4 * Support functions for Retu ASIC
6 * Copyright (C) 2004, 2005 Nokia Corporation
8 * Written by Juha Yrjölä <juha.yrjola@nokia.com>,
9 * David Weinehall <david.weinehall@nokia.com>, and
10 * Mikko Ylinen <mikko.k.ylinen@nokia.com>
12 * This file is subject to the terms and conditions of the GNU General
13 * Public License. See the file "COPYING" in the main directory of this
14 * archive for more details.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
26 #include <linux/module.h>
27 #include <linux/init.h>
29 #include <linux/config.h>
30 #include <linux/kernel.h>
31 #include <linux/errno.h>
32 #include <linux/device.h>
33 #include <linux/miscdevice.h>
34 #include <linux/poll.h>
36 #include <linux/interrupt.h>
37 #include <linux/platform_device.h>
39 #include <asm/uaccess.h>
41 #include <asm/arch/mux.h>
42 #include <asm/arch/gpio.h>
43 #include <asm/arch/board.h>
51 static int retu_initialized;
52 static int retu_irq_pin;
54 static struct tasklet_struct retu_tasklet;
55 spinlock_t retu_lock = SPIN_LOCK_UNLOCKED;
57 static struct completion device_release;
59 struct retu_irq_handler_desc {
60 int (*func)(unsigned long);
65 static struct retu_irq_handler_desc retu_irq_handlers[MAX_RETU_IRQ_HANDLERS];
68 * retu_read_reg - Read a value from a register in Retu
69 * @reg: the register to read from
71 * This function returns the contents of the specified register
73 int retu_read_reg(int reg)
75 BUG_ON(!retu_initialized);
76 return cbus_read_reg(cbus_host, RETU_ID, reg);
80 * retu_write_reg - Write a value to a register in Retu
81 * @reg: the register to write to
82 * @reg: the value to write to the register
84 * This function writes a value to the specified register
86 void retu_write_reg(int reg, u16 val)
88 BUG_ON(!retu_initialized);
89 cbus_write_reg(cbus_host, RETU_ID, reg, val);
92 #define ADC_MAX_CHAN_NUMBER 13
94 int retu_read_adc(int channel)
99 if (channel < 0 || channel > ADC_MAX_CHAN_NUMBER)
102 spin_lock_irqsave(&retu_lock, flags);
103 /* Select the channel and read result */
104 retu_write_reg(RETU_REG_ADCR, channel << 10);
105 res = retu_read_reg(RETU_REG_ADCR) & 0x3ff;
107 spin_unlock_irqrestore(&retu_lock, flags);
113 static u16 retu_disable_bogus_irqs(u16 mask)
117 for (i = 0; i < MAX_RETU_IRQ_HANDLERS; i++) {
120 if (retu_irq_handlers[i].func != NULL)
122 /* an IRQ was enabled but we don't have a handler for it */
123 printk(KERN_INFO PFX "disabling bogus IRQ %d\n", i);
130 * Disable given RETU interrupt
132 void retu_disable_irq(int id)
137 spin_lock_irqsave(&retu_lock, flags);
138 mask = retu_read_reg(RETU_REG_IMR);
140 mask = retu_disable_bogus_irqs(mask);
141 retu_write_reg(RETU_REG_IMR, mask);
142 spin_unlock_irqrestore(&retu_lock, flags);
146 * Enable given RETU interrupt
148 void retu_enable_irq(int id)
154 printk("Enabling Retu IRQ %d\n", id);
157 spin_lock_irqsave(&retu_lock, flags);
158 mask = retu_read_reg(RETU_REG_IMR);
160 mask = retu_disable_bogus_irqs(mask);
161 retu_write_reg(RETU_REG_IMR, mask);
162 spin_unlock_irqrestore(&retu_lock, flags);
166 * Acknowledge given RETU interrupt
168 void retu_ack_irq(int id)
170 retu_write_reg(RETU_REG_IDR, 1 << id);
174 * RETU interrupt handler. Only schedules the tasklet.
176 static irqreturn_t retu_irq_handler(int irq, void *dev_id, struct pt_regs *regs)
178 tasklet_schedule(&retu_tasklet);
185 static void retu_tasklet_handler(unsigned long data)
187 struct retu_irq_handler_desc *hnd;
193 id = retu_read_reg(RETU_REG_IDR);
194 im = ~retu_read_reg(RETU_REG_IMR);
200 for (i = 0; id != 0; i++, id >>= 1) {
203 hnd = &retu_irq_handlers[i];
204 if (hnd->func == NULL) {
205 /* Spurious retu interrupt - disable and ack it */
206 printk(KERN_INFO "Spurious Retu interrupt "
214 * Don't acknowledge the interrupt here
215 * It must be done explicitly
222 * Register the handler for a given RETU interrupt source.
224 int retu_request_irq(int id, void *irq_handler, unsigned long arg, char *name)
226 struct retu_irq_handler_desc *hnd;
228 if (irq_handler == NULL || id >= MAX_RETU_IRQ_HANDLERS ||
230 printk(KERN_ERR PFX "Invalid arguments to %s\n",
234 hnd = &retu_irq_handlers[id];
235 if (hnd->func != NULL) {
236 printk(KERN_ERR PFX "IRQ %d already reserved\n", id);
239 printk(KERN_INFO PFX "Registering interrupt %d for device %s\n",
241 hnd->func = irq_handler;
243 strlcpy(hnd->name, name, sizeof(hnd->name));
252 * Unregister the handler for a given RETU interrupt source.
