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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 603DFC433EF for ; Fri, 28 Jan 2022 08:47:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237823AbiA1IrT (ORCPT ); Fri, 28 Jan 2022 03:47:19 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:44934 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240484AbiA1IrT (ORCPT ); Fri, 28 Jan 2022 03:47:19 -0500 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 3A4911F391; Fri, 28 Jan 2022 08:47:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1643359638; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=fY/lSm8EzEnnwCDiVAHl0UiB6tFu/37NEmoH6LZYNVo=; b=d7WOtP2QmSf7v9hN0MO3ogKKiashVMfzsACJyilCGDAKftJ3hhTrocgf2NDB9N0xEO4kyW pCzAmAc278mheJc00OT+ifbbRCZRQjhAjFpNsrKwbfvj6o9VVoHo0bJ4ijbIIlDqi25dTB lfvGIcbU5XiY/NFxaXsLBGKflQYcvE0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1643359638; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=fY/lSm8EzEnnwCDiVAHl0UiB6tFu/37NEmoH6LZYNVo=; b=drnnON7D0ria5vTj/fdDSRkVFqWTMNnGUE667XceqQENbfMJvokbs0BxjG8V/fW3ZHSJt1 LmSFq+p6diSp+UAA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 1D1A413A66; Fri, 28 Jan 2022 08:47:18 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id beqqBpat82FjZQAAMHmgww (envelope-from ); Fri, 28 Jan 2022 08:47:18 +0000 Date: Fri, 28 Jan 2022 10:47:17 +0200 From: "Ivan T . Ivanov" To: Florian Fainelli , Ray Jui , Scott Branden , Nicolas Saenz Julienne Cc: linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Phil Elwell Subject: Re: [PATCH] i2c: bcm2835: Set clock-stretch timeout to 35ms Message-ID: <20220128084717.rbvbciprfqen4rvb@suse> References: <20220117102504.90585-1-iivanov@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220117102504.90585-1-iivanov@suse.de> Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On 01-17 11:25, Ivan T. Ivanov wrote: > Date: Mon, 17 Jan 2022 11:25:04 +0100 > From: "Ivan T. Ivanov" > To: Florian Fainelli , Ray Jui , > Scott Branden , Nicolas Saenz Julienne > > Cc: linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Phil > Elwell , "Ivan T . Ivanov" > Subject: [PATCH] i2c: bcm2835: Set clock-stretch timeout to 35ms > Message-Id: <20220117102504.90585-1-iivanov@suse.de> Tags: all arm i2c linux me ring rpi sent Hi, > > From: Phil Elwell > > The BCM2835 I2C blocks have a register to set the clock-stretch > timeout - how long the device is allowed to hold SCL low - in bus > cycles. The current driver doesn't write to the register, therefore > the default value of 64 cycles is being used for all devices. > > Set the timeout to the value recommended for SMBus - 35ms. > > See: https://github.com/raspberrypi/linux/issues/3064 It will be nice if we have this fix upstream. Regards, Ivan > > Signed-off-by: Phil Elwell > [iivanov@suse.de fix small coding style issue] > Signed-off-by: Ivan T. Ivanov > --- > drivers/i2c/busses/i2c-bcm2835.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c > index 37443edbf754..9cce0e15da32 100644 > --- a/drivers/i2c/busses/i2c-bcm2835.c > +++ b/drivers/i2c/busses/i2c-bcm2835.c > @@ -106,6 +106,7 @@ static int clk_bcm2835_i2c_set_rate(struct clk_hw *hw, unsigned long rate, > { > struct clk_bcm2835_i2c *div = to_clk_bcm2835_i2c(hw); > u32 redl, fedl; > + u32 clk_tout; > u32 divider = clk_bcm2835_i2c_calc_divider(rate, parent_rate); > > if (divider == -EINVAL) > @@ -129,6 +130,17 @@ static int clk_bcm2835_i2c_set_rate(struct clk_hw *hw, unsigned long rate, > bcm2835_i2c_writel(div->i2c_dev, BCM2835_I2C_DEL, > (fedl << BCM2835_I2C_FEDL_SHIFT) | > (redl << BCM2835_I2C_REDL_SHIFT)); > + > + /* > + * Set the clock stretch timeout to the SMBUs-recommended 35ms. > + */ > + if (rate > 0xffff * 1000 / 35) > + clk_tout = 0xffff; > + else > + clk_tout = 35 * rate / 1000; > + > + bcm2835_i2c_writel(div->i2c_dev, BCM2835_I2C_CLKT, clk_tout); > + > return 0; > } > > -- > 2.26.2 >