From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B63EC33F8B2; Thu, 30 Jul 2026 06:01:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785391320; cv=none; b=rW6aRtoxgzzNLvhFfeYGEV2q4tTRl6dKxJcBakgWz47vpUoJ/6Qlu1AJNMG/RjDCiXrdRMHdt4R06kSQsRcDb07QxAuFfVSX+vCrfJSJpxoLkVCkqqSgabUDq0Qq2uKXvuC6GAa6lgIrftciSQWz2tXXmhTB6neHX95PHRmvwbc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785391320; c=relaxed/simple; bh=CHRcDAcvCwYt7QmhZ9W30DATbHC2RoGiI/hskcwBRs4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=e2Dn4gB1KGVCYcGJhueRtiG2b9XmPO+OuM/lySy4zPvmMqIJpl3h9GLQ6mdZwVZgvEUuYcz6XAfteVsExvyHL2OkrqolXFpf6JSsT+ZbYW1tvHj3nfv3ZGVr71HLDLC1Q5oa+QcFtzJWGDy8FBo0cMYqxkTpWvrc2YWyrSd0iKM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g++jFDeQ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="g++jFDeQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEB5D1F000E9; Thu, 30 Jul 2026 06:01:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785391314; bh=vzf5E9YWmAZhDySeQdCiaA8p9qnrfA18758sslrcdpE=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=g++jFDeQmsP0fpaGxVUet1TluXjoHAC16+WEi0wcahlFrxUCP3V+/i7z0dqbP3DIn UQKqzComer9/SqrBVRHVCvv6HQnZ+z9jwjCkvoZE3prcGqzPX+Bhy05AOm4ZI8w/M5 pbkOjwvu2EsAfPsQ5CLdgyYGtBOcgC7KEUQ65wh4nNng7NGvh8gbGYBP8MtWqn8sJH rZD5tdUfhDzUPm8if0xwu+uMBnVzx0VH3U5+o68tDVlYpobKdUO3NQFn7Xgqex9Jzb +BiS24s/GtK3jf3O4JVGXmIFfj8gh69Q/HPK2QofMrKXhw/rWi0PLkocGLBEYQSCVl XxV1JI7VFBv7w== Message-ID: <1abc49c7-fca8-4aea-ab5e-0881176de840@kernel.org> Date: Thu, 30 Jul 2026 08:01:49 +0200 Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 11/14] serial: 8250_mxpcie: add break support for RS485 using MUEx50 features To: Crescent Hsieh , Greg Kroah-Hartman , Andy Shevchenko Cc: FangpingFP.Cheng@moxa.com, Epson.Chiang@moxa.com, EddieSY.Lin@moxa.com, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org References: <20260729060602.492430-1-crescentcy.hsieh@moxa.com> <20260729060602.492430-12-crescentcy.hsieh@moxa.com> Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 29. 07. 26, 8:05, Crescent Hsieh wrote: > On MUEx50, break signaling under RS485 requires a driver-specific > sequence and cannot be handled correctly by the generic 8250 break > implementation alone. > > Implement a mxpcie break_ctl callback that performs MUEx50-specific > break handling when RS485 is enabled and fall back to the default 8250 > break handling for other modes. > > Signed-off-by: Crescent Hsieh > --- > drivers/tty/serial/8250/8250_mxpcie.c | 49 +++++++++++++++++++++++++++ > 1 file changed, 49 insertions(+) > > diff --git a/drivers/tty/serial/8250/8250_mxpcie.c b/drivers/tty/serial/8250/8250_mxpcie.c > index 927615f2d724..878fc64c4451 100644 > --- a/drivers/tty/serial/8250/8250_mxpcie.c > +++ b/drivers/tty/serial/8250/8250_mxpcie.c > @@ -54,6 +54,7 @@ > > /* Special Function Register (SFR) */ > #define MOXA_PUART_SFR 0x07 > +#define MOXA_PUART_SFR_FORCE_TX BIT(0) > #define MOXA_PUART_SFR_950 BIT(5) > > /* Enhanced Function Register (EFR) */ > @@ -384,6 +385,53 @@ static int mxpcie8250_handle_irq(struct uart_port *port) > return 1; > } > > +static void mxpcie8250_software_break_ctl(struct uart_port *port, int break_state) > +{ > + struct uart_8250_port *up = up_to_u8250p(port); > + struct tty_struct *tty = port->state->port.tty; > + unsigned char tx_byte = 0x01; Do you actually need the variable? If so, it should be u8, given you call byte and use it as such. > + unsigned int baud, quot; > + u8 sfr; > + > + guard(uart_port_lock_irqsave)(port); > + > + if (break_state == -1) { > + serial_out(up, UART_LCR, up->lcr | UART_LCR_DLAB); > + serial_dl_write(up, 0); > + serial_out(up, UART_LCR, up->lcr); > + > + serial_out(up, MOXA_PUART_TX_FIFO_MEM, tx_byte); thanks, -- js suse labs