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[84.226.167.205]) by smtp.googlemail.com with ESMTPSA id cn8sm5335926edb.18.2020.11.23.08.58.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Nov 2020 08:59:00 -0800 (PST) Date: Mon, 23 Nov 2020 17:58:58 +0100 From: Krzysztof Kozlowski To: Alice Guo Subject: Re: [PATCH v5 4/4] soc: imx8m: change to use platform driver Message-ID: <20201123165858.GD214677@kozik-lap> References: <20201123095108.19724-1-alice.guo@nxp.com> <20201123095108.19724-4-alice.guo@nxp.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201123095108.19724-4-alice.guo@nxp.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201123_115902_918615_B6E53465 X-CRM114-Status: GOOD ( 14.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, peng.fan@nxp.com, s.hauer@pengutronix.de, linux-kernel@vger.kernel.org, robh+dt@kernel.org, linux-imx@nxp.com, shawnguo@kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Nov 23, 2020 at 05:51:08PM +0800, Alice Guo wrote: > Directly reading ocotp register depends on that bootloader enables ocotp > clk, which is not always effective, so change to use nvmem API. Using > nvmem API requires to support driver defer probe and thus change > soc-imx8m.c to use platform driver. > > The other reason is that directly reading ocotp register causes kexec > kernel hang because the 1st kernel running will disable unused clks > after kernel boots up, and then ocotp clk will be disabled even if > bootloader enables it. When kexec kernel, ocotp clk needs to be enabled > before reading ocotp registers, and nvmem API with platform driver > supported can accomplish this. > > Signed-off-by: Alice Guo > --- > Reviewed-by: Krzysztof Kozlowski Best regards, Krzysztof _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel