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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; | |
55 | bool gpi_reserved; | |
56 | bool gpo_reserved; | |
57 | }; | |
58 | ||
59 | /* resolve a GPIx into the corresponding bit position */ | |
60 | static inline u_int32_t gpi_i_bit(int i) | |
61 | { | |
62 | if (i < 10) | |
63 | return 1 << i; | |
64 | else | |
65 | return 1 << (i + 14); | |
66 | } | |
67 | ||
68 | static inline u_int32_t gpo_o_bit(int i) | |
69 | { | |
70 | if (i < 11) | |
71 | return 1 << i; | |
72 | else | |
73 | return 1 << (i + 14); | |
74 | } | |
75 | ||
76 | static inline u_int32_t gpio_i_bit(int i) | |
77 | { | |
78 | if (i < 14) | |
79 | return 1 << (i + 10); | |
80 | else | |
81 | return 1 << (i + 14); | |
82 | } | |
83 | ||
84 | static inline u_int32_t gpio_o_bit(int i) | |
85 | { | |
86 | if (i < 14) | |
87 | return 1 << (i + 11); | |
88 | else | |
89 | return 1 << (i + 13); | |
90 | } | |
91 | ||
92 | /* Mapping betwee numeric GPIO ID and the actual GPIO hardware numbering: | |
93 | * 0..13 GPI 0..13 | |
94 | * 14..26 GPO 0..12 | |
95 | * 27..41 GPIO 0..14 | |
96 | */ | |
97 | ||
98 | static int vx855gpio_direction_input(struct gpio_chip *gpio, | |
99 | unsigned int nr) | |
100 | { | |
101 | struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio); | |
102 | unsigned long flags; | |
103 | u_int32_t reg_out; | |
104 | ||
105 | /* Real GPI bits are always in input direction */ | |
106 | if (nr < NR_VX855_GPI) | |
107 | return 0; | |
108 | ||
109 | /* Real GPO bits cannot be put in output direction */ | |
110 | if (nr < NR_VX855_GPInO) | |
111 | return -EINVAL; | |
112 | ||
113 | /* Open Drain GPIO have to be set to one */ | |
114 | spin_lock_irqsave(&vg->lock, flags); | |
115 | reg_out = inl(vg->io_gpo); | |
116 | reg_out |= gpio_o_bit(nr - NR_VX855_GPInO); | |
117 | outl(reg_out, vg->io_gpo); | |
118 | spin_unlock_irqrestore(&vg->lock, flags); | |
119 | ||
120 | return 0; | |
121 | } | |
122 | ||
123 | static int vx855gpio_get(struct gpio_chip *gpio, unsigned int nr) | |
124 | { | |
125 | struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio); | |
126 | u_int32_t reg_in; | |
127 | int ret = 0; | |
128 | ||
129 | if (nr < NR_VX855_GPI) { | |
130 | reg_in = inl(vg->io_gpi); | |
131 | if (reg_in & gpi_i_bit(nr)) | |
132 | ret = 1; | |
133 | } else if (nr < NR_VX855_GPInO) { | |
134 | /* GPO don't have an input bit, we need to read it | |
135 | * back from the output register */ | |
136 | reg_in = inl(vg->io_gpo); | |
137 | if (reg_in & gpo_o_bit(nr - NR_VX855_GPI)) | |
138 | ret = 1; | |
139 | } else { | |
140 | reg_in = inl(vg->io_gpi); | |
141 | if (reg_in & gpio_i_bit(nr - NR_VX855_GPInO)) | |
142 | ret = 1; | |
143 | } | |
144 | ||
145 | return ret; | |
146 | } | |
147 | ||
148 | static void vx855gpio_set(struct gpio_chip *gpio, unsigned int nr, | |
149 | int val) | |
150 | { | |
151 | struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio); | |
152 | unsigned long flags; | |
153 | u_int32_t reg_out; | |
154 | ||
155 | /* True GPI cannot be switched to output mode */ | |
