Message-ID: <CAHpyw9fw54hQrsPa4psbUs2VfBqHj+gMKDceL2N5k8_jU+434w@mail.gmail.com>
Date:   Wed, 18 May 2022 11:11:00 +0800
From:   Medad Young <medadyoung@...il.com>
To:     Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     Benjamin Fair <benjaminfair@...gle.com>,
        Nancy Yuen <yuenn@...gle.com>,
        Patrick Venture <venture@...gle.com>,
        Tali Perry <tali.perry1@...il.com>,
        Tomer Maimon <tmaimon77@...il.com>,
        Avi Fishman <avifishman70@...il.com>,
        Rob Herring <robh+dt@...nel.org>, a.zummo@...ertech.it,
        KWLIU@...oton.com, YSCHU@...oton.com, JJLIU0@...oton.com,
        KFTING <KFTING@...oton.com>, ctcchien@...oton.com,
        OpenBMC Maillist <openbmc@...ts.ozlabs.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-rtc@...r.kernel.org
Subject: Re: [PATCH v2 3/3] RTC: nuvoton: Add NCT3018Y real time clock driver

Dear Alexandre,

thanks for your comments.

Alexandre Belloni <alexandre.belloni@...tlin.com> 於 2022年5月18日 週三 上午3:11寫道：
>
> Hello,
>
> Thank you for your submission. There are a bunch of checkpatch --strict issues,
> please fix them.
>
> On 17/05/2022 17:29:26+0800, Medad CChien wrote:
> > Add real time clock support for NCT3018Y.
>
> Is the NCT3018Y an SoC or a discrete RTC?

NCT3018Y is a discrete RTC

>
> >
> > Fix the following warnings and errors:
> > error:
> >    drivers/rtc/rtc-nct3018y.c:513:39: warning: format '%d' expects argument of type 'int', but argument 5 has type 'long unsigned int'
> >    drivers/rtc/rtc-nct3018y.c:513:39: warning: format '%d' expects argument of type 'int', but argument 5 has type 'long unsigned int'
> > warnings:
> >    drivers/rtc/rtc-nct3018y.c:192:26: warning: unused variable 'nct3018y'
> >    drivers/rtc/rtc-nct3018y.c:513:39: warning: format '%d' expects argument of type 'int', but argument 5 has type 'long unsigned int'
> > Reported-by: kernel test robot <lkp@...el.com>
> >
>
> This part doesn't belong in the commit message as the patch introducing
> the issue will never be upstream

OK, I got your point,
I will remove this part.

>
> > Signed-off-by: Medad CChien <ctcchien@...oton.com>
> > ---
> >  drivers/rtc/Kconfig        |  10 +
> >  drivers/rtc/Makefile       |   1 +
> >  drivers/rtc/rtc-nct3018y.c | 592 +++++++++++++++++++++++++++++++++++++
> >  3 files changed, 603 insertions(+)
> >  create mode 100644 drivers/rtc/rtc-nct3018y.c
> >
> > diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> > index d85a3c31347c..d83d31c76443 100644
> > --- a/drivers/rtc/Kconfig
> > +++ b/drivers/rtc/Kconfig
> > @@ -383,6 +383,16 @@ config RTC_DRV_MAX77686
> >         This driver can also be built as a module. If so, the module
> >         will be called rtc-max77686.
> >
> > +config RTC_DRV_NCT3018Y
> > +     tristate "Nuvoton Real Time Clock"
>
> This definitively needs a better description

