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                                 of_node_put(child);
  58                                 return ret;
  59                         }
  60                 }
  61         }
  62
  63         return 0;
  64 }
  65
  66 static const struct of_device_id integrator_ap_syscon_match[] = {
  67         { .compatible = "arm,integrator-ap-syscon"},
  68         { },
  69 };
  70
  71 static 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         of_node_put(syscon);
  89         if (IS_ERR(map)) {
  90                 dev_err(dev,
  91                         "could not find Integrator/AP system controller\n");
  92                 return PTR_ERR(map);
  93         }
  94
  95         ret = regmap_read(map, INTEGRATOR_SC_DEC_OFFSET, &val);
  96         if (ret) {
  97                 dev_err(dev, "could not read from Integrator/AP syscon\n");
  98                 return ret;
  99         }
 100
 101         /* Loop over the connected modules */
 102         for (i = 0; i < 4; i++) {
 103                 if (!(val & BIT(4 + i)))
 104                         continue;
 105
 106                 dev_info(dev, "detected module in slot %d\n", i);
 107                 ret = integrator_lm_populate(i, dev);
 108                 if (ret)
 109                         return ret;
 110         }
 111
 112         return 0;
 113 }
 114
 115 static const struct of_device_id integrator_ap_lm_match[] = {
 116         { .compatible = "arm,integrator-ap-lm"},
 117         { },
 118 };
 119
 120 static struct platform_driver integrator_ap_lm_driver = {
 121         .probe = integrator_ap_lm_probe,
 122         .driver = {
 123                 .name = "integratorap-lm",
 124                 .of_match_table = integrator_ap_lm_match,
 125         },
 126 };
 127 module_platform_driver(integrator_ap_lm_driver);
 128 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 129 MODULE_DESCRIPTION("Integrator AP Logical Module driver");