From patchwork Tue Sep 6 13:55:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergiu Moga X-Patchwork-Id: 603306 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 3BE96ECAAD5 for ; Tue, 6 Sep 2022 14:39:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241973AbiIFOjw (ORCPT ); Tue, 6 Sep 2022 10:39:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49154 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242215AbiIFOir (ORCPT ); Tue, 6 Sep 2022 10:38:47 -0400 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C1F49A964; Tue, 6 Sep 2022 07:00:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1662472857; x=1694008857; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=pk0hBeRzv9yrSvjx77z7pR8KMLbpypDtOQMtHWLcCCU=; b=OWPO9sIzkxP4jocz/tYqCEZPLZBqAyq6myzvB1OVIVjJN+6TmZhgdVBH uCGp7bXKA4cMtUf1S3g6cthOgsgMnpjpEqNV+xqVVCva96n3Hk6JROMxv UOleduYl7jCJ7jYwGEH7s3HgFoSef66iEN3cHXJrekfkbDoZ0b1mT4Xfh ylfBkPI8pAYIeWkXLrpYkvJUjpWM8LIPmVLSlm4RoWvB4nWp6YPKUNmOj KOWvK7xVqrs6MSGKfMyw57daMPKUT3CTuZG5bW+6dcnX8TaGIOIGTvcPl neJdUZz7k9+inxZjsLicfSRfCuh3zv2HyFKGOv4NEKx4InCS5DmRT6poh w==; X-IronPort-AV: E=Sophos;i="5.93,294,1654585200"; d="scan'208";a="175830165" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa2.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 06 Sep 2022 06:57:31 -0700 Received: from chn-vm-ex04.mchp-main.com (10.10.85.152) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.12; Tue, 6 Sep 2022 06:57:26 -0700 Received: from ROB-ULT-M68701.microchip.com (10.10.115.15) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server id 15.1.2507.12 via Frontend Transport; Tue, 6 Sep 2022 06:57:21 -0700 From: Sergiu Moga To: , , , , , , , , , , , , , , , , CC: , , , , , Subject: [PATCH v2 10/13] tty: serial: atmel: Only divide Clock Divisor if the IP is USART Date: Tue, 6 Sep 2022 16:55:09 +0300 Message-ID: <20220906135511.144725-11-sergiu.moga@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220906135511.144725-1-sergiu.moga@microchip.com> References: <20220906135511.144725-1-sergiu.moga@microchip.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Make sure that the driver only divides the clock divisor if the IP handled at that point is USART, since UART IP's do not support implicit peripheral clock division. Instead, in the case of UART, go with the highest possible clock divisor. Signed-off-by: Sergiu Moga --- v1 -> v2: - Nothing, this patch was not here before and is mainly meant as both cleanup and as a way to introduce a new field into struct atmel_uart_port that will be used by the last patch to diferentiate between USART and UART regarding the location of the Baudrate Clock Source bitmask. drivers/tty/serial/atmel_serial.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 7450d3853031..6aa01ca5489c 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -150,6 +150,7 @@ struct atmel_uart_port { u32 rts_low; bool ms_irq_enabled; u32 rtor; /* address of receiver timeout register if it exists */ + bool is_usart; bool has_frac_baudrate; bool has_hw_timer; struct timer_list uart_timer; @@ -1825,6 +1826,7 @@ static void atmel_get_ip_name(struct uart_port *port) */ atmel_port->has_frac_baudrate = false; atmel_port->has_hw_timer = false; + atmel_port->is_usart = false; if (name == new_uart) { dev_dbg(port->dev, "Uart with hw timer"); @@ -1834,6 +1836,7 @@ static void atmel_get_ip_name(struct uart_port *port) dev_dbg(port->dev, "Usart\n"); atmel_port->has_frac_baudrate = true; atmel_port->has_hw_timer = true; + atmel_port->is_usart = true; atmel_port->rtor = ATMEL_US_RTOR; version = atmel_uart_readl(port, ATMEL_US_VERSION); switch (version) { @@ -1863,6 +1866,7 @@ static void atmel_get_ip_name(struct uart_port *port) dev_dbg(port->dev, "This version is usart\n"); atmel_port->has_frac_baudrate = true; atmel_port->has_hw_timer = true; + atmel_port->is_usart = true; atmel_port->rtor = ATMEL_US_RTOR; break; case 0x203: @@ -2282,10 +2286,17 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios, cd = uart_get_divisor(port, baud); } - if (cd > 65535) { /* BRGR is 16-bit, so switch to slower clock */ + /* + * BRGR is 16-bit, so switch to slower clock. + * Otherwise, keep the highest possible value for the clock divisor. + */ + if (atmel_port->is_usart && cd > 65535) { cd /= 8; mode |= ATMEL_US_USCLKS_MCK_DIV8; + } else { + cd &= 65535; } + quot = cd | fp << ATMEL_US_FP_OFFSET; if (!(port->iso7816.flags & SER_ISO7816_ENABLED))