[lm-sensors] [PATCH] hwmon: (nct7904) Strenghten detect function

[lm-sensors] [PATCH] hwmon: (nct7904) Strenghten detect function

[Guenter Roeck]

The bank register has five unused bits. Verify that those bits are zero
to strenghten the detect function.

Cc: Vadim V. Vlasov <vvlasov@dev.rtsoft.ru>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
Vadim, it would be great if you can confirm that/if this works.
If yes, I'll use the same code in sensors-detect.

Thanks,
Guenter

 drivers/hwmon/nct7904.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/nct7904.c b/drivers/hwmon/nct7904.c
index eaa8234..b77b82f 100644
--- a/drivers/hwmon/nct7904.c
+++ b/drivers/hwmon/nct7904.c
@@ -502,7 +502,8 @@ static int nct7904_detect(struct i2c_client *client,
 	/* Determine the chip type. */
 	if (i2c_smbus_read_byte_data(client, VENDOR_ID_REG) != NUVOTON_ID ||
 	    i2c_smbus_read_byte_data(client, CHIP_ID_REG) != NCT7904_ID ||
-	    (i2c_smbus_read_byte_data(client, DEVICE_ID_REG) & 0xf0) != 0x50)
+	    (i2c_smbus_read_byte_data(client, DEVICE_ID_REG) & 0xf0) != 0x50 ||
+	    (i2c_smbus_read_byte_data(client, BANK_SEL_REG) & 0xf8) != 0x00)
 		return -ENODEV;
 
 	strlcpy(info->type, "nct7904", I2C_NAME_SIZE);
-- 
2.1.0


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Re: [lm-sensors] [PATCH] hwmon: (nct7904) Strenghten detect function

[Vadim V. Vlasov]

Hi Guenter!

Yes, I can confirm that the bits are always zero, even if the bank
is set to an invalid number.

I used i2cset/i2cdump and regardless of the bank selection
(I tried 5, 6, 0x32, 0x66 and 0xff) the higher bits are read back
as zero. However, the lower bits return the selected bank
number even if it is invalid (i.e. 5, 6, 2, 6 and 7 for the above
tests).

The ID bytes (0x7a-0x7c) are always correct (0x50, 0xc5, 0x51) for
invalid banks as well (the rest of the bytes are 0xff's).

Thanks.
Vadim.

On Fri, 2015-02-27 at 08:36 -0800, Guenter Roeck wrote:
> The bank register has five unused bits. Verify that those bits are zero
> to strenghten the detect function.
> 
> Cc: Vadim V. Vlasov <vvlasov@dev.rtsoft.ru>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Vadim, it would be great if you can confirm that/if this works.
> If yes, I'll use the same code in sensors-detect.
> 
> Thanks,
> Guenter
> 
>  drivers/hwmon/nct7904.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/nct7904.c b/drivers/hwmon/nct7904.c
> index eaa8234..b77b82f 100644
> --- a/drivers/hwmon/nct7904.c
> +++ b/drivers/hwmon/nct7904.c
> @@ -502,7 +502,8 @@ static int nct7904_detect(struct i2c_client *client,
>  	/* Determine the chip type. */
>  	if (i2c_smbus_read_byte_data(client, VENDOR_ID_REG) != NUVOTON_ID ||
>  	    i2c_smbus_read_byte_data(client, CHIP_ID_REG) != NCT7904_ID ||
> -	    (i2c_smbus_read_byte_data(client, DEVICE_ID_REG) & 0xf0) != 0x50)
> +	    (i2c_smbus_read_byte_data(client, DEVICE_ID_REG) & 0xf0) != 0x50 ||
> +	    (i2c_smbus_read_byte_data(client, BANK_SEL_REG) & 0xf8) != 0x00)
>  		return -ENODEV;
>  
>  	strlcpy(info->type, "nct7904", I2C_NAME_SIZE);



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Re: [lm-sensors] [PATCH] hwmon: (nct7904) Strenghten detect function

[Guenter Roeck]

On Fri, Feb 27, 2015 at 08:27:04PM +0300, Vadim V. Vlasov wrote:
> Hi Guenter!
> 
> Yes, I can confirm that the bits are always zero, even if the bank
> is set to an invalid number.
> 
> I used i2cset/i2cdump and regardless of the bank selection
> (I tried 5, 6, 0x32, 0x66 and 0xff) the higher bits are read back
> as zero. However, the lower bits return the selected bank
> number even if it is invalid (i.e. 5, 6, 2, 6 and 7 for the above
> tests).
> 
That is what I suspected.

