[PATCH v6 1/1] rtc: nuvoton: Compatible with NCT3015Y-R and NCT3018Y-R

[Mining Lin]

Dear Alexandre,

Thanks for your comments.
The replies are as follow.

Thanks.
Best regard,
Mia

Sent from my iPhone

> On Nov 4, 2023, at 7:16 AM, Alexandre Belloni <alexandre.belloni at bootlin.com> wrote:
> 
> On 13/09/2023 09:37:19+0800, Mia Lin wrote:
>> The NCT3015Y-R and NCT3018Y-R use the same datasheet
>>    but have different topologies as follows.
>> - Topology (Only 1st i2c can set TWO bit and HF bit)
>>  In NCT3015Y-R,
>>    rtc 1st i2c is connected to a host CPU
>>    rtc 2nd i2c is connected to a BMC
>>  In NCT3018Y-R,
>>    rtc 1st i2c is connected to a BMC
>>    rtc 2nd i2c is connected to a host CPU
>> In order to be compatible with NCT3015Y-R and NCT3018Y-R,
>> - In probe,
>>  If part number is NCT3018Y-R, only set HF bit to 24-Hour format.
>>  Else, do nothing
>> - In set_time,
>>  If part number is NCT3018Y-R && TWO bit is 0,
>>     change TWO bit to 1, and restore TWO bit after updating time.
>> 
>> Signed-off-by: Mia Lin <mimi05633 at gmail.com>
>> ---
>> drivers/rtc/rtc-nct3018y.c | 52 +++++++++++++++++++++++++++++++++-----
>> 1 file changed, 46 insertions(+), 6 deletions(-)
>> 
>> diff --git a/drivers/rtc/rtc-nct3018y.c b/drivers/rtc/rtc-nct3018y.c
>> index ed4e606be8e5..b006b58e15e2 100644
>> --- a/drivers/rtc/rtc-nct3018y.c
>> +++ b/drivers/rtc/rtc-nct3018y.c
>> @@ -23,6 +23,7 @@
>> #define NCT3018Y_REG_CTRL    0x0A /* timer control */
>> #define NCT3018Y_REG_ST        0x0B /* status */
>> #define NCT3018Y_REG_CLKO    0x0C /* clock out */
>> +#define NCT3018Y_REG_PART    0x21 /* part info */
>> 
>> #define NCT3018Y_BIT_AF        BIT(7)
>> #define NCT3018Y_BIT_ST        BIT(7)
>> @@ -37,10 +38,12 @@
>> #define NCT3018Y_REG_BAT_MASK        0x07
>> #define NCT3018Y_REG_CLKO_F_MASK    0x03 /* frequenc mask */
>> #define NCT3018Y_REG_CLKO_CKE        0x80 /* clock out enabled */
>> +#define NCT3018Y_REG_PART_NCT3018Y    0x02
>> 
>> struct nct3018y {
>>    struct rtc_device *rtc;
>>    struct i2c_client *client;
>> +    int part_num;
>> #ifdef CONFIG_COMMON_CLK
>>    struct clk_hw clkout_hw;
>> #endif
>> @@ -177,8 +180,27 @@ static int nct3018y_rtc_read_time(struct device *dev, struct rtc_time *tm)
>> static int nct3018y_rtc_set_time(struct device *dev, struct rtc_time *tm)
>> {
>>    struct i2c_client *client = to_i2c_client(dev);
>> +    struct nct3018y *nct3018y = dev_get_drvdata(dev);
>>    unsigned char buf[4] = {0};
>> -    int err;
>> +    int err, flags;
>> +    int restore_flags = 0;
>> +
>> +    flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
>> +    if (flags < 0) {
>> +        dev_dbg(&client->dev, "Failed to read NCT3018Y_REG_CTRL.\n");
>> +        return flags;
>> +    }
>> +
>> +    /* Check and set TWO bit */
>> +    if ((nct3018y->part_num & NCT3018Y_REG_PART_NCT3018Y) && !(flags & NCT3018Y_BIT_TWO)) {
>> +        restore_flags = 1;
>> +        flags |= NCT3018Y_BIT_TWO;
>> +        err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
>> +        if (err < 0) {
>> +            dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL.\n");
>> +            return err;
>> +        }
>> +    }
>> 
>>    buf[0] = bin2bcd(tm->tm_sec);
>>    err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SC, buf[0]);
>> @@ -212,6 +234,18 @@ static int nct3018y_rtc_set_time(struct device *dev, struct rtc_time *tm)
>>        return -EIO;
>>    }
>> 
>> +    /* Restore TWO bit */
>> +    if (restore_flags) {
>> +        if (nct3018y->part_num & NCT3018Y_REG_PART_NCT3018Y)
>> +            flags &= ~NCT3018Y_BIT_TWO;
>> +
>> +        err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
>> +        if (err < 0) {
>> +            dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL.\n");
>> +            return err;
>> +        }
>> +    }
>> +
>>    return err;
>> }
>> 
>> @@ -479,11 +513,17 @@ static int nct3018y_probe(struct i2c_client *client)
>>        dev_dbg(&client->dev, "%s: NCT3018Y_BIT_TWO is set\n", __func__);
>>    }
>> 
>> -    flags = NCT3018Y_BIT_TWO;
>> -    err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
>> -    if (err < 0) {
>> -        dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL\n");
>> -        return err;
>> +    nct3018y->part_num = i2c_smbus_read_byte_data(client, NCT3018Y_REG_PART);
>> +    if (nct3018y->part_num < 0) {
>> +        dev_dbg(&client->dev, "Failed to read NCT3018Y_REG_PART.\n");
>> +        return nct3018y->part_num;
>> +    } else if (nct3018y->part_num & NCT3018Y_REG_PART_NCT3018Y) {
> 
> This is a weird way to check as this will accept any value of
> NCT3018Y_REG_PART as long as bit 1 is set, is this really what you want?
［Mia] Thanks for your comments. I’ll fix it.
> 
>> +        flags = NCT3018Y_BIT_HF;
>> +        err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
>> +        if (err < 0) {
>> +            dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL.\n");
>> +            return err;
>> +        }
>>    }
>> 
>>    flags = 0;
>> -- 
>> 2.17.1
>> 
> 
> -- 
> Alexandre Belloni, co-owner and COO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com