[PATCH 0/4] usb: dwc3-am62: module removal and errata fixes

[PATCH 0/4] usb: dwc3-am62: module removal and errata fixes

[Roger Quadros]

Hi,

This series fixes errors during module removal. It also
implements PHY core voltage selection as per TI recommendation
and workaround for Errata i2409 [1].

The workaround needs PHY2 region to be present in device node.
This is sent as a separate series [2].

[1] - https://www.ti.com/lit/er/sprz487d/sprz487d.pdf
[2] - https://lore.kernel.org/all/20240201120332.4811-6-rogerq@kernel.org/

cheers,
-roger

Roger Quadros (4):
  usb: dwc3-am62: call of_platform_depopulate in .remove()
  usb: dwc3-am62: fix error on module removal
  usb: dwc3-am62: Fix PHY core voltage selection
  usb: dwc3-am62: add workaround for Errata i2409

 drivers/usb/dwc3/dwc3-am62.c | 55 ++++++++++++++++++++++++++++--------
 1 file changed, 44 insertions(+), 11 deletions(-)


base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d
-- 
2.34.1

[PATCH 1/4] usb: dwc3-am62: call of_platform_depopulate in .remove()

[Roger Quadros]

We called of_platform_populate() in .probe() so call the
cleanup function of_platform_depopulate() in .remove().

Get rid of the now unnnecessary dwc3_ti_remove_core().

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/usb/dwc3/dwc3-am62.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
index 90a587bc29b7..1bfc9e67614f 100644
--- a/drivers/usb/dwc3/dwc3-am62.c
+++ b/drivers/usb/dwc3/dwc3-am62.c
@@ -267,21 +267,13 @@ static int dwc3_ti_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int dwc3_ti_remove_core(struct device *dev, void *c)
-{
-	struct platform_device *pdev = to_platform_device(dev);
-
-	platform_device_unregister(pdev);
-	return 0;
-}
-
 static void dwc3_ti_remove(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct dwc3_am62 *am62 = platform_get_drvdata(pdev);
 	u32 reg;
 
-	device_for_each_child(dev, NULL, dwc3_ti_remove_core);
+	of_platform_depopulate(dev);
 
 	/* Clear mode valid bit */
 	reg = dwc3_ti_readl(am62, USBSS_MODE_CONTROL);
-- 
2.34.1

[PATCH 2/4] usb: dwc3-am62: fix error on module removal

[Roger Quadros]

As runtime PM is enabled, the module can be runtime
suspended when .remove() is called.

Do a pm_runtime_get_sync() to make sure module is active
before doing any register operations.

Doing a pm_runtime_put_sync() should disable the refclk
so no need to disable it again.

Fixes the below warning at module removel.

[   39.705310] ------------[ cut here ]------------
[   39.710004] clk:162:3 already disabled
[   39.713941] WARNING: CPU: 0 PID: 921 at drivers/clk/clk.c:1090 clk_core_disable+0xb0/0xb8

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/usb/dwc3/dwc3-am62.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
index 1bfc9e67614f..600ba9cfefea 100644
--- a/drivers/usb/dwc3/dwc3-am62.c
+++ b/drivers/usb/dwc3/dwc3-am62.c
@@ -273,6 +273,11 @@ static void dwc3_ti_remove(struct platform_device *pdev)
 	struct dwc3_am62 *am62 = platform_get_drvdata(pdev);
 	u32 reg;
 
+	pm_runtime_get_sync(dev);
+
+	device_wakeup_disable(dev);
+	device_set_wakeup_capable(dev, false);
+
 	of_platform_depopulate(dev);
 
 	/* Clear mode valid bit */
@@ -281,7 +286,6 @@ static void dwc3_ti_remove(struct platform_device *pdev)
 	dwc3_ti_writel(am62, USBSS_MODE_CONTROL, reg);
 
 	pm_runtime_put_sync(dev);
-	clk_disable_unprepare(am62->usb2_refclk);
 	pm_runtime_disable(dev);
 	pm_runtime_set_suspended(dev);
 }
-- 
2.34.1

[PATCH 3/4] usb: dwc3-am62: Fix PHY core voltage selection

[Roger Quadros]

