From patchwork Thu Apr 7 08:13:54 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Tu X-Patchwork-Id: 558712 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9564AC433FE for ; Thu, 7 Apr 2022 08:30:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243034AbiDGIct (ORCPT ); Thu, 7 Apr 2022 04:32:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33098 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243028AbiDGIca (ORCPT ); Thu, 7 Apr 2022 04:32:30 -0400 Received: from mail-sh.amlogic.com (mail-sh.amlogic.com [58.32.228.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D97A3156088; Thu, 7 Apr 2022 01:30:30 -0700 (PDT) Received: from droid06.amlogic.com (10.18.11.248) by mail-sh.amlogic.com (10.18.11.5) with Microsoft SMTP Server id 15.1.2176.14; Thu, 7 Apr 2022 16:15:26 +0800 From: Yu Tu To: , , , , Neil Armstrong , Kevin Hilman , Jerome Brunet CC: Greg Kroah-Hartman , Jiri Slaby , Martin Blumenstingl , Yu Tu Subject: [PATCH 2/3] tty: serial: meson: Added 12Mhz as the clock source for calculating baud rate Date: Thu, 7 Apr 2022 16:13:54 +0800 Message-ID: <20220407081355.13602-3-yu.tu@amlogic.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20220407081355.13602-1-yu.tu@amlogic.com> References: <20220407081355.13602-1-yu.tu@amlogic.com> MIME-Version: 1.0 X-Originating-IP: [10.18.11.248] Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Starting with the g12A chip, add a 12Mhz clock to calculate the baud rate, since the BT module uses 3Mhz baud rate. 8Mhz calculations can lead to baud rate bias, causing some problems. Signed-off-by: Yu Tu --- drivers/tty/serial/meson_uart.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c index 8e59624935af..7e77693a1318 100644 --- a/drivers/tty/serial/meson_uart.c +++ b/drivers/tty/serial/meson_uart.c @@ -68,6 +68,7 @@ #define AML_UART_BAUD_MASK 0x7fffff #define AML_UART_BAUD_USE BIT(23) #define AML_UART_BAUD_XTAL BIT(24) +#define AML_UART_BAUD_XTAL_DIV2 BIT(27) #define AML_UART_PORT_NUM 12 #define AML_UART_PORT_OFFSET 6 @@ -80,6 +81,10 @@ static struct uart_driver meson_uart_driver; static struct uart_port *meson_ports[AML_UART_PORT_NUM]; +struct meson_uart_data { + bool has_xtal_div2; +}; + static void meson_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) { } @@ -293,13 +298,20 @@ static int meson_uart_startup(struct uart_port *port) static void meson_uart_change_speed(struct uart_port *port, unsigned long baud) { - u32 val; + struct meson_uart_data *private_data = port->private_data; + u32 val = 0; while (!meson_uart_tx_empty(port)) cpu_relax(); if (port->uartclk == 24000000) { - val = DIV_ROUND_CLOSEST(port->uartclk / 3, baud) - 1; + unsigned int xtal_div = 3; + + if (private_data->has_xtal_div2) { + xtal_div = 2; + val |= AML_UART_BAUD_XTAL_DIV2; + } + val |= DIV_ROUND_CLOSEST(port->uartclk / xtal_div, baud) - 1; val |= AML_UART_BAUD_XTAL; } else { val = DIV_ROUND_CLOSEST(port->uartclk / 4, baud) - 1; @@ -691,6 +703,7 @@ static int meson_uart_probe_clocks(struct platform_device *pdev, static int meson_uart_probe(struct platform_device *pdev) { + struct meson_uart_data *private_data; struct resource *res_mem; struct uart_port *port; u32 fifosize = 64; /* Default is 64, 128 for EE UART_0 */ @@ -733,6 +746,13 @@ static int meson_uart_probe(struct platform_device *pdev) if (!port) return -ENOMEM; + private_data = devm_kzalloc(&pdev->dev, sizeof(struct meson_uart_data), GFP_KERNEL); + if (!private_data) + return -ENOMEM; + + if ((bool)device_get_match_data(&pdev->dev)) + private_data->has_xtal_div2 = true; + ret = meson_uart_probe_clocks(pdev, port); if (ret) return ret; @@ -749,6 +769,7 @@ static int meson_uart_probe(struct platform_device *pdev) port->x_char = 0; port->ops = &meson_uart_ops; port->fifosize = fifosize; + port->private_data = private_data; meson_ports[pdev->id] = port; platform_set_drvdata(pdev, port);