linux-kernel - Re: [PATCH 2/3] hwmon: (sht3x) add medium repeatability support

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Date:   Wed, 14 Jun 2023 23:16:22 +0800
From:   JuenKit Yip <JuenKit_Yip@...mail.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
        jdelvare@...e.com
Subject: Re: [PATCH 2/3] hwmon: (sht3x) add medium repeatability support

在 2023/6/14 21:00, Guenter Roeck 写道:
> On 6/13/23 23:27, JuenKit Yip wrote:
>> add medium repeatability support for matching datasheet
>>
>> Signed-off-by: JuenKit Yip <JuenKit_Yip@...mail.com>
>> ---
>>   drivers/hwmon/sht3x.c | 29 +++++++++++++++++++++++++++--
>>   1 file changed, 27 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hwmon/sht3x.c b/drivers/hwmon/sht3x.c
>> index 5bc0001b1..eb968b9d3 100644
>> --- a/drivers/hwmon/sht3x.c
>> +++ b/drivers/hwmon/sht3x.c
>> @@ -25,6 +25,10 @@
>>   static const unsigned char sht3x_cmd_measure_blocking_hpm[] = { 
>> 0x2c, 0x06 };
>>   static const unsigned char sht3x_cmd_measure_nonblocking_hpm[] = { 
>> 0x24, 0x00 };
>>   +/* commands (medium repeatability mode) */
>> +static const unsigned char sht3x_cmd_measure_blocking_mpm[] = { 
>> 0x2c, 0x0d };
>> +static const unsigned char sht3x_cmd_measure_nonblocking_mpm[] = { 
>> 0x24, 0x0b };
>> +
>>   /* commands (low repeatability mode) */
>>   static const unsigned char sht3x_cmd_measure_blocking_lpm[] = { 
>> 0x2c, 0x10 };
>>   static const unsigned char sht3x_cmd_measure_nonblocking_lpm[] = { 
>> 0x24, 0x16 };
>> @@ -43,6 +47,7 @@ static const unsigned char 
>> sht3x_cmd_clear_status_reg[]        = { 0x30, 0x41 };
>>     /* delays for non-blocking i2c commands, both in us */
>>   #define SHT3X_NONBLOCKING_WAIT_TIME_HPM  15000
>> +#define SHT3X_NONBLOCKING_WAIT_TIME_MPM   6000
>>   #define SHT3X_NONBLOCKING_WAIT_TIME_LPM   4000
>>     #define SHT3X_WORD_LEN         2
>> @@ -69,8 +74,9 @@ enum sht3x_limits {
>>   };
>>     enum sht3x_repeatability {
>> -    low_repeatability,
>> -    high_repeatability,
>> +    low_repeatability    = 0,
>> +    medium_repeatability = 1,
>> +    high_repeatability   = 2,
>
> Why the assignments ?
>
Maybe it won't be needed.
>>   };
>>     DECLARE_CRC8_TABLE(sht3x_crc8_table);
>> @@ -89,6 +95,20 @@ static const char 
>> periodic_measure_commands_hpm[][SHT3X_CMD_LENGTH] = {
>>       {0x27, 0x37},
>>   };
>>   +/* periodic measure commands (medium repeatability) */
>> +static const char periodic_measure_commands_mpm[][SHT3X_CMD_LENGTH] = {
>
> FWIW, it might make sense to add the command for blocking mode
> (0 measurements per second) into this table to simplify the code.
>
I am trying to do it and review the effects.
>> +    /* 0.5 measurements per second */
>> +    {0x20, 0x24},
>> +    /* 1 measurements per second */
>> +    {0x21, 0x26},
>> +    /* 2 measurements per second */
>> +    {0x22, 0x20},
>> +    /* 4 measurements per second */
>> +    {0x23, 0x22},
>> +    /* 10 measurements per second */
>> +    {0x27, 0x21},
>> +};
>> +
>>   /* periodic measure commands (low repeatability mode) */
>>   static const char periodic_measure_commands_lpm[][SHT3X_CMD_LENGTH] 
>> = {
>>       /* 0.5 measurements per second */
>> @@ -448,6 +468,9 @@ static void sht3x_select_command(struct 
>> sht3x_data *data)
>>           if (data->repeatability == high_repeatability) {
>>               data->command = sht3x_cmd_measure_nonblocking_hpm;
>>               data->wait_time = SHT3X_NONBLOCKING_WAIT_TIME_HPM;
>> +        } else if (data->repeatability == medium_repeatability) {
>> +            data->command = sht3x_cmd_measure_nonblocking_mpm;
>> +            data->wait_time = SHT3X_NONBLOCKING_WAIT_TIME_MPM;
>>           } else {
>>               data->command = sht3x_cmd_measure_nonblocking_lpm;
>>               data->wait_time = SHT3X_NONBLOCKING_WAIT_TIME_LPM;
>> @@ -595,6 +618,8 @@ static ssize_t update_interval_store(struct 
>> device *dev,
>>       if (mode > 0) {
>>           if (data->repeatability == high_repeatability)
>>               command = periodic_measure_commands_hpm[mode - 1];
>> +        else if (data->repeatability == medium_repeatability)
>> +            command = periodic_measure_commands_mpm[mode - 1];
>>           else
>>               command = periodic_measure_commands_lpm[mode - 1];
>