[RFC][PATCH] mfd: twl4030: Check for i2c error code in protect_pm_master function

[RFC][PATCH] mfd: twl4030: Check for i2c error code in protect_pm_master function

[balajitk]

From: Balaji T K <balajitk@ti.com>

        Warn about error messages immediately after i2c write to R_PROTECT_KEY
	in functions protect_pm_master/unprotect_pm_master

Signed-off-by: Balaji T K <balajitk@ti.com>
---
 drivers/mfd/twl-core.c |   23 ++++++++++++++++++-----
 1 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/mfd/twl-core.c b/drivers/mfd/twl-core.c
index 42af794..74f93ed 100644
--- a/drivers/mfd/twl-core.c
+++ b/drivers/mfd/twl-core.c
@@ -804,6 +804,9 @@ static inline int __init protect_pm_master(void)
 
 	e = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, KEY_LOCK,
 			R_PROTECT_KEY);
+	if (e < 0)
+		pr_err("twl_core: Could not write value : %x to TWL"
+		       " register %x err %d\n", KEY_LOCK, R_PROTECT_KEY, e);
 	return e;
 }
 
@@ -811,10 +814,17 @@ static inline int __init unprotect_pm_master(void)
 {
 	int e = 0;
 
-	e |= twl_i2c_write_u8(TWL_MODULE_PM_MASTER, KEY_UNLOCK1,
+	e = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, KEY_UNLOCK1,
 			R_PROTECT_KEY);
-	e |= twl_i2c_write_u8(TWL_MODULE_PM_MASTER, KEY_UNLOCK2,
+	if (e < 0)
+		pr_err("twl_core: Could not write value : %x to TWL"
+		       " register %x err %d\n", KEY_UNLOCK1, R_PROTECT_KEY, e);
+
+	e = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, KEY_UNLOCK2,
 			R_PROTECT_KEY);
+	if (e < 0)
+		pr_err("twl_core: Could not write value : %x to TWL"
+		       " register %x err %d\n", KEY_UNLOCK1, R_PROTECT_KEY, e);
 	return e;
 }
 
@@ -865,10 +875,13 @@ static void clocks_init(struct device *dev)
 	}
 
 	ctrl |= HIGH_PERF_SQ;
-	e |= unprotect_pm_master();
+	e = unprotect_pm_master();
 	/* effect->MADC+USB ck en */
-	e |= twl_i2c_write_u8(TWL_MODULE_PM_MASTER, ctrl, R_CFG_BOOT);
-	e |= protect_pm_master();
+	e = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, ctrl, R_CFG_BOOT);
+	if (e < 0)
+		pr_err("twl_core: Could not write value : %x to TWL"
+		       " register %x err %d\n", ctrl, R_CFG_BOOT, e);
+	e = protect_pm_master();
 
 	if (e < 0)
 		pr_err("%s: clock init err [%d]\n", DRIVER_NAME, e);
-- 
1.5.4.7

Re: [RFC][PATCH] mfd: twl4030: Check for i2c error code in protect_pm_master function

[Samuel Ortiz]

Hi Balaji,

On Fri, Dec 11, 2009 at 09:59:18PM +0530, balajitk@ti.com wrote:
> From: Balaji T K <balajitk@ti.com>
> 
>         Warn about error messages immediately after i2c write to R_PROTECT_KEY
> 	in functions protect_pm_master/unprotect_pm_master
> 
> Signed-off-by: Balaji T K <balajitk@ti.com>
> ---
>  drivers/mfd/twl-core.c |   23 ++++++++++++++++++-----
>  1 files changed, 18 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mfd/twl-core.c b/drivers/mfd/twl-core.c
> index 42af794..74f93ed 100644
> --- a/drivers/mfd/twl-core.c
> +++ b/drivers/mfd/twl-core.c
> @@ -804,6 +804,9 @@ static inline int __init protect_pm_master(void)
>  
>  	e = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, KEY_LOCK,
>  			R_PROTECT_KEY);
> +	if (e < 0)
> +		pr_err("twl_core: Could not write value : %x to TWL"
> +		       " register %x err %d\n", KEY_LOCK, R_PROTECT_KEY, e);
>  	return e;
>  }
>  
> @@ -811,10 +814,17 @@ static inline int __init unprotect_pm_master(void)
>  {
>  	int e = 0;
>  
> -	e |= twl_i2c_write_u8(TWL_MODULE_PM_MASTER, KEY_UNLOCK1,
> +	e = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, KEY_UNLOCK1,
>  			R_PROTECT_KEY);
> -	e |= twl_i2c_write_u8(TWL_MODULE_PM_MASTER, KEY_UNLOCK2,
> +	if (e < 0)
> +		pr_err("twl_core: Could not write value : %x to TWL"
> +		       " register %x err %d\n", KEY_UNLOCK1, R_PROTECT_KEY, e);
> +
Does it make sense to continue here ? If the key unlocking failed, shouldnt we
just return the error and leave ?


> +	e = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, KEY_UNLOCK2,
>  			R_PROTECT_KEY);
> +	if (e < 0)
> +		pr_err("twl_core: Could not write value : %x to TWL"
> +		       " register %x err %d\n", KEY_UNLOCK1, R_PROTECT_KEY, e);
>  	return e;
>  }
>  
> @@ -865,10 +875,13 @@ static void clocks_init(struct device *dev)
>  	}
>  
>  	ctrl |= HIGH_PERF_SQ;
> -	e |= unprotect_pm_master();
> +	e = unprotect_pm_master();
Same here: If the unprotection failed, the rest probably will fail as well,
right ?

Cheers,
Samuel.

>  	/* effect->MADC+USB ck en */
> -	e |= twl_i2c_write_u8(TWL_MODULE_PM_MASTER, ctrl, R_CFG_BOOT);
> -	e |= protect_pm_master();
> +	e = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, ctrl, R_CFG_BOOT);
> +	if (e < 0)
> +		pr_err("twl_core: Could not write value : %x to TWL"
> +		       " register %x err %d\n", ctrl, R_CFG_BOOT, e);
> +	e = protect_pm_master();
>  
>  	if (e < 0)
>  		pr_err("%s: clock init err [%d]\n", DRIVER_NAME, e);
> -- 
> 1.5.4.7
> 

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