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
  31 #define PWR_ISR1 0
  32 #define PWR_IMR1 1
  33 #define PWR_SIH_CTRL 7
  34 #define PWR_SIH_CTRL_COR (1<<2)
  35
  36 static u8 twl4030_pwrirq_mask;
  37 static u8 twl4030_pwrirq_pending_unmask;
  38
  39 static struct task_struct *twl4030_pwrirq_unmask_thread;
  40
  41 static void twl4030_pwrirq_ack(unsigned int irq) {}
  42
  43 static void twl4030_pwrirq_disableint(unsigned int irq) {}
  44
  45 static void twl4030_pwrirq_enableint(unsigned int irq)
  46 {
  47         twl4030_pwrirq_pending_unmask |= 1 << (irq - TWL4030_PWR_IRQ_BASE);
  48         if (twl4030_pwrirq_unmask_thread &&
  49                 twl4030_pwrirq_unmask_thread->state != TASK_RUNNING)
  50                 wake_up_process(twl4030_pwrirq_unmask_thread);
  51 }
  52
  53 static struct irq_chip twl4030_pwrirq_chip = {
  54         .name   = "twl4030-pwr",
  55         .ack    = twl4030_pwrirq_ack,
  56         .mask   = twl4030_pwrirq_disableint,
  57         .unmask = twl4030_pwrirq_enableint,
  58 };
  59
  60 static void do_twl4030_pwrmodule_irq(unsigned int irq, irq_desc_t *desc)
  61 {
  62         struct irqaction *action;
  63         const unsigned int cpu = smp_processor_id();
  64
  65         desc->status |= IRQ_LEVEL;
  66
  67         if (!desc->depth) {
  68                 kstat_cpu(cpu).irqs[irq]++;
  69
  70                 action = desc->action;
  71                 if (action) {
  72                         int ret;
  73                         int status = 0;
  74                         int retval = 0;
  75
  76                         do {
  77                                 ret = action->handler(irq, action->dev_id);
  78                                 if (ret == IRQ_HANDLED)
  79                                         status |= action->flags;
  80                                 retval |= ret;
  81                                 action = action->next;
  82                         } while (action);
  83
  84                         if (status & IRQF_SAMPLE_RANDOM)
  85                                 add_interrupt_randomness(irq);
  86
  87                         if (retval != IRQ_HANDLED)
  88                                 printk(KERN_ERR "ISR for TWL4030 power module"
  89                                         " irq %d can't handle interrupt\n",
  90                                         irq);
  91                 } else {
  92                         local_irq_disable();
  93                         twl4030_pwrirq_mask |= 1 << (irq - TWL4030_PWR_IRQ_BASE);
  94                         local_irq_enable();
  95                         twl4030_i2c_write_u8(TWL4030_MODULE_INT,
  96                                                 twl4030_pwrirq_mask, PWR_IMR1);
  97                 }
  98         }
  99 }
 100
 101 static void do_twl4030_pwrirq(unsigned int irq, irq_desc_t *desc)
 102 {
 103         const unsigned int cpu = smp_processor_id();
 104
 105         desc->status |= IRQ_LEVEL;
 106
 107         desc->chip->ack(irq);
 108
 109         if (!desc->depth) {
 110                 int ret;
 111                 int module_irq;
 112                 u8 pwr_isr;
 113
 114                 kstat_cpu(cpu).irqs[irq]++;
 115
 116                 local_irq_enable();
 117                 ret = twl4030_i2c_read_u8(TWL4030_MODULE_INT, &pwr_isr,
 118                                                 PWR_ISR1);
 119                 if (ret) {
 120                         printk(KERN_WARNING
 121                                 "I2C error %d while reading TWL4030"
 122                                 "INT PWR_ISR1 register\n", ret);
 123                         return;
 124                 }
 125
 126                 for (module_irq = TWL4030_PWR_IRQ_BASE; pwr_isr != 0;
 127                         module_irq++, pwr_isr >>= 1) {
 128                         if (pwr_isr & 1) {
 129                                 irq_desc_t *d = irq_desc + module_irq;
 130                                 d->handle_irq(module_irq, d);
 131                         }
 132                 }
 133
 134                 local_irq_disable();
 135                 desc->chip->unmask(irq);
 136         }
 137 }
 138
 139 static int twl4030_pwrirq_thread(void *data)
 140 {
 141         current->flags |= PF_NOFREEZE;
 142
 143         while (!kthread_should_stop()) {
 144                 u8 local_unmask;
 145
 146                 local_irq_disable();
 147                 local_unmask = twl4030_pwrirq_pending_unmask;
 148                 twl4030_pwrirq_pending_unmask = 0;
 149                 local_irq_enable();
 150
 151                 twl4030_pwrirq_mask &= ~local_unmask;
 152
 153                 twl4030_i2c_write_u8(TWL4030_MODULE_INT, twl4030_pwrirq_mask,
 154                                         PWR_IMR1);
 155
 156                 local_irq_disable();
 157                 if (!twl4030_pwrirq_pending_unmask)
 158                         set_current_state(TASK_INTERRUPTIBLE);
 159                 local_irq_enable();
 160
 161                 schedule();
 162         }
 163         set_current_state(TASK_RUNNING);
 164         return 0;
 165 }
 166
 167 static int __init twl4030_pwrirq_init(void)
 168 {
 169         int i, err;
 170
 171         twl4030_pwrirq_mask = 0xff;
 172         twl4030_pwrirq_pending_unmask = 0;
 173
 174         err = twl4030_i2c_write_u8(TWL4030_MODULE_INT, twl4030_pwrirq_mask,
 175                                         PWR_IMR1);
 176         if (err)
 177                 return err;
 178
 179         /* Enable clear on read */
 180
 181         err = twl4030_i2c_write_u8(TWL4030_MODULE_INT, PWR_SIH_CTRL_COR,
 182                                         PWR_SIH_CTRL);
 183         if (err)
 184                 return err;
 185
 186         twl4030_pwrirq_unmask_thread = kthread_create(twl4030_pwrirq_thread,
 187                 NULL, "twl4030 pwrirq");
 188         if (!twl4030_pwrirq_unmask_thread) {
 189                 printk(KERN_ERR
 190                         "%s: could not create twl4030 pwrirq unmask thread!\n",
 191                                 __func__);
 192                 return -ENOMEM;
 193         }
 194
 195         for (i = TWL4030_PWR_IRQ_BASE; i < TWL4030_PWR_IRQ_END; i++) {
 196                 set_irq_chip(i, &twl4030_pwrirq_chip);
 197                 set_irq_handler(i, do_twl4030_pwrmodule_irq);
 198                 set_irq_flags(i, IRQF_VALID);
 199         }
 200
 201         set_irq_chained_handler(TWL4030_MODIRQ_PWR, do_twl4030_pwrirq);
 202
 203         return 0;
 204 }
 205
 206 static void __exit twl4030_pwrirq_exit(void)
 207 {
 208
 209         int i;
 210
 211         set_irq_handler(TWL4030_MODIRQ_PWR, NULL);
 212         set_irq_flags(TWL4030_MODIRQ_PWR, 0);
 213
 214         for (i = TWL4030_PWR_IRQ_BASE; i < TWL4030_PWR_IRQ_END; i++) {
 215                 set_irq_handler(i, NULL);
 216                 set_irq_flags(i, 0);
 217         }
 218
 219         if (twl4030_pwrirq_unmask_thread) {
 220                 kthread_stop(twl4030_pwrirq_unmask_thread);
 221                 twl4030_pwrirq_unmask_thread = NULL;
 222         }
 223 }
 224
 225 subsys_initcall(twl4030_pwrirq_init);
 226 module_exit(twl4030_pwrirq_exit);