mmc: bcm2835: Introduce proper clock handling

The custom sdhost controller on BCM2835 is feed by the critical VPU clock.
In preparation for PM suspend/resume support, add a proper clock handling
to the driver like in the other clock consumers (e.g. I2C).

Move the clock handling behind mmc_of_parse(), because it could return
with -EPROBE_DEFER and we want to minimize potential clock operation during
boot phase.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Message-ID: <20241025103621.4780-5-wahrenst@gmx.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/bcm2835.c b/drivers/mmc/host/bcm2835.c
index 9d619a7c8360e653eaabd68c949b982fbf60fa3c..7847f0c8b4652a7cb46f4cf5cde1f8b034ae5985 100644 (file)
--- a/drivers/mmc/host/bcm2835.c
+++ b/drivers/mmc/host/bcm2835.c
@@ -148,6 +148,7 @@ struct bcm2835_host {
        void __iomem            *ioaddr;
        u32                     phys_addr;
 
+       struct clk              *clk;
        struct platform_device  *pdev;
 
        unsigned int            clock;          /* Current clock speed */
@@ -1345,7 +1346,6 @@ static int bcm2835_add_host(struct bcm2835_host *host)
 static int bcm2835_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
-       struct clk *clk;
        struct bcm2835_host *host;
        struct mmc_host *mmc;
        const __be32 *regaddr_p;
@@ -1393,15 +1393,6 @@ static int bcm2835_probe(struct platform_device *pdev)
                /* Ignore errors to fall back to PIO mode */
        }
 
-
-       clk = devm_clk_get(dev, NULL);
-       if (IS_ERR(clk)) {
-               ret = dev_err_probe(dev, PTR_ERR(clk), "could not get clk\n");
-               goto err;
-       }
-
-       host->max_clk = clk_get_rate(clk);
-
        host->irq = platform_get_irq(pdev, 0);
        if (host->irq < 0) {
                ret = host->irq;
@@ -1412,16 +1403,30 @@ static int bcm2835_probe(struct platform_device *pdev)
        if (ret)
                goto err;
 
-       ret = bcm2835_add_host(host);
+       host->clk = devm_clk_get(dev, NULL);
+       if (IS_ERR(host->clk)) {
+               ret = dev_err_probe(dev, PTR_ERR(host->clk), "could not get clk\n");
+               goto err;
+       }
+
+       ret = clk_prepare_enable(host->clk);
        if (ret)
                goto err;
 
+       host->max_clk = clk_get_rate(host->clk);
+
+       ret = bcm2835_add_host(host);
+       if (ret)
+               goto err_clk;
+
        platform_set_drvdata(pdev, host);
 
        dev_dbg(dev, "%s -> OK\n", __func__);
 
        return 0;
 
+err_clk:
+       clk_disable_unprepare(host->clk);
 err:
        dev_dbg(dev, "%s -> err %d\n", __func__, ret);
        if (host->dma_chan_rxtx)
@@ -1445,6 +1450,8 @@ static void bcm2835_remove(struct platform_device *pdev)
        cancel_work_sync(&host->dma_work);
        cancel_delayed_work_sync(&host->timeout_work);
 
+       clk_disable_unprepare(host->clk);
+
        if (host->dma_chan_rxtx)
                dma_release_channel(host->dma_chan_rxtx);