arch/mips/pmc-sierra/msp71xx/msp_hwbutton.c

   1 /*
   2  * Sets up interrupt handlers for various hardware switches which are
   3  * connected to interrupt lines.
   4  *
   5  * Copyright 2005-2207 PMC-Sierra, Inc.
   6  *
   7  *  This program is free software; you can redistribute  it and/or modify it
   8  *  under  the terms of  the GNU General  Public License as published by the
   9  *  Free Software Foundation;  either version 2 of the  License, or (at your
  10  *  option) any later version.
  11  *
  12  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
  13  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
  14  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  15  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
  16  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  17  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
  18  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  19  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
  20  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  21  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  22  *
  23  *  You should have received a copy of the  GNU General Public License along
  24  *  with this program; if not, write  to the Free Software Foundation, Inc.,
  25  *  675 Mass Ave, Cambridge, MA 02139, USA.
  26  */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/init.h>
  30 #include <linux/interrupt.h>
  31
  32 #include <msp_int.h>
  33 #include <msp_regs.h>
  34 #include <msp_regops.h>
  35
  36 /* For hwbutton_interrupt->initial_state */
  37 #define HWBUTTON_HI     0x1
  38 #define HWBUTTON_LO     0x2
  39
  40 /*
  41  * This struct describes a hardware button
  42  */
  43 struct hwbutton_interrupt {
  44         char *name;                     /* Name of button */
  45         int irq;                        /* Actual LINUX IRQ */
  46         int eirq;                       /* Extended IRQ number (0-7) */
  47         int initial_state;              /* The "normal" state of the switch */
  48         void (*handle_hi)(void *);      /* Handler: switch input has gone HI */
  49         void (*handle_lo)(void *);      /* Handler: switch input has gone LO */
  50         void *data;                     /* Optional data to pass to handler */
  51 };
  52
  53 #ifdef CONFIG_PMC_MSP7120_GW
  54 extern void msp_restart(char *);
  55
  56 static void softreset_push(void *data)
  57 {
  58         printk(KERN_WARNING "SOFTRESET switch was pushed\n");
  59
  60         /*
  61          * In the future you could move this to the release handler,
  62          * timing the difference between the 'push' and 'release', and only
  63          * doing this ungraceful restart if the button has been down for
  64          * a certain amount of time; otherwise doing a graceful restart.
  65          */
  66
  67         msp_restart(NULL);
  68 }
  69
  70 static void softreset_release(void *data)
  71 {
  72         printk(KERN_WARNING "SOFTRESET switch was released\n");
  73
  74         /* Do nothing */
  75 }
  76
  77 static void standby_on(void *data)
  78 {
  79         printk(KERN_WARNING "STANDBY switch was set to ON (not implemented)\n");
  80
  81         /* TODO: Put board in standby mode */
  82 }
  83
  84 static void standby_off(void *data)
  85 {
  86         printk(KERN_WARNING
  87                 "STANDBY switch was set to OFF (not implemented)\n");
  88
  89         /* TODO: Take out of standby mode */
  90 }
  91
  92 static struct hwbutton_interrupt softreset_sw = {
  93         .name = "Softreset button",
  94         .irq = MSP_INT_EXT0,
  95         .eirq = 0,
  96         .initial_state = HWBUTTON_HI,
  97         .handle_hi = softreset_release,
  98         .handle_lo = softreset_push,
  99         .data = NULL,
 100 };
 101
 102 static struct hwbutton_interrupt standby_sw = {
 103         .name = "Standby switch",
 104         .irq = MSP_INT_EXT1,
 105         .eirq = 1,
 106         .initial_state = HWBUTTON_HI,
 107         .handle_hi = standby_off,
 108         .handle_lo = standby_on,
 109         .data = NULL,
 110 };
 111 #endif /* CONFIG_PMC_MSP7120_GW */
 112
 113 static irqreturn_t hwbutton_handler(int irq, void *data)
 114 {
 115         struct hwbutton_interrupt *hirq = data;
 116         unsigned long cic_ext = *CIC_EXT_CFG_REG;
 117
 118         if (CIC_EXT_IS_ACTIVE_HI(cic_ext, hirq->eirq)) {
 119                 /* Interrupt: pin is now HI */
 120                 CIC_EXT_SET_ACTIVE_LO(cic_ext, hirq->eirq);
 121                 hirq->handle_hi(hirq->data);
 122         } else {
 123                 /* Interrupt: pin is now LO */
 124                 CIC_EXT_SET_ACTIVE_HI(cic_ext, hirq->eirq);
 125                 hirq->handle_lo(hirq->data);
 126         }
 127
 128         /*
 129          * Invert the POLARITY of this level interrupt to ack the interrupt
 130          * Thus next state change will invoke the opposite message
 131          */
 132         *CIC_EXT_CFG_REG = cic_ext;
 133
 134         return IRQ_HANDLED;
 135 }
 136
 137 static int msp_hwbutton_register(struct hwbutton_interrupt *hirq)
 138 {
 139         unsigned long cic_ext;
 140
 141         if (hirq->handle_hi == NULL || hirq->handle_lo == NULL)
 142                 return -EINVAL;
 143
 144         cic_ext = *CIC_EXT_CFG_REG;
 145         CIC_EXT_SET_TRIGGER_LEVEL(cic_ext, hirq->eirq);
 146         if (hirq->initial_state == HWBUTTON_HI)
 147                 CIC_EXT_SET_ACTIVE_LO(cic_ext, hirq->eirq);
 148         else
 149                 CIC_EXT_SET_ACTIVE_HI(cic_ext, hirq->eirq);
 150         *CIC_EXT_CFG_REG = cic_ext;
 151
 152         return request_irq(hirq->irq, hwbutton_handler, IRQF_DISABLED,
 153                            hirq->name, hirq);
 154 }
 155
 156 static int __init msp_hwbutton_setup(void)
 157 {
 158 #ifdef CONFIG_PMC_MSP7120_GW
 159         msp_hwbutton_register(&softreset_sw);
 160         msp_hwbutton_register(&standby_sw);
 161 #endif
 162         return 0;
 163 }
 164
 165 subsys_initcall(msp_hwbutton_setup);