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Message-ID: <CAFBinCAWEEKdsG2ZGCsFd1XyTUerAJpxJFEGGF-6j3UmpOmc=Q@mail.gmail.com>
Date: Mon, 11 Mar 2019 22:56:30 +0100
From: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
To: Neil Armstrong <narmstrong@...libre.com>
Cc: gregkh@...uxfoundation.org, hminas@...opsys.com, balbi@...nel.org,
kishon@...com, linux-amlogic@...ts.infradead.org,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 8/8] usb: dwc3: Add Amlogic G12A DWC3 glue
Hi Neil,
On Mon, Mar 4, 2019 at 11:41 AM Neil Armstrong <narmstrong@...libre.com> wrote:
[...]
> +static void dwc3_meson_g12a_usb_init_mode(struct dwc3_meson_g12a *priv)
> +{
> + if (priv->otg_phy_mode == PHY_MODE_USB_DEVICE) {
> + regmap_update_bits(priv->regmap, USB_R0,
> + USB_R0_U2D_ACT, USB_R0_U2D_ACT);
> + regmap_update_bits(priv->regmap, USB_R0,
> + USB_R0_U2D_SS_SCALEDOWN_MODE_MASK, 0);
> + regmap_update_bits(priv->regmap, USB_R4,
> + USB_R4_P21_SLEEP_M0, USB_R4_P21_SLEEP_M0);
> + } else {
> + regmap_update_bits(priv->regmap, USB_R0,
> + USB_R0_U2D_ACT, 0);
> + regmap_update_bits(priv->regmap, USB_R4,
> + USB_R4_P21_SLEEP_M0, 0);
> + }
> +}
I was already confused by the name of this function in v1.
do you think "dwc3_meson_g12a_usb_otg_apply_mode" is a suitable name?
[...]
> +static int dwc3_meson_g12a_otg_mode_set(struct dwc3_meson_g12a *priv,
> + enum phy_mode mode)
> +{
> + int ret;
> +
> + if (!priv->phys[USB2_OTG_PHY])
> + return -EINVAL;
> +
> + if (mode == PHY_MODE_USB_HOST)
> + dev_info(priv->dev, "switching to Host Mode\n");
> + else
> + dev_info(priv->dev, "switching to Device Mode\n");
> +
> + if (priv->vbus) {
> + if (mode == PHY_MODE_USB_DEVICE)
> + ret = regulator_disable(priv->vbus);
> + else
> + ret = regulator_enable(priv->vbus);
do we need to track the regulator status (whether it's enabled or not)?
the regulator framework WARN()s if it detects "unbalanced disables for
<regulator>"
(I haven't tested this on one of my boards yet, so maybe it works
because the callers of dwc3_meson_g12a_otg_mode_set() protect against
this by not calling this function if the mode doesn't change)
> + if (ret)
> + return ret;
> + }
> +
> + priv->otg_phy_mode = mode;
> +
> + dwc3_meson_g12a_usb2_set_mode(priv, USB2_OTG_PHY, mode);
> +
> + dwc3_meson_g12a_usb_init_mode(priv);
> +
> + return phy_set_mode(priv->phys[USB2_OTG_PHY], mode);
> + }
this is the only place where phy_set_mode is called
I'm fine with keeping it but then it should be consistent at least for
all USB2 PHYs.
I suggest to either move the phy_set_mode call to
dwc3_meson_g12a_usb2_set_mode or to remove it.
[...]
> +static int dwc3_meson_g12a_role_set(struct device *dev, enum usb_role role)
> +{
> + struct dwc3_meson_g12a *priv = dev_get_drvdata(dev);
> + enum phy_mode mode;
> +
> + if (role == USB_ROLE_NONE)
> + return 0;
> +
> + mode = role == USB_ROLE_HOST ? PHY_MODE_USB_HOST : PHY_MODE_USB_DEVICE;
(without surrounding parens I find the "role == USB_ROLE_HOST" part
hard to distinguish from the "mode =" operation. if more people think
this way then please speak up - otherwise it's probably just my
personal taste)
[...]
