arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * R-Car Generation 2 da9063/da9210 regulator quirk
   4  *
   5  * Certain Gen2 development boards have an da9063 and one or more da9210
   6  * regulators. All of these regulators have their interrupt request lines
   7  * tied to the same interrupt pin (IRQ2) on the SoC.
   8  *
   9  * After cold boot or da9063-induced restart, both the da9063 and da9210 seem
  10  * to assert their interrupt request lines.  Hence as soon as one driver
  11  * requests this irq, it gets stuck in an interrupt storm, as it only manages
  12  * to deassert its own interrupt request line, and the other driver hasn't
  13  * installed an interrupt handler yet.
  14  *
  15  * To handle this, install a quirk that masks the interrupts in both the
  16  * da9063 and da9210.  This quirk has to run after the i2c master driver has
  17  * been initialized, but before the i2c slave drivers are initialized.
  18  *
  19  * Copyright (C) 2015 Glider bvba
  20  */
  21
  22 #include <linux/device.h>
  23 #include <linux/i2c.h>
  24 #include <linux/init.h>
  25 #include <linux/io.h>
  26 #include <linux/list.h>
  27 #include <linux/notifier.h>
  28 #include <linux/of.h>
  29 #include <linux/of_irq.h>
  30 #include <linux/mfd/da9063/registers.h>
  31
  32 #define IRQC_BASE               0xe61c0000
  33 #define IRQC_MONITOR            0x104   /* IRQn Signal Level Monitor Register */
  34
  35 #define REGULATOR_IRQ_MASK      BIT(2)  /* IRQ2, active low */
  36
  37 /* start of DA9210 System Control and Event Registers */
  38 #define DA9210_REG_MASK_A               0x54
  39
  40 struct regulator_quirk {
  41         struct list_head                list;
  42         const struct of_device_id       *id;
  43         struct device_node              *np;
  44         struct of_phandle_args          irq_args;
  45         struct i2c_msg                  i2c_msg;
  46         bool                            shared; /* IRQ line is shared */
  47 };
  48
  49 static LIST_HEAD(quirk_list);
  50 static void __iomem *irqc;
  51
  52 /* first byte sets the memory pointer, following are consecutive reg values */
  53 static u8 da9063_irq_clr[] = { DA9063_REG_IRQ_MASK_A, 0xff, 0xff, 0xff, 0xff };
  54 static u8 da9210_irq_clr[] = { DA9210_REG_MASK_A, 0xff, 0xff };
  55
  56 static struct i2c_msg da9063_msg = {
  57         .len = ARRAY_SIZE(da9063_irq_clr),
  58         .buf = da9063_irq_clr,
  59 };
  60
  61 static struct i2c_msg da9210_msg = {
  62         .len = ARRAY_SIZE(da9210_irq_clr),
  63         .buf = da9210_irq_clr,
  64 };
  65
  66 static const struct of_device_id rcar_gen2_quirk_match[] = {
  67         { .compatible = "dlg,da9063", .data = &da9063_msg },
  68         { .compatible = "dlg,da9210", .data = &da9210_msg },
  69         {},
  70 };
  71
  72 static int regulator_quirk_notify(struct notifier_block *nb,
  73                                   unsigned long action, void *data)
  74 {
  75         struct regulator_quirk *pos, *tmp;
  76         struct device *dev = data;
  77         struct i2c_client *client;
  78         static bool done;
  79         int ret;
  80         u32 mon;
  81
  82         if (done)
  83                 return 0;
  84
  85         mon = ioread32(irqc + IRQC_MONITOR);
  86         dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
  87         if (mon & REGULATOR_IRQ_MASK)
  88                 goto remove;
  89
  90         if (action != BUS_NOTIFY_ADD_DEVICE || dev->type == &i2c_adapter_type)
  91                 return 0;
  92
  93         client = to_i2c_client(dev);
  94         dev_dbg(dev, "Detected %s\n", client->name);
  95
  96         /*
  97          * Send message to all PMICs that share an IRQ line to deassert it.
  98          *
  99          * WARNING: This works only if all the PMICs are on the same I2C bus.
