Hi Neil,
On 2022/4/21 16:46, Neil Armstrong wrote:
[ EXTERNAL EMAIL ]
Hi Andy,
On 18/04/2022 14:09, Andy Shevchenko wrote:
On Mon, Apr 18, 2022 at 8:50 AM Yu Tu <yu.tu@xxxxxxxxxxx> wrote:
A /2 divider over XTAL was introduced since G12A, and is preferred
to be used over the still present /3 divider since it provides much
closer frequencies vs the request baudrate.Especially the BT module
'e. E' (mind the space)
uses 3Mhz baud rate. 8Mhz calculations can lead to baud rate bias,
causing some problems.
...
+struct meson_uart_data {
+ bool has_xtal_div2;
I would prefer to see this as an unsigned int and with a less
particular name, e.g. xtal_div would suffice.
+};
...
+ unsigned int xtal_div = 3;
+ if (private_data && private_data->has_xtal_div2) {
+ xtal_div = 2;
Better to define privata data always
While I'm in favor of defining private data, here 3 and 2 are actually
the values
2 and 3 used to divide.
The code is easy to read and we quickly understand this value is the
clock divider.
Therefore, this place should be modified according to your previous
suggestion.I will prepare the next version.
+ val |= AML_UART_BAUD_XTAL_DIV2;
+ }
+ val |= DIV_ROUND_CLOSEST(port->uartclk / xtal_div,
baud) - 1;
.
