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[188.155.181.108]) by smtp.gmail.com with ESMTPSA id kq26-20020a170906abda00b006da87077172sm1469596ejb.29.2022.03.03.23.07.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 03 Mar 2022 23:07:58 -0800 (PST) Message-ID: <887c5cf8-8dda-3311-0aa7-27fbceb6a6f9@canonical.com> Date: Fri, 4 Mar 2022 08:07:57 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH] clk/samsung: Use of_device_get_match_data() Content-Language: en-US To: cgel.zte@gmail.com Cc: alim.akhtar@samsung.com, chi.minghao@zte.com.cn, cw00.choi@samsung.com, linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org, mturquette@baylibre.com, s.nawrocki@samsung.com, sboyd@kernel.org, tomasz.figa@gmail.com, zealci@zte.com.cn References: <77a147f9-794c-83ca-070b-fb17d665ed8f@canonical.com> <20220304011155.2061393-1-chi.minghao@zte.com.cn> From: Krzysztof Kozlowski In-Reply-To: <20220304011155.2061393-1-chi.minghao@zte.com.cn> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/03/2022 02:11, cgel.zte@gmail.com wrote: > From: Minghao Chi (CGEL ZTE) > > Use of_device_get_match_data() to simplify the code. > > Signed-off-by: Minghao Chi (CGEL ZTE) > --- > drivers/clk/samsung/clk-exynos-clkout.c | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > > diff --git a/drivers/clk/samsung/clk-exynos-clkout.c b/drivers/clk/samsung/clk-exynos-clkout.c > index e6d6cbf8c4e6..feed1a347c09 100644 > --- a/drivers/clk/samsung/clk-exynos-clkout.c > +++ b/drivers/clk/samsung/clk-exynos-clkout.c > @@ -81,19 +81,13 @@ MODULE_DEVICE_TABLE(of, exynos_clkout_ids); > static int exynos_clkout_match_parent_dev(struct device *dev, u32 *mux_mask) > { > const struct exynos_clkout_variant *variant; > - const struct of_device_id *match; > > if (!dev->parent) { > dev_err(dev, "not instantiated from MFD\n"); > return -EINVAL; > } > > - match = of_match_device(exynos_clkout_ids, dev->parent); > - if (!match) { > - dev_err(dev, "cannot match parent device\n"); > - return -EINVAL; > - } > - variant = match->data; > + variant = of_device_get_match_data(dev->parent); > What about possible NULL pointer exception? Device is being instantiated by MFD, so the match here could be false if MFD driver is updated but this one here not. With your change returned NULL will be dereferenced line below. > *mux_mask = variant->mux_mask; > Best regards, Krzysztof