regmap: mmio: Allow passing an empty config->reg_stride

Regmap's stride is used for MMIO regmaps to check the correctness of
reg_width. However, it's acceptable to pass an empty config->reg_stride,
in that case the actual stride used is 1.

There are valid cases now to pass an empty stride, when using
down/upshifting of register address. In this case, the stride value
loses its sense, so ignore the reg_width when the stride isn't set.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com
Link: https://lore.kernel.org/r/20230511142735.316445-1-maxime.chevallier@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org

diff --git a/drivers/base/regmap/regmap-mmio.c b/drivers/base/regmap/regmap-mmio.c
index 3ccdd86a97e77609fa747499b45228de3c804cd1..8132b5c101c42e06958635564f465c6642833235 100644 (file)
--- a/drivers/base/regmap/regmap-mmio.c
+++ b/drivers/base/regmap/regmap-mmio.c
@@ -448,7 +448,7 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
        if (min_stride < 0)
                return ERR_PTR(min_stride);
 
-       if (config->reg_stride < min_stride)
+       if (config->reg_stride && config->reg_stride < min_stride)
                return ERR_PTR(-EINVAL);
 
        if (config->use_relaxed_mmio && config->io_port)