TRM information is outdated and design team has confirmed
that PHY_CORE_VOLTAGE should be 0 irrespective of
VDD_CORE voltage.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/usb/dwc3/dwc3-am62.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
index 600ba9cfefea..af1ce934e7fb 100644
--- a/drivers/usb/dwc3/dwc3-am62.c
+++ b/drivers/usb/dwc3/dwc3-am62.c
@@ -97,7 +97,8 @@
 #define USBSS_VBUS_STAT_SESSVALID	BIT(2)
 #define USBSS_VBUS_STAT_VBUSVALID	BIT(0)
 
-/* Mask for PHY PLL REFCLK */
+/* USB_PHY_CTRL register bits in CTRL_MMR */
+#define PHY_CORE_VOLTAGE_MASK	BIT(31)
 #define PHY_PLL_REFCLK_MASK	GENMASK(3, 0)
 
 #define DWC3_AM62_AUTOSUSPEND_DELAY	100
@@ -162,6 +163,13 @@ static int phy_syscon_pll_refclk(struct dwc3_am62 *am62)
 
 	am62->offset = args.args[0];
 
+	/* Core voltage. PHY_CORE_VOLTAGE bit Recommended to be 0 always */
+	ret = regmap_update_bits(am62->syscon, am62->offset, PHY_CORE_VOLTAGE_MASK, 0);
+	if (ret) {
+		dev_err(dev, "failed to set phy core voltage\n");
+		return ret;
+	}
+
 	ret = regmap_update_bits(am62->syscon, am62->offset, PHY_PLL_REFCLK_MASK, am62->rate_code);
 	if (ret) {
 		dev_err(dev, "failed to set phy pll reference clock rate\n");
-- 
2.34.1

[PATCH 4/4] usb: dwc3-am62: add workaround for Errata i2409

[Roger Quadros]

All AM62 devices have Errata i2409 [1] due to which
USB2 PHY may lock up due to short suspend.

Workaround involves setting bit 5 and 4 PLL_REG12
in PHY2 register space after USB controller is brought
out of LPSC reset but before controller initialization.

Handle this workaround.

[1] - https://www.ti.com/lit/er/sprz487d/sprz487d.pdf

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/usb/dwc3/dwc3-am62.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
index af1ce934e7fb..35d7a2fb128e 100644
--- a/drivers/usb/dwc3/dwc3-am62.c
+++ b/drivers/usb/dwc3/dwc3-am62.c
@@ -101,11 +101,17 @@
 #define PHY_CORE_VOLTAGE_MASK	BIT(31)
 #define PHY_PLL_REFCLK_MASK	GENMASK(3, 0)
 
+/* USB PHY2 register offsets */
+#define	USB_PHY_PLL_REG12		0x130
+#define	USB_PHY_PLL_LDO_REF_EN		BIT(5)
+#define	USB_PHY_PLL_LDO_REF_EN_EN	BIT(4)
+
 #define DWC3_AM62_AUTOSUSPEND_DELAY	100
 
 struct dwc3_am62 {
 	struct device *dev;
 	void __iomem *usbss;
+	void __iomem *phy;
 	struct clk *usb2_refclk;
 	int rate_code;
 	struct regmap *syscon;
@@ -140,6 +146,16 @@ static inline void dwc3_ti_writel(struct dwc3_am62 *am62, u32 offset, u32 value)
 	writel(value, (am62->usbss) + offset);
 }
 
+static inline u32 dwc3_ti_phy_readl(struct dwc3_am62 *am62, u32 offset)
+{
+	return readl((am62->phy) + offset);
+}
+
+static inline void dwc3_ti_phy_writel(struct dwc3_am62 *am62, u32 offset, u32 value)
+{
+	writel(value, (am62->phy) + offset);
+}
+
 static int phy_syscon_pll_refclk(struct dwc3_am62 *am62)
 {
 	struct device *dev = am62->dev;
@@ -201,6 +217,12 @@ static int dwc3_ti_probe(struct platform_device *pdev)
 		return PTR_ERR(am62->usbss);
 	}
 
+	am62->phy = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(am62->phy)) {
+		dev_err(dev, "can't map PHY IOMEM resource. Won't apply i2409 fix.\n");
+		am62->phy = NULL;
+	}
+
 	am62->usb2_refclk = devm_clk_get(dev, "ref");
 	if (IS_ERR(am62->usb2_refclk)) {
 		dev_err(dev, "can't get usb2_refclk\n");
@@ -227,6 +249,13 @@ static int dwc3_ti_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	/* Workaround Errata i2409 */
+	if (am62->phy) {
+		reg = dwc3_ti_phy_readl(am62, USB_PHY_PLL_REG12);
+		reg |= USB_PHY_PLL_LDO_REF_EN | USB_PHY_PLL_LDO_REF_EN_EN;
+		dwc3_ti_phy_writel(am62, USB_PHY_PLL_REG12, reg);
+	}
+
 	/* VBUS divider select */
 	am62->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
 	reg = dwc3_ti_readl(am62, USBSS_PHY_CONFIG);
-- 
2.34.1

