drm: sti: add VTAC drivers

Video Traffic Advance Communication Rx and Tx drivers are designed
for inter-die communication.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Reviewed-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/sti/Makefile

@@ -1,2 +1,3 @@
 obj-$(CONFIG_DRM_STI) = \
-	sti_vtg.o
+	sti_vtg.o \
+	sti_vtac.o

drivers/gpu/drm/sti/sti_vtac.c

@@ -0,0 +1,215 @@
+/*
+ * Copyright (C) STMicroelectronics SA 2014
+ * Author: Benjamin Gaignard <benjamin.gaignard@st.com> for STMicroelectronics.
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#include <drm/drmP.h>
+
+/* registers offset */
+#define VTAC_CONFIG                     0x00
+#define VTAC_RX_FIFO_CONFIG             0x04
+#define VTAC_FIFO_CONFIG_VAL            0x04
+
+#define VTAC_SYS_CFG8521                0x824
+#define VTAC_SYS_CFG8522                0x828
+
+/* Number of phyts per pixel */
+#define VTAC_2_5_PPP                    0x0005
+#define VTAC_3_PPP                      0x0006
+#define VTAC_4_PPP                      0x0008
+#define VTAC_5_PPP                      0x000A
+#define VTAC_6_PPP                      0x000C
+#define VTAC_13_PPP                     0x001A
+#define VTAC_14_PPP                     0x001C
+#define VTAC_15_PPP                     0x001E
+#define VTAC_16_PPP                     0x0020
+#define VTAC_17_PPP                     0x0022
+#define VTAC_18_PPP                     0x0024
+
+/* enable bits */
+#define VTAC_ENABLE                     0x3003
+
+#define VTAC_TX_PHY_ENABLE_CLK_PHY      BIT(0)
+#define VTAC_TX_PHY_ENABLE_CLK_DLL      BIT(1)
+#define VTAC_TX_PHY_PLL_NOT_OSC_MODE    BIT(3)
+#define VTAC_TX_PHY_RST_N_DLL_SWITCH    BIT(4)
+#define VTAC_TX_PHY_PROG_N3             BIT(9)
+
+
+/**
+ * VTAC mode structure
+ *
+ * @vid_in_width: Video Data Resolution
+ * @phyts_width: Width of phyt buses(phyt low and phyt high).
+ * @phyts_per_pixel: Number of phyts sent per pixel
+ */
+struct sti_vtac_mode {
+	u32 vid_in_width;
+	u32 phyts_width;
+	u32 phyts_per_pixel;
+};
+
+static const struct sti_vtac_mode vtac_mode_main = {0x2, 0x2, VTAC_5_PPP};
+static const struct sti_vtac_mode vtac_mode_aux = {0x1, 0x0, VTAC_17_PPP};
+
+/**
+ * VTAC structure
+ *
+ * @dev: pointer to device structure
+ * @regs: ioremapped registers for RX and TX devices
+ * @phy_regs: phy registers for TX device
+ * @clk: clock
+ * @mode: main or auxillary configuration mode
+ */
+struct sti_vtac {
+	struct device *dev;
+	void __iomem *regs;
+	void __iomem *phy_regs;
+	struct clk *clk;
+	const struct sti_vtac_mode *mode;
+};
+
+static void sti_vtac_rx_set_config(struct sti_vtac *vtac)
+{
+	u32 config;
+
+	/* Enable VTAC clock */
+	if (clk_prepare_enable(vtac->clk))
+		DRM_ERROR("Failed to prepare/enable vtac_rx clock.\n");
+
+	writel(VTAC_FIFO_CONFIG_VAL, vtac->regs + VTAC_RX_FIFO_CONFIG);
+
+	config = VTAC_ENABLE;
+	config |= vtac->mode->vid_in_width << 4;
+	config |= vtac->mode->phyts_width << 16;
+	config |= vtac->mode->phyts_per_pixel << 23;
+	writel(config, vtac->regs + VTAC_CONFIG);
+}
+
