drm/fsl-dcu: add TCON driver

Add driver for the TCON (timing controller) module. The TCON module
is a separate module attached after the DCU (display controller
unit). Each DCU instance has its own, directly connected TCON
instance. The DCU's RGB and timing signals are passing through
the TCON module. TCON can provide timing signals for raw TFT panels
or operate in a bypass mode which leaves all signals unaltered.

The driver currently only supports the bypass mode.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stefan Agner <stefan@agner.ch>

Documentation/devicetree/bindings/display/fsl,dcu.txt

@@ -14,6 +14,9 @@ Required properties:
 - big-endian		Boolean property, LS1021A DCU registers are big-endian.
 - fsl,panel:		The phandle to panel node.
 
+Optional properties:
+- fsl,tcon:		The phandle to the timing controller node.
+
 Examples:
 dcu: dcu@2ce0000 {
 	compatible = "fsl,ls1021a-dcu";
@@ -22,4 +25,5 @@ dcu: dcu@2ce0000 {
 	clock-names = "dcu", "pix";
 	big-endian;
 	fsl,panel = <&panel>;
+	fsl,tcon = <&tcon>;
 };

Documentation/devicetree/bindings/display/fsl,tcon.txt

+Device Tree bindings for Freescale TCON Driver
+
+Required properties:
+- compatible:		Should be one of
+	* "fsl,vf610-tcon".
+
+- reg:			Address and length of the register set for tcon.
+- clocks:		From common clock binding: handle to tcon ipg clock.
+- clock-names:		From common clock binding: Shall be "ipg".
+
+Examples:
+timing-controller@4003d000 {
+	compatible = "fsl,vf610-tcon";
+	reg = <0x4003d000 0x1000>;
+	clocks = <&clks VF610_CLK_TCON0>;
+	clock-names = "ipg";
+	status = "okay";
+};

MAINTAINERS

@@ -3822,6 +3822,7 @@ L:	dri-devel@lists.freedesktop.org
 S:	Supported
 F:	drivers/gpu/drm/fsl-dcu/
 F:	Documentation/devicetree/bindings/display/fsl,dcu.txt
+F:	Documentation/devicetree/bindings/display/fsl,tcon.txt
 F:	Documentation/devicetree/bindings/display/panel/nec,nl4827hc19_05b.txt
 
 DRM DRIVERS FOR FREESCALE IMX

drivers/gpu/drm/fsl-dcu/Makefile

@@ -3,5 +3,6 @@ fsl-dcu-drm-y := fsl_dcu_drm_drv.o \
 		 fsl_dcu_drm_rgb.o \
 		 fsl_dcu_drm_plane.o \
 		 fsl_dcu_drm_crtc.o \
-		 fsl_dcu_drm_fbdev.o
+		 fsl_dcu_drm_fbdev.o \
+		 fsl_tcon.o
 obj-$(CONFIG_DRM_FSL_DCU)	+= fsl-dcu-drm.o

drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c

@@ -27,6 +27,7 @@
 
 #include "fsl_dcu_drm_crtc.h"
 #include "fsl_dcu_drm_drv.h"
+#include "fsl_tcon.h"
 
 static bool fsl_dcu_drm_is_volatile_reg(struct device *dev, unsigned int reg)
 {
@@ -357,6 +358,8 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
 		goto unregister_pix_clk;
 	}
 
+	fsl_dev->tcon = fsl_tcon_init(dev);
+
 	drm = drm_dev_alloc(driver, dev);
 	if (!drm) {
 		ret = -ENOMEM;

drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h

@@ -184,6 +184,7 @@ struct fsl_dcu_drm_device {
 	int irq;
 	struct clk *clk;
 	struct clk *pix_clk;
+	struct fsl_tcon *tcon;
 	/*protects hardware register*/
 	spinlock_t irq_lock;
 	struct drm_device *drm;

drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c

@@ -17,6 +17,7 @@
 #include <drm/drm_panel.h>
 
 #include "fsl_dcu_drm_drv.h"
+#include "fsl_tcon.h"
 
 static int
 fsl_dcu_drm_encoder_atomic_check(struct drm_encoder *encoder,
@@ -28,10 +29,20 @@ fsl_dcu_drm_encoder_atomic_check(struct drm_encoder *encoder,
 
 static void fsl_dcu_drm_encoder_disable(struct drm_encoder *encoder)
 {
+	struct drm_device *dev = encoder->dev;
+	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
+
+	if (fsl_dev->tcon)
+		fsl_tcon_bypass_disable(fsl_dev->tcon);
 }
 
