[PATCH] ARM: shmobile: R-Car Gen2: Add da9063/da9210 regulator quirk

From: Geert Uytterhoeven
Date: Mon Mar 09 2015 - 15:50:49 EST

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.
As it depends on i2c, select I2C if one of the affected platforms is
enabled in the kernel config.

On koelsch, the following happens:

- Cold boot or reboot using the da9063 restart handler:

IRQ2 is asserted, installing da9063/da9210 regulator quirk
...
i2c i2c-6: regulator_quirk_notify: 1, IRQC_MONITOR = 0x3fb
i2c 6-0058: regulator_quirk_notify: 1, IRQC_MONITOR = 0x3fb
i2c 6-0058: Detected da9063
i2c 6-0058: Masking da9063 interrupt sources
i2c 6-0068: regulator_quirk_notify: 1, IRQC_MONITOR = 0x3fb
i2c 6-0068: Detected da9210
i2c 6-0068: Masking da9210 interrupt sources
i2c 6-0068: IRQ2 is not asserted, removing quirk

- Warm boot (reset button):

rcar_gen2_regulator_quirk: IRQ2 is not asserted, not installing quirk

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Tested-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Mark Brown <broonie@xxxxxxxxxx>
---
v2:
- Add Tested-by, Reviewed-by,
- Add check for "renesas,lager", which is known to be affected (thanks
Wolfram),
- Make ARCH_R8A7790 and ARCH_R8A7791 select I2C, as the quirk needs
i2c to be builtin, and drop the #ifdef on CONFIG_I2C,
- Use the passed notifier_block to unregister the notifier, so we can
get rid of the forward declaration,
- Move the quirk code to a separate file for easier maintenance,
- Postpone iounmap() until after bus_unregister_notifier(),
- Remove error checking for bus_{,un}register_notifier(); these
currently cannot fail, and if they ever do, there's nothing we can
do about it,
- Comment rewording and restructuring,
- Drop RFC state.

I do not have schematics for r8a7793/gose, but according to the BSP, it
has both da9210 and da9063, so most probably it's also affected.

References:
- "ARM: shmobile: koelsch: da9210/da9063 interrupt storm (was: Re:
[PATCH 3/4] ARM: shmobile: koelsch: Add DA9063 PMIC device node for
system restart") (https://lkml.org/lkml/2015/2/17/254),
- "[PATCH/RFC 1/2] regulator: da9210: Mask all interrupt sources to
deassert interrupt line" (https://lkml.org/lkml/2015/2/17/274)
- "[PATCH/RFC 2/2] regulator: da9210: Add optional interrupt support"
(https://lkml.org/lkml/2015/2/17/275)
---
arch/arm/mach-shmobile/Kconfig | 2 +
arch/arm/mach-shmobile/Makefile | 2 +
arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c | 147 +++++++++++++++++++++
3 files changed, 151 insertions(+)
create mode 100644 arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c

diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index c2952f58e7683ac7..0fb484221c90e0eb 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -73,10 +73,12 @@ 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 d3aca07b51a8a149..9e9d6788de512d31 100644
--- a/arch/arm/mach-shmobile/Makefile
+++ b/arch/arm/mach-shmobile/Makefile
@@ -32,6 +32,8 @@ 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 0000000000000000..384e6e934b876528
--- /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);
--
1.9.1

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