Re: [PATCH] phy: ti-pipe3: Add set_mode callback to configure usb3 phy as pcie phy

[Roger Quadros <rogerq@ti.com>]

On 30/01/19 15:59, Kishon Vijay Abraham I wrote:
> Hi,
> 
> On 30/01/19 7:27 PM, Roger Quadros wrote:
>> +Rob,
>>
>> On 30/01/19 15:00, Kishon Vijay Abraham I wrote:
>>> Hi Roger,
>>>
>>> On 30/01/19 6:11 PM, Roger Quadros wrote:
>>>> Kishon,
>>>>
>>>> On 30/01/19 12:59, Kishon Vijay Abraham I wrote:
>>>>> Hi Roger,
>>>>>
>>>>> On 30/01/19 4:18 PM, Roger Quadros wrote:
>>>>>> Hi Kishon,
>>>>>>
>>>>>> On 24/01/19 12:48, Kishon Vijay Abraham I wrote:
>>>>>>> DRA72 platform has the second instance of PHY shared between USB3
>>>>>>> controller and PCIe controller with default as USB3 controller.
>>>>>>> Since it is used with USB3 controller by default, it uses the
>>>>>>> compatible specific to USB (ti,omap-usb3).
>>>>>>>
>>>>>>> Populate set_mode callback so that the USB3 PHY can be configured
>>>>>>> to be used with PCIe controller.
>>>>>>
>>>>>> What is the use case of this? At what point and who decides the
>>>>>> phy_set_mode() to be called with USB vs PCIe?
>>>>>
>>>>> The PHY by default is configured to be used with USB controller (That's why it
>>>>> has a compatible of ti,omap-usb3). However there is a special case where this
>>>>> PHY has to be used PCIe controller. So the set_mode() will help the PHY driver
>>>>> to configure the USB PHY to be used with PCIe controller.
>>>>>
>>>>> This is not a shared PHY, so the PHY as such can be used only with USB or PCIe
>>>>> and is determined at designtime
>>>>
>>>> If type is defined at design time then the design using the PHY for PCIe shouldn't be
>>>> using "ti,omap-usb3" compatible. Right?
>>> The second instance of PIPE3 PHY in dra72x SoC can be used either with USB3 or
>>> as a second lane of the 1st PCIe instance. How it is connected is based on
>>> board design. DRA72x EVM will need board modification for the PHY to be used
>>> with PCIe (by default it is connected to USB). AM571x IDK doesn't have a USB3
>>> port so the PIPE3 PHY is used with PCIe (USB2 also doesn't work with this
>>> configuration but that is a different HW issue).
>>>
>>> I'm not sure if we should change the compatible in board dts file as it is
>>> based on board design. Previously I added a dt property to indicate the PHY
>>> should be configured for PCIe but Rob Herring suggested to use set_mode [1].
>>
>> That is because you tried to add a new property "ti,configure-as-pcie" which
>> does seem unnecessary.
>>
>> Wouldn't it work if you just use "ti,phy-pipe3-pcie" in the relevant device tree?
> 
> No, it won't. The configuration required for a PCIe PHY is different from a USB
> PHY to be used for PCIe.

I understand now. Compatible shouldn't change. I have a couple of comments still.
I'll respond to the main patch.