+static void sti_vtac_tx_set_config(struct sti_vtac *vtac)
+{
+	u32 phy_config;
+	u32 config;
+
+	/* Enable VTAC clock */
+	if (clk_prepare_enable(vtac->clk))
+		DRM_ERROR("Failed to prepare/enable vtac_tx clock.\n");
+
+	/* Configure vtac phy */
+	phy_config = 0x00000000;
+	writel(phy_config, vtac->phy_regs + VTAC_SYS_CFG8522);
+	phy_config = VTAC_TX_PHY_ENABLE_CLK_PHY;
+	writel(phy_config, vtac->phy_regs + VTAC_SYS_CFG8521);
+	phy_config = readl(vtac->phy_regs + VTAC_SYS_CFG8521);
+	phy_config |= VTAC_TX_PHY_PROG_N3;
+	writel(phy_config, vtac->phy_regs + VTAC_SYS_CFG8521);
+	phy_config = readl(vtac->phy_regs + VTAC_SYS_CFG8521);
+	phy_config |= VTAC_TX_PHY_ENABLE_CLK_DLL;
+	writel(phy_config, vtac->phy_regs + VTAC_SYS_CFG8521);
+	phy_config = readl(vtac->phy_regs + VTAC_SYS_CFG8521);
+	phy_config |= VTAC_TX_PHY_RST_N_DLL_SWITCH;
+	writel(phy_config, vtac->phy_regs + VTAC_SYS_CFG8521);
+	phy_config = readl(vtac->phy_regs + VTAC_SYS_CFG8521);
+	phy_config |= VTAC_TX_PHY_PLL_NOT_OSC_MODE;
+	writel(phy_config, vtac->phy_regs + VTAC_SYS_CFG8521);
+
+	/* Configure vtac tx */
+	config = VTAC_ENABLE;
+	config |= vtac->mode->vid_in_width << 4;
+	config |= vtac->mode->phyts_width << 16;
+	config |= vtac->mode->phyts_per_pixel << 23;
+	writel(config, vtac->regs + VTAC_CONFIG);
+}
+
+static const struct of_device_id vtac_of_match[] = {
+	{
+		.compatible = "st,vtac-main",
+		.data = &vtac_mode_main,
+	}, {
+		.compatible = "st,vtac-aux",
+		.data = &vtac_mode_aux,
+	}, {
+		/* end node */
+	}
+};
+MODULE_DEVICE_TABLE(of, vtac_of_match);
+
+static int sti_vtac_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	const struct of_device_id *id;
+	struct sti_vtac *vtac;
+	struct resource *res;
+
+	vtac = devm_kzalloc(dev, sizeof(*vtac), GFP_KERNEL);
+	if (!vtac)
+		return -ENOMEM;
+
+	vtac->dev = dev;
+
+	id = of_match_node(vtac_of_match, np);
+	if (!id)
+		return -ENOMEM;
+
+	vtac->mode = id->data;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		DRM_ERROR("Invalid resource\n");
+		return -ENOMEM;
+	}
+	vtac->regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(vtac->regs))
+		return PTR_ERR(vtac->regs);
+
+
+	vtac->clk = devm_clk_get(dev, "vtac");
+	if (IS_ERR(vtac->clk)) {
+		DRM_ERROR("Cannot get vtac clock\n");
+		return PTR_ERR(vtac->clk);
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (res) {
+		vtac->phy_regs = devm_ioremap_nocache(dev, res->start,
+						 resource_size(res));
+		sti_vtac_tx_set_config(vtac);
+	} else {
+
+		sti_vtac_rx_set_config(vtac);
+	}
+
+	platform_set_drvdata(pdev, vtac);
+	DRM_INFO("%s %s\n", __func__, dev_name(vtac->dev));
+
+	return 0;
+}
+
+static int sti_vtac_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+struct platform_driver sti_vtac_driver = {
+	.driver = {
+		.name = "sti-vtac",
+		.owner = THIS_MODULE,
+		.of_match_table = vtac_of_match,
+	},
+	.probe = sti_vtac_probe,
+	.remove = sti_vtac_remove,
+};
+
+module_platform_driver(sti_vtac_driver);
+
+MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics SoC DRM driver");
+MODULE_LICENSE("GPL");