Re: [PATCH 4/4] usb: dwc3-am62: add workaround for Errata i2409

[Andrew Davis]

On 2/1/24 6:12 AM, Roger Quadros wrote:
> All AM62 devices have Errata i2409 [1] due to which
> USB2 PHY may lock up due to short suspend.
> 
> Workaround involves setting bit 5 and 4 PLL_REG12
> in PHY2 register space after USB controller is brought
> out of LPSC reset but before controller initialization.
> 
> Handle this workaround.
> 
> [1] - https://www.ti.com/lit/er/sprz487d/sprz487d.pdf
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>
> ---
>   drivers/usb/dwc3/dwc3-am62.c | 29 +++++++++++++++++++++++++++++
>   1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
> index af1ce934e7fb..35d7a2fb128e 100644
> --- a/drivers/usb/dwc3/dwc3-am62.c
> +++ b/drivers/usb/dwc3/dwc3-am62.c
> @@ -101,11 +101,17 @@
>   #define PHY_CORE_VOLTAGE_MASK	BIT(31)
>   #define PHY_PLL_REFCLK_MASK	GENMASK(3, 0)
>   
> +/* USB PHY2 register offsets */
> +#define	USB_PHY_PLL_REG12		0x130
> +#define	USB_PHY_PLL_LDO_REF_EN		BIT(5)
> +#define	USB_PHY_PLL_LDO_REF_EN_EN	BIT(4)
> +
>   #define DWC3_AM62_AUTOSUSPEND_DELAY	100
>   
>   struct dwc3_am62 {
>   	struct device *dev;
>   	void __iomem *usbss;
> +	void __iomem *phy;

Why do you need this in the driver data? You only use it in probe(),
just have it be a local variable.

>   	struct clk *usb2_refclk;
>   	int rate_code;
>   	struct regmap *syscon;
> @@ -140,6 +146,16 @@ static inline void dwc3_ti_writel(struct dwc3_am62 *am62, u32 offset, u32 value)
>   	writel(value, (am62->usbss) + offset);
>   }
>   
> +static inline u32 dwc3_ti_phy_readl(struct dwc3_am62 *am62, u32 offset)
> +{

Do you really need these one line functions? They add more code than
they save and just hide a single deference? Just do that directly.

Andrew

> +	return readl((am62->phy) + offset);
> +}
> +
> +static inline void dwc3_ti_phy_writel(struct dwc3_am62 *am62, u32 offset, u32 value)
> +{
> +	writel(value, (am62->phy) + offset);
> +}
> +
>   static int phy_syscon_pll_refclk(struct dwc3_am62 *am62)
>   {
>   	struct device *dev = am62->dev;
> @@ -201,6 +217,12 @@ static int dwc3_ti_probe(struct platform_device *pdev)
>   		return PTR_ERR(am62->usbss);
>   	}
>   
> +	am62->phy = devm_platform_ioremap_resource(pdev, 1);
> +	if (IS_ERR(am62->phy)) {
> +		dev_err(dev, "can't map PHY IOMEM resource. Won't apply i2409 fix.\n");
> +		am62->phy = NULL;
> +	}
> +
>   	am62->usb2_refclk = devm_clk_get(dev, "ref");
>   	if (IS_ERR(am62->usb2_refclk)) {
>   		dev_err(dev, "can't get usb2_refclk\n");
> @@ -227,6 +249,13 @@ static int dwc3_ti_probe(struct platform_device *pdev)
>   	if (ret)
>   		return ret;
>   
> +	/* Workaround Errata i2409 */
> +	if (am62->phy) {
> +		reg = dwc3_ti_phy_readl(am62, USB_PHY_PLL_REG12);
> +		reg |= USB_PHY_PLL_LDO_REF_EN | USB_PHY_PLL_LDO_REF_EN_EN;
> +		dwc3_ti_phy_writel(am62, USB_PHY_PLL_REG12, reg);
> +	}
> +
>   	/* VBUS divider select */
>   	am62->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
>   	reg = dwc3_ti_readl(am62, USBSS_PHY_CONFIG);

