clk: imx8qxp-lpcg: Warn against devm_platform_ioremap_resource (249fce6f) · Commits · 戴 / test

On imx8 the LPCG nodes map entire subsystems and overlap peripherals, this means that using devm_platform_ioremap_resource will cause many devices to fail to probe including serial ports. Well-meaning but boot-breaking patches were posted multiple times so add a comment explaining this issue. Suggested-by:

Peng Fan <peng.fan@nxp.com> Signed-off-by:

Leonard Crestez <leonard.crestez@nxp.com> Reviewed-by:

Peng Fan <peng.fan@nxp.com> Signed-off-by:

Shawn Guo <shawnguo@kernel.org>

drivers/clk/imx/clk-imx8qxp-lpcg.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -173,6 +173,17 @@ static int imx8qxp_lpcg_clk_probe(struct platform_device *pdev)
		if (!ss_lpcg)
		return -ENODEV;

		/*
		* Please don't replace this with devm_platform_ioremap_resource.
		*
		* devm_platform_ioremap_resource calls devm_ioremap_resource which
		* differs from devm_ioremap by also calling devm_request_mem_region
		* and preventing other mappings in the same area.
		*
		* On imx8 the LPCG nodes map entire subsystems and overlap
		* peripherals, this means that using devm_platform_ioremap_resource
		* will cause many devices to fail to probe including serial ports.
		*/
		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
		if (!res)
		return -EINVAL;

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