linux-kernel - Re: [PATCH V1] mfd: da9053: ensure the FAULT

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Message-ID: <20160805090512.GU5243@dell>
Date:	Fri, 5 Aug 2016 10:05:12 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Steve Twiss <stwiss.opensource@...semi.com>
Cc:	LINUXKERNEL <linux-kernel@...r.kernel.org>,
	Support Opensource <support.opensource@...semi.com>
Subject: Re: [PATCH V1] mfd: da9053: ensure the FAULT_LOG is cleared during
 MFD driver probe

On Wed, 06 Jul 2016, Steve Twiss wrote:

> From: Steve Twiss <stwiss.opensource@...semi.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@...semi.com>
> Reviewed-by: Adam Thomson <adam.thomson.opensource@...semi.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@...semi.com>
>   Date:   Tue May 19 11:32:45 2015 +0100

Looks like much of the same code.  Can you have a pop at generifying
this to avoid any unnecessary duplication?

>  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);
>  

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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