clocksource/drivers/sh_mtu2: Do not loop using platform_get_irq_by_name()

As platform_get_irq_by_name() now prints an error when the interrupt
does not exist, looping over possibly non-existing interrupts causes the
printing of scary messages like:

    sh_mtu2 fcff0000.timer: IRQ tgi1a not found
    sh_mtu2 fcff0000.timer: IRQ tgi2a not found

Fix this by using the platform_irq_count() helper, to avoid touching
non-existent interrupts.  Limit the returned number of interrupts to the
maximum number of channels currently supported by the driver in a
future-proof way, i.e. using ARRAY_SIZE() instead of a hardcoded number.

Fixes: 7723f4c5ecdb8d83 ("driver core: platform: Add an error message to platform_get_irq*()")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20191016143003.28561-1-geert+renesas@glider.be

diff --git a/drivers/clocksource/sh_mtu2.c b/drivers/clocksource/sh_mtu2.c
index 354b27d14a19bfcef43656f3555e69a32b28da2d..62812f80b5cc0916d3a38146ac6b3b75c4b9915f 100644 (file)
--- a/drivers/clocksource/sh_mtu2.c
+++ b/drivers/clocksource/sh_mtu2.c
@@ -328,12 +328,13 @@ static int sh_mtu2_register(struct sh_mtu2_channel *ch, const char *name)
        return 0;
 }
 
+static const unsigned int sh_mtu2_channel_offsets[] = {
+       0x300, 0x380, 0x000,
+};
+
 static int sh_mtu2_setup_channel(struct sh_mtu2_channel *ch, unsigned int index,
                                 struct sh_mtu2_device *mtu)
 {
-       static const unsigned int channel_offsets[] = {
-               0x300, 0x380, 0x000,
-       };
        char name[6];
        int irq;
        int ret;
@@ -356,7 +357,7 @@ static int sh_mtu2_setup_channel(struct sh_mtu2_channel *ch, unsigned int index,
                return ret;
        }
 
-       ch->base = mtu->mapbase + channel_offsets[index];
+       ch->base = mtu->mapbase + sh_mtu2_channel_offsets[index];
        ch->index = index;
 
        return sh_mtu2_register(ch, dev_name(&mtu->pdev->dev));
@@ -408,7 +409,12 @@ static int sh_mtu2_setup(struct sh_mtu2_device *mtu,
        }
 
        /* Allocate and setup the channels. */
-       mtu->num_channels = 3;
+       ret = platform_irq_count(pdev);
+       if (ret < 0)
+               goto err_unmap;
+
+       mtu->num_channels = min_t(unsigned int, ret,
+                                 ARRAY_SIZE(sh_mtu2_channel_offsets));
 
        mtu->channels = kcalloc(mtu->num_channels, sizeof(*mtu->channels),
                                GFP_KERNEL);