From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C0419C433F5 for ; Wed, 22 Dec 2021 09:28:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:CC:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=OcDOroI83o51pNyK0g2bbfYyIKgSWj8KUJNSzug5OQA=; b=W13BNLS2dZ44kl 7Afx6JlTmMmZTelf18DumHIctmyY3DZQJ+WZn1wh74qk+EBfILftmvN2hb3eMP7W9qrbABreqvC8k 9VlmqNi2tQVvAGu7zd+NOaz23NQGLTCcCirPNI8eRCvXkx5loGJEXX8mqvWFb3MDDkEGrbTWj/95k GPOXODnaOUhLiLAiHCJGdjCJVeLdDZUQBWbK3YeNbZNZQKB4nbJQt5I1cYEeHYusXZxV0iLqG7syI u9GRNtsGGO+h2XjdVnSiQ50y50JDo07n+5JxnrzVbK3QtAtO3S8/mTPXGzX1bzw497QHWhkDHmcU+ tYl0GAyvVgQ40Oomm94g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mzxv3-009tEU-E9; Wed, 22 Dec 2021 09:28:21 +0000 Received: from mail-sh.amlogic.com ([58.32.228.43]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mzxur-009tC7-3e; Wed, 22 Dec 2021 09:28:10 +0000 Received: from [10.18.29.173] (10.18.29.173) by mail-sh.amlogic.com (10.18.11.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.14; Wed, 22 Dec 2021 17:28:04 +0800 Message-ID: Date: Wed, 22 Dec 2021 17:28:04 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [PATCH 3/3] tty: serial: meson: add UART driver compatible with S4 SoC on-chip Content-Language: en-US To: Greg Kroah-Hartman CC: , , , , Jiri Slaby , Neil Armstrong , Kevin Hilman , Jerome Brunet , Martin Blumenstingl References: <20211221071634.25980-1-yu.tu@amlogic.com> <20211221071634.25980-4-yu.tu@amlogic.com> From: Yu Tu In-Reply-To: X-Originating-IP: [10.18.29.173] X-ClientProxiedBy: mail-sh.amlogic.com (10.18.11.5) To mail-sh.amlogic.com (10.18.11.5) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211222_012809_190831_1C13FF1B X-CRM114-Status: GOOD ( 26.57 ) X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org On 2021/12/21 15:34, Greg Kroah-Hartman wrote: > [ EXTERNAL EMAIL ] > > On Tue, Dec 21, 2021 at 03:16:34PM +0800, Yu Tu wrote: >> The S4 SoC on-chip UART uses a 12M clock as the clock source for >> calculating the baud rate of the UART. But previously, chips used 24M or >> other clock sources. So add this change. The specific clock source is >> determined by chip design. >> >> Signed-off-by: Yu Tu >> --- >> drivers/tty/serial/meson_uart.c | 62 +++++++++++++++++++++++++++++---- >> 1 file changed, 55 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c >> index 69450a461c48..557c24d954a2 100644 >> --- a/drivers/tty/serial/meson_uart.c >> +++ b/drivers/tty/serial/meson_uart.c >> @@ -19,6 +19,7 @@ >> #include >> #include >> #include >> +#include >> >> /* Register offsets */ >> #define AML_UART_WFIFO 0x00 >> @@ -68,6 +69,8 @@ >> #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_TICK BIT(26) >> +#define AML_UART_BAUD_XTAL_DIV2 BIT(27) >> >> #define AML_UART_PORT_NUM 12 >> #define AML_UART_PORT_OFFSET 6 >> @@ -80,6 +83,11 @@ static struct uart_driver meson_uart_driver; >> >> static struct uart_port *meson_ports[AML_UART_PORT_NUM]; >> >> +struct meson_uart_data { >> + /*A clock source that calculates baud rates*/ > > Please use spaces in your comments. I will correct this mistake in the next patch. > >> + unsigned int xtal_tick_en; > > What is "_en" for? > > "enabled"? > > Spell it out please. You're right.I will correct as you suggested. > > And why an unsigned int for a boolean flag? It is my thoughtless, I will correct. > >> +}; >> + >> static void meson_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) >> { >> } >> @@ -294,16 +302,29 @@ static int meson_uart_startup(struct uart_port *port) >> >> static void meson_uart_change_speed(struct uart_port *port, unsigned long baud) >> { >> + struct meson_uart_data *uart_data = port->private_data; >> u32 val; >> >> while (!meson_uart_tx_empty(port)) >> cpu_relax(); >> >> + val = readl_relaxed(port->membase + AML_UART_REG5); >> + val &= ~AML_UART_BAUD_MASK; >> + >> if (port->uartclk == 24000000) { >> - val = ((port->uartclk / 3) / baud) - 1; >> - val |= AML_UART_BAUD_XTAL; >> + if (uart_data->xtal_tick_en) { >> + val = (port->uartclk / 2 + baud / 2) / baud - 1; >> + val |= (AML_UART_BAUD_XTAL | AML_UART_BAUD_XTAL_DIV2); >> + } else { >> + val = ((port->uartclk / 3) + baud / 2) / baud - 1; >> + val &= (~(AML_UART_BAUD_XTAL_TICK | >> + AML_UART_BAUD_XTAL_DIV2)); >> + val |= AML_UART_BAUD_XTAL; >> + } >> } else { >> val = ((port->uartclk * 10 / (baud * 4) + 5) / 10) - 1; >> + val &= (~(AML_UART_BAUD_XTAL | AML_UART_BAUD_XTAL_TICK | >> + AML_UART_BAUD_XTAL_DIV2)); >> } >> val |= AML_UART_BAUD_USE; >> writel(val, port->membase + AML_UART_REG5); >> @@ -714,6 +735,7 @@ static int meson_uart_probe(struct platform_device *pdev) >> { >> struct resource *res_mem, *res_irq; >> struct uart_port *port; >> + struct meson_uart_data *uart_data; >> int ret = 0; >> int id = -1; >> >> @@ -729,6 +751,10 @@ static int meson_uart_probe(struct platform_device *pdev) >> } >> } >> >> + uart_data = of_device_get_match_data(&pdev->dev); >> + if (!uart_data) >> + return -EINVAL; > > Wrong spacing. > > Always use checkpatch.pl on your patches before sending them out. Sorry, this is a rookie mistake.But I did check it locally before sending it. I will follow your advice strictly later. > > And did you just break existing systems? Do you know if all older ones > will still work with that call? > It does affect older systems, but the new and older baud rates are not the same. I checked the documents before I made any changes. So this change is compatible with the older. >> + >> if (pdev->id < 0 || pdev->id >= AML_UART_PORT_NUM) >> return -EINVAL; >> >> @@ -770,6 +796,7 @@ static int meson_uart_probe(struct platform_device *pdev) >> port->x_char = 0; >> port->ops = &meson_uart_ops; >> port->fifosize = 64; >> + port->private_data = uart_data; >> >> meson_ports[pdev->id] = port; >> platform_set_drvdata(pdev, port); >> @@ -798,14 +825,35 @@ static int meson_uart_remove(struct platform_device *pdev) >> return 0; >> } >> >> +static const struct meson_uart_data meson_uart_data = { >> + .xtal_tick_en = 0, >> +}; >> + >> +static const struct meson_uart_data s4_meson_uart_data = { >> + .xtal_tick_en = 1, >> +}; > > As your whole structure just has one bit, why not just use that as the > data value, instead of a structure? No need to be complex here at all. > It is my thoughtless, I will correct. > thanks, > > greg k-h > _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic