From:   Sherry Sun <sherry.sun@nxp.com>
To:     gregkh@linuxfoundation.org, jirislaby@kernel.org
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-imx@nxp.com
Subject: [PATCH 3/6] tty: serial: fsl_lpuart: Fix the wrong RXWATER setting for rx dma case
Date:   Mon, 30 Jan 2023 14:44:46 +0800
Message-Id: <20230130064449.9564-4-sherry.sun@nxp.com>
In-Reply-To: <20230130064449.9564-1-sherry.sun@nxp.com>
References: <20230130064449.9564-1-sherry.sun@nxp.com>
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The RXWATER value must be greater than 0 according to the LPUART
reference manual. And when the number of datawords in the receive
FIFO is greater than RXWATER, an interrupt or a DMA request is
generated, so no need to set the different value for lpuart interrupt
case and dma case. Here delete the wrong RXWATER setting for dma case
directly.

Fixes: 42b68768e51b ("serial: fsl_lpuart: DMA support for 32-bit variant")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
---
 drivers/tty/serial/fsl_lpuart.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 868c2783d2c7..ba6ade784ac5 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1729,12 +1729,6 @@ static void lpuart32_configure(struct lpuart_port *sport)
 {
 	unsigned long temp;
 
-	if (sport->lpuart_dma_rx_use) {
-		/* RXWATER must be 0 */
-		temp = lpuart32_read(&sport->port, UARTWATER);
-		temp &= ~(UARTWATER_WATER_MASK << UARTWATER_RXWATER_OFF);
-		lpuart32_write(&sport->port, temp, UARTWATER);
-	}
 	temp = lpuart32_read(&sport->port, UARTCTRL);
 	if (!sport->lpuart_dma_rx_use)
 		temp |= UARTCTRL_RIE | UARTCTRL_ILIE;
-- 
2.17.1