Re: [PATCH 4/4] usb: dwc3-am62: add workaround for Errata i2409

[Roger Quadros]

On 01/02/2024 20:52, Andrew Davis wrote:
> On 2/1/24 6:12 AM, Roger Quadros wrote:
>> All AM62 devices have Errata i2409 [1] due to which
>> USB2 PHY may lock up due to short suspend.
>>
>> Workaround involves setting bit 5 and 4 PLL_REG12
>> in PHY2 register space after USB controller is brought
>> out of LPSC reset but before controller initialization.
>>
>> Handle this workaround.
>>
>> [1] - https://www.ti.com/lit/er/sprz487d/sprz487d.pdf
>>
>> Signed-off-by: Roger Quadros <rogerq@kernel.org>
>> ---
>>   drivers/usb/dwc3/dwc3-am62.c | 29 +++++++++++++++++++++++++++++
>>   1 file changed, 29 insertions(+)
>>
>> diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
>> index af1ce934e7fb..35d7a2fb128e 100644
>> --- a/drivers/usb/dwc3/dwc3-am62.c
>> +++ b/drivers/usb/dwc3/dwc3-am62.c
>> @@ -101,11 +101,17 @@
>>   #define PHY_CORE_VOLTAGE_MASK    BIT(31)
>>   #define PHY_PLL_REFCLK_MASK    GENMASK(3, 0)
>>   +/* USB PHY2 register offsets */
>> +#define    USB_PHY_PLL_REG12        0x130
>> +#define    USB_PHY_PLL_LDO_REF_EN        BIT(5)
>> +#define    USB_PHY_PLL_LDO_REF_EN_EN    BIT(4)
>> +
>>   #define DWC3_AM62_AUTOSUSPEND_DELAY    100
>>     struct dwc3_am62 {
>>       struct device *dev;
>>       void __iomem *usbss;
>> +    void __iomem *phy;
> 
> Why do you need this in the driver data? You only use it in probe(),
> just have it be a local variable.

OK.

> 
>>       struct clk *usb2_refclk;
>>       int rate_code;
>>       struct regmap *syscon;
>> @@ -140,6 +146,16 @@ static inline void dwc3_ti_writel(struct dwc3_am62 *am62, u32 offset, u32 value)
>>       writel(value, (am62->usbss) + offset);
>>   }
>>   +static inline u32 dwc3_ti_phy_readl(struct dwc3_am62 *am62, u32 offset)
>> +{
> 
> Do you really need these one line functions? They add more code than
> they save and just hide a single deference? Just do that directly.

Sure. Thanks.
> 
> Andrew
> 
>> +    return readl((am62->phy) + offset);
>> +}
>> +
>> +static inline void dwc3_ti_phy_writel(struct dwc3_am62 *am62, u32 offset, u32 value)
>> +{
>> +    writel(value, (am62->phy) + offset);
>> +}
>> +
>>   static int phy_syscon_pll_refclk(struct dwc3_am62 *am62)
>>   {
>>       struct device *dev = am62->dev;
>> @@ -201,6 +217,12 @@ static int dwc3_ti_probe(struct platform_device *pdev)
>>           return PTR_ERR(am62->usbss);
>>       }
>>   +    am62->phy = devm_platform_ioremap_resource(pdev, 1);
>> +    if (IS_ERR(am62->phy)) {
>> +        dev_err(dev, "can't map PHY IOMEM resource. Won't apply i2409 fix.\n");
>> +        am62->phy = NULL;
>> +    }
>> +
>>       am62->usb2_refclk = devm_clk_get(dev, "ref");
>>       if (IS_ERR(am62->usb2_refclk)) {
>>           dev_err(dev, "can't get usb2_refclk\n");
>> @@ -227,6 +249,13 @@ static int dwc3_ti_probe(struct platform_device *pdev)
>>       if (ret)
>>           return ret;
>>   +    /* Workaround Errata i2409 */
>> +    if (am62->phy) {
>> +        reg = dwc3_ti_phy_readl(am62, USB_PHY_PLL_REG12);
>> +        reg |= USB_PHY_PLL_LDO_REF_EN | USB_PHY_PLL_LDO_REF_EN_EN;
>> +        dwc3_ti_phy_writel(am62, USB_PHY_PLL_REG12, reg);
>> +    }
>> +
>>       /* VBUS divider select */
>>       am62->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
>>       reg = dwc3_ti_readl(am62, USBSS_PHY_CONFIG);

-- 
cheers,
-roger