 100          */
 101         list_for_each_entry(pos, &quirk_list, list) {
 102                 if (!pos->shared)
 103                         continue;
 104
 105                 if (pos->np->parent != client->dev.parent->of_node)
 106                         continue;
 107
 108                 dev_info(&client->dev, "clearing %s@0x%02x interrupts\n",
 109                          pos->id->compatible, pos->i2c_msg.addr);
 110
 111                 ret = i2c_transfer(client->adapter, &pos->i2c_msg, 1);
 112                 if (ret != 1)
 113                         dev_err(&client->dev, "i2c error %d\n", ret);
 114         }
 115
 116         mon = ioread32(irqc + IRQC_MONITOR);
 117         if (mon & REGULATOR_IRQ_MASK)
 118                 goto remove;
 119
 120         return 0;
 121
 122 remove:
 123         dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
 124
 125         list_for_each_entry_safe(pos, tmp, &quirk_list, list) {
 126                 list_del(&pos->list);
 127                 kfree(pos);
 128         }
 129
 130         done = true;
 131         iounmap(irqc);
 132         return 0;
 133 }
 134
 135 static struct notifier_block regulator_quirk_nb = {
 136         .notifier_call = regulator_quirk_notify
 137 };
 138
 139 static int __init rcar_gen2_regulator_quirk(void)
 140 {
 141         struct regulator_quirk *quirk, *pos, *tmp;
 142         struct of_phandle_args *argsa, *argsb;
 143         const struct of_device_id *id;
 144         struct device_node *np;
 145         u32 mon, addr;
 146         int ret;
 147
 148         if (!of_machine_is_compatible("renesas,koelsch") &&
 149             !of_machine_is_compatible("renesas,lager") &&
 150             !of_machine_is_compatible("renesas,stout") &&
 151             !of_machine_is_compatible("renesas,gose"))
 152                 return -ENODEV;
 153
 154         for_each_matching_node_and_match(np, rcar_gen2_quirk_match, &id) {
 155                 if (!of_device_is_available(np))
 156                         break;
 157
 158                 ret = of_property_read_u32(np, "reg", &addr);
 159                 if (ret)        /* Skip invalid entry and continue */
 160                         continue;
 161
 162                 quirk = kzalloc(sizeof(*quirk), GFP_KERNEL);
 163                 if (!quirk) {
 164                         ret = -ENOMEM;
 165                         goto err_mem;
 166                 }
 167
 168                 argsa = &quirk->irq_args;
 169                 memcpy(&quirk->i2c_msg, id->data, sizeof(quirk->i2c_msg));
 170
 171                 quirk->id = id;
 172                 quirk->np = np;
 173                 quirk->i2c_msg.addr = addr;
 174
 175                 ret = of_irq_parse_one(np, 0, argsa);
 176                 if (ret) {      /* Skip invalid entry and continue */
 177                         kfree(quirk);
 178                         continue;
 179                 }
 180
 181                 list_for_each_entry(pos, &quirk_list, list) {
 182                         argsb = &pos->irq_args;
 183
 184                         if (argsa->args_count != argsb->args_count)
 185                                 continue;
 186
 187                         ret = memcmp(argsa->args, argsb->args,
 188                                      argsa->args_count *
 189                                      sizeof(argsa->args[0]));
 190                         if (!ret) {
 191                                 pos->shared = true;
 192                                 quirk->shared = true;
 193                         }
 194                 }
 195
 196                 list_add_tail(&quirk->list, &quirk_list);
 197         }
 198
 199         irqc = ioremap(IRQC_BASE, PAGE_SIZE);
 200         if (!irqc) {
 201                 ret = -ENOMEM;
 202                 goto err_mem;
 203         }
 204
 205         mon = ioread32(irqc + IRQC_MONITOR);
 206         if (mon & REGULATOR_IRQ_MASK) {
 207                 pr_debug("%s: IRQ2 is not asserted, not installing quirk\n",
 208                          __func__);
 209                 ret = 0;
 210                 goto err_free;
 211         }
 212
 213         pr_info("IRQ2 is asserted, installing da9063/da9210 regulator quirk\n");
 214
 215         bus_register_notifier(&i2c_bus_type, &regulator_quirk_nb);
 216         return 0;
 217
 218 err_free:
 219         iounmap(irqc);
 220 err_mem:
 221         list_for_each_entry_safe(pos, tmp, &quirk_list, list) {
 222                 list_del(&pos->list);
 223                 kfree(pos);
 224         }
 225
 226         return ret;
 227 }
 228
 229 arch_initcall(rcar_gen2_regulator_quirk);