mfd: syscon: Re-use resource_size() to count max_register

Instead of open coded variant use resource_size() and replace
weird '- 3' to more understandable '- 4'.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index e22197c..13626bb 100644 (file)
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -245,7 +245,7 @@ static int syscon_probe(struct platform_device *pdev)
        if (!base)
                return -ENOMEM;
 
-       syscon_config.max_register = res->end - res->start - 3;
+       syscon_config.max_register = resource_size(res) - 4;
        if (pdata)
                syscon_config.name = pdata->label;
        syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);