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| Started by | Stephen Boyd <sboyd@codeaurora.org> |
|---|---|
| First post | 2015-11-21 00:40 +0100 |
| Last post | 2015-11-24 02:10 +0100 |
| Articles | 3 — 2 participants |
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[PATCH] nvmem: qfprom: Specify LE device endianness Stephen Boyd <sboyd@codeaurora.org> - 2015-11-21 00:40 +0100
Re: [PATCH] nvmem: qfprom: Specify LE device endianness Srinivas Kandagatla <srinivas.kandagatla@linaro.org> - 2015-11-21 14:50 +0100
Re: [PATCH] nvmem: qfprom: Specify LE device endianness Stephen Boyd <sboyd@codeaurora.org> - 2015-11-24 02:10 +0100
| From | Stephen Boyd <sboyd@codeaurora.org> |
|---|---|
| Date | 2015-11-21 00:40 +0100 |
| Subject | [PATCH] nvmem: qfprom: Specify LE device endianness |
| Message-ID | <qx3rA-5CJ-15@gated-at.bofh.it> |
The qfprom is a little endian device, but so far we've been
relying on the regmap mmio bus handling this for us without
explicitly stating that fact. After commit 4a98da2164cf
(regmap-mmio: Use native endianness for read/write, 2015-10-29),
the regmap mmio bus will read/write with the __raw_*() IO
accessors, instead of using the readl/writel() APIs that do
proper byte swapping for little endian devices.
So if we're running on a big endian processor and haven't
specified the endianness explicitly in the regmap config or in
DT, we're going to switch from doing little endian byte swapping
to big endian accesses without byte swapping, leading to some
confusing results. Specify the endianness explicitly so that the
regmap core properly byte swaps the accesses for us.
Cc: Rajendra Nayak <rnayak@codeaurora.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Tyler Baker <tyler.baker@linaro.org>
Cc: Simon Arlott <simon@fire.lp0.eu>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
drivers/nvmem/qfprom.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c
index afb67e7eeee4..3829e5fbf8c3 100644
--- a/drivers/nvmem/qfprom.c
+++ b/drivers/nvmem/qfprom.c
@@ -21,6 +21,7 @@ static struct regmap_config qfprom_regmap_config = {
.reg_bits = 32,
.val_bits = 8,
.reg_stride = 1,
+ .val_format_endian = REGMAP_ENDIAN_LITTLE,
};
static struct nvmem_config econfig = {
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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| From | Srinivas Kandagatla <srinivas.kandagatla@linaro.org> |
|---|---|
| Date | 2015-11-21 14:50 +0100 |
| Message-ID | <qxgI9-5XE-5@gated-at.bofh.it> |
| In reply to | #1274496 |
Hi Stephen,
Thanks for the fix.
I will send it to Greg for next rc.
--srini
On 20/11/15 23:37, Stephen Boyd wrote:
> The qfprom is a little endian device, but so far we've been
> relying on the regmap mmio bus handling this for us without
> explicitly stating that fact. After commit 4a98da2164cf
> (regmap-mmio: Use native endianness for read/write, 2015-10-29),
> the regmap mmio bus will read/write with the __raw_*() IO
> accessors, instead of using the readl/writel() APIs that do
> proper byte swapping for little endian devices.
>
> So if we're running on a big endian processor and haven't
> specified the endianness explicitly in the regmap config or in
> DT, we're going to switch from doing little endian byte swapping
> to big endian accesses without byte swapping, leading to some
> confusing results. Specify the endianness explicitly so that the
> regmap core properly byte swaps the accesses for us.
>
> Cc: Rajendra Nayak <rnayak@codeaurora.org>
> Cc: Kevin Hilman <khilman@linaro.org>
> Cc: Tyler Baker <tyler.baker@linaro.org>
> Cc: Simon Arlott <simon@fire.lp0.eu>
> Cc: Mark Brown <broonie@kernel.org>
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> ---
> drivers/nvmem/qfprom.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c
> index afb67e7eeee4..3829e5fbf8c3 100644
> --- a/drivers/nvmem/qfprom.c
> +++ b/drivers/nvmem/qfprom.c
> @@ -21,6 +21,7 @@ static struct regmap_config qfprom_regmap_config = {
> .reg_bits = 32,
> .val_bits = 8,
> .reg_stride = 1,
> + .val_format_endian = REGMAP_ENDIAN_LITTLE,
> };
>
> static struct nvmem_config econfig = {
>
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| From | Stephen Boyd <sboyd@codeaurora.org> |
|---|---|
| Date | 2015-11-24 02:10 +0100 |
| Message-ID | <qyahk-1bG-3@gated-at.bofh.it> |
| In reply to | #1274657 |
On 11/21, Srinivas Kandagatla wrote: > Hi Stephen, > > Thanks for the fix. > > I will send it to Greg for next rc. Thanks. The change in regmap core that causes the problem is only in -next. I'm not sure if it's going to hit mainline this release cycle, so if it doesn't you could queue this for the next version. No rush. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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