 static void fsl_dcu_drm_encoder_enable(struct drm_encoder *encoder)
 {
+	struct drm_device *dev = encoder->dev;
+	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
+
+	if (fsl_dev->tcon)
+		fsl_tcon_bypass_enable(fsl_dev->tcon);
 }
 
 static const struct drm_encoder_helper_funcs encoder_helper_funcs = {

drivers/gpu/drm/fsl-dcu/fsl_tcon.c

+/*
+ * Copyright 2015 Toradex AG
+ *
+ * Stefan Agner <stefan@agner.ch>
+ *
+ * Freescale TCON device driver
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "fsl_tcon.h"
+
+void fsl_tcon_bypass_disable(struct fsl_tcon *tcon)
+{
+	regmap_update_bits(tcon->regs, FSL_TCON_CTRL1,
+			   FSL_TCON_CTRL1_TCON_BYPASS, 0);
+}
+
+void fsl_tcon_bypass_enable(struct fsl_tcon *tcon)
+{
+	regmap_update_bits(tcon->regs, FSL_TCON_CTRL1,
+			   FSL_TCON_CTRL1_TCON_BYPASS,
+			   FSL_TCON_CTRL1_TCON_BYPASS);
+}
+
+static struct regmap_config fsl_tcon_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+
+	.name = "tcon",
+};
+
+static int fsl_tcon_init_regmap(struct device *dev,
+				struct fsl_tcon *tcon,
+				struct device_node *np)
+{
+	struct resource res;
+	void __iomem *regs;
+
+	if (of_address_to_resource(np, 0, &res))
+		return -EINVAL;
+
+	regs = devm_ioremap_resource(dev, &res);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	tcon->regs = devm_regmap_init_mmio(dev, regs,
+					   &fsl_tcon_regmap_config);
+	if (IS_ERR(tcon->regs))
+		return PTR_ERR(tcon->regs);
+
+	return 0;
+}
+
+struct fsl_tcon *fsl_tcon_init(struct device *dev)
+{
+	struct fsl_tcon *tcon;
+	struct device_node *np;
+	int ret;
+
+	/* TCON node is not mandatory, some devices do not provide TCON */
+	np = of_parse_phandle(dev->of_node, "fsl,tcon", 0);
+	if (!np)
+		return NULL;
+
+	tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL);
+	if (!tcon) {
+		ret = -ENOMEM;
+		goto err_node_put;
+	}
+
+	ret = fsl_tcon_init_regmap(dev, tcon, np);
+	if (ret) {
+		dev_err(dev, "Couldn't create the TCON regmap\n");
+		goto err_node_put;
+	}
+
+	tcon->ipg_clk = of_clk_get_by_name(np, "ipg");
+	if (IS_ERR(tcon->ipg_clk)) {
+		dev_err(dev, "Couldn't get the TCON bus clock\n");
+		goto err_node_put;
+	}
+
+	clk_prepare_enable(tcon->ipg_clk);
+
+	dev_info(dev, "Using TCON in bypass mode\n");
+
+	return tcon;
+
+err_node_put:
+	of_node_put(np);
+	return NULL;
+}
+
+void fsl_tcon_free(struct fsl_tcon *tcon)
+{
+	clk_disable_unprepare(tcon->ipg_clk);
+	clk_put(tcon->ipg_clk);
+}
+

drivers/gpu/drm/fsl-dcu/fsl_tcon.h

+/*
+ * Copyright 2015 Toradex AG
+ *
+ * Stefan Agner <stefan@agner.ch>
+ *
+ * Freescale TCON device driver
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __FSL_TCON_H__
+#define __FSL_TCON_H__
+
+#include <linux/bitops.h>
+
+#define FSL_TCON_CTRL1			0x0
+#define FSL_TCON_CTRL1_TCON_BYPASS	BIT(29)
+
+struct fsl_tcon {
+	struct regmap		*regs;
+	struct clk		*ipg_clk;
+};
+
+struct fsl_tcon *fsl_tcon_init(struct device *dev);
+void fsl_tcon_free(struct fsl_tcon *tcon);
+
+void fsl_tcon_bypass_disable(struct fsl_tcon *tcon);
+void fsl_tcon_bypass_enable(struct fsl_tcon *tcon);
+
+#endif /* __FSL_TCON_H__ */