drivers/i2c/chips/twl4030-pwrirq.c

   1 /*
   2  * twl4030-pwrirq.c - handle power interrupts from TWL3040
   3  *
   4  * Copyright (C) 2008 Nokia Corporation
   5  *
   6  * Written by Peter De Schrijver <peter.de-schrijver@nokia.com>
   7  *
   8  * This file is subject to the terms and conditions of the GNU General
   9  * Public License. See the file "COPYING" in the main directory of this
  10  * archive for more details.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <linux/kernel_stat.h>
  23 #include <linux/module.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/irq.h>
  26 #include <linux/i2c.h>
  27 #include <linux/random.h>
  28 #include <linux/kthread.h>
  29 #include <linux/i2c/twl4030.h>
  30 #include <linux/i2c/twl4030-pwrirq.h>
  31
  32 #define PWR_SIH_CTRL_COR (1<<2)
  33
  34 static u8 twl4030_pwrirq_mask;
  35 static u8 twl4030_pwrirq_pending_unmask;
  36
  37 static struct task_struct *twl4030_pwrirq_unmask_thread;
  38
  39 static void twl4030_pwrirq_ack(unsigned int irq) {}
  40
  41 static void twl4030_pwrirq_disableint(unsigned int irq) {}
  42
  43 static void twl4030_pwrirq_enableint(unsigned int irq)
  44 {
  45         twl4030_pwrirq_pending_unmask |= 1 << (irq - TWL4030_PWR_IRQ_BASE);
  46         if (twl4030_pwrirq_unmask_thread &&
  47                 twl4030_pwrirq_unmask_thread->state != TASK_RUNNING)
  48                 wake_up_process(twl4030_pwrirq_unmask_thread);
  49 }
  50
  51 static struct irq_chip twl4030_pwrirq_chip = {
  52         .name   = "twl4030-pwr",
  53         .ack    = twl4030_pwrirq_ack,
  54         .mask   = twl4030_pwrirq_disableint,
  55         .unmask = twl4030_pwrirq_enableint,
  56 };
  57
  58 static void do_twl4030_pwrmodule_irq(unsigned int irq, irq_desc_t *desc)
  59 {
  60         struct irqaction *action;
  61         const unsigned int cpu = smp_processor_id();
  62
  63         desc->status |= IRQ_LEVEL;
  64
  65         if (!desc->depth) {
  66                 kstat_cpu(cpu).irqs[irq]++;
  67
  68                 action = desc->action;
  69                 if (action) {
  70                         int ret;
  71                         int status = 0;
  72                         int retval = 0;
  73
  74                         do {
  75                                 ret = action->handler(irq, action->dev_id);
  76                                 if (ret == IRQ_HANDLED)
  77                                         status |= action->flags;
  78                                 retval |= ret;
  79                                 action = action->next;
  80                         } while (action);
  81
  82                         if (status & IRQF_SAMPLE_RANDOM)
  83                                 add_interrupt_randomness(irq);
  84
  85                         if (retval != IRQ_HANDLED)
  86                                 printk(KERN_ERR "ISR for TWL4030 power module"
  87                                         " irq %d can't handle interrupt\n",
  88                                         irq);
  89                 } else {
  90                         local_irq_disable();
  91                         twl4030_pwrirq_mask |= 1 << (irq - TWL4030_PWR_IRQ_BASE);
  92                         local_irq_enable();
  93                         twl4030_i2c_write_u8(TWL4030_MODULE_INT,
  94                                              twl4030_pwrirq_mask,
  95                                              TWL4030_INT_PWR_IMR1);
  96                 }
  97         }
  98 }
  99
 100 static void do_twl4030_pwrirq(unsigned int irq, irq_desc_t *desc)
 101 {
 102         const unsigned int cpu = smp_processor_id();
 103
 104         desc->status |= IRQ_LEVEL;
 105
 106         desc->chip->ack(irq);
 107
 108         if (!desc->depth) {
 109                 int ret;
 110                 int module_irq;
 111                 u8 pwr_isr;
 112
 113                 kstat_cpu(cpu).irqs[irq]++;
 114
 115                 local_irq_enable();
