regmap: mmio: Fix value endianness selection

Currently when selecting value endianness we check the register endiannes, not the value endianness.

---
 drivers/base/regmap/regmap-mmio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 7526906ca080..b27573c69af7 100644
@@ -245,7 +245,7 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 	ctx->val_bytes = config->val_bits / 8;
 	ctx->clk = ERR_PTR(-ENODEV);
 
-	switch (config->reg_format_endian) {
+	switch (config->val_format_endian) {
 	case REGMAP_ENDIAN_DEFAULT:
 	case REGMAP_ENDIAN_LITTLE:
 #ifdef __LITTLE_ENDIAN

2.7.0

Thanks and best regards,
Alexander

The patch

regmap: mmio: Fix value endianness selection

has been applied to the regmap tree at

git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.

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Thanks,
Mark

From: Mark Brown <[email protected]>
Date: Wed, 23 Mar 2016 12:13:12 +0000
Subject: [PATCH] regmap: mmio: Fix value endianness selection

Currently when selecting value endianness we check the register endiannes, not the value endianness.

---
 drivers/base/regmap/regmap-mmio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 7526906ca080..b27573c69af7 100644
@@ -245,7 +245,7 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 	ctx->val_bytes = config->val_bits / 8;
 	ctx->clk = ERR_PTR(-ENODEV);
 
-	switch (config->reg_format_endian) {
+	switch (config->val_format_endian) {
 	case REGMAP_ENDIAN_DEFAULT:
 	case REGMAP_ENDIAN_LITTLE:
 #ifdef __LITTLE_ENDIAN

2.7.0

Mh, while this _does_ fix the problem regarding accessing SCFG peripheral using syscon, it _does not_ fix the access for spi-fsl-dspi, this is still using little-endian.
The difference in those drivers is that syscon manually sets config.val_format_endian before calling regmap_init_mmio. spi-fsl-dspi does not. I guess this driver relies on this configuration being done in regmap_get_val_endian. But this is never reached because after setting map->reg_read this code is skipped due to "goto skip_format_initialization;" IMHO a call to regmap_get_val_endian should be added to regmap_mmio_gen_context.

Best regards,
Alexander

Does this IP exist in configurations where it is anything other than big endian? If not then this probably shouldn't be in DT.

That sounds reasonable.

AFAIK it is included once or twice in the VFxxx series. CC'ed Stefan Agner for confirmation.
Stefan: Is the DCU on VFxxx attached little-endian, e.g. no byte swapping needed when accessing the periphery?

Best regards,
Alexander

Yes, DCU as well as DSPI is attached little endian on Vybrid (aka. vf610).

--
Stefan