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