From: Krzysztof Kozlowski <krzk@kernel.org>
To: Alice Guo <alice.guo@nxp.com>
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
Subject: Re: [PATCH v5 4/4] soc: imx8m: change to use platform driver
Date: Mon, 23 Nov 2020 17:58:58 +0100 [thread overview]
Message-ID: <20201123165858.GD214677@kozik-lap> (raw)
In-Reply-To: <20201123095108.19724-4-alice.guo@nxp.com>
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 <alice.guo@nxp.com>
> ---
>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Best regards,
Krzysztof
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WARNING: multiple messages have this Message-ID (diff)
From: Krzysztof Kozlowski <krzk@kernel.org>
To: Alice Guo <alice.guo@nxp.com>
Cc: robh+dt@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de,
linux-imx@nxp.com, peng.fan@nxp.com, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v5 4/4] soc: imx8m: change to use platform driver
Date: Mon, 23 Nov 2020 17:58:58 +0100 [thread overview]
Message-ID: <20201123165858.GD214677@kozik-lap> (raw)
In-Reply-To: <20201123095108.19724-4-alice.guo@nxp.com>
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 <alice.guo@nxp.com>
> ---
>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Best regards,
Krzysztof
next prev parent reply other threads:[~2020-11-23 16:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-23 9:51 [PATCH v5 1/4] dt-bindings: soc: imx8m: add DT Binding doc for soc unique ID Alice Guo
2020-11-23 9:51 ` Alice Guo
2020-11-23 9:51 ` [PATCH v5 2/4] arm64: dts: imx8m: add SoC ID compatible Alice Guo
2020-11-23 9:51 ` Alice Guo
2020-11-23 16:57 ` Krzysztof Kozlowski
2020-11-23 16:57 ` Krzysztof Kozlowski
2020-11-23 9:51 ` [PATCH v5 3/4] arm64: dts: imx8m: add NVMEM provider and consumer to read soc unique ID Alice Guo
2020-11-23 9:51 ` Alice Guo
2020-11-23 16:57 ` Krzysztof Kozlowski
2020-11-23 16:57 ` Krzysztof Kozlowski
2020-11-23 9:51 ` [PATCH v5 4/4] soc: imx8m: change to use platform driver Alice Guo
2020-11-23 9:51 ` Alice Guo
2020-11-23 16:58 ` Krzysztof Kozlowski [this message]
2020-11-23 16:58 ` Krzysztof Kozlowski
2020-11-23 16:56 ` [PATCH v5 1/4] dt-bindings: soc: imx8m: add DT Binding doc for soc unique ID Krzysztof Kozlowski
2020-11-23 16:56 ` Krzysztof Kozlowski
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