OK, I will add a better description.
>
> > +     depends on OF
> > +     help
> > +        If you say yes here you get support for the Nuvoton NCT3018Y RTC
> > +        module.
> > +
> > +        This driver can also be built as a module, if so, the module will
> > +        be called "rtc-nct3018y".
> > +
> >  config RTC_DRV_RK808
> >       tristate "Rockchip RK805/RK808/RK809/RK817/RK818 RTC"
> >       depends on MFD_RK808
> > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> > index e92f3e943245..d3c100e43d1f 100644
> > --- a/drivers/rtc/Makefile
> > +++ b/drivers/rtc/Makefile
> > @@ -112,6 +112,7 @@ obj-$(CONFIG_RTC_DRV_MV)  += rtc-mv.o
> >  obj-$(CONFIG_RTC_DRV_MXC)    += rtc-mxc.o
> >  obj-$(CONFIG_RTC_DRV_MXC_V2) += rtc-mxc_v2.o
> >  obj-$(CONFIG_RTC_DRV_GAMECUBE)       += rtc-gamecube.o
> > +obj-$(CONFIG_RTC_DRV_NCT3018Y)       += rtc-nct3018y.o
> >  obj-$(CONFIG_RTC_DRV_NTXEC)  += rtc-ntxec.o
> >  obj-$(CONFIG_RTC_DRV_OMAP)   += rtc-omap.o
> >  obj-$(CONFIG_RTC_DRV_OPAL)   += rtc-opal.o
> > diff --git a/drivers/rtc/rtc-nct3018y.c b/drivers/rtc/rtc-nct3018y.c
> > new file mode 100644
> > index 000000000000..4b2e66be8064
> > --- /dev/null
> > +++ b/drivers/rtc/rtc-nct3018y.c
> > @@ -0,0 +1,592 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +// Copyright (c) 2022 Nuvoton Technology Corporation
> > +
> > +#include <linux/bcd.h>
> > +#include <linux/clk-provider.h>
> > +#include <linux/err.h>
> > +#include <linux/i2c.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/rtc.h>
> > +#include <linux/slab.h>
> > +
> > +#define NCT3018Y_REG_SC              0x00 /* seconds */
> > +#define NCT3018Y_REG_SCA     0x01 /* alarm */
> > +#define NCT3018Y_REG_MN              0x02
> > +#define NCT3018Y_REG_MNA     0x03 /* alarm */
> > +#define NCT3018Y_REG_HR              0x04
> > +#define NCT3018Y_REG_HRA     0x05 /* alarm */
> > +#define NCT3018Y_REG_DW              0x06
> > +#define NCT3018Y_REG_DM              0x07
> > +#define NCT3018Y_REG_MO              0x08
> > +#define NCT3018Y_REG_YR              0x09
> > +#define NCT3018Y_REG_CTRL    0x0A /* timer control */
> > +#define NCT3018Y_REG_ST              0x0B /* status */
> > +#define NCT3018Y_REG_CLKO    0x0C /* clock out */
> > +
> > +#define NCT3018Y_BIT_AF              BIT(7)
> > +#define NCT3018Y_BIT_ST              BIT(7)
> > +#define NCT3018Y_BIT_DM              BIT(6)
> > +#define NCT3018Y_BIT_HF              BIT(5)
> > +#define NCT3018Y_BIT_DSM     BIT(4)
> > +#define NCT3018Y_BIT_AIE     BIT(3)
> > +#define NCT3018Y_BIT_OFIE    BIT(2)
> > +#define NCT3018Y_BIT_CIE     BIT(1)
> > +#define NCT3018Y_BIT_TWO     BIT(0)
> > +
> > +#define NCT3018Y_REG_CLKO_F_MASK     0x03 /* frequenc mask */
> > +#define NCT3018Y_REG_CLKO_CKE                0x80 /* clock out enabled */
> > +
> > +static struct i2c_driver nct3018y_driver;
>
> I prefer we avoid this forward declaration.

Ok, I will try to avoid it.

>
> > +
> > +struct nct3018y {
> > +     struct rtc_device *rtc;
> > +     struct i2c_client *client;
> > +     struct gpio_desc *wakeup_host;
> > +#ifdef CONFIG_COMMON_CLK
> > +     struct clk_hw           clkout_hw;
> > +#endif
> > +};
> > +
> > +static int nct3018y_read_block_data(struct i2c_client *client,
> > +                                 unsigned char reg, unsigned char length, unsigned char *buf)
> > +{
> > +     struct i2c_msg msgs[] = {
> > +             {/* setup read ptr */
> > +                     .addr = client->addr,
> > +                     .len = 1,
> > +                     .buf = &reg,
> > +             },
> > +             {
> > +                     .addr = client->addr,
> > +                     .flags = I2C_M_RD,
> > +                     .len = length,
> > +                     .buf = buf
> > +             },
> > +     };
> > +
> > +     if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
> > +             dev_err(&client->dev, "%s: read error\n", __func__);
>
> Please cut down on the error messages most of them will never be useful
> but will take some space. Also, you should probably use regmap instead
> of rolling your own function.
>

