From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: [PATCH v1] usb: phy: tegra: Add clarifying comments about the shared registers Date: Mon, 3 Feb 2020 01:42:59 +0300 Message-ID: <20200202224259.29187-1-digetx@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Greg Kroah-Hartman , Thierry Reding , Jonathan Hunter , Felipe Balbi Cc: linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org 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 --- 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) { -- 2.24.0