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[109.252.170.211]) by smtp.googlemail.com with ESMTPSA id 30sm7169937ljv.35.2020.09.07.07.31.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Sep 2020 07:31:38 -0700 (PDT) Subject: Re: [PATCH v5 01/36] i2c: tegra: Make tegra_i2c_flush_fifos() usable in atomic transfer To: Andy Shevchenko Cc: Thierry Reding , Jonathan Hunter , Laxman Dewangan , Wolfram Sang , =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , linux-i2c , linux-tegra@vger.kernel.org, Linux Kernel Mailing List References: <20200906185039.22700-1-digetx@gmail.com> <20200906185039.22700-2-digetx@gmail.com> From: Dmitry Osipenko Message-ID: <272065fe-950a-24e9-ba8f-8b1a782c203f@gmail.com> Date: Mon, 7 Sep 2020 17:31:37 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 07.09.2020 10:56, Andy Shevchenko пишет: > On Sun, Sep 6, 2020 at 9:51 PM Dmitry Osipenko wrote: >> >> The tegra_i2c_flush_fifos() shouldn't sleep in atomic transfer and jiffies >> are not updating if interrupts are disabled. Let's switch to use iopoll >> API helpers for register-polling. The iopoll API provides helpers for both >> atomic and non-atomic cases. >> >> Note that this patch doesn't fix any known problem because normally FIFO >> is flushed at the time of starting a new transfer. > > ... > >> + if (i2c_dev->is_curr_atomic_xfer) >> + err = readl_relaxed_poll_timeout_atomic(addr, val, !(val & mask), >> + 1000, 1000000); >> + else >> + err = readl_relaxed_poll_timeout(addr, val, !(val & mask), >> + 1000, 1000000); >> + >> + if (err) { >> + dev_err(i2c_dev->dev, "failed to flush FIFO\n"); > >> + return err; >> } >> return 0; > > return err; ? > The return 0 is intentional here because returned "err" implies that error happened and error code is returned, while 0 explicitly shows the success status. Hence it's always cleaner and more expressive to directly return 0 on success, IMO. I'd prefer to keep this part as-is.