> +static struct device *dwc3_meson_g12_find_child(struct device *dev,
> + const char *compatible)
> +{
> + struct platform_device *pdev;
> + struct device_node *np;
> +
> + np = of_find_compatible_node(dev->of_node, NULL, compatible);
> + if (!np)
> + return NULL;
> +
> + pdev = of_find_device_by_node(np);
maybe switch to of_get_compatible_child() here? This was done for the
MMC driver in c483a5cc9d09f4 ("mmc: meson-mx-sdio: fix OF child-node
lookup"), but I'm not sure if the problem described there also applies
to dwc3_meson_g12_find_child
[...]
> +static int dwc3_meson_g12a_probe(struct platform_device *pdev)
> +{
> + struct dwc3_meson_g12a *priv;
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev->of_node;
> + void __iomem *base;
> + struct resource *res;
> + enum phy_mode otg_id;
> + int ret, i;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(base))
> + return PTR_ERR(base);
> +
> + priv->regmap = devm_regmap_init_mmio(dev, base,
> + &phy_meson_g12a_usb3_regmap_conf);
> + if (IS_ERR(priv->regmap))
> + return PTR_ERR(priv->regmap);
> +
> + priv->vbus = devm_regulator_get_optional(dev, "vbus");
> + if (IS_ERR(priv->vbus)) {
> + if (PTR_ERR(priv->vbus) == -EPROBE_DEFER)
> + return PTR_ERR(priv->vbus);
> + priv->vbus = NULL;
> + }
> +
> + priv->clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(priv->clk))
> + return PTR_ERR(priv->clk);
> +
> + ret = clk_prepare_enable(priv->clk);
> + if (ret)
> + return ret;
> +
> + platform_set_drvdata(pdev, priv);
> + priv->dev = dev;
> +
> + priv->reset = devm_reset_control_get(dev, NULL);
> + if (IS_ERR(priv->reset)) {
> + ret = PTR_ERR(priv->reset);
> + dev_err(dev, "failed to get device reset, err=%d\n", ret);
> + return ret;
> + }
clk_prepare_enable is called a few lines above but this (and a few
more) error-paths don't call clk_disable_unprepare.
Jerome suggested in the dwmac-meson8b driver that I use something
like, which will even allow you to drop the clk_disable_unprepare call
from dwc3_meson_g12a_remove and catch all error cases in
dwc3_meson_g12a_probe at the same time:
devm_add_action_or_reset(dev, (void(*)(void
*))clk_disable_unprepare, priv->clk);
(if you go with this then you also need to remove the
clk_disable_unprepare after of_platform_populate)
[...]
> +static int dwc3_meson_g12a_remove(struct platform_device *pdev)
> +{
> + struct dwc3_meson_g12a *priv = platform_get_drvdata(pdev);
> + struct device *dev = &pdev->dev;
> + int i;
> +
> + usb_role_switch_unregister(priv->role_switch);
> +
> + of_platform_depopulate(dev);
> +
> + for (i = 0 ; i < PHY_COUNT ; ++i) {
> + phy_power_off(priv->phys[i]);
> + phy_exit(priv->phys[i]);
> + phy_put(priv->phys[i]);
> + }
> +
> + clk_disable_unprepare(priv->clk);
> + clk_put(priv->clk);
priv->clk is obtained with devm_clk_get so the common clock framework
will call clk_put for us automatically
[...]
> +static int __maybe_unused dwc3_meson_g12a_suspend(struct device *dev)
> +{
> + struct dwc3_meson_g12a *priv = dev_get_drvdata(dev);
> + int i;
> +
> + for (i = 0 ; i < PHY_COUNT ; ++i)
> + if (priv->phys[i])
> + phy_exit(priv->phys[i]);
phy_init is NULL-safe, so you can drop the NULL-check above
> +
> + reset_control_assert(priv->reset);
> +
> + return 0;
> +}
> +
> +static int __maybe_unused dwc3_meson_g12a_resume(struct device *dev)
> +{
> + struct dwc3_meson_g12a *priv = dev_get_drvdata(dev);
> + int i, ret;
> +
> + reset_control_deassert(priv->reset);
> +
> + dwc3_meson_g12a_usb_init(priv);
> +
> + /* Init PHYs */
> + for (i = 0 ; i < PHY_COUNT ; ++i) {
> + if (priv->phys[i]) {
> + ret = phy_init(priv->phys[i]);
phy_init is NULL-safe, so you can drop the NULL-check above
Regards
Martin
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