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Message-ID: <d1ca5d29-8ef4-4d7f-b1c8-bcb361e6c351@kernel.org>
Date: Thu, 7 Mar 2024 14:31:51 +0200
From: Roger Quadros <rogerq@...nel.org>
To: Théo Lebrun <theo.lebrun@...tlin.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>, Peter Chen <peter.chen@...nel.org>,
Pawel Laszczak <pawell@...ence.com>, Nishanth Menon <nm@...com>,
Vignesh Raghavendra <vigneshr@...com>, Tero Kristo <kristo@...nel.org>
Cc: Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Grégory Clement <gregory.clement@...tlin.com>,
Kevin Hilman <khilman@...nel.org>, Alan Stern <stern@...land.harvard.edu>,
linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 3/9] usb: cdns3-ti: move reg writes from probe into
->runtime_resume()
Hi,
On 07/03/2024 11:55, Théo Lebrun wrote:
> The hardware initialisation register write sequence is only used at
> probe. Move it from being done at explicitely at probe to being done
> implicitely by pm_runtime_get_sync() that calls ->runtime_resume().
explicitly / implicitly
>
> Keep devicetree parsing in probe and add a new field in the private
> struct to remember the USB2 refclk rate code computation result.
>
> This opens the door to having the init sequence being executed later
> down the road, at system-wide resume for example. This is NOT currently
> happening because runtime PM is disabled at suspend without the
> refcount being affected.
>
> Signed-off-by: Théo Lebrun <theo.lebrun@...tlin.com>
> ---
> drivers/usb/cdns3/cdns3-ti.c | 90 +++++++++++++++++++++++++-------------------
> 1 file changed, 52 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/usb/cdns3/cdns3-ti.c b/drivers/usb/cdns3/cdns3-ti.c
> index 5945c4b1e11f..4c8a557e6a6f 100644
> --- a/drivers/usb/cdns3/cdns3-ti.c
> +++ b/drivers/usb/cdns3/cdns3-ti.c
> @@ -57,6 +57,7 @@ struct cdns_ti {
> unsigned vbus_divider:1;
> struct clk *usb2_refclk;
> struct clk *lpm_clk;
> + int usb2_refclk_rate_code;
> };
>
> static const int cdns_ti_rate_table[] = { /* in KHZ */
> @@ -90,10 +91,8 @@ static int cdns_ti_probe(struct platform_device *pdev)
> struct device *dev = &pdev->dev;
> struct device_node *node = pdev->dev.of_node;
> struct cdns_ti *data;
> - int error;
> - u32 reg;
> - int rate_code, i;
> unsigned long rate;
> + int error, i;
>
> data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> if (!data)
> @@ -133,7 +132,9 @@ static int cdns_ti_probe(struct platform_device *pdev)
> return -EINVAL;
> }
>
> - rate_code = i;
> + data->usb2_refclk_rate_code = i;
> + data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
> + data->usb2_only = device_property_read_bool(dev, "ti,usb2-only");
>
> pm_runtime_enable(dev);
> error = pm_runtime_get_sync(dev);
> @@ -142,40 +143,6 @@ static int cdns_ti_probe(struct platform_device *pdev)
> goto err;
> }
>
> - /* assert RESET */
> - reg = cdns_ti_readl(data, USBSS_W1);
> - reg &= ~USBSS_W1_PWRUP_RST;
> - cdns_ti_writel(data, USBSS_W1, reg);
> -
> - /* set static config */
> - reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
> - reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
> - reg |= rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;
> -
> - reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
> - data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
> - if (data->vbus_divider)
> - reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;
> -
> - cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
> - reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
> -
> - /* set USB2_ONLY mode if requested */
> - reg = cdns_ti_readl(data, USBSS_W1);
> - data->usb2_only = device_property_read_bool(dev, "ti,usb2-only");
> - if (data->usb2_only)
> - reg |= USBSS_W1_USB2_ONLY;
> -
> - /* set default modestrap */
> - reg |= USBSS_W1_MODESTRAP_SEL;
> - reg &= ~USBSS_W1_MODESTRAP_MASK;
> - reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
> - cdns_ti_writel(data, USBSS_W1, reg);
> -
> - /* de-assert RESET */
> - reg |= USBSS_W1_PWRUP_RST;
> - cdns_ti_writel(data, USBSS_W1, reg);
> -
> error = of_platform_populate(node, NULL, NULL, dev);
> if (error) {
> dev_err(dev, "failed to create children: %d\n", error);
> @@ -211,6 +178,52 @@ static void cdns_ti_remove(struct platform_device *pdev)
> platform_set_drvdata(pdev, NULL);
> }
>
> +static int cdns_ti_runtime_resume(struct device *dev)
> +{
> + struct cdns_ti *data = dev_get_drvdata(dev);
> + u32 reg;
> +
> + /* assert RESET */
> + reg = cdns_ti_readl(data, USBSS_W1);
> + reg &= ~USBSS_W1_PWRUP_RST;
> + cdns_ti_writel(data, USBSS_W1, reg);
> +
> + /* set static config */
> + reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
> + reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
> + reg |= data->usb2_refclk_rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;
> +
> + reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
> +
> + if (data->vbus_divider)
> + reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;
> +
> + cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
> + reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
> +
> + /* set USB2_ONLY mode if requested */
> + reg = cdns_ti_readl(data, USBSS_W1);
> +
> + if (data->usb2_only)
> + reg |= USBSS_W1_USB2_ONLY;
> +
> + /* set default modestrap */
> + reg |= USBSS_W1_MODESTRAP_SEL;
> + reg &= ~USBSS_W1_MODESTRAP_MASK;
> + reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
> + cdns_ti_writel(data, USBSS_W1, reg);
> +
> + /* de-assert RESET */
> + reg |= USBSS_W1_PWRUP_RST;
> + cdns_ti_writel(data, USBSS_W1, reg);
I don't think USB controller requires a reset and re-init between runtime suspend/resume.
What you need is reset/re-init during system Resume on certain platforms.
So you should move this part of code into a helper function and call it
from .probe() and .system_resume()
> +
> + return 0;
> +}
> +
> +static const struct dev_pm_ops cdns_ti_pm_ops = {
> + RUNTIME_PM_OPS(NULL, cdns_ti_runtime_resume, NULL)
> +};
> +
> static const struct of_device_id cdns_ti_of_match[] = {
> { .compatible = "ti,j721e-usb", },
> { .compatible = "ti,am64-usb", },
> @@ -224,6 +237,7 @@ static struct platform_driver cdns_ti_driver = {
> .driver = {
> .name = "cdns3-ti",
> .of_match_table = cdns_ti_of_match,
> + .pm = pm_ptr(&cdns_ti_pm_ops),
> },
> };
>
>
--
cheers,
-roger
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