1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Support for viafb GPIO ports.
4 *
5 * Copyright 2009 Jonathan Corbet <corbet@lwn.net>
6 */
7
8 #include <linux/spinlock.h>
9 #include <linux/gpio/driver.h>
10 #include <linux/platform_device.h>
11 #include <linux/via-core.h>
12 #include <linux/via-gpio.h>
13 #include <linux/export.h>
14
15 /*
16 * The ports we know about. Note that the port-25 gpios are not
17 * mentioned in the datasheet.
18 */
19
20 struct viafb_gpio {
21 char *vg_name; /* Data sheet name */
22 u16 vg_io_port;
23 u8 vg_port_index;
24 int vg_mask_shift;
25 };
26
27 static struct viafb_gpio viafb_all_gpios[] = {
28 {
29 .vg_name = "VGPIO0", /* Guess - not in datasheet */
30 .vg_io_port = VIASR,
31 .vg_port_index = 0x25,
32 .vg_mask_shift = 1
33 },
34 {
35 .vg_name = "VGPIO1",
36 .vg_io_port = VIASR,
37 .vg_port_index = 0x25,
38 .vg_mask_shift = 0
39 },
40 {
41 .vg_name = "VGPIO2", /* aka DISPCLKI0 */
42 .vg_io_port = VIASR,
43 .vg_port_index = 0x2c,
44 .vg_mask_shift = 1
45 },
46 {
47 .vg_name = "VGPIO3", /* aka DISPCLKO0 */
48 .vg_io_port = VIASR,
49 .vg_port_index = 0x2c,
50 .vg_mask_shift = 0
51 },
52 {
53 .vg_name = "VGPIO4", /* DISPCLKI1 */
54 .vg_io_port = VIASR,
55 .vg_port_index = 0x3d,
56 .vg_mask_shift = 1
57 },
58 {
59 .vg_name = "VGPIO5", /* DISPCLKO1 */
60 .vg_io_port = VIASR,
61 .vg_port_index = 0x3d,
62 .vg_mask_shift = 0
63 },
64 };
65
66 #define VIAFB_NUM_GPIOS ARRAY_SIZE(viafb_all_gpios)
67
68 /*
69 * This structure controls the active GPIOs, which may be a subset
70 * of those which are known.
71 */
72
73 struct viafb_gpio_cfg {
74 struct gpio_chip gpio_chip;
75 struct viafb_dev *vdev;
76 struct viafb_gpio *active_gpios[VIAFB_NUM_GPIOS];
77 const char *gpio_names[VIAFB_NUM_GPIOS];
78 };
79
80 /*
81 * GPIO access functions
82 */
via_gpio_set(struct gpio_chip * chip,unsigned int nr,int value)83 static void via_gpio_set(struct gpio_chip *chip, unsigned int nr,
84 int value)
85 {
86 struct viafb_gpio_cfg *cfg = gpiochip_get_data(chip);
87 u8 reg;
88 struct viafb_gpio *gpio;
89 unsigned long flags;
90
91 spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
92 gpio = cfg->active_gpios[nr];
93 reg = via_read_reg(VIASR, gpio->vg_port_index);
94 reg |= 0x40 << gpio->vg_mask_shift; /* output enable */
95 if (value)
96 reg |= 0x10 << gpio->vg_mask_shift;
97 else
98 reg &= ~(0x10 << gpio->vg_mask_shift);
99 via_write_reg(VIASR, gpio->vg_port_index, reg);
100 spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
101 }
102
via_gpio_dir_out(struct gpio_chip * chip,unsigned int nr,int value)103 static int via_gpio_dir_out(struct gpio_chip *chip, unsigned int nr,
104 int value)
105 {
106 via_gpio_set(chip, nr, value);
107 return 0;
108 }
109
110 /*
111 * Set the input direction. I'm not sure this is right; we should
112 * be able to do input without disabling output.
113 */
via_gpio_dir_input(struct gpio_chip * chip,unsigned int nr)114 static int via_gpio_dir_input(struct gpio_chip *chip, unsigned int nr)
115 {
116 struct viafb_gpio_cfg *cfg = gpiochip_get_data(chip);
117 struct viafb_gpio *gpio;
118 unsigned long flags;
119
120 spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
121 gpio = cfg->active_gpios[nr];
122 via_write_reg_mask(VIASR, gpio->vg_port_index, 0,
123 0x40 << gpio->vg_mask_shift);
124 spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
125 return 0;
126 }
127
via_gpio_get(struct gpio_chip * chip,unsigned int nr)128 static int via_gpio_get(struct gpio_chip *chip, unsigned int nr)
129 {
130 struct viafb_gpio_cfg *cfg = gpiochip_get_data(chip);
131 u8 reg;
132 struct viafb_gpio *gpio;
133 unsigned long flags;
134
135 spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
136 gpio = cfg->active_gpios[nr];
137 reg = via_read_reg(VIASR, gpio->vg_port_index);
138 spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
139 return !!(reg & (0x04 << gpio->vg_mask_shift));
140 }
141
142
143 static struct viafb_gpio_cfg viafb_gpio_config = {
144 .gpio_chip = {
145 .label = "VIAFB onboard GPIO",
146 .owner = THIS_MODULE,
147 .direction_output = via_gpio_dir_out,
148 .set = via_gpio_set,
149 .direction_input = via_gpio_dir_input,
150 .get = via_gpio_get,
151 .base = -1,
152 .ngpio = 0,
153 .can_sleep = 0
154 }
155 };
156
157 /*
158 * Manage the software enable bit.