> The ID bytes (0x7a-0x7c) are always correct (0x50, 0xc5, 0x51) for
> invalid banks as well (the rest of the bytes are 0xff's).
> 
Great, thanks,

Guenter

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Re: [lm-sensors] [PATCH] hwmon: (nct7904) Strenghten detect function

[Jean Delvare]

On Fri, 27 Feb 2015 08:36:19 -0800, Guenter Roeck wrote:
> The bank register has five unused bits. Verify that those bits are zero
> to strenghten the detect function.
> 
> Cc: Vadim V. Vlasov <vvlasov@dev.rtsoft.ru>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Vadim, it would be great if you can confirm that/if this works.
> If yes, I'll use the same code in sensors-detect.
> 
> Thanks,
> Guenter
> 
>  drivers/hwmon/nct7904.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/nct7904.c b/drivers/hwmon/nct7904.c
> index eaa8234..b77b82f 100644
> --- a/drivers/hwmon/nct7904.c
> +++ b/drivers/hwmon/nct7904.c
> @@ -502,7 +502,8 @@ static int nct7904_detect(struct i2c_client *client,
>  	/* Determine the chip type. */
>  	if (i2c_smbus_read_byte_data(client, VENDOR_ID_REG) != NUVOTON_ID ||
>  	    i2c_smbus_read_byte_data(client, CHIP_ID_REG) != NCT7904_ID ||
> -	    (i2c_smbus_read_byte_data(client, DEVICE_ID_REG) & 0xf0) != 0x50)
> +	    (i2c_smbus_read_byte_data(client, DEVICE_ID_REG) & 0xf0) != 0x50 ||
> +	    (i2c_smbus_read_byte_data(client, BANK_SEL_REG) & 0xf8) != 0x00)
>  		return -ENODEV;
>  
>  	strlcpy(info->type, "nct7904", I2C_NAME_SIZE);

Reviewed-by: Jean Delvare <jdelvare@suse.de>

-- 
Jean Delvare
SUSE L3 Support

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Re: [lm-sensors] [PATCH] hwmon: (nct7904) Strenghten detect function

[Guenter Roeck]

On 02/27/2015 02:05 PM, Jean Delvare wrote:
> On Fri, 27 Feb 2015 08:36:19 -0800, Guenter Roeck wrote:
>> The bank register has five unused bits. Verify that those bits are zero
>> to strenghten the detect function.
>>
>> Cc: Vadim V. Vlasov <vvlasov@dev.rtsoft.ru>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> ---
>> Vadim, it would be great if you can confirm that/if this works.
>> If yes, I'll use the same code in sensors-detect.
>>
>> Thanks,
>> Guenter
>>
>>   drivers/hwmon/nct7904.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/hwmon/nct7904.c b/drivers/hwmon/nct7904.c
>> index eaa8234..b77b82f 100644
>> --- a/drivers/hwmon/nct7904.c
>> +++ b/drivers/hwmon/nct7904.c
>> @@ -502,7 +502,8 @@ static int nct7904_detect(struct i2c_client *client,
>>   	/* Determine the chip type. */
>>   	if (i2c_smbus_read_byte_data(client, VENDOR_ID_REG) != NUVOTON_ID ||
>>   	    i2c_smbus_read_byte_data(client, CHIP_ID_REG) != NCT7904_ID ||
>> -	    (i2c_smbus_read_byte_data(client, DEVICE_ID_REG) & 0xf0) != 0x50)
>> +	    (i2c_smbus_read_byte_data(client, DEVICE_ID_REG) & 0xf0) != 0x50 ||
>> +	    (i2c_smbus_read_byte_data(client, BANK_SEL_REG) & 0xf8) != 0x00)
>>   		return -ENODEV;
>>
>>   	strlcpy(info->type, "nct7904", I2C_NAME_SIZE);
>
> Reviewed-by: Jean Delvare <jdelvare@suse.de>
>
Thanks a lot!

Guenter


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