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@xxxxxxxxx>
> ---
> 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?
> + 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
