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driver: uart: npcx: Support APB clock of uart module up to 20MHz.

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Suport npcx UART module's APB clock up to 20MHz.

Signed-off-by: Mulin Chao <mlchao@nuvoton.com>
This commit is contained in:
Mulin Chao 2021-05-04 20:45:52 -07:00 • committed by Kumar Gala
commit f7f93d2207
1 changed files with 28 additions and 7 deletions
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35
drivers/serial/uart_npcx.c
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@ -55,6 +55,27 @@ struct uart_npcx_data {
(struct uart_reg *)(DRV_CONFIG(dev)->uconf.base)
/* UART local functions */
static int uart_set_npcx_baud_rate(struct uart_reg *const inst, int baud_rate,
int src_clk)
{
/* Fix baud rate to 115200 so far */
if (baud_rate == 115200) {
if (src_clk == 15000000) {
inst->UPSR = 0x38;
inst->UBAUD = 0x01;
} else if (src_clk == 20000000) {
inst->UPSR = 0x08;
inst->UBAUD = 0x0a;
} else {
return -EINVAL;
}
} else {
return -EINVAL;
}
return 0;
}
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
static int uart_npcx_tx_fifo_ready(const struct device *dev)
{
@ -352,14 +373,14 @@ static int uart_npcx_init(const struct device *dev)
LOG_ERR("Get UART clock rate error %d", ret);
return ret;
}
__ASSERT(uart_rate == 15000000, "Unsupported apb2 clock for UART!");
/* Fix baud rate to 115200 */
if (data->baud_rate == 115200) {
inst->UPSR = 0x38;
inst->UBAUD = 0x01;
} else
return -EINVAL;
/* Configure baud rate */
ret = uart_set_npcx_baud_rate(inst, data->baud_rate, uart_rate);
if (ret < 0) {
LOG_ERR("Set baud rate %d with unsupported apb clock %d failed",
data->baud_rate, uart_rate);
return ret;
}
/*
* 8-N-1, FIFO enabled. Must be done after setting