OK

> > +             return -EIO;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int nct3018y_write_block_data(struct i2c_client *client,
> > +                                  unsigned char reg, unsigned char length,
> > +                                  unsigned char *buf)
> > +{
> > +     int i, err;
> > +
> > +     for (i = 0; i < length; i++) {
> > +             unsigned char data[2] = { reg + i, buf[i] };
> > +
> > +             err = i2c_master_send(client, data, sizeof(data));
> > +             if (err != sizeof(data)) {
> > +                     dev_err(&client->dev, "%s: err=%d addr=%02x, data=%02x\n", __func__,
> > +                             err, data[0], data[1]);
> > +                     return -EIO;
> > +             }
>
> Are you sure you need to send data byte per byte?

OK, I will try to modify

>
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int nct3018y_set_alarm_mode(struct i2c_client *client, bool on)
> > +{
> > +     unsigned char buf;
> > +     int err;
> > +
> > +     dev_dbg(&client->dev, "%s:on:%d\n", __func__, on);
> > +     err = nct3018y_read_block_data(client, NCT3018Y_REG_CTRL, 1, &buf);
> > +     if (err < 0)
> > +             return err;
> > +
> > +     if (on)
> > +             buf |= NCT3018Y_BIT_AIE;
> > +     else
> > +             buf &= ~NCT3018Y_BIT_AIE;
> > +
> > +     buf |= NCT3018Y_BIT_CIE;
> > +     err = nct3018y_write_block_data(client, NCT3018Y_REG_CTRL, 1, &buf);
> > +     if (err < 0) {
> > +             dev_err(&client->dev, "%s: write NCT3018Y_REG_ST error\n", __func__);
> > +             return -EIO;
> > +     }
> > +
> > +     err = nct3018y_read_block_data(client, NCT3018Y_REG_ST, 1, &buf);
> > +     if (err < 0)
> > +             return err;
> > +
> > +     buf &= ~(NCT3018Y_BIT_AF);
> > +     err = nct3018y_write_block_data(client, NCT3018Y_REG_ST, 1, &buf);
> > +     if (err < 0) {
> > +             dev_err(&client->dev, "%s: write NCT3018Y_REG_ST error\n", __func__);
> > +             return -EIO;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int nct3018y_get_alarm_mode(struct i2c_client *client, unsigned char *alarm_enable,
> > +                               unsigned char *alarm_flag)
> > +{
> > +     unsigned char buf;
> > +     int err;
> > +
> > +     if (alarm_enable) {
> > +             dev_dbg(&client->dev, "%s:NCT3018Y_REG_CTRL\n", __func__);
> > +             err = nct3018y_read_block_data(client, NCT3018Y_REG_CTRL, 1, &buf);
> > +             if (err)
> > +                     return err;
> > +             *alarm_enable = buf & NCT3018Y_BIT_AIE;
> > +     }
> > +
> > +     if (alarm_flag) {
> > +             dev_dbg(&client->dev, "%s:NCT3018Y_REG_ST\n", __func__);
> > +             err = nct3018y_read_block_data(client, NCT3018Y_REG_ST, 1, &buf);
> > +             if (err)
> > +                     return err;
> > +             *alarm_flag = buf & NCT3018Y_BIT_AF;
> > +     }
> > +
> > +     dev_dbg(&client->dev, "%s:alarm_enable:%x alarm_flag:%x\n",
> > +             __func__, *alarm_enable, *alarm_flag);
> > +
> > +     return 0;
> > +}
> > +
> > +static irqreturn_t nct3018y_irq(int irq, void *dev_id)
> > +{
> > +     struct nct3018y *nct3018y = i2c_get_clientdata(dev_id);
> > +     struct i2c_client *client = nct3018y->client;
> > +     int err;
> > +     unsigned char alarm_flag;
> > +     unsigned char alarm_enable;
> > +
> > +     dev_dbg(&client->dev, "%s:irq:%d\n", __func__, irq);
> > +     err = nct3018y_get_alarm_mode(nct3018y->client, &alarm_enable, &alarm_flag);
> > +     if (err)
> > +             return IRQ_NONE;
> > +
> > +     if (alarm_flag) {
> > +             dev_dbg(&client->dev, "%s:alarm flag:%x\n",
> > +                     __func__, alarm_flag);
> > +             rtc_update_irq(nct3018y->rtc, 1, RTC_IRQF | RTC_AF);
> > +             nct3018y_set_alarm_mode(nct3018y->client, 1);
>
> Doesn't that rearm the alarm? I would expect the opposite here.

