commit b40de7469ef135161c80af0e8c462298cc5dac00 upstream.

The current implementation uses 0 as lower limit for the baud rate tolerance for tegra20 and tegra30 chips which causes isses on UART initialization as soon as baud rate clock is lower than required even when within the standard UART tolerance of +/- 4%.

This fix aligns the implementation with the initial commit description of +/- 4% tolerance for tegra chips other than tegra186 and tegra194.

Fixes: d781ec21bae6 ("serial: tegra: report clk rate errors") Cc: stable stable@vger.kernel.org Signed-off-by: Patrik John patrik.john@u-blox.com Link: https://lore.kernel.org/r/sig.19614244f8.20211123132737.88341-1-patrik.john@... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Backport for 5.4-stable

drivers/tty/serial/serial-tegra.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c index 64f18bf1e694..74c21152367a 100644 --- a/drivers/tty/serial/serial-tegra.c +++ b/drivers/tty/serial/serial-tegra.c @@ -1494,7 +1494,7 @@ static struct tegra_uart_chip_data tegra20_uart_chip_data = { .fifo_mode_enable_status = false, .uart_max_port = 5, .max_dma_burst_bytes = 4, - .error_tolerance_low_range = 0, + .error_tolerance_low_range = -4, .error_tolerance_high_range = 4, };

@@ -1505,7 +1505,7 @@ static struct tegra_uart_chip_data tegra30_uart_chip_data = { .fifo_mode_enable_status = false, .uart_max_port = 5, .max_dma_burst_bytes = 4, - .error_tolerance_low_range = 0, + .error_tolerance_low_range = -4, .error_tolerance_high_range = 4, };