[PATCH v1 2/2] mtd: mtk-nor: add suspend/resume support

[Guochun Mao]

Abstract functions of clock setting, to avoid duplicated code,
these functions been used in new feature.
Implement suspend/resume functions.

Signed-off-by: Guochun Mao <guochun....@mediatek.com>
---
 drivers/mtd/spi-nor/mtk-quadspi.c |   70 ++++++++++++++++++++++++++++++-------
 1 file changed, 58 insertions(+), 12 deletions(-)

diff --git a/drivers/mtd/spi-nor/mtk-quadspi.c 
b/drivers/mtd/spi-nor/mtk-quadspi.c
index c258c7a..abe455c 100644
--- a/drivers/mtd/spi-nor/mtk-quadspi.c
+++ b/drivers/mtd/spi-nor/mtk-quadspi.c
@@ -404,6 +404,29 @@ static int mt8173_nor_write_reg(struct spi_nor *nor, u8 
opcode, u8 *buf,
        return ret;
 }
 
+static void mt8173_nor_disable_clk(struct mt8173_nor *mt8173_nor)
+{
+       clk_disable_unprepare(mt8173_nor->spi_clk);
+       clk_disable_unprepare(mt8173_nor->nor_clk);
+}
+
+static int mt8173_nor_enable_clk(struct mt8173_nor *mt8173_nor)
+{
+       int ret;
+
+       ret = clk_prepare_enable(mt8173_nor->spi_clk);
+       if (ret)
+               return ret;
+
+       ret = clk_prepare_enable(mt8173_nor->nor_clk);
+       if (ret) {
+               clk_disable_unprepare(mt8173_nor->spi_clk);
+               return ret;
+       }
+
+       return 0;
+}
+
 static int mtk_nor_init(struct mt8173_nor *mt8173_nor,
                        struct device_node *flash_node)
 {
@@ -468,15 +491,11 @@ static int mtk_nor_drv_probe(struct platform_device *pdev)
                return PTR_ERR(mt8173_nor->nor_clk);
 
        mt8173_nor->dev = &pdev->dev;
-       ret = clk_prepare_enable(mt8173_nor->spi_clk);
+
+       ret = mt8173_nor_enable_clk(mt8173_nor);
        if (ret)
                return ret;
 
-       ret = clk_prepare_enable(mt8173_nor->nor_clk);
-       if (ret) {
-               clk_disable_unprepare(mt8173_nor->spi_clk);
-               return ret;
-       }
        /* only support one attached flash */
        flash_np = of_get_next_available_child(pdev->dev.of_node, NULL);
        if (!flash_np) {
@@ -487,10 +506,9 @@ static int mtk_nor_drv_probe(struct platform_device *pdev)
        ret = mtk_nor_init(mt8173_nor, flash_np);
 
 nor_free:
-       if (ret) {
-               clk_disable_unprepare(mt8173_nor->spi_clk);
-               clk_disable_unprepare(mt8173_nor->nor_clk);
-       }
+       if (ret)
+               mt8173_nor_disable_clk(mt8173_nor);
+
        return ret;
 }
 
@@ -498,11 +516,38 @@ static int mtk_nor_drv_remove(struct platform_device 
*pdev)
 {
        struct mt8173_nor *mt8173_nor = platform_get_drvdata(pdev);
 
-       clk_disable_unprepare(mt8173_nor->spi_clk);
-       clk_disable_unprepare(mt8173_nor->nor_clk);
+       mt8173_nor_disable_clk(mt8173_nor);
+
+       return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mtk_nor_suspend(struct device *dev)
+{
+       struct mt8173_nor *mt8173_nor = dev_get_drvdata(dev);
+
+       mt8173_nor_disable_clk(mt8173_nor);
+
        return 0;
 }
 
+static int mtk_nor_resume(struct device *dev)
+{
+       struct mt8173_nor *mt8173_nor = dev_get_drvdata(dev);
+
+       return mt8173_nor_enable_clk(mt8173_nor);
+}
+
+static const struct dev_pm_ops mtk_nor_dev_pm_ops = {
+       .suspend = mtk_nor_suspend,
+       .resume = mtk_nor_resume,
+};
+
+#define MTK_NOR_DEV_PM_OPS     (&mtk_nor_dev_pm_ops)
+#else
+#define MTK_NOR_DEV_PM_OPS     NULL
+#endif
+
 static const struct of_device_id mtk_nor_of_ids[] = {
        { .compatible = "mediatek,mt8173-nor"},
        { /* sentinel */ }
@@ -514,6 +559,7 @@ static int mtk_nor_drv_remove(struct platform_device *pdev)
        .remove = mtk_nor_drv_remove,
        .driver = {
                .name = "mtk-nor",
+               .pm = MTK_NOR_DEV_PM_OPS,
                .of_match_table = mtk_nor_of_ids,
        },
 };
-- 
1.7.9.5