spi: dw-mmio: support suspend/resume

Add system wide suspend and resume support, the implementation is
straightforward, just call spi_controller_suspend() then assert the
reset and disable clks for suspend, enable clks and deassert reset
then call spi_controller_resume() for resume.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://patch.msgid.link/20260122155046.12848-1-jszhang@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: xhackerustc

drivers/spi/spi-dw-mmio.c

@@ -392,6 +392,38 @@ static int dw_spi_mmio_probe(struct platform_device *pdev)
 	return ret;
 }
 
+static int dw_spi_mmio_suspend(struct device *dev)
+{
+	struct dw_spi_mmio *dwsmmio = dev_get_drvdata(dev);
+	int ret;
+
+	ret = dw_spi_suspend_controller(&dwsmmio->dws);
+	if (ret)
+		return ret;
+
+	reset_control_assert(dwsmmio->rstc);
+
+	clk_disable_unprepare(dwsmmio->pclk);
+	clk_disable_unprepare(dwsmmio->clk);
+
+	return 0;
+}
+
+static int dw_spi_mmio_resume(struct device *dev)
+{
+	struct dw_spi_mmio *dwsmmio = dev_get_drvdata(dev);
+
+	clk_prepare_enable(dwsmmio->clk);
+	clk_prepare_enable(dwsmmio->pclk);
+
+	reset_control_deassert(dwsmmio->rstc);
+
+	return dw_spi_resume_controller(&dwsmmio->dws);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(dw_spi_mmio_pm_ops,
+				dw_spi_mmio_suspend, dw_spi_mmio_resume);
+
 static void dw_spi_mmio_remove(struct platform_device *pdev)
 {
 	struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
@@ -435,6 +467,7 @@ static struct platform_driver dw_spi_mmio_driver = {
 		.name	= DRIVER_NAME,
 		.of_match_table = dw_spi_mmio_of_match,
 		.acpi_match_table = ACPI_PTR(dw_spi_mmio_acpi_match),
+		.pm	= pm_sleep_ptr(&dw_spi_mmio_pm_ops),
 	},
 };
 module_platform_driver(dw_spi_mmio_driver);