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>

1 files changed, 111 insertions, 0 deletions

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
new file mode 100644
index 000000000000..bbe34f1c0505
--- /dev/null
+++ b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
@@ -0,0 +1,111 @@
+/*
+ * 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);
+}
+