[PATCH 10/16] phy: renesas: rcar-gen3-usb2: Add support to initialize the bus

[Biju Das]

Hi Claudiu,

> -----Original Message-----
> From: Claudiu <claudiu.beznea at tuxon.dev>
> Sent: Thursday, August 22, 2024 4:28 PM
> Subject: [PATCH 10/16] phy: renesas: rcar-gen3-usb2: Add support to initialize the bus
> 
> From: Claudiu Beznea <claudiu.beznea.uj at bp.renesas.com>
> 
> The Renesas RZ/G3S need to initialize the USB BUS before transferring data due to hardware limitation.
> As the register that need to be touched for this is in the address space of the USB PHY, and the UBS
> PHY need to be initialized before any other USB drivers handling data transfer, add support to
> initialize the USB BUS.
> 
> As the USB PHY is probed before any other USB drivers that enables clocks and de-assert the reset
> signals and the BUS initialization is done in the probe phase, we need to add code to de-assert reset
> signal and runtime resume the device (which enables its clocks) before accessing the registers.
> 
> As the reset signals are not required by the USB PHY driver for the other USB PHY hardware variants,
> the reset signals and runtime PM was handled only in the function that initialize the USB BUS.
> 
> The PHY initialization was done right after runtime PM enable to have all in place when the PHYs are
> registered.

There is no user for this patch. The first user is RZ/G3S and you should merge this patch with
next one.

Cheers,
Biju

> 
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj at bp.renesas.com>
> ---
>  drivers/phy/renesas/phy-rcar-gen3-usb2.c | 50 ++++++++++++++++++++++--
>  1 file changed, 47 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/phy/renesas/phy-rcar-gen3-usb2.c b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> index 7594f64eb737..cf4299cea579 100644
> --- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> +++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> @@ -19,12 +19,14 @@
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/reset.h>
>  #include <linux/string.h>
>  #include <linux/usb/of.h>
>  #include <linux/workqueue.h>
> 
>  /******* USB2.0 Host registers (original offset is +0x200) *******/
>  #define USB2_INT_ENABLE		0x000
> +#define USB2_AHB_BUS_CTR	0x008
>  #define USB2_USBCTR		0x00c
>  #define USB2_SPD_RSM_TIMSET	0x10c
>  #define USB2_OC_TIMSET		0x110
> @@ -40,6 +42,10 @@
>  #define USB2_INT_ENABLE_USBH_INTB_EN	BIT(2)	/* For EHCI */
>  #define USB2_INT_ENABLE_USBH_INTA_EN	BIT(1)	/* For OHCI */
> 
> +/* AHB_BUS_CTR */
> +#define USB2_AHB_BUS_CTR_MBL_MASK	GENMASK(1, 0)
> +#define USB2_AHB_BUS_CTR_MBL_INCR4	2
> +
>  /* USBCTR */
>  #define USB2_USBCTR_DIRPD	BIT(2)
>  #define USB2_USBCTR_PLL_RST	BIT(1)
> @@ -111,6 +117,7 @@ struct rcar_gen3_chan {
>  	struct extcon_dev *extcon;
>  	struct rcar_gen3_phy rphys[NUM_OF_PHYS];
>  	struct regulator *vbus;
> +	struct reset_control *rstc;
>  	struct work_struct work;
>  	struct mutex lock;	/* protects rphys[...].powered */
>  	enum usb_dr_mode dr_mode;
> @@ -125,6 +132,7 @@ struct rcar_gen3_chan {  struct rcar_gen3_phy_drv_data {
>  	const struct phy_ops *phy_usb2_ops;
>  	bool no_adp_ctrl;
> +	bool init_bus;
>  };
> 
>  /*
> @@ -650,6 +658,35 @@ static enum usb_dr_mode rcar_gen3_get_dr_mode(struct device_node *np)
>  	return candidate;
>  }
> 
> +static int rcar_gen3_phy_usb2_init_bus(struct rcar_gen3_chan *channel)
> +{
> +	struct device *dev = channel->dev;
> +	int ret;
> +	u32 val;
> +
> +	channel->rstc = devm_reset_control_array_get_shared(dev);
> +	if (IS_ERR(channel->rstc))
> +		return PTR_ERR(channel->rstc);
> +
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = reset_control_deassert(channel->rstc);
> +	if (ret)
> +		goto rpm_put;
> +
> +	val = readl(channel->base + USB2_AHB_BUS_CTR);
> +	val &= ~USB2_AHB_BUS_CTR_MBL_MASK;
> +	val |= USB2_AHB_BUS_CTR_MBL_INCR4;
> +	writel(val, channel->base + USB2_AHB_BUS_CTR);
> +
> +rpm_put:
> +	pm_runtime_put(dev);
> +
> +	return ret;
> +}
> +
>  static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)  {
>  	const struct rcar_gen3_phy_drv_data *phy_data; @@ -703,6 +740,15 @@ static int
> rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
>  		goto error;
>  	}
> 
> +	platform_set_drvdata(pdev, channel);
> +	channel->dev = dev;
> +
> +	if (phy_data->init_bus) {
> +		ret = rcar_gen3_phy_usb2_init_bus(channel);
> +		if (ret)
> +			goto error;
> +	}
> +
>  	channel->soc_no_adp_ctrl = phy_data->no_adp_ctrl;
>  	if (phy_data->no_adp_ctrl)
>  		channel->obint_enable_bits = USB2_OBINT_IDCHG_EN; @@ -733,9 +779,6 @@ static int
> rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
>  		channel->vbus = NULL;
>  	}
> 
> -	platform_set_drvdata(pdev, channel);
> -	channel->dev = dev;
> -
>  	provider = devm_of_phy_provider_register(dev, rcar_gen3_phy_usb2_xlate);
>  	if (IS_ERR(provider)) {
>  		dev_err(dev, "Failed to register PHY provider\n"); @@ -762,6 +805,7 @@ static void
> rcar_gen3_phy_usb2_remove(struct platform_device *pdev)
>  	if (channel->is_otg_channel)
>  		device_remove_file(&pdev->dev, &dev_attr_role);
> 
> +	reset_control_assert(channel->rstc);
>  	pm_runtime_disable(&pdev->dev);
>  };
> 
> --
> 2.39.2