Re: [PATCH 09/10] iio: imu: kmx61: Drop odr_bits from kmx61_samp_freq_table

[Hartmut Knaack]

Jonathan Cameron schrieb am 04.01.2015 um 11:55:
> On 01/01/15 13:53, Hartmut Knaack wrote:
>> Daniel Baluta schrieb am 23.12.2014 um 14:22:
>>> odr_bits values are between 0 and 11, so we can use the index
>>> in kmx61_samp_freq_table instead of odr_bits structure member.
>> Basically looking good, but I would feel more comfortable to check
>> against the boundaries of the table. Please see inline.
>>
>>>
>>> Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx>
>>> ---
>>>  drivers/iio/imu/kmx61.c | 64 ++++++++++++++++++++-----------------------------
>>>  1 file changed, 26 insertions(+), 38 deletions(-)
>>>
>>> diff --git a/drivers/iio/imu/kmx61.c b/drivers/iio/imu/kmx61.c
>>> index eb3900e..98369eb 100644
>>> --- a/drivers/iio/imu/kmx61.c
>>> +++ b/drivers/iio/imu/kmx61.c
>>> @@ -169,19 +169,18 @@ u16 kmx61_uscale_table[] = {9582, 19163, 38326};
>>>  static const struct {
>>>  	int val;
>>>  	int val2;
>>> -	u8 odr_bits;
>>> -} kmx61_samp_freq_table[] = { {12, 500000, 0x00},
>>> -			{25, 0, 0x01},
>>> -			{50, 0, 0x02},
>>> -			{100, 0, 0x03},
>>> -			{200, 0, 0x04},
>>> -			{400, 0, 0x05},
>>> -			{800, 0, 0x06},
>>> -			{1600, 0, 0x07},
>>> -			{0, 781000, 0x08},
>>> -			{1, 563000, 0x09},
>>> -			{3, 125000, 0x0A},
>>> -			{6, 250000, 0x0B} };
>>> +} kmx61_samp_freq_table[] = { {12, 500000},
>>> +			{25, 0},
>>> +			{50, 0},
>>> +			{100, 0},
>>> +			{200, 0},
>>> +			{400, 0},
>>> +			{800, 0},
>>> +			{1600, 0},
>>> +			{0, 781000},
>>> +			{1, 563000},
>>> +			{3, 125000},
>>> +			{6, 250000} };
>>>  
>>>  static const struct {
>>>  	int val;
>>> @@ -302,24 +301,10 @@ static int kmx61_convert_freq_to_bit(int val, int val2)
>>>  	for (i = 0; i < ARRAY_SIZE(kmx61_samp_freq_table); i++)
>>>  		if (val == kmx61_samp_freq_table[i].val &&
>>>  		    val2 == kmx61_samp_freq_table[i].val2)
>>> -			return kmx61_samp_freq_table[i].odr_bits;
>>> -	return -EINVAL;
>>> -}
>>> -
>>> -static int kmx61_convert_bit_to_freq(u8 odr_bits, int *val, int *val2)
>>> -{
>>> -	int i;
>>> -
>>> -	for (i = 0; i < ARRAY_SIZE(kmx61_samp_freq_table); i++)
>>> -		if (odr_bits == kmx61_samp_freq_table[i].odr_bits) {
>>> -			*val = kmx61_samp_freq_table[i].val;
>>> -			*val2 = kmx61_samp_freq_table[i].val2;
>>> -			return 0;
>>> -		}
>>> +			return i;
>>>  	return -EINVAL;
>>>  }
>>>  
>>> -
>>>  static int kmx61_convert_wake_up_odr_to_bit(int val, int val2)
>>>  {
>>>  	int i;
>>> @@ -478,7 +463,7 @@ static int kmx61_set_odr(struct kmx61_data *data, int val, int val2, u8 device)
>>>  
>>>  static int kmx61_get_odr(struct kmx61_data *data, int *val, int *val2,
>>>  			 u8 device)
>>> -{	int i;
>>> +{
>>>  	u8 lodr_bits;
>>>  
>>>  	if (device & KMX61_ACC)
>>> @@ -490,13 +475,13 @@ static int kmx61_get_odr(struct kmx61_data *data, int *val, int *val2,
>>>  	else
>>>  		return -EINVAL;
>>>  
>>> -	for (i = 0; i < ARRAY_SIZE(kmx61_samp_freq_table); i++)
>>> -		if (lodr_bits == kmx61_samp_freq_table[i].odr_bits) {
>>> -			*val = kmx61_samp_freq_table[i].val;
>>> -			*val2 = kmx61_samp_freq_table[i].val2;
>>> -			return 0;
>>> -		}
>>> -	return -EINVAL;
>>> +	if (lodr_bits > 0xB)
>> Since we use it as an index, I regard it safer to check against
>> ARRAY_SIZE(kmx61_samp_freq_table) rather than a fix value.
> Makes sense to me as well - though obviously ARRAY_SIZE(kmx61_samp_freq_table) is
> 0xC (12) rather than 0xB (11) so you'll need a minus 1
> 
Instead of subtracting, I would favor this one:
	if !(lodr_bits < ARRAY_SIZE(...))

Or this one:
	if (lodr_bits >= ARRAY_SIZE(...))

> I'll leave this one for a new spin.
>>
>>> +		return -EINVAL;
>>> +
>>> +	*val = kmx61_samp_freq_table[lodr_bits].val;
>>> +	*val2 = kmx61_samp_freq_table[lodr_bits].val2;
>>> +
>>> +	return 0;
>>>  }
>>>  
>>>  static int kmx61_set_range(struct kmx61_data *data, u8 range)
>>> @@ -580,8 +565,11 @@ static int kmx61_chip_init(struct kmx61_data *data)
>>>  	}
>>>  	data->odr_bits = ret;
>>>  
>>> -	/* set output data rate for wake up (motion detection) function */
>>> -	ret = kmx61_convert_bit_to_freq(data->odr_bits, &val, &val2);
>>> +	/*
>>> +	 * set output data rate for wake up (motion detection) function
>>> +	 * to match data rate for accelerometer sampling
>>> +	 */
>>> +	ret = kmx61_get_odr(data, &val, &val2, KMX61_ACC);
>>>  	if (ret < 0)
>>>  		return ret;
>>>  
>>>
>>
> 
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