[PATCH v3 6/6] spi: spi-mtk-nor: Add power management support

From: Ikjoon Jang
Date: Fri Sep 25 2020 - 02:54:51 EST


This patch adds dev_pm_ops to mtk-nor to support suspend/resume,
auto suspend delay is set to -1 by default.

Accessing registers are only permitted after its clock is enabled
to deal with unknown state of operating clk at probe time,

Signed-off-by: Ikjoon Jang <ikjn@xxxxxxxxxxxx>
---

Changes in v3:
- Fix a bugfix of v2 in checking spi memory operation.
- split read_dma function into two (normal/bounce)
- Support 7bytes generic spi xfer

Changes in v2:
- Add power management support
- Fix bugs in checking spi memory operation.
- use dma_alloc_coherent for allocating bounce buffer
- code cleanups

drivers/spi/spi-mtk-nor.c | 98 ++++++++++++++++++++++++++++++---------
1 file changed, 76 insertions(+), 22 deletions(-)

diff --git a/drivers/spi/spi-mtk-nor.c b/drivers/spi/spi-mtk-nor.c
index 35205635ed42..bde4c846ce65 100644
--- a/drivers/spi/spi-mtk-nor.c
+++ b/drivers/spi/spi-mtk-nor.c
@@ -14,6 +14,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi-mem.h>
#include <linux/string.h>
@@ -592,22 +593,15 @@ static int mtk_nor_enable_clk(struct mtk_nor *sp)
return 0;
}

-static int mtk_nor_init(struct mtk_nor *sp)
+static void mtk_nor_init(struct mtk_nor *sp)
{
- int ret;
-
- ret = mtk_nor_enable_clk(sp);
- if (ret)
- return ret;
-
- sp->spi_freq = clk_get_rate(sp->spi_clk);
+ writel(0, sp->base + MTK_NOR_REG_IRQ_EN);
+ writel(MTK_NOR_IRQ_MASK, sp->base + MTK_NOR_REG_IRQ_STAT);

writel(MTK_NOR_ENABLE_SF_CMD, sp->base + MTK_NOR_REG_WP);
mtk_nor_rmw(sp, MTK_NOR_REG_CFG2, MTK_NOR_WR_CUSTOM_OP_EN, 0);
mtk_nor_rmw(sp, MTK_NOR_REG_CFG3,
MTK_NOR_DISABLE_WREN | MTK_NOR_DISABLE_SR_POLL, 0);
-
- return ret;
}

static irqreturn_t mtk_nor_irq_handler(int irq, void *data)
@@ -690,6 +684,7 @@ static int mtk_nor_probe(struct platform_device *pdev)
ctlr->num_chipselect = 1;
ctlr->setup = mtk_nor_setup;
ctlr->transfer_one_message = mtk_nor_transfer_one_message;
+ ctlr->auto_runtime_pm = true;

dev_set_drvdata(&pdev->dev, ctlr);

@@ -712,12 +707,19 @@ static int mtk_nor_probe(struct platform_device *pdev)
return -ENOMEM;
}

+ ret = mtk_nor_enable_clk(sp);
+ if (ret < 0)
+ return ret;
+
+ sp->spi_freq = clk_get_rate(sp->spi_clk);
+
+ mtk_nor_init(sp);
+
irq = platform_get_irq_optional(pdev, 0);
+
if (irq < 0) {
dev_warn(sp->dev, "IRQ not available.");
} else {
- writel(MTK_NOR_IRQ_MASK, base + MTK_NOR_REG_IRQ_STAT);
- writel(0, base + MTK_NOR_REG_IRQ_EN);
ret = devm_request_irq(sp->dev, irq, mtk_nor_irq_handler, 0,
pdev->name, sp);
if (ret < 0) {
@@ -728,34 +730,86 @@ static int mtk_nor_probe(struct platform_device *pdev)
}
}

- ret = mtk_nor_init(sp);
- if (ret < 0) {
- kfree(ctlr);
- return ret;
- }
+ pm_runtime_set_autosuspend_delay(&pdev->dev, -1);
+ pm_runtime_use_autosuspend(&pdev->dev);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_get_noresume(&pdev->dev);
+
+ ret = devm_spi_register_controller(&pdev->dev, ctlr);
+ if (ret < 0)
+ goto err_probe;
+
+ pm_runtime_mark_last_busy(&pdev->dev);
+ pm_runtime_put_autosuspend(&pdev->dev);

dev_info(&pdev->dev, "spi frequency: %d Hz\n", sp->spi_freq);

- return devm_spi_register_controller(&pdev->dev, ctlr);
+ return 0;
+
+err_probe:
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+ pm_runtime_dont_use_autosuspend(&pdev->dev);
+
+ mtk_nor_disable_clk(sp);
+
+ return ret;
}

static int mtk_nor_remove(struct platform_device *pdev)
{
- struct spi_controller *ctlr;
- struct mtk_nor *sp;
+ struct spi_controller *ctlr = dev_get_drvdata(&pdev->dev);
+ struct mtk_nor *sp = spi_controller_get_devdata(ctlr);

- ctlr = dev_get_drvdata(&pdev->dev);
- sp = spi_controller_get_devdata(ctlr);
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+ pm_runtime_dont_use_autosuspend(&pdev->dev);
+
+ mtk_nor_disable_clk(sp);
+
+ return 0;
+}
+
+static int __maybe_unused mtk_nor_runtime_suspend(struct device *dev)
+{
+ struct spi_controller *ctlr = dev_get_drvdata(dev);
+ struct mtk_nor *sp = spi_controller_get_devdata(ctlr);

mtk_nor_disable_clk(sp);

return 0;
}

+static int __maybe_unused mtk_nor_runtime_resume(struct device *dev)
+{
+ struct spi_controller *ctlr = dev_get_drvdata(dev);
+ struct mtk_nor *sp = spi_controller_get_devdata(ctlr);
+
+ return mtk_nor_enable_clk(sp);
+}
+
+static int __maybe_unused mtk_nor_suspend(struct device *dev)
+{
+ return pm_runtime_force_suspend(dev);
+}
+
+static int __maybe_unused mtk_nor_resume(struct device *dev)
+{
+ return pm_runtime_force_resume(dev);
+}
+
+static const struct dev_pm_ops mtk_nor_pm_ops = {
+ SET_RUNTIME_PM_OPS(mtk_nor_runtime_suspend,
+ mtk_nor_runtime_resume, NULL)
+ SET_SYSTEM_SLEEP_PM_OPS(mtk_nor_suspend, mtk_nor_resume)
+};
+
static struct platform_driver mtk_nor_driver = {
.driver = {
.name = DRIVER_NAME,
.of_match_table = mtk_nor_match,
+ .pm = &mtk_nor_pm_ops,
},
.probe = mtk_nor_probe,
.remove = mtk_nor_remove,
--
2.28.0.681.g6f77f65b4e-goog