From: Dmitry Osipenko <digetx@gmail.com>
Date: Mon, 3 Feb 2020 01:42:59 +0300
Subject: usb: phy: tegra: Add clarifying comments about the shared registers
Git-commit: a4a601948fc8d0a9661b83df03f5ee11e903efe6
Patch-mainline: v5.6-rc3
References: jsc#SLE-15847
Tools like Coccinelle may erroneously recommend to use the
devm_platform_ioremap_resource() API for the registers mapping because
these tools are not aware about the implementation details of the driver.
Let's add a clarifying comments to the code, which should help to stop
future attempts to break the driver.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20200202224259.29187-1-digetx@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
drivers/usb/phy/phy-tegra-usb.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c
index 037e8eee737d..6153cc35aba0 100644
--- a/drivers/usb/phy/phy-tegra-usb.c
+++ b/drivers/usb/phy/phy-tegra-usb.c
@@ -969,6 +969,10 @@ static int utmi_phy_probe(struct tegra_usb_phy *tegra_phy,
return -ENXIO;
}
+ /*
+ * Note that UTMI pad registers are shared by all PHYs, therefore
+ * devm_platform_ioremap_resource() can't be used here.
+ */
tegra_phy->pad_regs = devm_ioremap(&pdev->dev, res->start,
resource_size(res));
if (!tegra_phy->pad_regs) {
@@ -1087,6 +1091,10 @@ static int tegra_usb_phy_probe(struct platform_device *pdev)
return -ENXIO;
}
+ /*
+ * Note that PHY and USB controller are using shared registers,
+ * therefore devm_platform_ioremap_resource() can't be used here.
+ */
tegra_phy->regs = devm_ioremap(&pdev->dev, res->start,
resource_size(res));
if (!tegra_phy->regs) {
--
2.26.2