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

   1 /*
   2  * R-Car Generation 2 da9063/da9210 regulator quirk
   3  *
   4  * The r8a7790/lager and r8a7791/koelsch development boards have da9063 and
   5  * da9210 regulators.  Both regulators have their interrupt request lines tied
   6  * to the same interrupt pin (IRQ2) on the SoC.
   7  *
   8  * After cold boot or da9063-induced restart, both the da9063 and da9210 seem
   9  * to assert their interrupt request lines.  Hence as soon as one driver
  10  * requests this irq, it gets stuck in an interrupt storm, as it only manages
  11  * to deassert its own interrupt request line, and the other driver hasn't
  12  * installed an interrupt handler yet.
  13  *
  14  * To handle this, install a quirk that masks the interrupts in both the
  15  * da9063 and da9210.  This quirk has to run after the i2c master driver has
  16  * been initialized, but before the i2c slave drivers are initialized.
  17  *
  18  * Copyright (C) 2015 Glider bvba
  19  *
  20  * This program is free software; you can redistribute it and/or modify
  21  * it under the terms of the GNU General Public License as published by
  22  * the Free Software Foundation; version 2 of the License.
  23  *
  24  * This program is distributed in the hope that it will be useful,
  25  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27  * GNU General Public License for more details.
  28  */
  29
  30 #include <linux/device.h>
  31 #include <linux/i2c.h>
  32 #include <linux/init.h>
  33 #include <linux/io.h>
  34 #include <linux/notifier.h>
  35 #include <linux/of.h>
  36 #include <linux/mfd/da9063/registers.h>
  37
  38
  39 #define IRQC_BASE               0xe61c0000
  40 #define IRQC_MONITOR            0x104   /* IRQn Signal Level Monitor Register */
  41
  42 #define REGULATOR_IRQ_MASK      BIT(2)  /* IRQ2, active low */
  43
  44 /* start of DA9210 System Control and Event Registers */
  45 #define DA9210_REG_MASK_A               0x54
  46
  47 static void __iomem *irqc;
  48
  49 /* first byte sets the memory pointer, following are consecutive reg values */
  50 static u8 da9063_irq_clr[] = { DA9063_REG_IRQ_MASK_A, 0xff, 0xff, 0xff, 0xff };
  51 static u8 da9210_irq_clr[] = { DA9210_REG_MASK_A, 0xff, 0xff };
  52
  53 static struct i2c_msg da9xxx_msgs[2] = {
  54         {
  55                 .addr = 0x58,
  56                 .len = ARRAY_SIZE(da9063_irq_clr),
  57                 .buf = da9063_irq_clr,
  58         }, {
  59                 .addr = 0x68,
  60                 .len = ARRAY_SIZE(da9210_irq_clr),
  61                 .buf = da9210_irq_clr,
  62         },
  63 };
  64
  65 static int regulator_quirk_notify(struct notifier_block *nb,
  66                                   unsigned long action, void *data)
  67 {
  68         struct device *dev = data;
  69         struct i2c_client *client;
  70         u32 mon;
  71
  72         mon = ioread32(irqc + IRQC_MONITOR);
  73         dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
  74         if (mon & REGULATOR_IRQ_MASK)
  75                 goto remove;
  76
  77         if (action != BUS_NOTIFY_ADD_DEVICE || dev->type == &i2c_adapter_type)
  78                 return 0;
  79
  80         client = to_i2c_client(dev);
  81         dev_dbg(dev, "Detected %s\n", client->name);
  82
  83         if ((client->addr == 0x58 && !strcmp(client->name, "da9063")) ||
  84             (client->addr == 0x68 && !strcmp(client->name, "da9210"))) {
  85                 int ret;
  86
  87                 dev_info(&client->dev, "clearing da9063/da9210 interrupts\n");
  88                 ret = i2c_transfer(client->adapter, da9xxx_msgs, ARRAY_SIZE(da9xxx_msgs));
  89                 if (ret != ARRAY_SIZE(da9xxx_msgs))
  90                         dev_err(&client->dev, "i2c error %d\n", ret);
  91         }
  92
  93         mon = ioread32(irqc + IRQC_MONITOR);
  94         if (mon & REGULATOR_IRQ_MASK)
  95                 goto remove;
  96
  97         return 0;
  98
  99 remove:
 100         dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
 101
 102         bus_unregister_notifier(&i2c_bus_type, nb);
 103         iounmap(irqc);
 104         return 0;
 105 }
 106
 107 static struct notifier_block regulator_quirk_nb = {
 108         .notifier_call = regulator_quirk_notify
 109 };
 110
 111 static int __init rcar_gen2_regulator_quirk(void)
 112 {
 113         u32 mon;
 114
 115         if (!of_machine_is_compatible("renesas,koelsch") &&
 116             !of_machine_is_compatible("renesas,lager") &&
 117             !of_machine_is_compatible("renesas,gose"))
 118                 return -ENODEV;
 119
 120         irqc = ioremap(IRQC_BASE, PAGE_SIZE);
 121         if (!irqc)
 122                 return -ENOMEM;
 123
 124         mon = ioread32(irqc + IRQC_MONITOR);
 125         if (mon & REGULATOR_IRQ_MASK) {
 126                 pr_debug("%s: IRQ2 is not asserted, not installing quirk\n",
 127                          __func__);
 128                 iounmap(irqc);
 129                 return 0;
 130         }
 131
 132         pr_info("IRQ2 is asserted, installing da9063/da9210 regulator quirk\n");
 133
 134         bus_register_notifier(&i2c_bus_type, &regulator_quirk_nb);
 135         return 0;
 136 }
 137
 138 arch_initcall(rcar_gen2_regulator_quirk);