OK.

>
> > +             dev_dbg(&client->dev, "%s:IRQ_HANDLED\n", __func__);
> > +             return IRQ_HANDLED;
> > +     }
> > +
> > +     return IRQ_NONE;
> > +}
> > +
> > +/*
> > + * In the routines that deal directly with the nct3018y hardware, we use
> > + * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
> > + */
> > +static int nct3018y_rtc_read_time(struct device *dev, struct rtc_time *tm)
> > +{
> > +     struct i2c_client *client = to_i2c_client(dev);
> > +     unsigned char buf[10];
> > +     int err;
> > +
> > +     err = nct3018y_read_block_data(client, NCT3018Y_REG_ST, 1, buf);
> > +     if (err)
> > +             return err;
> > +
> > +     if (!buf[0]) {
> > +             dev_err(&client->dev, " voltage <=1.7, date/time is not reliable.\n");
>
> This error message is not actually useful, implement the RTC_VL_READ
> ioctl instead.

OK, I will check how other RTC drivers do.

>
> > +             return -EINVAL;
> > +     }
> > +
> > +     err = nct3018y_read_block_data(client, NCT3018Y_REG_SC, 10, buf);
> > +     if (err)
> > +             return err;
> > +
> > +     tm->tm_sec = bcd2bin(buf[0] & 0x7F);
> > +     tm->tm_min = bcd2bin(buf[2] & 0x7F);
> > +     tm->tm_hour = bcd2bin(buf[4] & 0x3F); /* rtc hr 0-24 */
>
> This comment is not accurate, as shown by the comment on top of the
> function. I would prefer no comment in that case.

OK

>
> > +     tm->tm_wday = buf[6] & 0x07;
> > +     tm->tm_mday = bcd2bin(buf[7] & 0x3F);
> > +     tm->tm_mon = bcd2bin(buf[8] & 0x1F) - 1 ; /* rtc mn 1-12 */
> > +     tm->tm_year = bcd2bin(buf[9]) + 100;
> > +
> > +     dev_dbg(&client->dev, "%s:s=%d, m=%d, hr=%d, md=%d, m=%d, yr=%d, wd=%d\n",
> > +             __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon,
> > +             tm->tm_year, tm->tm_wday);
> > +
> > +     return 0;
> > +}
> > +
> > +static int nct3018y_rtc_set_time(struct device *dev, struct rtc_time *tm)
> > +{
> > +     struct i2c_client *client = to_i2c_client(dev);
> > +     unsigned char buf[10] = {0};
> > +     int err;
> > +
> > +     dev_dbg(&client->dev, "%s:s=%d, m=%d, hr=%d, md=%d, m=%d, yr=%d, wd=%d\n",
> > +             __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon,
> > +             tm->tm_year, tm->tm_wday);
> > +
> > +     err = nct3018y_read_block_data(client, NCT3018Y_REG_CTRL, 1, buf);
> > +     if (err)
> > +             return err;
> > +
> > +     if (!(buf[0] & NCT3018Y_BIT_TWO)) {
> > +             dev_err(&client->dev,
> > +                     " TWO is not set.\n");
>
> This is not useful, what is TWO?

TWO stands for Time Registers Write Ownership
for NCT3018Y, driver needs to set this bit before writing to other registers

>
> > +             return -EINVAL;
> > +     }
> > +
> > +     /* hours, minutes and seconds */
> > +     buf[NCT3018Y_REG_SC] = bin2bcd(tm->tm_sec);
> > +     buf[NCT3018Y_REG_MN] = bin2bcd(tm->tm_min);
> > +     buf[NCT3018Y_REG_HR] = bin2bcd(tm->tm_hour);
> > +     buf[NCT3018Y_REG_DW] = tm->tm_wday & 0x07;
> > +     buf[NCT3018Y_REG_DM] = bin2bcd(tm->tm_mday);
> > +
> > +     /* month, 1 - 12 */
> > +     buf[NCT3018Y_REG_MO] = bin2bcd(tm->tm_mon+1);
> > +
> > +     /* year and century */
>
> Were is the century?

I will update the comment, for there is no century.

