FMC: add a software mezzanine driver

This simple do-nothing mezzanine driver shows how to write a mezzanine
driver, that can also handle interrupts reported by the carrier.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Juan David Gonzalez Cobas <dcobas@cern.ch>
Acked-by: Emilio G. Cota <cota@braap.org>
Acked-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 115 insertions, 0 deletions

diff --git a/drivers/fmc/Kconfig b/drivers/fmc/Kconfig
index 505e96b02a93..7eacef990be8 100644
--- a/drivers/fmc/Kconfig
+++ b/drivers/fmc/Kconfig
@@ -25,4 +25,11 @@ config FMC_FAKEDEV
           that can be rewritten at run time and usef for matching
           mezzanines.
 
+config FMC_TRIVIAL
+        tristate "FMC trivial mezzanine driver (software testing)"
+        help
+          This is a fake mezzanine driver, to show how FMC works and test it.
+          The driver also handles interrupts (we used it with a real carrier
+          before the mezzanines were produced)
+
 endif # FMC
diff --git a/drivers/fmc/Makefile b/drivers/fmc/Makefile
index 9832b79976b1..52624e6c0b1f 100644
--- a/drivers/fmc/Makefile
+++ b/drivers/fmc/Makefile
@@ -8,3 +8,4 @@ fmc-y += fru-parse.o
 fmc-y += fmc-dump.o
 
 obj-$(CONFIG_FMC_FAKEDEV) += fmc-fakedev.o
+obj-$(CONFIG_FMC_TRIVIAL) += fmc-trivial.o
diff --git a/drivers/fmc/fmc-trivial.c b/drivers/fmc/fmc-trivial.c
new file mode 100644
index 000000000000..6c590f54c79d
--- /dev/null
+++ b/drivers/fmc/fmc-trivial.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2012 CERN (www.cern.ch)
+ * Author: Alessandro Rubini <rubini@gnudd.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * The software is provided "as is"; the copyright holders disclaim
+ * all warranties and liabilities, to the extent permitted by
+ * applicable law.
+ */
+
+/* A trivial fmc driver that can load a gateware file and reports interrupts */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+#include <linux/fmc.h>
+
+static struct fmc_driver t_drv; /* initialized later */
+
+static irqreturn_t t_handler(int irq, void *dev_id)
+{
+        struct fmc_device *fmc = dev_id;
+
+        fmc->op->irq_ack(fmc);
+        dev_info(&fmc->dev, "received irq %i\n", irq);
+        return IRQ_HANDLED;
+}
+
+static struct fmc_gpio t_gpio[] = {
+        {
+                .gpio = FMC_GPIO_IRQ(0),
+                .mode = GPIOF_DIR_IN,
+                .irqmode = IRQF_TRIGGER_RISING,
+        }, {
+                .gpio = FMC_GPIO_IRQ(1),
+                .mode = GPIOF_DIR_IN,
+                .irqmode = IRQF_TRIGGER_RISING,
+        }
+};
+
+static int t_probe(struct fmc_device *fmc)
+{
+        int ret;
+        int index = 0;
+
+        if (fmc->op->validate)
+                index = fmc->op->validate(fmc, &t_drv);
+        if (index < 0)
+                return -EINVAL; /* not our device: invalid */
+
+        ret = fmc->op->irq_request(fmc, t_handler, "fmc-trivial", IRQF_SHARED);
+        if (ret < 0)
+                return ret;
+        /* ignore error code of call below, we really don't care */
+        fmc->op->gpio_config(fmc, t_gpio, ARRAY_SIZE(t_gpio));
+
+        /* Reprogram, if asked to. ESRCH == no filename specified */
+        ret = -ESRCH;
+        if (fmc->op->reprogram)
+                ret = fmc->op->reprogram(fmc, &t_drv, "");
+        if (ret == -ESRCH)
+                ret = 0;
+        if (ret < 0)
+                fmc->op->irq_free(fmc);
+
+        /* FIXME: reprogram LM32 too */
+        return ret;
+}
+
+static int t_remove(struct fmc_device *fmc)
+{
+        fmc->op->irq_free(fmc);
+        return 0;
+}
+
+static struct fmc_driver t_drv = {
+        .version = FMC_VERSION,
+        .driver.name = KBUILD_MODNAME,
+        .probe = t_probe,
+        .remove = t_remove,
+        /* no table, as the current match just matches everything */
+};
+
+ /* We accept the generic parameters */
+FMC_PARAM_BUSID(t_drv);
+FMC_PARAM_GATEWARE(t_drv);
+
+static int t_init(void)
+{
+        int ret;
+
+        ret = fmc_driver_register(&t_drv);
+        return ret;
+}
+
+static void t_exit(void)
+{
+        fmc_driver_unregister(&t_drv);
+}
+
+module_init(t_init);
+module_exit(t_exit);
+
+MODULE_LICENSE("Dual BSD/GPL");