[xen staging] drivers: char: omap-uart: provide a default clock frequency

[patchbot@xxxxxxx]

commit be9b405aef1c01bbb5af16b4ee519c648c26f556
Author:     Amneesh Singh <a-singh21@xxxxxx>
AuthorDate: Tue Aug 20 13:52:03 2024 +0530
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Thu Aug 22 10:59:52 2024 +0100

    drivers: char: omap-uart: provide a default clock frequency
    
    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, which is the same as the linux default (see
    8250_omap.c), if the device tree does not specify it.
    
    Signed-off-by: Amneesh Singh <a-singh21@xxxxxx>
    Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
---
 xen/drivers/char/omap-uart.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/char/omap-uart.c b/xen/drivers/char/omap-uart.c
index 1079198a8d..9f73d822ad 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;
--
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