156 | if (nr < NR_VX855_GPI) | |
157 | return; | |
158 | ||
159 | spin_lock_irqsave(&vg->lock, flags); | |
160 | reg_out = inl(vg->io_gpo); | |
161 | if (nr < NR_VX855_GPInO) { | |
162 | if (val) | |
163 | reg_out |= gpo_o_bit(nr - NR_VX855_GPI); | |
164 | else | |
165 | reg_out &= ~gpo_o_bit(nr - NR_VX855_GPI); | |
166 | } else { | |
167 | if (val) | |
168 | reg_out |= gpio_o_bit(nr - NR_VX855_GPInO); | |
169 | else | |
170 | reg_out &= ~gpio_o_bit(nr - NR_VX855_GPInO); | |
171 | } | |
172 | outl(reg_out, vg->io_gpo); | |
173 | spin_unlock_irqrestore(&vg->lock, flags); | |
174 | } | |
175 | ||
176 | static int vx855gpio_direction_output(struct gpio_chip *gpio, | |
177 | unsigned int nr, int val) | |
178 | { | |
179 | /* True GPI cannot be switched to output mode */ | |
180 | if (nr < NR_VX855_GPI) | |
181 | return -EINVAL; | |
182 | ||
183 | /* True GPO don't need to be switched to output mode, | |
184 | * and GPIO are open-drain, i.e. also need no switching, | |
185 | * so all we do is set the level */ | |
186 | vx855gpio_set(gpio, nr, val); | |
187 | ||
188 | return 0; | |
189 | } | |
190 | ||
191 | static const char *vx855gpio_names[NR_VX855_GP] = { | |
192 | "VX855_GPI0", "VX855_GPI1", "VX855_GPI2", "VX855_GPI3", "VX855_GPI4", | |
193 | "VX855_GPI5", "VX855_GPI6", "VX855_GPI7", "VX855_GPI8", "VX855_GPI9", | |
194 | "VX855_GPI10", "VX855_GPI11", "VX855_GPI12", "VX855_GPI13", | |
195 | "VX855_GPO0", "VX855_GPO1", "VX855_GPO2", "VX855_GPO3", "VX855_GPO4", | |
196 | "VX855_GPO5", "VX855_GPO6", "VX855_GPO7", "VX855_GPO8", "VX855_GPO9", | |
197 | "VX855_GPO10", "VX855_GPO11", "VX855_GPO12", | |
198 | "VX855_GPIO0", "VX855_GPIO1", "VX855_GPIO2", "VX855_GPIO3", | |
199 | "VX855_GPIO4", "VX855_GPIO5", "VX855_GPIO6", "VX855_GPIO7", | |
200 | "VX855_GPIO8", "VX855_GPIO9", "VX855_GPIO10", "VX855_GPIO11", | |
201 | "VX855_GPIO12", "VX855_GPIO13", "VX855_GPIO14" | |
202 | }; | |
203 | ||
204 | static void vx855gpio_gpio_setup(struct vx855_gpio *vg) | |
205 | { | |
206 | struct gpio_chip *c = &vg->gpio; | |
207 | ||
208 | c->label = "VX855 South Bridge"; | |
209 | c->owner = THIS_MODULE; | |
210 | c->direction_input = vx855gpio_direction_input; | |
211 | c->direction_output = vx855gpio_direction_output; | |
212 | c->get = vx855gpio_get; | |
213 | c->set = vx855gpio_set; | |
214 | c->dbg_show = NULL; | |
215 | c->base = 0; | |
216 | c->ngpio = NR_VX855_GP; | |
217 | c->can_sleep = 0; | |
218 | c->names = vx855gpio_names; | |
219 | } | |
220 | ||
221 | /* This platform device is ordinarily registered by the vx855 mfd driver */ | |
3836309d | 222 | static int vx855gpio_probe(struct platform_device *pdev) |
99ea2626 DD |
223 | { |
224 | struct resource *res_gpi; | |
225 | struct resource *res_gpo; | |
226 | struct vx855_gpio *vg; | |
227 | int ret; | |
228 | ||
229 | res_gpi = platform_get_resource(pdev, IORESOURCE_IO, 0); | |
230 | res_gpo = platform_get_resource(pdev, IORESOURCE_IO, 1); | |
231 | if (!res_gpi || !res_gpo) | |
232 | return -EBUSY; | |
233 | ||
234 | vg = kzalloc(sizeof(*vg), GFP_KERNEL); | |
