Re: [PATCH V6 4/5] tty: serial: meson: Make some bit of the REG5 register writable

Hi Jerome,
	Thank you very much for your reply. At present, the problem of 
switching uART baud rate stuck has been solved. I'm ready to send the 
next edition.

On 2022/1/21 5:49, Jerome Brunet wrote:

[ EXTERNAL EMAIL ]


On Tue 18 Jan 2022 at 11:09, Yu Tu [off-list ref] wrote:

quoted

The UART_REG5 register defaults to 0. The console port is set in
ROMCODE. But other UART ports default to 0, so make bit24 and
bit[26,27] writable so that the UART can choose a more
appropriate clock.

Suggestion: Instead of talking bits (which is a bit cryptic) tell us
what is actually does

Something like:
  Make the internal clock source mux and divider writeable, allowing the
  uart to deviate from the settings intially applied by the ROMCode and
  using the most appropriate clocks

Your description is better, I will follow your suggestion in the next 
edition.

quoted

Signed-off-by: Yu Tu <redacted>
---
  drivers/tty/serial/meson_uart.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
index 92fa91c825e6..4e7b2b38ab0a 100644
--- a/drivers/tty/serial/meson_uart.c
+++ b/drivers/tty/serial/meson_uart.c

@@ -678,7 +678,7 @@ static int meson_uart_probe_clocks(struct uart_port *port)
  							CLK_SET_RATE_NO_REPARENT,
  							port->membase + AML_UART_REG5,
  							26, 2,
-							CLK_DIVIDER_READ_ONLY,
+							CLK_DIVIDER_ROUND_CLOSEST,
  							xtal_div_table, NULL);
  		if (IS_ERR(hw))
  			return PTR_ERR(hw);

@@ -708,7 +708,7 @@ static int meson_uart_probe_clocks(struct uart_port *port)
  					CLK_SET_RATE_PARENT,
  					port->membase + AML_UART_REG5,
  					24, 0x1,
-					CLK_MUX_READ_ONLY,
+					CLK_MUX_ROUND_CLOSEST,
  					NULL, NULL);
  	if (IS_ERR(hw))
  		return PTR_ERR(hw);

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