>
> > +     buf[NCT3018Y_REG_YR] = bin2bcd(tm->tm_year - 100);
> > +
> > +     return nct3018y_write_block_data(client, NCT3018Y_REG_SC, 10, buf);
> > +}
> > +
> > +static int nct3018y_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
> > +{
> > +     struct i2c_client *client = to_i2c_client(dev);
> > +     unsigned char buf[5];
> > +     int err;
> > +
> > +     err = nct3018y_read_block_data(client, NCT3018Y_REG_SCA, 5, buf);
> > +     if (err)
> > +             return err;
> > +
> > +     dev_dbg(&client->dev, "%s: raw data is sec=%02x, min=%02x hr=%02x\n",
> > +             __func__, buf[0], buf[2], buf[4]);
> > +
> > +     tm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
> > +     tm->time.tm_min = bcd2bin(buf[2] & 0x7F);
> > +     tm->time.tm_hour = bcd2bin(buf[4] & 0x3F);
> > +
> > +     err = nct3018y_get_alarm_mode(client, &tm->enabled, &tm->pending);
> > +     if (err < 0)
> > +             return err;
> > +
> > +     dev_dbg(&client->dev, "%s:s=%d m=%d, hr=%d, enabled=%d, pending=%d\n",
> > +             __func__, tm->time.tm_sec, tm->time.tm_min,
> > +             tm->time.tm_hour, tm->enabled, tm->pending);
> > +
> > +     return 0;
> > +}
> > +
> > +static int nct3018y_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
> > +{
> > +     struct i2c_client *client = to_i2c_client(dev);
> > +     unsigned char buf[3];
> > +     int err;
> > +
> > +     dev_dbg(dev, "%s, sec=%d, min=%d hour=%d tm->enabled:%d\n",
> > +             __func__, tm->time.tm_sec, tm->time.tm_min, tm->time.tm_hour,
> > +             tm->enabled);
> > +
> > +     buf[0] = bin2bcd(tm->time.tm_sec);
> > +     buf[1] = bin2bcd(tm->time.tm_min);
> > +     buf[2] = bin2bcd(tm->time.tm_hour);
> > +
> > +     err = nct3018y_write_block_data(client, NCT3018Y_REG_SCA, 1, buf);
> > +     if (err)
> > +             return err;
>
>
> Writing byte per byte opens a huge window for a race condition here.
>

