mtd: rawnand: renesas: Use runtime PM instead of the raw clock API

This NAND controller is part of a well defined power domain handled by
the runtime PM core. Let's keep the harmony with the other RZ/N1 drivers
and exclusively use the runtime PM API to enable/disable the clocks.

We still need to retrieve the external clock rate in order to derive the
NAND timings, but that is not a big deal, we can still do that in the
probe and just save this value to reuse it later.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/linux-mtd/20220513104957.257721-3-miquel.raynal@bootlin.com

diff --git a/drivers/mtd/nand/raw/renesas-nand-controller.c b/drivers/mtd/nand/raw/renesas-nand-controller.c
index 6db063b..1620e25 100644 (file)
--- a/drivers/mtd/nand/raw/renesas-nand-controller.c
+++ b/drivers/mtd/nand/raw/renesas-nand-controller.c
@@ -16,6 +16,7 @@
 #include <linux/mtd/rawnand.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 
 #define COMMAND_REG 0x00
@@ -216,8 +217,7 @@ struct rnandc {
        struct nand_controller controller;
        struct device *dev;
        void __iomem *regs;
-       struct clk *hclk;
-       struct clk *eclk;
+       unsigned long ext_clk_rate;
        unsigned long assigned_cs;
        struct list_head chips;
        struct nand_chip *selected_chip;
@@ -891,7 +891,7 @@ static int rnandc_setup_interface(struct nand_chip *chip, int chipnr,
 {
        struct rnand_chip *rnand = to_rnand(chip);
        struct rnandc *rnandc = to_rnandc(chip->controller);
-       unsigned int period_ns = 1000000000 / clk_get_rate(rnandc->eclk);
+       unsigned int period_ns = 1000000000 / rnandc->ext_clk_rate;
        const struct nand_sdr_timings *sdr;
        unsigned int cyc, cle, ale, bef_dly, ca_to_data;
 
@@ -1319,6 +1319,7 @@ cleanup_chips:
 static int rnandc_probe(struct platform_device *pdev)
 {
        struct rnandc *rnandc;
+       struct clk *eclk;
        int irq, ret;
 
        rnandc = devm_kzalloc(&pdev->dev, sizeof(*rnandc), GFP_KERNEL);
@@ -1335,29 +1336,26 @@ static int rnandc_probe(struct platform_device *pdev)
        if (IS_ERR(rnandc->regs))
                return PTR_ERR(rnandc->regs);
 
-       /* APB clock */
-       rnandc->hclk = devm_clk_get(&pdev->dev, "hclk");
-       if (IS_ERR(rnandc->hclk))
-               return PTR_ERR(rnandc->hclk);
-
-       /* External NAND bus clock */
-       rnandc->eclk = devm_clk_get(&pdev->dev, "eclk");
-       if (IS_ERR(rnandc->eclk))
-               return PTR_ERR(rnandc->eclk);
-
-       ret = clk_prepare_enable(rnandc->hclk);
-       if (ret)
+       devm_pm_runtime_enable(&pdev->dev);
+       ret = pm_runtime_resume_and_get(&pdev->dev);
+       if (ret < 0)
                return ret;
 
-       ret = clk_prepare_enable(rnandc->eclk);
-       if (ret)
-               goto disable_hclk;
+       /* The external NAND bus clock rate is needed for computing timings */
+       eclk = clk_get(&pdev->dev, "eclk");
+       if (IS_ERR(eclk)) {
+               ret = PTR_ERR(eclk);
+               goto dis_runtime_pm;
+       }
+
+       rnandc->ext_clk_rate = clk_get_rate(eclk);
+       clk_put(eclk);
 
        rnandc_dis_interrupts(rnandc);
        irq = platform_get_irq_optional(pdev, 0);
        if (irq == -EPROBE_DEFER) {
                ret = irq;
-               goto disable_eclk;
+               goto dis_runtime_pm;
        } else if (irq < 0) {
                dev_info(&pdev->dev, "No IRQ found, fallback to polling\n");
                rnandc->use_polling = true;
@@ -1365,12 +1363,12 @@ static int rnandc_probe(struct platform_device *pdev)
                ret = devm_request_irq(&pdev->dev, irq, rnandc_irq_handler, 0,
                                       "renesas-nand-controller", rnandc);
                if (ret < 0)
-                       goto disable_eclk;
+                       goto dis_runtime_pm;
        }
 
        ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
        if (ret)
-               goto disable_eclk;
+               goto dis_runtime_pm;
 
        rnandc_clear_fifo(rnandc);
 
@@ -1378,14 +1376,12 @@ static int rnandc_probe(struct platform_device *pdev)
 
        ret = rnandc_chips_init(rnandc);
        if (ret)
-               goto disable_eclk;
+               goto dis_runtime_pm;
 
        return 0;
 
-disable_eclk:
-       clk_disable_unprepare(rnandc->eclk);
-disable_hclk:
-       clk_disable_unprepare(rnandc->hclk);
+dis_runtime_pm:
+       pm_runtime_put(&pdev->dev);
 
        return ret;
 }
@@ -1396,8 +1392,7 @@ static int rnandc_remove(struct platform_device *pdev)
 
        rnandc_chips_cleanup(rnandc);
 
-       clk_disable_unprepare(rnandc->eclk);
-       clk_disable_unprepare(rnandc->hclk);
+       pm_runtime_put(&pdev->dev);
 
        return 0;
 }