serial: 8250_dw: Use a fixed CPR value for UltraRISC DP1000 UART

The UltraRISC DP1000 UART does not provide the standard CPR register used
by 8250_dw to discover port capabilities.

Provide a fixed CPR value for the DP1000-specific compatible so the
driver can configure the port correctly.

Signed-off-by: Jia Wang <wangjia@ultrarisc.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260429-ultrarisc-serial-v7-4-e475cce9e274@ultrarisc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 480f82d89856f9c99180cc25705370db481a2366..55e40c10f46a295e6f36ba825397de9768629a38 100644 (file)
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -959,6 +959,15 @@ static const struct dw8250_platform_data dw8250_intc10ee = {
        .quirks = DW_UART_QUIRK_IER_KICK,
 };
 
+static const struct dw8250_platform_data dw8250_ultrarisc_dp1000_data = {
+       .usr_reg = DW_UART_USR,
+       .cpr_value = FIELD_PREP_CONST(DW_UART_CPR_ABP_DATA_WIDTH, 2) |
+                    DW_UART_CPR_THRE_MODE |
+                    DW_UART_CPR_DMA_EXTRA |
+                    DW_UART_CPR_FIFO_MODE_FROM_SIZE(32),
+       .quirks = DW_UART_QUIRK_CPR_VALUE,
+};
+
 static const struct of_device_id dw8250_of_match[] = {
        { .compatible = "snps,dw-apb-uart", .data = &dw8250_dw_apb },
        { .compatible = "cavium,octeon-3860-uart", .data = &dw8250_octeon_3860_data },
@@ -966,6 +975,7 @@ static const struct of_device_id dw8250_of_match[] = {
        { .compatible = "renesas,rzn1-uart", .data = &dw8250_renesas_rzn1_data },
        { .compatible = "sophgo,sg2044-uart", .data = &dw8250_skip_set_rate_data },
        { .compatible = "starfive,jh7100-uart", .data = &dw8250_skip_set_rate_data },
+       { .compatible = "ultrarisc,dp1000-uart", .data = &dw8250_ultrarisc_dp1000_data },
        { /* Sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, dw8250_of_match);