drivers/fmc/fmc-trivial.c

   1 /*
   2  * Copyright (C) 2012 CERN (www.cern.ch)
   3  * Author: Alessandro Rubini <rubini@gnudd.com>
   4  *
   5  * Permission to use, copy, modify, and/or distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * The software is provided "as is"; the copyright holders disclaim
  10  * all warranties and liabilities, to the extent permitted by
  11  * applicable law.
  12  */
  13
  14 /* A trivial fmc driver that can load a gateware file and reports interrupts */
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/gpio.h>
  19 #include <linux/fmc.h>
  20
  21 static struct fmc_driver t_drv; /* initialized later */
  22
  23 static irqreturn_t t_handler(int irq, void *dev_id)
  24 {
  25         struct fmc_device *fmc = dev_id;
  26
  27         fmc->op->irq_ack(fmc);
  28         dev_info(&fmc->dev, "received irq %i\n", irq);
  29         return IRQ_HANDLED;
  30 }
  31
  32 static struct fmc_gpio t_gpio[] = {
  33         {
  34                 .gpio = FMC_GPIO_IRQ(0),
  35                 .mode = GPIOF_DIR_IN,
  36                 .irqmode = IRQF_TRIGGER_RISING,
  37         }, {
  38                 .gpio = FMC_GPIO_IRQ(1),
  39                 .mode = GPIOF_DIR_IN,
  40                 .irqmode = IRQF_TRIGGER_RISING,
  41         }
  42 };
  43
  44 static int t_probe(struct fmc_device *fmc)
  45 {
  46         int ret;
  47         int index = 0;
  48
  49         if (fmc->op->validate)
  50                 index = fmc->op->validate(fmc, &t_drv);
  51         if (index < 0)
  52                 return -EINVAL; /* not our device: invalid */
  53
  54         ret = fmc->op->irq_request(fmc, t_handler, "fmc-trivial", IRQF_SHARED);
  55         if (ret < 0)
  56                 return ret;
  57         /* ignore error code of call below, we really don't care */
  58         fmc->op->gpio_config(fmc, t_gpio, ARRAY_SIZE(t_gpio));
  59
  60         /* Reprogram, if asked to. ESRCH == no filename specified */
  61         ret = -ESRCH;
  62         if (fmc->op->reprogram)
  63                 ret = fmc->op->reprogram(fmc, &t_drv, "");
  64         if (ret == -ESRCH)
  65                 ret = 0;
  66         if (ret < 0)
  67                 fmc->op->irq_free(fmc);
  68
  69         /* FIXME: reprogram LM32 too */
  70         return ret;
  71 }
  72
  73 static int t_remove(struct fmc_device *fmc)
  74 {
  75         fmc->op->irq_free(fmc);
  76         return 0;
  77 }
  78
  79 static struct fmc_driver t_drv = {
  80         .version = FMC_VERSION,
  81         .driver.name = KBUILD_MODNAME,
  82         .probe = t_probe,
  83         .remove = t_remove,
  84         /* no table, as the current match just matches everything */
  85 };
  86
  87  /* We accept the generic parameters */
  88 FMC_PARAM_BUSID(t_drv);
  89 FMC_PARAM_GATEWARE(t_drv);
  90
  91 static int t_init(void)
  92 {
  93         int ret;
  94
  95         ret = fmc_driver_register(&t_drv);
  96         return ret;
  97 }
  98
  99 static void t_exit(void)
 100 {
 101         fmc_driver_unregister(&t_drv);
 102 }
 103
 104 module_init(t_init);
 105 module_exit(t_exit);
 106
 107 MODULE_LICENSE("Dual BSD/GPL");