Re: [PATCH 2/6] usb: cdns3-ti: move reg writes from probe into an init_hw helper

Théo Lebrun
2023-11-15T14:23:22Z

Hello,

On Wed Nov 15, 2023 at 12:33 PM CET, Roger Quadros wrote:
> > --- a/drivers/usb/cdns3/cdns3-ti.c
> > +++ b/drivers/usb/cdns3/cdns3-ti.c

[...]

> > 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;
>
> Should we leave rate_code and get rid of i?

I see your point about i being usually a temp variable. Using rate_code
instead of i means the for-loop becomes rather long (column 87) &
should ideally be split.

How about moving the data->usb2_refclk_rate_code assignment up, closer
to the computation of i? That way we don't reference i three blocks
down the road, seemingly out of nowhere.

Regards,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

------------------------------------------------------------------------

> > data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> > if (!data)
> > @@ -133,8 +169,6 @@ static int cdns_ti_probe(struct platform_device *pdev)
> > return -EINVAL;
> > }
> >
> > - rate_code = i;
> > -
> > pm_runtime_enable(dev);
> > error = pm_runtime_get_sync(dev)> if (error < 0) {
> > @@ -142,39 +176,11 @@ 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);
> > + data->usb2_refclk_rate_code = i;
>
> because 'i' seems temporary.
>
> >
> > - /* de-assert RESET */
> > - reg |= USBSS_W1_PWRUP_RST;
> > - cdns_ti_writel(data, USBSS_W1, reg);
> > + cdns_ti_init_hw(data);
> >
> > error = of_platform_populate(node, NULL, NULL, dev);
> > if (error) {
> >