LXR linux/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
  47static void __iomem *irqc;
  48
  49/* first byte sets the memory pointer, following are consecutive reg values */
  50static u8 da9063_irq_clr[] = { DA9063_REG_IRQ_MASK_A, 0xff, 0xff, 0xff, 0xff };
  51static u8 da9210_irq_clr[] = { DA9210_REG_MASK_A, 0xff, 0xff };
  52
  53static 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
  65static 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        static bool done;
  71        u32 mon;
  72
  73        if (done)
  74                return 0;
  75
  76        mon = ioread32(irqc + IRQC_MONITOR);
  77        dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
  78        if (mon & REGULATOR_IRQ_MASK)
  79                goto remove;
  80
  81        if (action != BUS_NOTIFY_ADD_DEVICE || dev->type == &i2c_adapter_type)
  82                return 0;
  83
  84        client = to_i2c_client(dev);
  85        dev_dbg(dev, "Detected %s\n", client->name);
  86
  87        if ((client->addr == 0x58 && !strcmp(client->name, "da9063")) ||
  88            (client->addr == 0x68 && !strcmp(client->name, "da9210"))) {
  89                int ret;
  90
  91                dev_info(&client->dev, "clearing da9063/da9210 interrupts\n");
  92                ret = i2c_transfer(client->adapter, da9xxx_msgs, ARRAY_SIZE(da9xxx_msgs));
  93                if (ret != ARRAY_SIZE(da9xxx_msgs))
  94                        dev_err(&client->dev, "i2c error %d\n", ret);
  95        }
  96
  97        mon = ioread32(irqc + IRQC_MONITOR);
  98        if (mon & REGULATOR_IRQ_MASK)
  99                goto remove;
 100
 101        return 0;
 102
 103remove:
 104        dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
 105
 106        done = true;
 107        iounmap(irqc);
 108        return 0;
 109}
 110
 111static struct notifier_block regulator_quirk_nb = {
 112        .notifier_call = regulator_quirk_notify
 113};
 114
 115static int __init rcar_gen2_regulator_quirk(void)
 116{
 117        u32 mon;
 118
 119        if (!of_machine_is_compatible("renesas,koelsch") &&
 120            !of_machine_is_compatible("renesas,lager") &&
 121            !of_machine_is_compatible("renesas,gose"))
 122                return -ENODEV;
 123
 124        irqc = ioremap(IRQC_BASE, PAGE_SIZE);
 125        if (!irqc)
 126                return -ENOMEM;
 127
 128        mon = ioread32(irqc + IRQC_MONITOR);
 129        if (mon & REGULATOR_IRQ_MASK) {
 130                pr_debug("%s: IRQ2 is not asserted, not installing quirk\n",
 131                         __func__);
 132                iounmap(irqc);
 133                return 0;
 134        }
 135
 136        pr_info("IRQ2 is asserted, installing da9063/da9210 regulator quirk\n");
 137
 138        bus_register_notifier(&i2c_bus_type, &regulator_quirk_nb);
 139        return 0;
 140}
 141
 142arch_initcall(rcar_gen2_regulator_quirk);
 143