3 files changed, 151 insertions, 0 deletions

diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index 2f36c85eec4b..347b6a58fc3e 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -69,10 +69,12 @@ config ARCH_R8A7779
 config ARCH_R8A7790
         bool "R-Car H2 (R8A77900)"
         select ARCH_RCAR_GEN2
+        select I2C
 
 config ARCH_R8A7791
         bool "R-Car M2-W (R8A77910)"
         select ARCH_RCAR_GEN2
+        select I2C
 
 config ARCH_R8A7794
         bool "R-Car E2 (R8A77940)"
diff --git a/arch/arm/mach-shmobile/Makefile b/arch/arm/mach-shmobile/Makefile
index d53996e6da97..fb9ef904f4b5 100644
--- a/arch/arm/mach-shmobile/Makefile
+++ b/arch/arm/mach-shmobile/Makefile
@@ -35,6 +35,8 @@ cpu-y				:= platsmp.o headsmp.o
 # Shared SoC family objects
 obj-$(CONFIG_ARCH_RCAR_GEN2)    += setup-rcar-gen2.o platsmp-apmu.o $(cpu-y)
 CFLAGS_setup-rcar-gen2.o        += -march=armv7-a
+obj-$(CONFIG_ARCH_R8A7790)      += regulator-quirk-rcar-gen2.o
+obj-$(CONFIG_ARCH_R8A7791)      += regulator-quirk-rcar-gen2.o
 
 # SMP objects
 smp-y                           := $(cpu-y)
diff --git a/arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c b/arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c
new file mode 100644
index 000000000000..384e6e934b87
--- /dev/null
+++ b/arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c
@@ -0,0 +1,147 @@
+/*
+ * R-Car Generation 2 da9063/da9210 regulator quirk
+ *
+ * The r8a7790/lager and r8a7791/koelsch development boards have da9063 and
+ * da9210 regulators.  Both regulators have their interrupt request lines tied
+ * to the same interrupt pin (IRQ2) on the SoC.
+ *
+ * After cold boot or da9063-induced restart, both the da9063 and da9210 seem
+ * to assert their interrupt request lines.  Hence as soon as one driver
+ * requests this irq, it gets stuck in an interrupt storm, as it only manages
+ * to deassert its own interrupt request line, and the other driver hasn't
+ * installed an interrupt handler yet.
+ *
+ * To handle this, install a quirk that masks the interrupts in both the
+ * da9063 and da9210.  This quirk has to run after the i2c master driver has
+ * been initialized, but before the i2c slave drivers are initialized.
+ *
+ * Copyright (C) 2015 Glider bvba
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/mfd/da9063/registers.h>
+
+
+#define IRQC_BASE               0xe61c0000
+#define IRQC_MONITOR            0x104   /* IRQn Signal Level Monitor Register */
+
+#define REGULATOR_IRQ_MASK      BIT(2)  /* IRQ2, active low */
+
+static void __iomem *irqc;
+
+static const u8 da9063_mask_regs[] = {
+        DA9063_REG_IRQ_MASK_A,
+        DA9063_REG_IRQ_MASK_B,
+        DA9063_REG_IRQ_MASK_C,
+        DA9063_REG_IRQ_MASK_D,
+};
+
+/* DA9210 System Control and Event Registers */
+#define DA9210_REG_MASK_A               0x54
+#define DA9210_REG_MASK_B               0x55
+
+static const u8 da9210_mask_regs[] = {
+        DA9210_REG_MASK_A,
+        DA9210_REG_MASK_B,
+};
+
+static void da9xxx_mask_irqs(struct i2c_client *client, const u8 regs[],
+                             unsigned int nregs)
+{
+        unsigned int i;
+
+        dev_info(&client->dev, "Masking %s interrupt sources\n", client->name);
+
+        for (i = 0; i < nregs; i++) {
+                int error = i2c_smbus_write_byte_data(client, regs[i], ~0);
+                if (error) {
+                        dev_err(&client->dev, "i2c error %d\n", error);
+                        return;
+                }
+        }
+}
+
+static int regulator_quirk_notify(struct notifier_block *nb,
+                                  unsigned long action, void *data)
+{
+        struct device *dev = data;
+        struct i2c_client *client;
+        u32 mon;
+
+        mon = ioread32(irqc + IRQC_MONITOR);
+        dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
+        if (mon & REGULATOR_IRQ_MASK)
+                goto remove;
+
+        if (action != BUS_NOTIFY_ADD_DEVICE || dev->type == &i2c_adapter_type)
+                return 0;
+
+        client = to_i2c_client(dev);
+        dev_dbg(dev, "Detected %s\n", client->name);
+
+        if ((client->addr == 0x58 && !strcmp(client->name, "da9063")))
+                da9xxx_mask_irqs(client, da9063_mask_regs,
+                                 ARRAY_SIZE(da9063_mask_regs));
+        else if (client->addr == 0x68 && !strcmp(client->name, "da9210"))
+                da9xxx_mask_irqs(client, da9210_mask_regs,
+                                 ARRAY_SIZE(da9210_mask_regs));
+
+        mon = ioread32(irqc + IRQC_MONITOR);
+        if (mon & REGULATOR_IRQ_MASK)
+                goto remove;
+
+        return 0;
+
+remove:
+        dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
+
+        bus_unregister_notifier(&i2c_bus_type, nb);
+        iounmap(irqc);
+        return 0;
+}
+
+static struct notifier_block regulator_quirk_nb = {
+        .notifier_call = regulator_quirk_notify
+};
+
+static int __init rcar_gen2_regulator_quirk(void)
+{
+        u32 mon;
+
+        if (!of_machine_is_compatible("renesas,koelsch") &&
+            !of_machine_is_compatible("renesas,lager"))
+                return -ENODEV;
+
+        irqc = ioremap(IRQC_BASE, PAGE_SIZE);
+        if (!irqc)
+                return -ENOMEM;
+
+        mon = ioread32(irqc + IRQC_MONITOR);
+        if (mon & REGULATOR_IRQ_MASK) {
+                pr_debug("%s: IRQ2 is not asserted, not installing quirk\n",
+                         __func__);
+                iounmap(irqc);
+                return 0;
+        }
+
+        pr_info("IRQ2 is asserted, installing da9063/da9210 regulator quirk\n");
+
+        bus_register_notifier(&i2c_bus_type, &regulator_quirk_nb);
+        return 0;
+}
+
+arch_initcall(rcar_gen2_regulator_quirk);