mfd: ab8500-sysctrl: Handle probe deferral

In the current boot, clients making use of the AB8500 sysctrl
may be probed before the ab8500-sysctrl driver. This gives them
-EINVAL, but should rather give -EPROBE_DEFER.

Before this, the abx500 clock driver didn't probe properly,
and as a result the codec driver in turn using the clocks did
not probe properly. After this patch, everything probes
properly.

Also add OF compatible-string probing. This driver is all
device tree, so let's just make a drive-by-fix of that as
well.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/ab8500-sysctrl.c b/drivers/mfd/ab8500-sysctrl.c
index 80c0efa..5b0a085 100644 (file)
--- a/drivers/mfd/ab8500-sysctrl.c
+++ b/drivers/mfd/ab8500-sysctrl.c
@@ -101,7 +101,7 @@ int ab8500_sysctrl_read(u16 reg, u8 *value)
        u8 bank;
 
        if (sysctrl_dev == NULL)
-               return -EINVAL;
+               return -EPROBE_DEFER;
 
        bank = (reg >> 8);
        if (!valid_bank(bank))
@@ -117,11 +117,13 @@ int ab8500_sysctrl_write(u16 reg, u8 mask, u8 value)
        u8 bank;
 
        if (sysctrl_dev == NULL)
-               return -EINVAL;
+               return -EPROBE_DEFER;
 
        bank = (reg >> 8);
-       if (!valid_bank(bank))
+       if (!valid_bank(bank)) {
+               pr_err("invalid bank\n");
                return -EINVAL;
+       }
 
        return abx500_mask_and_set_register_interruptible(sysctrl_dev, bank,
                (u8)(reg & 0xFF), mask, value);
@@ -148,9 +150,15 @@ static int ab8500_sysctrl_remove(struct platform_device *pdev)
        return 0;
 }
 
+static const struct of_device_id ab8500_sysctrl_match[] = {
+       { .compatible = "stericsson,ab8500-sysctrl", },
+       {}
+};
+
 static struct platform_driver ab8500_sysctrl_driver = {
        .driver = {
                .name = "ab8500-sysctrl",
+               .of_match_table = ab8500_sysctrl_match,
        },
        .probe = ab8500_sysctrl_probe,
        .remove = ab8500_sysctrl_remove,