235 | if (!vg) | |
236 | return -ENOMEM; | |
237 | ||
238 | platform_set_drvdata(pdev, vg); | |
239 | ||
240 | dev_info(&pdev->dev, "found VX855 GPIO controller\n"); | |
241 | vg->io_gpi = res_gpi->start; | |
242 | vg->io_gpo = res_gpo->start; | |
243 | spin_lock_init(&vg->lock); | |
244 | ||
245 | /* | |
246 | * A single byte is used to control various GPIO ports on the VX855, | |
247 | * and in the case of the OLPC XO-1.5, some of those ports are used | |
248 | * for switches that are interpreted and exposed through ACPI. ACPI | |
249 | * will have reserved the region, so our own reservation will not | |
250 | * succeed. Ignore and continue. | |
251 | */ | |
252 | ||
253 | if (!request_region(res_gpi->start, resource_size(res_gpi), | |
254 | MODULE_NAME "_gpi")) | |
255 | dev_warn(&pdev->dev, | |
256 | "GPI I/O resource busy, probably claimed by ACPI\n"); | |
257 | else | |
258 | vg->gpi_reserved = true; | |
259 | ||
260 | if (!request_region(res_gpo->start, resource_size(res_gpo), | |
261 | MODULE_NAME "_gpo")) | |
262 | dev_warn(&pdev->dev, | |
263 | "GPO I/O resource busy, probably claimed by ACPI\n"); | |
264 | else | |
265 | vg->gpo_reserved = true; | |
266 | ||
267 | vx855gpio_gpio_setup(vg); | |
268 | ||
269 | ret = gpiochip_add(&vg->gpio); | |
270 | if (ret) { | |
271 | dev_err(&pdev->dev, "failed to register GPIOs\n"); | |
272 | goto out_release; | |
273 | } | |
274 | ||
275 | return 0; | |
276 | ||
277 | out_release: | |
278 | if (vg->gpi_reserved) | |
279 | release_region(res_gpi->start, resource_size(res_gpi)); | |
280 | if (vg->gpo_reserved) | |
281 | release_region(res_gpi->start, resource_size(res_gpo)); | |
99ea2626 DD |
282 | kfree(vg); |
283 | return ret; | |
284 | } | |
285 | ||
206210ce | 286 | static int vx855gpio_remove(struct platform_device *pdev) |
99ea2626 DD |
287 | { |
288 | struct vx855_gpio *vg = platform_get_drvdata(pdev); | |
289 | struct resource *res; | |
290 | ||
291 | if (gpiochip_remove(&vg->gpio)) | |
292 | dev_err(&pdev->dev, "unable to remove gpio_chip?\n"); | |
293 | ||
294 | if (vg->gpi_reserved) { | |
295 | res = platform_get_resource(pdev, IORESOURCE_IO, 0); | |
296 | release_region(res->start, resource_size(res)); | |
297 | } | |
298 | if (vg->gpo_reserved) { | |
299 | res = platform_get_resource(pdev, IORESOURCE_IO, 1); | |
300 | release_region(res->start, resource_size(res)); | |
301 | } | |
302 | ||
99ea2626 DD |
303 | kfree(vg); |
304 | return 0; | |
305 | } | |
306 | ||
307 | static struct platform_driver vx855gpio_driver = { | |
308 | .driver = { | |
309 | .name = MODULE_NAME, | |
310 | .owner = THIS_MODULE, | |
311 | }, | |
312 | .probe = vx855gpio_probe, | |
8283c4ff | 313 | .remove = vx855gpio_remove, |
99ea2626 DD |
314 | }; |
315 | ||
6f61415e | 316 | module_platform_driver(vx855gpio_driver); |
99ea2626 DD |
317 | |
318 | MODULE_LICENSE("GPL"); | |
319 | MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>"); | |
320 | MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset"); | |
321 | MODULE_ALIAS("platform:vx855_gpio"); |