drivers/bus/arm-integrator-lm.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * ARM Integrator Logical Module bus driver
0004  * Copyright (C) 2020 Linaro Ltd.
0005  * Author: Linus Walleij <linus.walleij@linaro.org>
0006  *
0007  * See the device tree bindings for this block for more details on the
0008  * hardware.
0009  */
0010
0011 #include <linux/module.h>
0012 #include <linux/err.h>
0013 #include <linux/io.h>
0014 #include <linux/of.h>
0015 #include <linux/of_address.h>
0016 #include <linux/of_platform.h>
0017 #include <linux/init.h>
0018 #include <linux/slab.h>
0019 #include <linux/platform_device.h>
0020 #include <linux/bitops.h>
0021 #include <linux/mfd/syscon.h>
0022 #include <linux/regmap.h>
0023
0024 /* All information about the connected logic modules are in here */
0025 #define INTEGRATOR_SC_DEC_OFFSET    0x10
0026
0027 /* Base address for the expansion modules */
0028 #define INTEGRATOR_AP_EXP_BASE      0xc0000000
0029 #define INTEGRATOR_AP_EXP_STRIDE    0x10000000
0030
0031 static int integrator_lm_populate(int num, struct device *dev)
0032 {
0033     struct device_node *np = dev->of_node;
0034     struct device_node *child;
0035     u32 base;
0036     int ret;
0037
0038     base = INTEGRATOR_AP_EXP_BASE + (num * INTEGRATOR_AP_EXP_STRIDE);
0039
0040     /* Walk over the child nodes and see what chipselects we use */
0041     for_each_available_child_of_node(np, child) {
0042         struct resource res;
0043
0044         ret = of_address_to_resource(child, 0, &res);
0045         if (ret) {
0046             dev_info(dev, "no valid address on child\n");
0047             continue;
0048         }
0049
0050         /* First populate the syscon then any devices */
0051         if (res.start == base) {
0052             dev_info(dev, "populate module @0x%08x from DT\n",
0053                  base);
0054             ret = of_platform_default_populate(child, NULL, dev);
0055             if (ret) {
0056                 dev_err(dev, "failed to populate module\n");
0057                 of_node_put(child);
0058                 return ret;
0059             }
0060         }
0061     }
0062
0063     return 0;
0064 }
0065
0066 static const struct of_device_id integrator_ap_syscon_match[] = {
0067     { .compatible = "arm,integrator-ap-syscon"},
0068     { },
0069 };
0070
0071 static int integrator_ap_lm_probe(struct platform_device *pdev)
0072 {
0073     struct device *dev = &pdev->dev;
0074     struct device_node *syscon;
0075     static struct regmap *map;
0076     u32 val;
0077     int ret;
0078     int i;
0079
0080     /* Look up the system controller */
0081     syscon = of_find_matching_node(NULL, integrator_ap_syscon_match);
0082     if (!syscon) {
0083         dev_err(dev,
0084             "could not find Integrator/AP system controller\n");
0085         return -ENODEV;
0086     }
0087     map = syscon_node_to_regmap(syscon);
0088     if (IS_ERR(map)) {
0089         dev_err(dev,
0090             "could not find Integrator/AP system controller\n");
0091         return PTR_ERR(map);
0092     }
0093
0094     ret = regmap_read(map, INTEGRATOR_SC_DEC_OFFSET, &val);
0095     if (ret) {
0096         dev_err(dev, "could not read from Integrator/AP syscon\n");
0097         return ret;
0098     }
0099
0100     /* Loop over the connected modules */
0101     for (i = 0; i < 4; i++) {
0102         if (!(val & BIT(4 + i)))
0103             continue;
0104
0105         dev_info(dev, "detected module in slot %d\n", i);
0106         ret = integrator_lm_populate(i, dev);
0107         if (ret)
0108             return ret;
0109     }
0110
0111     return 0;
0112 }
0113
0114 static const struct of_device_id integrator_ap_lm_match[] = {
0115     { .compatible = "arm,integrator-ap-lm"},
0116     { },
0117 };
0118
0119 static struct platform_driver integrator_ap_lm_driver = {
0120     .probe = integrator_ap_lm_probe,
0121     .driver = {
0122         .name = "integratorap-lm",
0123         .of_match_table = integrator_ap_lm_match,
0124     },
0125 };
0126 module_platform_driver(integrator_ap_lm_driver);
0127 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
0128 MODULE_DESCRIPTION("Integrator AP Logical Module driver");
0129 MODULE_LICENSE("GPL v2");