PCI: ftpci100: Release the clock resources

Smatch reported:
1. drivers/pci/controller/pci-ftpci100.c:526 faraday_pci_probe() warn:
'clk' from clk_prepare_enable() not released on lines: 442,451,462,478,512,517.
2. drivers/pci/controller/pci-ftpci100.c:526 faraday_pci_probe() warn:
'p->bus_clk' from clk_prepare_enable() not released on lines: 451,462,478,512,517.

The clock resource is obtained by devm_clk_get(), and then
clk_prepare_enable() makes the clock resource ready for use. After that,
clk_disable_unprepare() should be called to release the clock resource
when it is no longer needed. However, while doing some error handling
in faraday_pci_probe(), clk_disable_unprepare() is not called to release
clk and p->bus_clk before returning. These return lines are exactly 442,
451, 462, 478, 512, 517.

Fix this warning by replacing devm_clk_get() with devm_clk_get_enabled(),
which is equivalent to devm_clk_get() + clk_prepare_enable(). And with
devm_clk_get_enabled(), the clock will automatically be disabled,
unprepared and freed when the device is unbound from the bus.

Link: https://lore.kernel.org/r/20230508043641.23807-1-yejunyan@hust.edu.cn
Fixes: b3c433efb8a3 ("PCI: faraday: Fix wrong pointer passed to PTR_ERR()")
Fixes: 2eeb02b28579 ("PCI: faraday: Add clock handling")
Fixes: 783a862563f7 ("PCI: faraday: Use pci_parse_request_of_pci_ranges()")
Fixes: d3c68e0a7e34 ("PCI: faraday: Add Faraday Technology FTPCI100 PCI Host Bridge driver")
Fixes: f1e8bd21e39e ("PCI: faraday: Convert IRQ masking to raw PCI config accessors")
Signed-off-by: Junyan Ye <yejunyan@hust.edu.cn>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/pci/controller/pci-ftpci100.c b/drivers/pci/controller/pci-ftpci100.c
index ecd3009..6e7981d 100644 (file)
--- a/drivers/pci/controller/pci-ftpci100.c
+++ b/drivers/pci/controller/pci-ftpci100.c
@@ -429,22 +429,12 @@ static int faraday_pci_probe(struct platform_device *pdev)
        p->dev = dev;
 
        /* Retrieve and enable optional clocks */
-       clk = devm_clk_get(dev, "PCLK");
+       clk = devm_clk_get_enabled(dev, "PCLK");
        if (IS_ERR(clk))
                return PTR_ERR(clk);
-       ret = clk_prepare_enable(clk);
-       if (ret) {
-               dev_err(dev, "could not prepare PCLK\n");
-               return ret;
-       }
-       p->bus_clk = devm_clk_get(dev, "PCICLK");
+       p->bus_clk = devm_clk_get_enabled(dev, "PCICLK");
        if (IS_ERR(p->bus_clk))
                return PTR_ERR(p->bus_clk);
-       ret = clk_prepare_enable(p->bus_clk);
-       if (ret) {
-               dev_err(dev, "could not prepare PCICLK\n");
-               return ret;
-       }
 
        p->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(p->base))