cheers,
-roger

> 
> Thanks
> Kishon
> 
>>
>> cheers,
>> -roger
>>
>>>
>>> Thanks
>>> Kishon
>>>
>>> [1] -> https://lore.kernel.org/patchwork/patch/865398/
>>>>
>>>> Maybe we should fix the DT? Which board/PHY is this about?
>>>>
>>>> cheers,
>>>> -roger
>>>>
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
>>>>>>> ---
>>>>>>>  drivers/phy/ti/phy-ti-pipe3.c | 66 ++++++++++++++++++++++++++++-------
>>>>>>>  1 file changed, 54 insertions(+), 12 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/phy/ti/phy-ti-pipe3.c b/drivers/phy/ti/phy-ti-pipe3.c
>>>>>>> index 68ce4a082b9b..8c98f366416d 100644
>>>>>>> --- a/drivers/phy/ti/phy-ti-pipe3.c
>>>>>>> +++ b/drivers/phy/ti/phy-ti-pipe3.c
>>>>>>> @@ -56,6 +56,12 @@
>>>>>>>  
>>>>>>>  #define SATA_PLL_SOFT_RESET	BIT(18)
>>>>>>>  
>>>>>>> +#define PHY_RX_ANA_PRGRAMMABILITY_REG	0xC
>>>>>>> +#define MEM_EN_PLLBYP			BIT(7)
>>>>>>> +
>>>>>>> +#define PHY_TX_TEST_CONFIG		0x2C
>>>>>>> +#define MEM_ENTESTCLK			BIT(31)
>>>>>>> +
>>>>>>>  #define PIPE3_PHY_PWRCTL_CLK_CMD_MASK	0x003FC000
>>>>>>>  #define PIPE3_PHY_PWRCTL_CLK_CMD_SHIFT	14
>>>>>>>  
>>>>>>> @@ -110,6 +116,8 @@
>>>>>>>  #define PLL_IDLE_TIME	100	/* in milliseconds */
>>>>>>>  #define PLL_LOCK_TIME	100	/* in milliseconds */
>>>>>>>  
>>>>>>> +#define PIPE3_PHY_DISABLE_SYNC_POWER	BIT(4)
>>>>>>> +
>>>>>>>  struct pipe3_dpll_params {
>>>>>>>  	u16	m;
>>>>>>>  	u8	n;
>>>>>>> @@ -141,6 +149,7 @@ struct ti_pipe3 {
>>>>>>>  	unsigned int		power_reg; /* power reg. index within syscon */
>>>>>>>  	unsigned int		pcie_pcs_reg; /* pcs reg. index in syscon */
>>>>>>>  	bool			sata_refclk_enabled;
>>>>>>> +	u32			mode;
>>>>>>>  };
>>>>>>>  
>>>>>>>  static struct pipe3_dpll_map dpll_map_usb[] = {
>>>>>>> @@ -233,7 +242,10 @@ static int ti_pipe3_power_on(struct phy *x)
>>>>>>>  	rate = rate / 1000000;
>>>>>>>  	mask = OMAP_CTRL_PIPE3_PHY_PWRCTL_CLK_CMD_MASK |
>>>>>>>  		  OMAP_CTRL_PIPE3_PHY_PWRCTL_CLK_FREQ_MASK;
>>>>>>> -	val = PIPE3_PHY_TX_RX_POWERON << PIPE3_PHY_PWRCTL_CLK_CMD_SHIFT;
>>>>>>> +	val = PIPE3_PHY_TX_RX_POWERON;
>>>>>>> +	if (phy->mode == PHY_MODE_PCIE)
>>>>>>> +		val |= PIPE3_PHY_DISABLE_SYNC_POWER;
>>>>>>> +	val <<= PIPE3_PHY_PWRCTL_CLK_CMD_SHIFT;
>>>>>>>  	val |= rate << OMAP_CTRL_PIPE3_PHY_PWRCTL_CLK_FREQ_SHIFT;
>>>>>>>  
>>>>>>>  	ret = regmap_update_bits(phy->phy_power_syscon, phy->power_reg,
>>>>>>> @@ -328,13 +340,11 @@ static void ti_pipe3_calibrate(struct ti_pipe3 *phy)
>>>>>>>  	ti_pipe3_writel(phy->phy_rx, PCIEPHYRX_EQUALIZER, val);
>>>>>>>  }
>>>>>>>  
>>>>>>> -static int ti_pipe3_init(struct phy *x)
>>>>>>> +static int ti_pipe3_pcie_init(struct ti_pipe3 *phy)
>>>>>>>  {
