hwrng: xgene - Simplify using devm_clk_get_optional_enabled()

Instead of ignoring errors returned by devm_clk_get() and manually
enabling the clk for the whole lifetime of the bound device, use
devm_clk_get_optional_enabled(). This is simpler and also more correct
as it doesn't ignore errors. This is also more correct because now the
call to clk_disable_unprepare() can be dropped from xgene_rng_remove()
which happened while the hwrn device was still registered. With the devm
callback disabling the clk happens correctly only after
devm_hwrng_register() is undone.

As a result struct xgene_rng_dev::clk is only used in xgene_rng_probe, and
so the struct member can be replaced by a local variable.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/xgene-rng.c b/drivers/char/hw_random/xgene-rng.c
index a6a3068..3166261 100644 (file)
--- a/drivers/char/hw_random/xgene-rng.c
+++ b/drivers/char/hw_random/xgene-rng.c
@@ -84,7 +84,6 @@ struct xgene_rng_dev {
        unsigned long failure_ts;/* First failure timestamp */
        struct timer_list failure_timer;
        struct device *dev;
-       struct clk *clk;
 };
 
 static void xgene_rng_expired_timer(struct timer_list *t)
@@ -314,6 +313,7 @@ static struct hwrng xgene_rng_func = {
 static int xgene_rng_probe(struct platform_device *pdev)
 {
        struct xgene_rng_dev *ctx;
+       struct clk *clk;
        int rc = 0;
 
        ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
@@ -341,45 +341,30 @@ static int xgene_rng_probe(struct platform_device *pdev)
                return dev_err_probe(&pdev->dev, rc, "Could not request RNG alarm IRQ\n");
 
        /* Enable IP clock */
-       ctx->clk = devm_clk_get(&pdev->dev, NULL);
-       if (IS_ERR(ctx->clk)) {
-               dev_warn(&pdev->dev, "Couldn't get the clock for RNG\n");
-       } else {
-               rc = clk_prepare_enable(ctx->clk);
-               if (rc)
-                       return dev_err_probe(&pdev->dev, rc,
-                                            "clock prepare enable failed for RNG");
-       }
+       clk = devm_clk_get_optional_enabled(&pdev->dev, NULL);
+       if (IS_ERR(clk))
+               return dev_err_probe(&pdev->dev, PTR_ERR(clk), "Couldn't get the clock for RNG\n");
 
        xgene_rng_func.priv = (unsigned long) ctx;
 
        rc = devm_hwrng_register(&pdev->dev, &xgene_rng_func);
-       if (rc) {
-               if (!IS_ERR(ctx->clk))
-                       clk_disable_unprepare(ctx->clk);
+       if (rc)
                return dev_err_probe(&pdev->dev, rc, "RNG registering failed\n");
-       }
 
        rc = device_init_wakeup(&pdev->dev, 1);
-       if (rc) {
-               if (!IS_ERR(ctx->clk))
-                       clk_disable_unprepare(ctx->clk);
+       if (rc)
                return dev_err_probe(&pdev->dev, rc, "RNG device_init_wakeup failed\n");
-       }
 
        return 0;
 }
 
 static int xgene_rng_remove(struct platform_device *pdev)
 {
-       struct xgene_rng_dev *ctx = platform_get_drvdata(pdev);
        int rc;
 
        rc = device_init_wakeup(&pdev->dev, 0);
        if (rc)
                dev_err(&pdev->dev, "RNG init wakeup failed error %d\n", rc);
-       if (!IS_ERR(ctx->clk))
-               clk_disable_unprepare(ctx->clk);
 
        return rc;
 }