855_GPIO5", "VX855_GPIO6", "VX855_GPIO7", | |
198 | "VX855_GPIO8", "VX855_GPIO9", "VX855_GPIO10", "VX855_GPIO11", | |
199 | "VX855_GPIO12", "VX855_GPIO13", "VX855_GPIO14" | |
200 | }; | |
201 | ||
202 | static void vx855gpio_gpio_setup(struct vx855_gpio *vg) | |
203 | { | |
204 | struct gpio_chip *c = &vg->gpio; | |
205 | ||
206 | c->label = "VX855 South Bridge"; | |
207 | c->owner = THIS_MODULE; | |
208 | c->direction_input = vx855gpio_direction_input; | |
209 | c->direction_output = vx855gpio_direction_output; | |
210 | c->get = vx855gpio_get; | |
211 | c->set = vx855gpio_set; | |
212 | c->dbg_show = NULL; | |
213 | c->base = 0; | |
214 | c->ngpio = NR_VX855_GP; | |
9fb1f39e | 215 | c->can_sleep = false; |
99ea2626 DD |
216 | c->names = vx855gpio_names; |
217 | } | |
218 | ||
219 | /* This platform device is ordinarily registered by the vx855 mfd driver */ | |
3836309d | 220 | static int vx855gpio_probe(struct platform_device *pdev) |
99ea2626 DD |
221 | { |
222 | struct resource *res_gpi; | |
223 | struct resource *res_gpo; | |
224 | struct vx855_gpio *vg; | |
99ea2626 DD |
225 | |
226 | res_gpi = platform_get_resource(pdev, IORESOURCE_IO, 0); | |
227 | res_gpo = platform_get_resource(pdev, IORESOURCE_IO, 1); | |
228 | if (!res_gpi || !res_gpo) | |
229 | return -EBUSY; | |
230 | ||
5b6a342b | 231 | vg = devm_kzalloc(&pdev->dev, sizeof(*vg), GFP_KERNEL); |
99ea2626 DD |
232 | if (!vg) |
233 | return -ENOMEM; | |
234 | ||
235 | platform_set_drvdata(pdev, vg); | |
236 | ||
237 | dev_info(&pdev->dev, "found VX855 GPIO controller\n"); | |
238 | vg->io_gpi = res_gpi->start; | |
239 | vg->io_gpo = res_gpo->start; | |
240 | spin_lock_init(&vg->lock); | |
241 | ||
242 | /* | |
243 | * A single byte is used to control various GPIO ports on the VX855, | |
244 | * and in the case of the OLPC XO-1.5, some of those ports are used | |
245 | * for switches that are interpreted and exposed through ACPI. ACPI | |
246 | * will have reserved the region, so our own reservation will not | |
247 | * succeed. Ignore and continue. | |
248 | */ | |
249 | ||
5b6a342b AL |
250 | if (!devm_request_region(&pdev->dev, res_gpi->start, |
251 | resource_size(res_gpi), MODULE_NAME "_gpi")) | |
99ea2626 DD |
252 | dev_warn(&pdev->dev, |
253 | "GPI I/O resource busy, probably claimed by ACPI\n"); | |
99ea2626 | 254 | |
5b6a342b AL |
255 | if (!devm_request_region(&pdev->dev, res_gpo->start, |
256 | resource_size(res_gpo), MODULE_NAME "_gpo")) | |
99ea2626 DD |
257 | dev_warn(&pdev->dev, |
258 | "GPO I/O resource busy, probably claimed by ACPI\n"); | |
99ea2626 DD |
259 | |
260 | vx855gpio_gpio_setup(vg); | |
261 | ||
5b6a342b | 262 | return gpiochip_add(&vg->gpio); |
99ea2626 DD |
263 | } |
264 | ||
206210ce | 265 | static int vx855gpio_remove(struct platform_device *pdev) |
99ea2626 DD |
266 | { |
267 | struct vx855_gpio *vg = platform_get_drvdata(pdev); | |
99ea2626 | 268 | |
9f5132ae | 269 | gpiochip_remove(&vg->gpio); |
99ea2626 | 270 | |
99ea2626 DD |
271 | return 0; |
272 | } | |
273 | ||
274 | static struct platform_driver vx855gpio_driver = { | |
275 | .driver = { | |
276 | .name = MODULE_NAME, | |
99ea2626 DD |
277 | }, |
278 | .probe = vx855gpio_probe, | |
8283c4ff | 279 | .remove = vx855gpio_remove, |
99ea2626 DD |
280 | }; |
281 | ||
6f61415e | 282 | module_platform_driver(vx855gpio_driver); |
99ea2626 DD |
283 | |
284 | MODULE_LICENSE("GPL"); | |
285 | MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>"); | |
286 | MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset"); | |
287 | MODULE_ALIAS("platform:vx855_gpio"); |