2 * Support for viafb GPIO ports.
4 * Copyright 2009 Jonathan Corbet <corbet@lwn.net>
5 * Distributable under version 2 of the GNU General Public License.
8 #include <linux/spinlock.h>
9 #include <linux/gpio.h>
15 * The ports we know about. Note that the port-25 gpios are not
16 * mentioned in the datasheet.
20 char *vg_name; /* Data sheet name */
26 static struct viafb_gpio viafb_all_gpios[] = {
28 .vg_name = "VGPIO0", /* Guess - not in datasheet */
30 .vg_port_index = 0x25,
36 .vg_port_index = 0x25,
40 .vg_name = "VGPIO2", /* aka DISPCLKI0 */
42 .vg_port_index = 0x2c,
46 .vg_name = "VGPIO3", /* aka DISPCLKO0 */
48 .vg_port_index = 0x2c,
52 .vg_name = "VGPIO4", /* DISPCLKI1 */
54 .vg_port_index = 0x3d,
58 .vg_name = "VGPIO5", /* DISPCLKO1 */
60 .vg_port_index = 0x3d,
65 #define VIAFB_NUM_GPIOS ARRAY_SIZE(viafb_all_gpios)
68 * This structure controls the active GPIOs, which may be a subset
69 * of those which are known.
72 struct viafb_gpio_cfg {
73 struct gpio_chip gpio_chip;
74 struct viafb_dev *vdev;
75 struct viafb_gpio *active_gpios[VIAFB_NUM_GPIOS];
76 char *gpio_names[VIAFB_NUM_GPIOS];
80 * GPIO access functions
82 static void via_gpio_set(struct gpio_chip *chip, unsigned int nr,
85 struct viafb_gpio_cfg *cfg = container_of(chip,
86 struct viafb_gpio_cfg,
89 struct viafb_gpio *gpio;
92 spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
93 gpio = cfg->active_gpios[nr];
94 reg = viafb_read_reg(VIASR, gpio->vg_port_index);
95 reg |= 0x40 << gpio->vg_mask_shift; /* output enable */
97 reg |= 0x10 << gpio->vg_mask_shift;
99 reg &= ~(0x10 << gpio->vg_mask_shift);
100 viafb_write_reg(gpio->vg_port_index, VIASR, reg);
101 spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
104 static int via_gpio_dir_out(struct gpio_chip *chip, unsigned int nr,
107 via_gpio_set(chip, nr, value);
112 * Set the input direction. I'm not sure this is right; we should
113 * be able to do input without disabling output.
115 static int via_gpio_dir_input(struct gpio_chip *chip, unsigned int nr)
117 struct viafb_gpio_cfg *cfg = container_of(chip,
118 struct viafb_gpio_cfg,
120 struct viafb_gpio *gpio;
123 spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
124 gpio = cfg->active_gpios[nr];
125 viafb_write_reg_mask(gpio->vg_port_index, VIASR, 0,
126 0x40 << gpio->vg_mask_shift);
127 spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
131 static int via_gpio_get(struct gpio_chip *chip, unsigned int nr)
133 struct viafb_gpio_cfg *cfg = container_of(chip,
134 struct viafb_gpio_cfg,
137 struct viafb_gpio *gpio;
140 spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
141 gpio = cfg->active_gpios[nr];
142 reg = viafb_read_reg(VIASR, gpio->vg_port_index);
143 spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
144 return reg & (0x04 << gpio->vg_mask_shift);
148 static struct viafb_gpio_cfg gpio_config = {
150 .label = "VIAFB onboard GPIO",
151 .owner = THIS_MODULE,
152 .direction_output = via_gpio_dir_out,
154 .direction_input = via_gpio_dir_input,
163 * Manage the software enable bit.
165 static void viafb_gpio_enable(struct viafb_gpio *gpio)
167 viafb_write_reg_mask(gpio->vg_port_index, VIASR, 0x02, 0x02);
170 static void viafb_gpio_disable(struct viafb_gpio *gpio)
172 viafb_write_reg_mask(gpio->vg_port_index, VIASR, 0, 0x02);
178 int viafb_create_gpios(struct viafb_dev *vdev,
179 const struct via_port_cfg *port_cfg)
181 int i, ngpio = 0, ret;
182 struct viafb_gpio *gpio;
186 * Set up entries for all GPIOs which have been configured to
187 * operate as such (as opposed to as i2c ports).
189 for (i = 0; i < VIAFB_NUM_PORTS; i++) {
190 if (port_cfg[i].mode != VIA_MODE_GPIO)
192 for (gpio = viafb_all_gpios;
193 gpio < viafb_all_gpios + VIAFB_NUM_GPIOS; gpio++)
194 if (gpio->vg_port_index == port_cfg[i].ioport_index) {
195 gpio_config.active_gpios[ngpio] = gpio;
196 gpio_config.gpio_names[ngpio] = gpio->vg_name;
200 gpio_config.gpio_chip.ngpio = ngpio;
201 gpio_config.gpio_chip.names = gpio_config.gpio_names;
202 gpio_config.vdev = vdev;
204 printk(KERN_INFO "viafb: no GPIOs configured\n");
208 * Enable the ports. They come in pairs, with a single
209 * enable bit for both.
211 spin_lock_irqsave(&gpio_config.vdev->reg_lock, flags);
212 for (i = 0; i < ngpio; i += 2)
213 viafb_gpio_enable(gpio_config.active_gpios[i]);
214 spin_unlock_irqrestore(&gpio_config.vdev->reg_lock, flags);
218 gpio_config.gpio_chip.base = -1; /* Dynamic */
219 ret = gpiochip_add(&gpio_config.gpio_chip);
221 printk(KERN_ERR "viafb: failed to add gpios (%d)\n", ret);
222 gpio_config.gpio_chip.ngpio = 0;
229 int viafb_destroy_gpios(void)
234 spin_lock_irqsave(&gpio_config.vdev->reg_lock, flags);
238 if (gpio_config.gpio_chip.ngpio > 0) {
239 ret = gpiochip_remove(&gpio_config.gpio_chip);
240 if (ret) { /* Somebody still using it? */
241 printk(KERN_ERR "Viafb: GPIO remove failed\n");
248 for (i = 0; i < gpio_config.gpio_chip.ngpio; i += 2)
249 viafb_gpio_disable(gpio_config.active_gpios[i]);
250 gpio_config.gpio_chip.ngpio = 0;
252 spin_unlock_irqrestore(&gpio_config.vdev->reg_lock, flags);
257 * Look up a specific gpio and return the number it was assigned.
259 int viafb_gpio_lookup(const char *name)
263 for (i = 0; i < gpio_config.gpio_chip.ngpio; i++)
264 if (!strcmp(name, gpio_config.active_gpios[i]->vg_name))
265 return gpio_config.gpio_chip.base + i;
268 EXPORT_SYMBOL_GPL(viafb_gpio_lookup);