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

[claudiu beznea <claudiu.beznea@tuxon.dev>]

Hi, Biju,

On 23.08.2024 10:35, Biju Das wrote:
> Hi Claudiu,
> 
>> -----Original Message-----
>> From: Claudiu <claudiu.beznea@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@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.

I think this is a matter of taste... This is how I usually format the
patches (for scenarios like this) and got no request for squashing.

Anyway, I can do it your way, too.

Thank you,
Claudiu Beznea

> 
> Cheers,
> Biju
> 
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@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
>