159 */
viafb_gpio_enable(struct viafb_gpio * gpio)160 static void viafb_gpio_enable(struct viafb_gpio *gpio)
161 {
162 via_write_reg_mask(VIASR, gpio->vg_port_index, 0x02, 0x02);
163 }
164
viafb_gpio_disable(struct viafb_gpio * gpio)165 static void viafb_gpio_disable(struct viafb_gpio *gpio)
166 {
167 via_write_reg_mask(VIASR, gpio->vg_port_index, 0, 0x02);
168 }
169
170 #ifdef CONFIG_PM
171
viafb_gpio_suspend(void * private)172 static int viafb_gpio_suspend(void *private)
173 {
174 return 0;
175 }
176
viafb_gpio_resume(void * private)177 static int viafb_gpio_resume(void *private)
178 {
179 int i;
180
181 for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i += 2)
182 viafb_gpio_enable(viafb_gpio_config.active_gpios[i]);
183 return 0;
184 }
185
186 static struct viafb_pm_hooks viafb_gpio_pm_hooks = {
187 .suspend = viafb_gpio_suspend,
188 .resume = viafb_gpio_resume
189 };
190 #endif /* CONFIG_PM */
191
192 /*
193 * Look up a specific gpio and return the number it was assigned.
194 */
viafb_gpio_lookup(const char * name)195 int viafb_gpio_lookup(const char *name)
196 {
197 int i;
198
199 for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i++)
200 if (!strcmp(name, viafb_gpio_config.active_gpios[i]->vg_name))
201 return viafb_gpio_config.gpio_chip.base + i;
202 return -1;
203 }
204 EXPORT_SYMBOL_GPL(viafb_gpio_lookup);
205
206 /*
207 * Platform device stuff.
208 */
viafb_gpio_probe(struct platform_device * platdev)209 static int viafb_gpio_probe(struct platform_device *platdev)
210 {
211 struct viafb_dev *vdev = platdev->dev.platform_data;
212 struct via_port_cfg *port_cfg = vdev->port_cfg;
213 int i, ngpio = 0, ret;
214 struct viafb_gpio *gpio;
215 unsigned long flags;
216
217 /*
218 * Set up entries for all GPIOs which have been configured to
219 * operate as such (as opposed to as i2c ports).
220 */
221 for (i = 0; i < VIAFB_NUM_PORTS; i++) {
222 if (port_cfg[i].mode != VIA_MODE_GPIO)
223 continue;
224 for (gpio = viafb_all_gpios;
225 gpio < viafb_all_gpios + VIAFB_NUM_GPIOS; gpio++)
226 if (gpio->vg_port_index == port_cfg[i].ioport_index) {
227 viafb_gpio_config.active_gpios[ngpio] = gpio;
228 viafb_gpio_config.gpio_names[ngpio] =
229 gpio->vg_name;
230 ngpio++;
231 }
232 }
233 viafb_gpio_config.gpio_chip.ngpio = ngpio;
234 viafb_gpio_config.gpio_chip.names = viafb_gpio_config.gpio_names;
235 viafb_gpio_config.vdev = vdev;
236 if (ngpio == 0) {
237 printk(KERN_INFO "viafb: no GPIOs configured\n");
238 return 0;
239 }
240 /*
241 * Enable the ports. They come in pairs, with a single
242 * enable bit for both.
243 */
244 spin_lock_irqsave(&viafb_gpio_config.vdev->reg_lock, flags);
245 for (i = 0; i < ngpio; i += 2)
246 viafb_gpio_enable(viafb_gpio_config.active_gpios[i]);
247 spin_unlock_irqrestore(&viafb_gpio_config.vdev->reg_lock, flags);
248 /*
249 * Get registered.
250 */
251 viafb_gpio_config.gpio_chip.base = -1; /* Dynamic */
252 ret = gpiochip_add_data(&viafb_gpio_config.gpio_chip,
253 &viafb_gpio_config);
254 if (ret) {
255 printk(KERN_ERR "viafb: failed to add gpios (%d)\n", ret);
256 viafb_gpio_config.gpio_chip.ngpio = 0;
257 }
258 #ifdef CONFIG_PM
259 viafb_pm_register(&viafb_gpio_pm_hooks);
260 #endif
261 return ret;
262 }
263
264
viafb_gpio_remove(struct platform_device * platdev)265 static int viafb_gpio_remove(struct platform_device *platdev)
266 {
267 unsigned long flags;
268 int i;
269
270 #ifdef CONFIG_PM
271 viafb_pm_unregister(&viafb_gpio_pm_hooks);
272 #endif
273
274 /*
275 * Get unregistered.
276 */
277 if (viafb_gpio_config.gpio_chip.ngpio > 0) {
278 gpiochip_remove(&viafb_gpio_config.gpio_chip);
279 }
280 /*
281 * Disable the ports.
282 */
283 spin_lock_irqsave(&viafb_gpio_config.vdev->reg_lock, flags);
284 for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i += 2)
285 viafb_gpio_disable(viafb_gpio_config.active_gpios[i]);
286 viafb_gpio_config.gpio_chip.ngpio = 0;
287 spin_unlock_irqrestore(&viafb_gpio_config.vdev->reg_lock, flags);
288 return 0;
289 }
290
291 static struct platform_driver via_gpio_driver = {
292 .driver = {
293 .name = "viafb-gpio",
294 },
295 .probe = viafb_gpio_probe,
296 .remove = viafb_gpio_remove,
297 };
298
viafb_gpio_init(void)299 int viafb_gpio_init(void)
300 {
301 return platform_driver_register(&via_gpio_driver);
302 }
303
viafb_gpio_exit(void)304 void viafb_gpio_exit(void)
305 {
306 platform_driver_unregister(&via_gpio_driver);
307 }
308