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// SPDX-License-Identifier: GPL-2.0
/*
* Versatile Express PL111 handling
* Copyright (C) 2018 Linus Walleij
*
* This module binds to the "arm,vexpress-muxfpga" device on the
* Versatile Express configuration bus and sets up which CLCD instance
* gets muxed out on the DVI bridge.
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/vexpress.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include "pl111_drm.h"
#include "pl111_vexpress.h"
#define VEXPRESS_FPGAMUX_MOTHERBOARD 0x00
#define VEXPRESS_FPGAMUX_DAUGHTERBOARD_1 0x01
#define VEXPRESS_FPGAMUX_DAUGHTERBOARD_2 0x02
int pl111_vexpress_clcd_init(struct device *dev,
struct pl111_drm_dev_private *priv,
struct regmap *map)
{
struct device_node *root;
struct device_node *child;
struct device_node *ct_clcd = NULL;
bool has_coretile_clcd = false;
bool has_coretile_hdlcd = false;
bool mux_motherboard = true;
u32 val;
int ret;
/*
* Check if we have a CLCD or HDLCD on the core tile by checking if a
* CLCD or HDLCD is available in the root of the device tree.
*/
root = of_find_node_by_path("/");
if (!root)
return -EINVAL;
for_each_available_child_of_node(root, child) {
if (of_device_is_compatible(child, "arm,pl111")) {
has_coretile_clcd = true;
ct_clcd = child;
break;
}
if (of_device_is_compatible(child, "arm,hdlcd")) {
has_coretile_hdlcd = true;
break;
}
}
of_node_put(root);
/*
* If there is a coretile HDLCD and it has a driver,
* do not mux the CLCD on the motherboard to the DVI.
*/
if (has_coretile_hdlcd && IS_ENABLED(CONFIG_DRM_HDLCD))
mux_motherboard = false;
/*
* On the Vexpress CA9 we let the CLCD on the coretile
* take precedence, so also in this case do not mux the
* motherboard to the DVI.
*/
if (has_coretile_clcd)
mux_motherboard = false;
if (mux_motherboard) {
dev_info(dev, "DVI muxed to motherboard CLCD\n");
val = VEXPRESS_FPGAMUX_MOTHERBOARD;
} else if (ct_clcd == dev->of_node) {
dev_info(dev,
"DVI muxed to daughterboard 1 (core tile) CLCD\n");
val = VEXPRESS_FPGAMUX_DAUGHTERBOARD_1;
} else {
dev_info(dev, "core tile graphics present\n");
dev_info(dev, "this device will be deactivated\n");
return -ENODEV;
}
ret = regmap_write(map, 0, val);
if (ret) {
dev_err(dev, "error setting DVI muxmode\n");
return -ENODEV;
}
return 0;
}
/*
* This sets up the regmap pointer that will then be retrieved by
* the detection code in pl111_versatile.c and passed in to the
* pl111_vexpress_clcd_init() function above.
*/
static int vexpress_muxfpga_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct regmap *map;
map = devm_regmap_init_vexpress_config(&pdev->dev);
if (IS_ERR(map))
return PTR_ERR(map);
dev_set_drvdata(dev, map);
return 0;
}
static const struct of_device_id vexpress_muxfpga_match[] = {
{ .compatible = "arm,vexpress-muxfpga", },
{}
};
static struct platform_driver vexpress_muxfpga_driver = {
.driver = {
.name = "vexpress-muxfpga",
.of_match_table = of_match_ptr(vexpress_muxfpga_match),
},
.probe = vexpress_muxfpga_probe,
};
int vexpress_muxfpga_init(void)
{
int ret;
ret = platform_driver_register(&vexpress_muxfpga_driver);
/* -EBUSY just means this driver is already registered */
if (ret == -EBUSY)
ret = 0;
return ret;
}
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