 116                 ret = twl4030_i2c_read_u8(TWL4030_MODULE_INT, &pwr_isr,
 117                                           TWL4030_INT_PWR_ISR1);
 118                 if (ret) {
 119                         printk(KERN_WARNING
 120                                 "I2C error %d while reading TWL4030"
 121                                 "INT PWR_ISR1 register\n", ret);
 122                         return;
 123                 }
 124
 125                 for (module_irq = TWL4030_PWR_IRQ_BASE; pwr_isr != 0;
 126                         module_irq++, pwr_isr >>= 1) {
 127                         if (pwr_isr & 1) {
 128                                 irq_desc_t *d = irq_desc + module_irq;
 129                                 d->handle_irq(module_irq, d);
 130                         }
 131                 }
 132
 133                 local_irq_disable();
 134                 desc->chip->unmask(irq);
 135         }
 136 }
 137
 138 static int twl4030_pwrirq_thread(void *data)
 139 {
 140         current->flags |= PF_NOFREEZE;
 141
 142         while (!kthread_should_stop()) {
 143                 u8 local_unmask;
 144
 145                 local_irq_disable();
 146                 local_unmask = twl4030_pwrirq_pending_unmask;
 147                 twl4030_pwrirq_pending_unmask = 0;
 148                 local_irq_enable();
 149
 150                 twl4030_pwrirq_mask &= ~local_unmask;
 151
 152                 twl4030_i2c_write_u8(TWL4030_MODULE_INT, twl4030_pwrirq_mask,
 153                                      TWL4030_INT_PWR_IMR1);
 154
 155                 local_irq_disable();
 156                 if (!twl4030_pwrirq_pending_unmask)
 157                         set_current_state(TASK_INTERRUPTIBLE);
 158                 local_irq_enable();
 159
 160                 schedule();
 161         }
 162         set_current_state(TASK_RUNNING);
 163         return 0;
 164 }
 165
 166 static int __init twl4030_pwrirq_init(void)
 167 {
 168         int i, err;
 169
 170         twl4030_pwrirq_mask = 0xff;
 171         twl4030_pwrirq_pending_unmask = 0;
 172
 173         err = twl4030_i2c_write_u8(TWL4030_MODULE_INT, twl4030_pwrirq_mask,
 174                                         TWL4030_INT_PWR_IMR1);
 175         if (err)
 176                 return err;
 177
 178         /* Enable clear on read */
 179
 180         err = twl4030_i2c_write_u8(TWL4030_MODULE_INT, PWR_SIH_CTRL_COR,
 181                                    TWL4030_INT_PWR_SIH_CTRL);
 182         if (err)
 183                 return err;
 184
 185         twl4030_pwrirq_unmask_thread = kthread_create(twl4030_pwrirq_thread,
 186                 NULL, "twl4030 pwrirq");
 187         if (!twl4030_pwrirq_unmask_thread) {
 188                 printk(KERN_ERR
 189                         "%s: could not create twl4030 pwrirq unmask thread!\n",
 190                                 __func__);
 191                 return -ENOMEM;
 192         }
 193
 194         for (i = TWL4030_PWR_IRQ_BASE; i < TWL4030_PWR_IRQ_END; i++) {
 195                 set_irq_chip(i, &twl4030_pwrirq_chip);
 196                 set_irq_handler(i, do_twl4030_pwrmodule_irq);
 197                 set_irq_flags(i, IRQF_VALID);
 198         }
 199
 200         set_irq_chained_handler(TWL4030_MODIRQ_PWR, do_twl4030_pwrirq);
 201
 202         return 0;
 203 }
 204
 205 static void __exit twl4030_pwrirq_exit(void)
 206 {
 207
 208         int i;
 209
 210         set_irq_handler(TWL4030_MODIRQ_PWR, NULL);
 211         set_irq_flags(TWL4030_MODIRQ_PWR, 0);
 212
 213         for (i = TWL4030_PWR_IRQ_BASE; i < TWL4030_PWR_IRQ_END; i++) {
 214                 set_irq_handler(i, NULL);
 215                 set_irq_flags(i, 0);
 216         }
 217
 218         if (twl4030_pwrirq_unmask_thread) {
 219                 kthread_stop(twl4030_pwrirq_unmask_thread);
 220                 twl4030_pwrirq_unmask_thread = NULL;
 221         }
 222 }
 223
 224 MODULE_ALIAS("i2c:twl4030-pwrirq");
 225 subsys_initcall(twl4030_pwrirq_init);
 226 module_exit(twl4030_pwrirq_exit);