| Message ID | 20241207001225.203262-1-hui.wang@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [stable-kernel-only,5.15.y,5.10.y] serial: sc16is7xx: the reg needs to shift in regmap_noinc | expand |
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. >
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; } /*
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(-)