>>>>>>> -	struct ti_pipe3 *phy = phy_get_drvdata(x);
>>>>>>> -	u32 val;
>>>>>>>  	int ret = 0;
>>>>>>> +	u32 val;
>>>>>>>  
>>>>>>> -	ti_pipe3_enable_clocks(phy);
>>>>>>>  	/*
>>>>>>>  	 * Set pcie_pcs register to 0x96 for proper functioning of phy
>>>>>>>  	 * as recommended in AM572x TRM SPRUHZ6, section 18.5.2.2, table
>>>>>>> @@ -353,10 +363,31 @@ static int ti_pipe3_init(struct phy *x)
>>>>>>>  			return ret;
>>>>>>>  
>>>>>>>  		ti_pipe3_calibrate(phy);
>>>>>>> -
>>>>>>> -		return 0;
>>>>>>> +	} else {
>>>>>>> +		val = ti_pipe3_readl(phy->phy_rx,
>>>>>>> +				     PHY_RX_ANA_PRGRAMMABILITY_REG);
>>>>>>> +		val |= MEM_EN_PLLBYP;
>>>>>>> +		ti_pipe3_writel(phy->phy_rx, PHY_RX_ANA_PRGRAMMABILITY_REG,
>>>>>>> +				val);
>>>>>>> +		val = ti_pipe3_readl(phy->phy_tx, PHY_TX_TEST_CONFIG);
>>>>>>> +		val |= MEM_ENTESTCLK;
>>>>>>> +		ti_pipe3_writel(phy->phy_tx, PHY_TX_TEST_CONFIG, val);
>>>>>>>  	}
>>>>>>>  
>>>>>>> +	return 0;
>>>>>>> +}
>>>>>>> +
>>>>>>> +static int ti_pipe3_init(struct phy *x)
>>>>>>> +{
>>>>>>> +	struct ti_pipe3 *phy = phy_get_drvdata(x);
>>>>>>> +	u32 val;
>>>>>>> +	int ret = 0;
>>>>>>> +
>>>>>>> +	ti_pipe3_enable_clocks(phy);
>>>>>>> +
>>>>>>> +	if (phy->mode == PHY_MODE_PCIE)
>>>>>>> +		return ti_pipe3_pcie_init(phy);
>>>>>>> +
>>>>>>>  	/* Bring it out of IDLE if it is IDLE */
>>>>>>>  	val = ti_pipe3_readl(phy->pll_ctrl_base, PLL_CONFIGURATION2);
>>>>>>>  	if (val & PLL_IDLE) {
>>>>>>> @@ -395,7 +426,7 @@ static int ti_pipe3_exit(struct phy *x)
>>>>>>>  		return 0;
>>>>>>>  
>>>>>>>  	/* PCIe doesn't have internal DPLL */
>>>>>>> -	if (!of_device_is_compatible(phy->dev->of_node, "ti,phy-pipe3-pcie")) {
>>>>>>> +	if (!(phy->mode == PHY_MODE_PCIE)) {
>>>>>>>  		/* Put DPLL in IDLE mode */
>>>>>>>  		val = ti_pipe3_readl(phy->pll_ctrl_base, PLL_CONFIGURATION2);
>>>>>>>  		val |= PLL_IDLE;
>>>>>>> @@ -429,11 +460,25 @@ static int ti_pipe3_exit(struct phy *x)
>>>>>>>  
>>>>>>>  	return 0;
>>>>>>>  }
>>>>>>> +
>>>>>>> +static int ti_pipe3_set_mode(struct phy *x, enum phy_mode mode, int submode)
>>>>>>> +{
>>>>>>> +	struct ti_pipe3 *phy = phy_get_drvdata(x);
>>>>>>> +
>>>>>>> +	if (phy->mode != PHY_MODE_INVALID)
>>>>>>> +		return -EBUSY;
>>>>>>> +
>>>>>>> +	phy->mode = mode;
>>>>>>
>>>>>> You are only saving the mode. But not really switching modes here.
>>>>>> How is this intended to work?
>>>>>
>>>>> The PHY doesn't have a specific mode. Rather it is a set of configurations
>>>>> required to operate in a particular mode.
>>>>>
>>>>> This mode value will be used in other init, power_on callback functions.
>>>>>
>>>>> Thanks
>>>>> Kishon
>>>>>
>>>>
>>

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