[PATCH v7 4/4] serial: 8250_dw: Use a fixed CPR value for UltraRISC DP1000 UART
Jia Wang
wangjia at ultrarisc.com
Wed Apr 29 02:13:28 PDT 2026
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 at ultrarisc.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
---
drivers/tty/serial/8250/8250_dw.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 480f82d89856..55e40c10f46a 100644
--- 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);
--
2.34.1
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