bus: ti-sysc: Implement display subsystem reset quirk

The display subsystem (DSS) needs the child outputs disabled for reset.
In order to prepare to probe DSS without legacy platform data, let's
implement sysc_pre_reset_quirk_dss() similar to what we have for the
platform data with omap_dss_reset().

Note that we cannot directly use the old omap_dss_reset() without
platform data callbacks and updating omap_dss_reset() to understand
struct device. And we will be dropping omap_dss_reset() anyways when
all the SoCs are probing with device tree, so let's not mess with the
legacy code at all.

Cc: Jyri Sarha <jsarha@ti.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

drivers/bus/ti-sysc.c

@@ -1303,11 +1303,11 @@ static const struct sysc_revision_quirk sysc_revision_quirks[] = {
 	SYSC_QUIRK("dcan", 0x48480000, 0x20, -ENODEV, -ENODEV, 0xa3170504, 0xffffffff,
 		   SYSC_QUIRK_CLKDM_NOAUTO),
 	SYSC_QUIRK("dss", 0x4832a000, 0, 0x10, 0x14, 0x00000020, 0xffffffff,
-		   SYSC_QUIRK_OPT_CLKS_IN_RESET),
+		   SYSC_QUIRK_OPT_CLKS_IN_RESET | SYSC_MODULE_QUIRK_DSS_RESET),
 	SYSC_QUIRK("dss", 0x58000000, 0, -ENODEV, 0x14, 0x00000040, 0xffffffff,
-		   SYSC_QUIRK_OPT_CLKS_IN_RESET),
+		   SYSC_QUIRK_OPT_CLKS_IN_RESET | SYSC_MODULE_QUIRK_DSS_RESET),
 	SYSC_QUIRK("dss", 0x58000000, 0, -ENODEV, 0x14, 0x00000061, 0xffffffff,
-		   SYSC_QUIRK_OPT_CLKS_IN_RESET),
+		   SYSC_QUIRK_OPT_CLKS_IN_RESET | SYSC_MODULE_QUIRK_DSS_RESET),
 	SYSC_QUIRK("dwc3", 0x48880000, 0, 0x10, -ENODEV, 0x500a0200, 0xffffffff,
 		   SYSC_QUIRK_CLKDM_NOAUTO),
 	SYSC_QUIRK("dwc3", 0x488c0000, 0, 0x10, -ENODEV, 0x500a0200, 0xffffffff,
@@ -1468,6 +1468,128 @@ static void sysc_init_revision_quirks(struct sysc *ddata)
 	}
 }
 
