Revert "ARM: OMAP2+: Remove legacy mux code for display.c"

Commit e30b06f4 (ARM: OMAP2+: Remove
legacy mux code for display.c) removed non-DT DSI and HDMI pinmuxing.
However, DSI pinmuxing is still needed, and removing that caused DSI
displays not to work.

This reverts the DSI parts of the commit.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/display.c

@@ -101,13 +101,51 @@ static const struct omap_dss_hwmod_data omap4_dss_hwmod_data[] __initconst = {
 	{ "dss_hdmi", "omapdss_hdmi", -1 },
 };
 
+static int omap4_dsi_mux_pads(int dsi_id, unsigned lanes)
+{
+	u32 enable_mask, enable_shift;
+	u32 pipd_mask, pipd_shift;
+	u32 reg;
+
+	if (dsi_id == 0) {
+		enable_mask = OMAP4_DSI1_LANEENABLE_MASK;
+		enable_shift = OMAP4_DSI1_LANEENABLE_SHIFT;
+		pipd_mask = OMAP4_DSI1_PIPD_MASK;
+		pipd_shift = OMAP4_DSI1_PIPD_SHIFT;
+	} else if (dsi_id == 1) {
+		enable_mask = OMAP4_DSI2_LANEENABLE_MASK;
+		enable_shift = OMAP4_DSI2_LANEENABLE_SHIFT;
+		pipd_mask = OMAP4_DSI2_PIPD_MASK;
+		pipd_shift = OMAP4_DSI2_PIPD_SHIFT;
+	} else {
+		return -ENODEV;
+	}
+
+	reg = omap4_ctrl_pad_readl(OMAP4_CTRL_MODULE_PAD_CORE_CONTROL_DSIPHY);
+
+	reg &= ~enable_mask;
+	reg &= ~pipd_mask;
+
+	reg |= (lanes << enable_shift) & enable_mask;
+	reg |= (lanes << pipd_shift) & pipd_mask;
+
+	omap4_ctrl_pad_writel(reg, OMAP4_CTRL_MODULE_PAD_CORE_CONTROL_DSIPHY);
+
+	return 0;
+}
+
 static int omap_dsi_enable_pads(int dsi_id, unsigned lane_mask)
 {
+	if (cpu_is_omap44xx())
+		return omap4_dsi_mux_pads(dsi_id, lane_mask);
+
 	return 0;
 }
 
 static void omap_dsi_disable_pads(int dsi_id, unsigned lane_mask)
 {
+	if (cpu_is_omap44xx())
+		omap4_dsi_mux_pads(dsi_id, 0);
 }
 
 static int omap_dss_set_min_bus_tput(struct device *dev, unsigned long tput)