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; }
/*