serial: 8250: dw: Move the USR register to pdata

This offset is a good candidate to pdata's because it changes depending
on the vendor implementation. Let's move the usr_reg entry from regular
to pdata. This way we can drop initializing it at run time.

Let's also use a define for it instead of defining only the default
value.
Suggested-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220422180615.9098-4-miquel.raynal@bootlin.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_dw.c

@@ -35,6 +35,8 @@
 /* Offsets for the DesignWare specific registers */
 #define DW_UART_USR	0x1f /* UART Status Register */
 
+#define OCTEON_UART_USR	0x27 /* UART Status Register */
+
 /* DesignWare specific register fields */
 #define DW_UART_MCR_SIRE		BIT(6)
 
@@ -251,7 +253,7 @@ static int dw8250_handle_irq(struct uart_port *p)
 
 	if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
 		/* Clear the USR */
-		(void)p->serial_in(p, d->usr_reg);
+		(void)p->serial_in(p, d->pdata->usr_reg);
 
 		return 1;
 	}
@@ -387,7 +389,6 @@ static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data)
 			p->serial_out = dw8250_serial_outq;
 			p->flags = UPF_SKIP_TEST | UPF_SHARE_IRQ | UPF_FIXED_TYPE;
 			p->type = PORT_OCTEON;
-			data->usr_reg = 0x27;
 			data->skip_autocfg = true;
 		}
 #endif
@@ -462,7 +463,6 @@ static int dw8250_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	data->data.dma.fn = dw8250_fallback_dma_filter;
-	data->usr_reg = DW_UART_USR;
 	data->pdata = device_get_match_data(p->dev);
 	p->private_data = &data->data;
 
@@ -681,20 +681,25 @@ static const struct dev_pm_ops dw8250_pm_ops = {
 };
 
 static const struct dw8250_platform_data dw8250_dw_apb = {
+	.usr_reg = DW_UART_USR,
 };
 
 static const struct dw8250_platform_data dw8250_octeon_3860_data = {
+	.usr_reg = OCTEON_UART_USR,
 	.quirks = DW_UART_QUIRK_OCTEON,
 };
 
 static const struct dw8250_platform_data dw8250_armada_38x_data = {
+	.usr_reg = DW_UART_USR,
 	.quirks = DW_UART_QUIRK_ARMADA_38X,
 };
 
 static const struct dw8250_platform_data dw8250_renesas_rzn1_data = {
+	.usr_reg = DW_UART_USR,
 };
 
 static const struct dw8250_platform_data dw8250_starfive_jh7100_data = {
+	.usr_reg = DW_UART_USR,
 	.quirks = DW_UART_QUIRK_SKIP_SET_RATE,
 };
 

drivers/tty/serial/8250/8250_dwlib.h

@@ -22,6 +22,7 @@ struct dw8250_port_data {
 };
 
 struct dw8250_platform_data {
+	u8 usr_reg;
 	unsigned int quirks;
 };
 
@@ -29,7 +30,6 @@ struct dw8250_data {
 	struct dw8250_port_data	data;
 	const struct dw8250_platform_data *pdata;
 
-	u8			usr_reg;
 	int			msr_mask_on;
 	int			msr_mask_off;
 	struct clk		*clk;