usb: dwc3: make HIRD threshold configurable

HIRD threshold should be configurable by different platforms.

From DesignWare databook:
When HIRD_Threshold[4] is set to 1b1 and HIRD value is greater than or
equal to the value in HIRD_Threshold[3:0], dwc3 asserts output signals
utmi_l1_suspend_n to put PHY into Deep Low-Power mode in L1.

When HIRD_Threshold[4] is set to 1b0 or the HIRD value is less than
HIRD_Threshold[3:0], dwc3 asserts output signals utmi_sleep_n on L1.
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Documentation/devicetree/bindings/usb/dwc3.txt

@@ -34,6 +34,9 @@ Optional properties:
 			LTSSM during USB3 Compliance mode.
  - snps,dis_u3_susphy_quirk: when set core will disable USB3 suspend phy.
  - snps,dis_u2_susphy_quirk: when set core will disable USB2 suspend phy.
+ - snps,is-utmi-l1-suspend: true when DWC3 asserts output signal
+			utmi_l1_suspend_n, false when asserts utmi_sleep_n
+ - snps,hird-threshold: HIRD threshold
 
 This is usually a subnode to DWC3 glue to which it is connected.
 

drivers/usb/dwc3/core.c

@@ -730,6 +730,7 @@ static int dwc3_probe(struct platform_device *pdev)
 	struct dwc3		*dwc;
 	u8			lpm_nyet_threshold;
 	u8			tx_de_emphasis;
+	u8			hird_threshold;
 
 	int			ret;
 
@@ -791,12 +792,22 @@ static int dwc3_probe(struct platform_device *pdev)
 	/* default to -3.5dB de-emphasis */
 	tx_de_emphasis = 1;
 
+	/*
+	 * default to assert utmi_sleep_n and use maximum allowed HIRD
+	 * threshold value of 0b1100
+	 */
+	hird_threshold = 12;
+
 	if (node) {
 		dwc->maximum_speed = of_usb_get_maximum_speed(node);
 		dwc->has_lpm_erratum = of_property_read_bool(node,
 				"snps,has-lpm-erratum");
 		of_property_read_u8(node, "snps,lpm-nyet-threshold",
 				&lpm_nyet_threshold);
+		dwc->is_utmi_l1_suspend = of_property_read_bool(node,
+				"snps,is-utmi-l1-suspend");
+		of_property_read_u8(node, "snps,hird-threshold",
+				&hird_threshold);
 
 		dwc->needs_fifo_resize = of_property_read_bool(node,
 				"tx-fifo-resize");
@@ -832,6 +843,9 @@ static int dwc3_probe(struct platform_device *pdev)
 		dwc->has_lpm_erratum = pdata->has_lpm_erratum;
 		if (pdata->lpm_nyet_threshold)
 			lpm_nyet_threshold = pdata->lpm_nyet_threshold;
+		dwc->is_utmi_l1_suspend = pdata->is_utmi_l1_suspend;
+		if (pdata->hird_threshold)
+			hird_threshold = pdata->hird_threshold;
 
 		dwc->needs_fifo_resize = pdata->tx_fifo_resize;
 		dwc->dr_mode = pdata->dr_mode;
@@ -859,6 +873,9 @@ static int dwc3_probe(struct platform_device *pdev)
 	dwc->lpm_nyet_threshold = lpm_nyet_threshold;
 	dwc->tx_de_emphasis = tx_de_emphasis;
 
+	dwc->hird_threshold = hird_threshold
+		| (dwc->is_utmi_l1_suspend << 4);
+
 	ret = dwc3_core_get_phy(dwc);
 	if (ret)
 		return ret;

drivers/usb/dwc3/core.h

@@ -675,12 +675,16 @@ struct dwc3_scratchpad_array {
  * @test_mode: true when we're entering a USB test mode
  * @test_mode_nr: test feature selector
  * @lpm_nyet_threshold: LPM NYET response threshold
+ * @hird_threshold: HIRD threshold
  * @delayed_status: true when gadget driver asks for delayed status
  * @ep0_bounced: true when we used bounce buffer
  * @ep0_expect_in: true when we expect a DATA IN transfer
  * @has_hibernation: true when dwc3 was configured with Hibernation
  * @has_lpm_erratum: true when core was configured with LPM Erratum. Note that
  *			there's now way for software to detect this in runtime.
+ * @is_utmi_l1_suspend: the core asserts output signal
+ * 	0	- utmi_sleep_n
+ * 	1	- utmi_l1_suspend_n
  * @is_selfpowered: true when we are selfpowered
  * @is_fpga: true when we are using the FPGA board
  * @needs_fifo_resize: not all users might want fifo resizing, flag it
@@ -797,12 +801,14 @@ struct dwc3 {
 	u8			test_mode;
 	u8			test_mode_nr;
 	u8			lpm_nyet_threshold;
+	u8			hird_threshold;
 
 	unsigned		delayed_status:1;
 	unsigned		ep0_bounced:1;
 	unsigned		ep0_expect_in:1;
 	unsigned		has_hibernation:1;
 	unsigned		has_lpm_erratum:1;
+	unsigned		is_utmi_l1_suspend:1;
 	unsigned		is_selfpowered:1;
 	unsigned		is_fpga:1;
 	unsigned		needs_fifo_resize:1;

drivers/usb/dwc3/gadget.c

@@ -2295,11 +2295,7 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
 		reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 		reg &= ~(DWC3_DCTL_HIRD_THRES_MASK | DWC3_DCTL_L1_HIBER_EN);
 
-		/*
-		 * TODO: This should be configurable. For now using
-		 * maximum allowed HIRD threshold value of 0b1100
-		 */
-		reg |= DWC3_DCTL_HIRD_THRES(12);
+		reg |= DWC3_DCTL_HIRD_THRES(dwc->hird_threshold);
 
 		/*
 		 * When dwc3 revisions >= 2.40a, LPM Erratum is enabled and

drivers/usb/dwc3/platform_data.h

@@ -25,6 +25,9 @@ struct dwc3_platform_data {
 	enum usb_dr_mode dr_mode;
 	bool tx_fifo_resize;
 
+	unsigned is_utmi_l1_suspend:1;
+	u8 hird_threshold;
+
 	u8 lpm_nyet_threshold;
 
 	unsigned disable_scramble_quirk:1;