From 82816b4ffce96e7b0df3de583037490ba7dc8792 Mon Sep 17 00:00:00 2001 From: Krishna Yarlagadda Date: Mon, 7 Mar 2022 19:26:26 +0530 Subject: [PATCH] reset: ACPI reset support Some of the IO devices like I2C or SPI require reset at runtime to recover from an error condition without changing the power state of the system. Added check for ACPI handle and a call to method '__RST' if supported. Devices using device tree method are unaffected by this. Signed-off-by: Krishna Yarlagadda [p.zabel@pengutronix.de: wrap in #ifdef CONFIG_ACPI due to missing stubs] Signed-off-by: Philipp Zabel Link: https://lore.kernel.org/r/20220307135626.16673-1-kyarlagadda@nvidia.com --- drivers/reset/core.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/reset/core.c b/drivers/reset/core.c index 61e688882643..f0a076e94118 100644 --- a/drivers/reset/core.c +++ b/drivers/reset/core.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -1100,13 +1101,25 @@ EXPORT_SYMBOL_GPL(__devm_reset_control_bulk_get); * * Convenience wrapper for __reset_control_get() and reset_control_reset(). * This is useful for the common case of devices with single, dedicated reset - * lines. + * lines. _RST firmware method will be called for devices with ACPI. */ int __device_reset(struct device *dev, bool optional) { struct reset_control *rstc; int ret; +#ifdef CONFIG_ACPI + acpi_handle handle = ACPI_HANDLE(dev); + + if (handle) { + if (!acpi_has_method(handle, "_RST")) + return optional ? 0 : -ENOENT; + if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL, + NULL))) + return -EIO; + } +#endif + rstc = __reset_control_get(dev, NULL, 0, 0, optional, true); if (IS_ERR(rstc)) return PTR_ERR(rstc);