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Subject[PATCH V1] mfd: da9053: ensure the FAULT_LOG is cleared during MFD driver probe
From: Steve Twiss <stwiss.opensource@diasemi.com>

The function da9052_clear_fault_log() is added to mitigate the case of
persistent data being transferred between reboots.

Clearance of any the persistent information within the DA9053 FAULT_LOG
register must be completed during start-up so the fault-log does not
continue with previous values. A clearance function has been added here in
the kernel driver because wiping the fault-log cannot be counted on outside
the Linux kernel.

Signed-off-by: Steve Twiss <stwiss.opensource@diasemi.com>
Reviewed-by: Adam Thomson <adam.thomson.opensource@diasemi.com>

---
This patch applies against linux-next and v4.7-rc6


Hi Lee,

This patch is similar to the requirements for DA9062 and DA9063: to ensure
the FAULT_LOG is started from a 'clean' position.

The Dialog datasheet for DA9053 suggests: "The FAULT_LOG register has to
be cleared from the host after reading, by writing a value of 11111111".

See reference:
commit 9011e4a8a6fe57f76511609930ed00d305389089
Author: Steve Twiss <stwiss.opensource@diasemi.com>
Date: Tue May 19 11:32:45 2015 +0100

Regards,
Steve


drivers/mfd/da9052-core.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 51 insertions(+)

diff --git a/drivers/mfd/da9052-core.c b/drivers/mfd/da9052-core.c
index c0bf68a..a88c206 100644
--- a/drivers/mfd/da9052-core.c
+++ b/drivers/mfd/da9052-core.c
@@ -167,6 +167,7 @@ static bool da9052_reg_writeable(struct device *dev, unsigned int reg)
case DA9052_EVENT_B_REG:
case DA9052_EVENT_C_REG:
case DA9052_EVENT_D_REG:
+ case DA9052_FAULTLOG_REG:
case DA9052_IRQ_MASK_A_REG:
case DA9052_IRQ_MASK_B_REG:
case DA9052_IRQ_MASK_C_REG:
@@ -541,6 +542,52 @@ const struct regmap_config da9052_regmap_config = {
};
EXPORT_SYMBOL_GPL(da9052_regmap_config);

+static int da9052_clear_fault_log(struct da9052 *da9052)
+{
+ int ret = 0;
+ int fault_log = 0;
+
+ fault_log = da9052_reg_read(da9052, DA9052_FAULTLOG_REG);
+ if (fault_log < 0) {
+ dev_err(da9052->dev,
+ "Cannot read FAULT_LOG %d\n", fault_log);
+ return fault_log;
+ }
+
+ if (fault_log) {
+ if (fault_log & DA9052_FAULTLOG_TWDERROR)
+ dev_dbg(da9052->dev,
+ "Fault log entry detected: TWD_ERROR\n");
+ if (fault_log & DA9052_FAULTLOG_VDDFAULT)
+ dev_dbg(da9052->dev,
+ "Fault log entry detected: VDD_FAULT\n");
+ if (fault_log & DA9052_FAULTLOG_VDDSTART)
+ dev_dbg(da9052->dev,
+ "Fault log entry detected: VDD_START\n");
+ if (fault_log & DA9052_FAULTLOG_TEMPOVER)
+ dev_dbg(da9052->dev,
+ "Fault log entry detected: TEMP_OVER\n");
+ if (fault_log & DA9052_FAULTLOG_KEYSHUT)
+ dev_dbg(da9052->dev,
+ "Fault log entry detected: KEY_SHUT\n");
+ if (fault_log & DA9052_FAULTLOG_NSDSET)
+ dev_dbg(da9052->dev,
+ "Fault log entry detected: nSD_SHUT\n");
+ if (fault_log & DA9052_FAULTLOG_WAITSET)
+ dev_dbg(da9052->dev,
+ "Fault log entry detected: WAIT_SHUT\n");
+
+ ret = da9052_reg_write(da9052,
+ DA9052_FAULTLOG_REG,
+ 0xFF);
+ if (ret < 0)
+ dev_err(da9052->dev,
+ "Cannot reset FAULT_LOG values %d\n", ret);
+ }
+
+ return ret;
+}
+
int da9052_device_init(struct da9052 *da9052, u8 chip_id)
{
struct da9052_pdata *pdata = dev_get_platdata(da9052->dev);
@@ -549,6 +596,10 @@ int da9052_device_init(struct da9052 *da9052, u8 chip_id)
mutex_init(&da9052->auxadc_lock);
init_completion(&da9052->done);

+ ret = da9052_clear_fault_log(da9052);
+ if (ret < 0)
+ dev_warn(da9052->dev, "Cannot clear FAULT_LOG\n");
+
if (pdata && pdata->init != NULL)
pdata->init(da9052);

--
end-of-patch for PATCH V1
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