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Message-ID: <20231103231735b4769ca4@mail.local>
Date: Sat, 4 Nov 2023 00:17:35 +0100
From: Alexandre Belloni <alexandre.belloni@...tlin.com>
To: Mia Lin <mimi05633@...il.com>
Cc: avifishman70@...il.com, tmaimon77@...il.com, tali.perry1@...il.com,
venture@...gle.com, yuenn@...gle.com, benjaminfair@...gle.com,
a.zummo@...ertech.it, KWLIU@...oton.com, JJLIU0@...oton.com,
KFLIN@...oton.com, mylin1@...oton.com, openbmc@...ts.ozlabs.org,
linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 1/1] rtc: nuvoton: Compatible with NCT3015Y-R and
NCT3018Y-R
On 04/11/2023 00:16:40+0100, Alexandre Belloni 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@...il.com>
> > ---
I forgot to add, please include a changelog here, this will make my
reviews easier (and faster).
> > 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
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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