[stable-kernel-only][5.15.y][5.10.y][PATCH] serial: sc16is7xx: the reg needs to shift in regmap_noinc
Recently we found the fifo_read() and fifo_write() are broken in our 5.15 and 5.4 kernels after cherry-pick the commit e635f652696e ("serial: sc16is7xx: convert from _raw_ to _noinc_ regmap functions for FIFO"), that is because the reg needs to shift if we don't cherry-pick a prerequiste commit 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port").
Here fix it by shifting the reg as regmap_volatile() does.
Signed-off-by: Hui Wang hui.wang@canonical.com --- drivers/tty/serial/sc16is7xx.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index d274a847c6ab..87e34099f369 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -487,7 +487,14 @@ static bool sc16is7xx_regmap_precious(struct device *dev, unsigned int reg)
static bool sc16is7xx_regmap_noinc(struct device *dev, unsigned int reg) { - return reg == SC16IS7XX_RHR_REG; + switch (reg >> SC16IS7XX_REG_SHIFT) { + case SC16IS7XX_RHR_REG: + return true; + default: + break; + } + + return false; }
/*
Hi,
Thanks for your patch.
FYI: kernel test robot notices the stable kernel rule is not satisfied.
The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#opti...
Rule: add the tag "Cc: stable@vger.kernel.org" in the sign-off area to have the patch automatically included in the stable tree. Subject: [stable-kernel-only][5.15.y][5.10.y][PATCH] serial: sc16is7xx: the reg needs to shift in regmap_noinc Link: https://lore.kernel.org/stable/20241207001225.203262-1-hui.wang%40canonical....
[ Sasha's backport helper bot ]
Hi,
No upstream commit was identified. Using temporary commit for testing.
Results of testing on various branches:
| Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-5.15.y | Success | Success | | stable/linux-5.10.y | Success | Success |
On Sat, Dec 07, 2024 at 08:12:25AM +0800, Hui Wang wrote:
Recently we found the fifo_read() and fifo_write() are broken in our 5.15 and 5.4 kernels after cherry-pick the commit e635f652696e ("serial: sc16is7xx: convert from _raw_ to _noinc_ regmap functions for FIFO"), that is because the reg needs to shift if we don't cherry-pick a prerequiste commit 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port").
Here fix it by shifting the reg as regmap_volatile() does.
Signed-off-by: Hui Wang hui.wang@canonical.com
drivers/tty/serial/sc16is7xx.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
Why not take the proper upstream commit instead?
On 12/7/24 14:31, Greg KH wrote:
On Sat, Dec 07, 2024 at 08:12:25AM +0800, Hui Wang wrote:
Recently we found the fifo_read() and fifo_write() are broken in our 5.15 and 5.4 kernels after cherry-pick the commit e635f652696e ("serial: sc16is7xx: convert from _raw_ to _noinc_ regmap functions for FIFO"), that is because the reg needs to shift if we don't cherry-pick a prerequiste commit 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port").
Here fix it by shifting the reg as regmap_volatile() does.
Signed-off-by: Hui Wang hui.wang@canonical.com
drivers/tty/serial/sc16is7xx.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
Why not take the proper upstream commit instead?
The prerequisite commit 3837a0379533 will introduce significant change and significant conflict if backport it to 5.15.y/5.10.y, It is more likely to bring new regression.
linux-stable-mirror@lists.linaro.org
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Greg KH -
Hui Wang -
kernel test robot -
Sasha Levin