From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752218AbeESLzE (ORCPT ); Sat, 19 May 2018 07:55:04 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:35626 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751994AbeESLzA (ORCPT ); Sat, 19 May 2018 07:55:00 -0400 Date: Sat, 19 May 2018 12:54:41 +0100 From: Russell King - ARM Linux To: ilialin@codeaurora.org Cc: "'Viresh Kumar'" , mark.rutland@arm.com, nm@ti.com, catalin.marinas@arm.com, mturquette@baylibre.com, will.deacon@arm.com, tfinkel@codeaurora.org, linux-kernel@vger.kernel.org, david.brown@linaro.org, nicolas.dechesne@linaro.org, linux-clk@vger.kernel.org, robh@kernel.org, andy.gross@linaro.org, celster@codeaurora.org, devicetree@vger.kernel.org, linux-pm@vger.kernel.org, linux-arm-msm@vger.kernel.org, broonie@kernel.org, linux-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, rnayak@codeaurora.org, sboyd@kernel.org, rjw@rjwysocki.net, lgirdwood@gmail.com, amit.kucheria@linaro.org Subject: Re: [PATCH v8 10/15] cpufreq: Add Kryo CPU scaling driver Message-ID: <20180519115441.GK17671@n2100.armlinux.org.uk> References: <1526555955-29960-1-git-send-email-ilialin@codeaurora.org> <1526555955-29960-11-git-send-email-ilialin@codeaurora.org> <20180518014538.duphof6enscpm5vp@vireshk-i7> <018701d3ef61$dfd5e700$9f81b500$@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <018701d3ef61$dfd5e700$9f81b500$@codeaurora.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 19, 2018 at 02:09:24PM +0300, ilialin@codeaurora.org wrote: > +static int __init qcom_cpufreq_kryo_driver_init(void) > +{ > + struct device *cpu_dev_silver, *cpu_dev_gold; > + struct opp_table *opp_silver, *opp_gold; > + enum _msm8996_version msm8996_version; > + struct nvmem_cell *speedbin_nvmem; > + struct platform_device *pdev; > + struct device_node *np; > + u8 *speedbin; > + u32 versions; > + size_t len; > + int ret; > + > + cpu_dev_silver = get_cpu_device(SILVER_LEAD); > + if (IS_ERR_OR_NULL(cpu_dev_silver)) > + return PTR_ERR(cpu_dev_silver); > + > + cpu_dev_gold = get_cpu_device(SILVER_LEAD); > + if (IS_ERR_OR_NULL(cpu_dev_gold)) > + return PTR_ERR(cpu_dev_gold); > + > + msm8996_version = qcom_cpufreq_kryo_get_msm_id(); > + if (NUM_OF_MSM8996_VERSIONS == msm8996_version) { > + dev_err(cpu_dev_silver, "Not Snapdragon 820/821!"); > + return -ENODEV; > + } > + > + np = dev_pm_opp_of_get_opp_desc_node(cpu_dev_silver); > + if (IS_ERR_OR_NULL(np)) > + return PTR_ERR(np); This function (qcom_cpufreq_kryo_driver_init) returns zero on success. You are checking "np" here for being an error pointer, or NULL. What value do you think PTR_ERR() returns in the case of PTR_ERR(NULL)? IS_ERR_OR_NULL() is considered by some (me included) as being _very_ harmful because programmers generally fail to look at linux/err.h and consider what it means when used as above. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up