1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * ARM Integrator Logical Module bus driver
  4 * Copyright (C) 2020 Linaro Ltd.
  5 * Author: Linus Walleij <linus.walleij@linaro.org>
  6 *
  7 * See the device tree bindings for this block for more details on the
  8 * hardware.
  9 */
 10
 11#include <linux/module.h>
 12#include <linux/err.h>
 13#include <linux/io.h>
 14#include <linux/of.h>
 15#include <linux/of_address.h>
 16#include <linux/of_platform.h>
 17#include <linux/init.h>
 18#include <linux/slab.h>
 19#include <linux/platform_device.h>
 20#include <linux/bitops.h>
 21#include <linux/mfd/syscon.h>
 22#include <linux/regmap.h>
 23
 24/* All information about the connected logic modules are in here */
 25#define INTEGRATOR_SC_DEC_OFFSET	0x10
 26
 27/* Base address for the expansion modules */
 28#define INTEGRATOR_AP_EXP_BASE		0xc0000000
 29#define INTEGRATOR_AP_EXP_STRIDE	0x10000000
 30
 31static int integrator_lm_populate(int num, struct device *dev)
 32{
 33	struct device_node *np = dev->of_node;
 34	struct device_node *child;
 35	u32 base;
 36	int ret;
 37
 38	base = INTEGRATOR_AP_EXP_BASE + (num * INTEGRATOR_AP_EXP_STRIDE);
 39
 40	/* Walk over the child nodes and see what chipselects we use */
 41	for_each_available_child_of_node(np, child) {
 42		struct resource res;
 43
 44		ret = of_address_to_resource(child, 0, &res);
 45		if (ret) {
 46			dev_info(dev, "no valid address on child\n");
 47			continue;
 48		}
 49
 50		/* First populate the syscon then any devices */
 51		if (res.start == base) {
 52			dev_info(dev, "populate module @0x%08x from DT\n",
 53				 base);
 54			ret = of_platform_default_populate(child, NULL, dev);
 55			if (ret) {
 56				dev_err(dev, "failed to populate module\n");
 57				of_node_put(child);
 58				return ret;
 59			}
 60		}
 61	}
 62
 63	return 0;
 64}
 65
 66static const struct of_device_id integrator_ap_syscon_match[] = {
 67	{ .compatible = "arm,integrator-ap-syscon"},
 68	{ },
 69};
 70
 71static int integrator_ap_lm_probe(struct platform_device *pdev)
 72{
 73	struct device *dev = &pdev->dev;
 74	struct device_node *syscon;
 75	static struct regmap *map;
 76	u32 val;
 77	int ret;
 78	int i;
 79
 80	/* Look up the system controller */
 81	syscon = of_find_matching_node(NULL, integrator_ap_syscon_match);
 82	if (!syscon) {
 83		dev_err(dev,
 84			"could not find Integrator/AP system controller\n");
 85		return -ENODEV;
 86	}
 87	map = syscon_node_to_regmap(syscon);
 88	if (IS_ERR(map)) {
 89		dev_err(dev,
 90			"could not find Integrator/AP system controller\n");
 91		return PTR_ERR(map);
 92	}
 93
 94	ret = regmap_read(map, INTEGRATOR_SC_DEC_OFFSET, &val);
 95	if (ret) {
 96		dev_err(dev, "could not read from Integrator/AP syscon\n");
 97		return ret;
 98	}
 99
100	/* Loop over the connected modules */
101	for (i = 0; i < 4; i++) {
102		if (!(val & BIT(4 + i)))
103			continue;
104
105		dev_info(dev, "detected module in slot %d\n", i);
106		ret = integrator_lm_populate(i, dev);
107		if (ret)
108			return ret;
109	}
110
111	return 0;
112}
113
114static const struct of_device_id integrator_ap_lm_match[] = {
115	{ .compatible = "arm,integrator-ap-lm"},
116	{ },
117};
118
119static struct platform_driver integrator_ap_lm_driver = {
120	.probe = integrator_ap_lm_probe,
121	.driver = {
122		.name = "integratorap-lm",
123		.of_match_table = integrator_ap_lm_match,
124	},
125};
126module_platform_driver(integrator_ap_lm_driver);
127MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
128MODULE_DESCRIPTION("Integrator AP Logical Module driver");