drm/exynos: gsc: add device tree support and remove usage of static mappings

This patch adds device tree support for exynos_drm_gsc. This patch
also fixed build issue on non-Exynos platforms, thus dependency on
!ARCH_MULTIPLATFORM can be now removed. The driver cannot be used
simultaneously with V4L2 Mem2Mem GScaller driver thought.

Signed-off-by: Seung-Woo Kim <[e-mail]>
Signed-off-by: Marek Szyprowski <[e-mail]>
Acked-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Inki Dae <[e-mail]>

Documentation/devicetree/bindings/media/exynos5-gsc.txt

···
 - reg: should contain G-Scaler physical address location and length.
 - interrupts: should contain G-Scaler interrupt number
 
+Optional properties:
+- samsung,sysreg: handle to syscon used to control the system registers to
+  set writeback input and destination
+
 Example:
 
 gsc_0:  gsc@0x13e00000 {

drivers/gpu/drm/exynos/Kconfig

···
 
 config DRM_EXYNOS_GSC
 	bool "GScaler"
-	depends on DRM_EXYNOS_IPP && ARCH_EXYNOS5 && !ARCH_MULTIPLATFORM
+	depends on DRM_EXYNOS_IPP && ARCH_EXYNOS5 && !VIDEO_SAMSUNG_EXYNOS_GSC
 	help
 	  Choose this option if you want to use Exynos GSC for DRM.
 

drivers/gpu/drm/exynos/exynos_drm_gsc.c

···
 #include <linux/platform_device.h>
 #include <linux/clk.h>
 #include <linux/pm_runtime.h>
-#include <plat/map-base.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
 
 #include <drm/drmP.h>
 #include <drm/exynos_drm.h>
···
  * @ippdrv: prepare initialization using ippdrv.
  * @regs_res: register resources.
  * @regs: memory mapped io registers.
+ * @sysreg: handle to SYSREG block regmap.
  * @lock: locking of operations.
  * @gsc_clk: gsc gate clock.
  * @sc: scaler infomations.
···
 	struct exynos_drm_ippdrv	ippdrv;
 	struct resource	*regs_res;
 	void __iomem	*regs;
+	struct regmap	*sysreg;
 	struct mutex	lock;
 	struct clk	*gsc_clk;
 	struct gsc_scaler	sc;
···
 
 static void gsc_set_gscblk_fimd_wb(struct gsc_context *ctx, bool enable)
 {
-	u32 gscblk_cfg;
+	unsigned int gscblk_cfg;
 
-	gscblk_cfg = readl(SYSREG_GSCBLK_CFG1);
+	if (!ctx->sysreg)
+		return;
+
+	regmap_read(ctx->sysreg, SYSREG_GSCBLK_CFG1, &gscblk_cfg);
 
 	if (enable)
 		gscblk_cfg |= GSC_BLK_DISP1WB_DEST(ctx->id) |
···
 	else
 		gscblk_cfg |= GSC_BLK_PXLASYNC_LO_MASK_WB(ctx->id);
 
-	writel(gscblk_cfg, SYSREG_GSCBLK_CFG1);
+	regmap_write(ctx->sysreg, SYSREG_GSCBLK_CFG1, gscblk_cfg);
 }
 
 static void gsc_handle_irq(struct gsc_context *ctx, bool enable,
···
 	if (!ctx)
 		return -ENOMEM;
 
+	if (dev->of_node) {
+		ctx->sysreg = syscon_regmap_lookup_by_phandle(dev->of_node,
+							"samsung,sysreg");
+		if (IS_ERR(ctx->sysreg)) {
+			dev_warn(dev, "failed to get system register.\n");
+			ctx->sysreg = NULL;
+		}
+	}
+
 	/* clock control */
 	ctx->gsc_clk = devm_clk_get(dev, "gscl");
 	if (IS_ERR(ctx->gsc_clk)) {
···
 	SET_RUNTIME_PM_OPS(gsc_runtime_suspend, gsc_runtime_resume, NULL)
 };
 
+static const struct of_device_id exynos_drm_gsc_of_match[] = {
+	{ .compatible = "samsung,exynos5-gsc" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, exynos_drm_gsc_of_match);
+
 struct platform_driver gsc_driver = {
 	.probe		= gsc_probe,
 	.remove		= gsc_remove,
···
 		.name	= "exynos-drm-gsc",
 		.owner	= THIS_MODULE,
 		.pm	= &gsc_pm_ops,
+		.of_match_table = of_match_ptr(exynos_drm_gsc_of_match),
 	},
 };
 

drivers/gpu/drm/exynos/regs-gsc.h

···
 #define GSC_CLK_GATE_MODE_SNOOP_CNT(x)	((x) << 0)
 
 /* SYSCON. GSCBLK_CFG */
-#define SYSREG_GSCBLK_CFG1		(S3C_VA_SYS + 0x0224)
+#define SYSREG_GSCBLK_CFG1		0x0224
 #define GSC_BLK_DISP1WB_DEST(x)		(x << 10)
 #define GSC_BLK_SW_RESET_WB_DEST(x)	(1 << (18 + x))
 #define GSC_BLK_PXLASYNC_LO_MASK_WB(x)	(0 << (14 + x))
 #define GSC_BLK_GSCL_WB_IN_SRC_SEL(x)	(1 << (2 * x))
-#define SYSREG_GSCBLK_CFG2		(S3C_VA_SYS + 0x2000)
+#define SYSREG_GSCBLK_CFG2		0x2000
 #define PXLASYNC_LO_MASK_CAMIF_GSCL(x)	(1 << (x))
 
 #endif /* EXYNOS_REGS_GSC_H_ */