[PATCH v2] drivers: char: omap-uart: provide a default clock frequency

[Amneesh Singh <a-singh21@xxxxxx>]

Quite a few TI K3 devices do not have clock-frequency specified in their
respective UART nodes. However hard-coding the frequency is not a
solution as the function clock input can differ between SoCs. So, use a
default frequency of 48MHz if the device tree does not specify one.

Signed-off-by: Amneesh Singh <a-singh21@xxxxxx>
---
 xen/drivers/char/omap-uart.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
---
v1: https://lore.kernel.org/all/20240719113313.145587-1-a-singh21@xxxxxx/T/

v1 -> v2
- Ditch adding a dtuart option
- Use a default value instead

This default is the same one as found in the 8250_omap driver of the
linux tree. Already tested with Xen.

diff --git a/xen/drivers/char/omap-uart.c b/xen/drivers/char/omap-uart.c
index 1079198..9d3d39c 100644
--- a/xen/drivers/char/omap-uart.c
+++ b/xen/drivers/char/omap-uart.c
@@ -48,6 +48,9 @@
 /* System configuration register */
 #define UART_OMAP_SYSC_DEF_CONF   0x0d   /* autoidle mode, wakeup is enabled */
 
+/* default clock frequency in hz */
+#define UART_OMAP_DEFAULT_CLK_SPEED 48000000
+
 #define omap_read(uart, off)       readl((uart)->regs + ((off) << REG_SHIFT))
 #define omap_write(uart, off, val) writel(val, \
                                           (uart)->regs + ((off) << REG_SHIFT))
@@ -322,8 +325,9 @@ static int __init omap_uart_init(struct dt_device_node *dev,
     res = dt_property_read_u32(dev, "clock-frequency", &clkspec);
     if ( !res )
     {
-        printk("omap-uart: Unable to retrieve the clock frequency\n");
-        return -EINVAL;
+        printk("omap-uart: Unable to retrieve the clock frequency, "
+               "defaulting to %uHz\n", UART_OMAP_DEFAULT_CLK_SPEED);
+        clkspec = UART_OMAP_DEFAULT_CLK_SPEED;
     }
 
     uart->clock_hz = clkspec;
-- 
2.34.1