+/*
+ * DSS needs dispc outputs disabled to reset modules. Returns mask of
+ * enabled DSS interrupts. Eventually we may be able to do this on
+ * dispc init rather than top-level DSS init.
+ */
+static u32 sysc_quirk_dispc(struct sysc *ddata, int dispc_offset,
+			    bool disable)
+{
+	bool lcd_en, digit_en, lcd2_en = false, lcd3_en = false;
+	const int lcd_en_mask = BIT(0), digit_en_mask = BIT(1);
+	int manager_count;
+	bool framedonetv_irq;
+	u32 val, irq_mask = 0;
+
+	switch (sysc_soc->soc) {
+	case SOC_2420 ... SOC_3630:
+		manager_count = 2;
+		framedonetv_irq = false;
+		break;
+	case SOC_4430 ... SOC_4470:
+		manager_count = 3;
+		break;
+	case SOC_5430:
+	case SOC_DRA7:
+		manager_count = 4;
+		break;
+	case SOC_AM4:
+		manager_count = 1;
+		break;
+	case SOC_UNKNOWN:
+	default:
+		return 0;
+	};
+
+	/* Remap the whole module range to be able to reset dispc outputs */
+	devm_iounmap(ddata->dev, ddata->module_va);
+	ddata->module_va = devm_ioremap(ddata->dev,
+					ddata->module_pa,
+					ddata->module_size);
+	if (!ddata->module_va)
+		return -EIO;
+
+	/* DISP_CONTROL */
+	val = sysc_read(ddata, dispc_offset + 0x40);
+	lcd_en = val & lcd_en_mask;
+	digit_en = val & digit_en_mask;
+	if (lcd_en)
+		irq_mask |= BIT(0);			/* FRAMEDONE */
+	if (digit_en) {
+		if (framedonetv_irq)
+			irq_mask |= BIT(24);		/* FRAMEDONETV */
+		else
+			irq_mask |= BIT(2) | BIT(3);	/* EVSYNC bits */
+	}
+	if (disable & (lcd_en | digit_en))
+		sysc_write(ddata, dispc_offset + 0x40,
+			   val & ~(lcd_en_mask | digit_en_mask));
+
+	if (manager_count <= 2)
+		return irq_mask;
+
+	/* DISPC_CONTROL2 */
+	val = sysc_read(ddata, dispc_offset + 0x238);
+	lcd2_en = val & lcd_en_mask;
+	if (lcd2_en)
+		irq_mask |= BIT(22);			/* FRAMEDONE2 */
+	if (disable && lcd2_en)
+		sysc_write(ddata, dispc_offset + 0x238,
+			   val & ~lcd_en_mask);
+
+	if (manager_count <= 3)
+		return irq_mask;
+
+	/* DISPC_CONTROL3 */
+	val = sysc_read(ddata, dispc_offset + 0x848);
+	lcd3_en = val & lcd_en_mask;
+	if (lcd3_en)
+		irq_mask |= BIT(30);			/* FRAMEDONE3 */
+	if (disable && lcd3_en)
+		sysc_write(ddata, dispc_offset + 0x848,
+			   val & ~lcd_en_mask);
+
+	return irq_mask;
+}
+
+/* DSS needs child outputs disabled and SDI registers cleared for reset */
+static void sysc_pre_reset_quirk_dss(struct sysc *ddata)
+{
+	const int dispc_offset = 0x1000;
+	int error;
+	u32 irq_mask, val;
+
+	/* Get enabled outputs */
+	irq_mask = sysc_quirk_dispc(ddata, dispc_offset, false);
+	if (!irq_mask)
+		return;
+
+	/* Clear IRQSTATUS */
+	sysc_write(ddata, 0x1000 + 0x18, irq_mask);
+
+	/* Disable outputs */
+	val = sysc_quirk_dispc(ddata, dispc_offset, true);
+
+	/* Poll IRQSTATUS */
+	error = readl_poll_timeout(ddata->module_va + dispc_offset + 0x18,
+				   val, val != irq_mask, 100, 50);
+	if (error)
+		dev_warn(ddata->dev, "%s: timed out %08x !+ %08x\n",
+			 __func__, val, irq_mask);
+
+	if (sysc_soc->soc == SOC_3430) {
+		/* Clear DSS_SDI_CONTROL */
+		sysc_write(ddata, dispc_offset + 0x44, 0);
+
+		/* Clear DSS_PLL_CONTROL */
+		sysc_write(ddata, dispc_offset + 0x48, 0);
+	}
+
+	/* Clear DSS_CONTROL to switch DSS clock sources to PRCM if not */
+	sysc_write(ddata, dispc_offset + 0x40, 0);
+}
+
 /* 1-wire needs module's internal clocks enabled for reset */
 static void sysc_pre_reset_quirk_hdq1w(struct sysc *ddata)
 {
@@ -1606,6 +1728,9 @@ static void sysc_init_module_quirks(struct sysc *ddata)
 	if (ddata->cfg.quirks & SYSC_MODULE_QUIRK_AESS)
 		ddata->module_enable_quirk = sysc_module_enable_quirk_aess;
 
+	if (ddata->cfg.quirks & SYSC_MODULE_QUIRK_DSS_RESET)
+		ddata->pre_reset_quirk = sysc_pre_reset_quirk_dss;
+
 	if (ddata->cfg.quirks & SYSC_MODULE_QUIRK_RTC_UNLOCK) {
 		ddata->module_unlock_quirk = sysc_module_unlock_quirk_rtc;
 		ddata->module_lock_quirk = sysc_module_lock_quirk_rtc;

include/linux/platform_data/ti-sysc.h

@@ -49,6 +49,7 @@ struct sysc_regbits {
 	s8 emufree_shift;
 };
 
+#define SYSC_MODULE_QUIRK_DSS_RESET	BIT(23)
 #define SYSC_MODULE_QUIRK_RTC_UNLOCK	BIT(22)
 #define SYSC_QUIRK_CLKDM_NOAUTO		BIT(21)
 #define SYSC_QUIRK_FORCE_MSTANDBY	BIT(20)