drivers/bus/arm-integrator-lm.c

   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
  31 static 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                                 return ret;
  58                         }
  59                 }
  60         }
  61
  62         return 0;
  63 }
  64
  65 static const struct of_device_id integrator_ap_syscon_match[] = {
  66         { .compatible = "arm,integrator-ap-syscon"},
  67         { },
  68 };
  69
  70 static int integrator_ap_lm_probe(struct platform_device *pdev)
  71 {
  72         struct device *dev = &pdev->dev;
  73         struct device_node *syscon;
  74         static struct regmap *map;
  75         u32 val;
  76         int ret;
  77         int i;
  78
  79         /* Look up the system controller */
  80         syscon = of_find_matching_node(NULL, integrator_ap_syscon_match);
  81         if (!syscon) {
  82                 dev_err(dev,
  83                         "could not find Integrator/AP system controller\n");
  84                 return -ENODEV;
  85         }
  86         map = syscon_node_to_regmap(syscon);
  87         if (IS_ERR(map)) {
  88                 dev_err(dev,
  89                         "could not find Integrator/AP system controller\n");
  90                 return PTR_ERR(map);
  91         }
  92
  93         ret = regmap_read(map, INTEGRATOR_SC_DEC_OFFSET, &val);
  94         if (ret) {
  95                 dev_err(dev, "could not read from Integrator/AP syscon\n");
  96                 return ret;
  97         }
  98
  99         /* Loop over the connected modules */
 100         for (i = 0; i < 4; i++) {
 101                 if (!(val & BIT(4 + i)))
 102                         continue;
 103
 104                 dev_info(dev, "detected module in slot %d\n", i);
 105                 ret = integrator_lm_populate(i, dev);
 106                 if (ret)
 107                         return ret;
 108         }
 109
 110         return 0;
 111 }
 112
 113 static const struct of_device_id integrator_ap_lm_match[] = {
 114         { .compatible = "arm,integrator-ap-lm"},
 115         { },
 116 };
 117
 118 static struct platform_driver integrator_ap_lm_driver = {
 119         .probe = integrator_ap_lm_probe,
 120         .driver = {
 121                 .name = "integratorap-lm",
 122                 .of_match_table = integrator_ap_lm_match,
 123         },
 124 };
 125 module_platform_driver(integrator_ap_lm_driver);
 126 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 127 MODULE_DESCRIPTION("Integrator AP Logical Module driver");
 128 MODULE_LICENSE("GPL v2");