tty: serial: fsl_lpuart: add imx8ulp support

The lpuart of imx8ulp is basically the same as imx7ulp, but it supports
some new features based on imx7ulp, such as it can assert the DMA
request on EOP(end-of-packet).

Here add lpuart support for imx8ulp, and rx_watermark is set to 3 as
imx8ulp RX FIFO depth is 8.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230130064449.9564-7-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/fsl_lpuart.c

@@ -252,6 +252,7 @@ enum lpuart_type {
 	LS1021A_LPUART,
 	LS1028A_LPUART,
 	IMX7ULP_LPUART,
+	IMX8ULP_LPUART,
 	IMX8QXP_LPUART,
 	IMXRT1050_LPUART,
 };
@@ -319,6 +320,13 @@ static struct lpuart_soc_data imx7ulp_data = {
 	.rx_watermark = 1,
 };
 
+static struct lpuart_soc_data imx8ulp_data = {
+	.devtype = IMX8ULP_LPUART,
+	.iotype = UPIO_MEM32,
+	.reg_off = IMX_REG_OFF,
+	.rx_watermark = 3,
+};
+
 static struct lpuart_soc_data imx8qxp_data = {
 	.devtype = IMX8QXP_LPUART,
 	.iotype = UPIO_MEM32,
@@ -337,6 +345,7 @@ static const struct of_device_id lpuart_dt_ids[] = {
 	{ .compatible = "fsl,ls1021a-lpuart",	.data = &ls1021a_data, },
 	{ .compatible = "fsl,ls1028a-lpuart",	.data = &ls1028a_data, },
 	{ .compatible = "fsl,imx7ulp-lpuart",	.data = &imx7ulp_data, },
+	{ .compatible = "fsl,imx8ulp-lpuart",	.data = &imx8ulp_data, },
 	{ .compatible = "fsl,imx8qxp-lpuart",	.data = &imx8qxp_data, },
 	{ .compatible = "fsl,imxrt1050-lpuart",	.data = &imxrt1050_data},
 	{ /* sentinel */ }
@@ -357,6 +366,11 @@ static inline bool is_imx7ulp_lpuart(struct lpuart_port *sport)
 	return sport->devtype == IMX7ULP_LPUART;
 }
 
+static inline bool is_imx8ulp_lpuart(struct lpuart_port *sport)
+{
+	return sport->devtype == IMX8ULP_LPUART;
+}
+
 static inline bool is_imx8qxp_lpuart(struct lpuart_port *sport)
 {
 	return sport->devtype == IMX8QXP_LPUART;
@@ -2691,7 +2705,7 @@ static int lpuart_global_reset(struct lpuart_port *sport)
 		return ret;
 	}
 
-	if (is_imx7ulp_lpuart(sport) || is_imx8qxp_lpuart(sport)) {
+	if (is_imx7ulp_lpuart(sport) || is_imx8ulp_lpuart(sport) || is_imx8qxp_lpuart(sport)) {
 		/*
 		 * If the transmitter is used by earlycon, wait for transmit engine to
 		 * complete and then reset.