254 void retu_free_irq(int id)
256 struct retu_irq_handler_desc *hnd;
258 if (id >= MAX_RETU_IRQ_HANDLERS) {
259 printk(KERN_ERR PFX "Invalid argument to %s\n",
263 hnd = &retu_irq_handlers[id];
264 if (hnd->func == NULL) {
265 printk(KERN_ERR PFX "IRQ %d already freed\n", id);
269 retu_disable_irq(id);
274 * retu_power_off - Shut down power to system
276 * This function puts the system in power off state
278 static void retu_power_off(void)
280 /* Ignore power button state */
281 retu_write_reg(RETU_REG_CC1, retu_read_reg(RETU_REG_CC1) | 2);
282 /* Expire watchdog immediately */
283 retu_write_reg(RETU_REG_WATCHDOG, 0);
284 /* Wait for poweroff*/
289 * retu_probe - Probe for Retu ASIC
290 * @dev: the Retu device
292 * Probe for the Retu ASIC and allocate memory
293 * for its device-struct if found
295 static int __devinit retu_probe(struct device *dev)
297 const struct omap_em_asic_bb5_config * em_asic_config;
300 /* Prepare tasklet */
301 tasklet_init(&retu_tasklet, retu_tasklet_handler, 0);
303 em_asic_config = omap_get_config(OMAP_TAG_EM_ASIC_BB5,
304 struct omap_em_asic_bb5_config);
305 if (em_asic_config == NULL) {
306 printk(KERN_ERR PFX "Unable to retrieve config data\n");
310 retu_irq_pin = em_asic_config->retu_irq_gpio;
312 if ((ret = omap_request_gpio(retu_irq_pin)) < 0) {
313 printk(KERN_ERR PFX "Unable to reserve IRQ GPIO\n");
317 /* Set the pin as input */
318 omap_set_gpio_direction(retu_irq_pin, 1);
320 /* Rising edge triggers the IRQ */
321 set_irq_type(OMAP_GPIO_IRQ(retu_irq_pin), IRQT_RISING);
323 retu_initialized = 1;
324 /* Mask all RETU interrupts */
325 retu_write_reg(RETU_REG_IMR, 0xffff);
327 ret = request_irq(OMAP_GPIO_IRQ(retu_irq_pin), retu_irq_handler, 0,
331 printk(KERN_ERR PFX "Unable to register IRQ handler\n");
332 omap_free_gpio(retu_irq_pin);
336 /* Register power off function */
337 pm_power_off = retu_power_off;
339 #ifdef CONFIG_CBUS_RETU_USER
340 /* Initialize user-space interface */
341 if (retu_user_init() < 0) {
342 printk(KERN_ERR "Unable to initialize driver\n");
343 free_irq(OMAP_GPIO_IRQ(retu_irq_pin), 0);
344 omap_free_gpio(retu_irq_pin);
352 static int retu_remove(struct device *dev)
354 #ifdef CONFIG_CBUS_RETU_USER
357 /* Mask all RETU interrupts */
358 retu_write_reg(RETU_REG_IMR, 0xffff);
359 free_irq(OMAP_GPIO_IRQ(retu_irq_pin), 0);
360 omap_free_gpio(retu_irq_pin);
361 tasklet_kill(&retu_tasklet);
366 static void retu_device_release(struct device *dev)
368 complete(&device_release);
371 static struct device_driver retu_driver = {
373 .bus = &platform_bus_type,
375 .remove = retu_remove,
378 static struct platform_device retu_device = {
382 .release = retu_device_release,
387 * retu_init - initialise Retu driver
389 * Initialise the Retu driver and return 0 if everything worked ok
391 static int __init retu_init(void)
395 printk(KERN_INFO "Retu driver initialising\n");
397 init_completion(&device_release);
399 if ((ret = driver_register(&retu_driver)) < 0)
402 if ((ret = platform_device_register(&retu_device)) < 0) {
403 driver_unregister(&retu_driver);
412 static void __exit retu_exit(void)
414 platform_device_unregister(&retu_device);
415 driver_unregister(&retu_driver);
416 wait_for_completion(&device_release);
419 EXPORT_SYMBOL(retu_request_irq);
420 EXPORT_SYMBOL(retu_free_irq);
421 EXPORT_SYMBOL(retu_enable_irq);
422 EXPORT_SYMBOL(retu_disable_irq);
423 EXPORT_SYMBOL(retu_ack_irq);
424 EXPORT_SYMBOL(retu_read_reg);
425 EXPORT_SYMBOL(retu_write_reg);
427 subsys_initcall(retu_init);
428 module_exit(retu_exit);
430 MODULE_DESCRIPTION("Retu ASIC control");
431 MODULE_LICENSE("GPL");
432 MODULE_AUTHOR("Juha Yrjölä, David Weinehall, and Mikko Ylinen");