I write byte per byte,
because these three registers are not continuous

> > +
> > +     err = nct3018y_write_block_data(client, NCT3018Y_REG_MNA, 1, buf+1);
> > +     if (err)
> > +             return err;
> > +
> > +     err = nct3018y_write_block_data(client, NCT3018Y_REG_HRA, 1, buf+2);
> > +     if (err)
> > +             return err;
> > +
> > +     return nct3018y_set_alarm_mode(client, tm->enabled);
> > +}
> > +
> > +static int nct3018y_irq_enable(struct device *dev, unsigned int enabled)
> > +{
> > +     dev_dbg(dev, "%s: alarm enable=%d\n", __func__, enabled);
> > +
> > +     return nct3018y_set_alarm_mode(to_i2c_client(dev), enabled);
> > +}
> > +
> > +#ifdef CONFIG_COMMON_CLK
> > +/*
> > + * Handling of the clkout
> > + */
> > +
> > +#define clkout_hw_to_nct3018y(_hw) container_of(_hw, struct nct3018y, clkout_hw)
> > +
> > +static const int clkout_rates[] = {
> > +     32768,
> > +     1024,
> > +     32,
> > +     1,
> > +};
> > +
> > +static unsigned long nct3018y_clkout_recalc_rate(struct clk_hw *hw,
> > +                                              unsigned long parent_rate)
> > +{
> > +     struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
> > +     struct i2c_client *client = nct3018y->client;
> > +     unsigned char buf;
> > +     int ret = nct3018y_read_block_data(client, NCT3018Y_REG_CLKO, 1, &buf);
> > +
> > +     if (ret < 0)
> > +             return 0;
> > +
> > +     buf &= NCT3018Y_REG_CLKO_F_MASK;
> > +     return clkout_rates[buf];
> > +}
> > +
> > +static long nct3018y_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
> > +                                    unsigned long *prate)
> > +{
> > +     int i;
> > +
> > +     for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
> > +             if (clkout_rates[i] <= rate)
> > +                     return clkout_rates[i];
> > +
> > +     return 0;
> > +}
> > +
> > +static int nct3018y_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
> > +                                unsigned long parent_rate)
> > +{
> > +     struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
> > +     struct i2c_client *client = nct3018y->client;
> > +     unsigned char buf;
> > +     int ret = nct3018y_read_block_data(client, NCT3018Y_REG_CLKO, 1, &buf);
> > +     int i;
> > +
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
> > +             if (clkout_rates[i] == rate) {
> > +                     buf &= ~NCT3018Y_REG_CLKO_F_MASK;
> > +                     buf |= i;
> > +                     ret = nct3018y_write_block_data(client, NCT3018Y_REG_CLKO, 1, &buf);
> > +                     return ret;
> > +             }
> > +
> > +     return -EINVAL;
> > +}
> > +
> > +static int nct3018y_clkout_control(struct clk_hw *hw, bool enable)
> > +{
> > +     struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
> > +     struct i2c_client *client = nct3018y->client;
> > +     unsigned char buf;
> > +     int ret = nct3018y_read_block_data(client, NCT3018Y_REG_CLKO, 1, &buf);
> > +
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     if (enable)
> > +             buf |= NCT3018Y_REG_CLKO_CKE;
> > +     else
> > +             buf &= ~NCT3018Y_REG_CLKO_CKE;
> > +
> > +     ret = nct3018y_write_block_data(client, NCT3018Y_REG_CLKO, 1, &buf);
> > +     return ret;
> > +}
> > +
> > +static int nct3018y_clkout_prepare(struct clk_hw *hw)
> > +{
> > +     return nct3018y_clkout_control(hw, 1);
> > +}
> > +
> > +static void nct3018y_clkout_unprepare(struct clk_hw *hw)
> > +{
> > +     nct3018y_clkout_control(hw, 0);
> > +}
> > +
> > +static int nct3018y_clkout_is_prepared(struct clk_hw *hw)
> > +{
> > +     struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
> > +     struct i2c_client *client = nct3018y->client;
> > +     unsigned char buf;
> > +     int ret = nct3018y_read_block_data(client, NCT3018Y_REG_CLKO, 1, &buf);
> > +
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     return buf & NCT3018Y_REG_CLKO_CKE;
> > +}
> > +
> > +static const struct clk_ops nct3018y_clkout_ops = {
> > +     .prepare = nct3018y_clkout_prepare,
> > +     .unprepare = nct3018y_clkout_unprepare,
> > +     .is_prepared = nct3018y_clkout_is_prepared,
> > +     .recalc_rate = nct3018y_clkout_recalc_rate,
> > +     .round_rate = nct3018y_clkout_round_rate,
> > +     .set_rate = nct3018y_clkout_set_rate,
> > +};
> > +
> > +static struct clk *nct3018y_clkout_register_clk(struct nct3018y *nct3018y)
> > +{
> > +     struct i2c_client *client = nct3018y->client;
> > +     struct device_node *node = client->dev.of_node;
> > +     struct clk *clk;
> > +     struct clk_init_data init;
> > +     int ret;
> > +     unsigned char buf;
> > +
> > +     /* disable the clkout output */
> > +     buf = 0;
> > +     ret = nct3018y_write_block_data(client, NCT3018Y_REG_CLKO, 1, &buf);
> > +     if (ret < 0)
> > +             return ERR_PTR(ret);
> > +
> > +     init.name = "nct3018y-clkout";
> > +     init.ops = &nct3018y_clkout_ops;
> > +     init.flags = 0;
> > +     init.parent_names = NULL;
> > +     init.num_parents = 0;
> > +     nct3018y->clkout_hw.init = &init;
> > +
> > +     /* optional override of the clockname */
> > +     of_property_read_string(node, "clock-output-names", &init.name);
> > +
> > +     /* register the clock */
> > +     clk = devm_clk_register(&client->dev, &nct3018y->clkout_hw);
> > +
> > +     if (!IS_ERR(clk))
> > +             of_clk_add_provider(node, of_clk_src_simple_get, clk);
> > +
> > +     return clk;
> > +}
> > +#endif
> > +
> > +static const struct rtc_class_ops nct3018y_rtc_ops = {
> > +     .read_time      = nct3018y_rtc_read_time,
> > +     .set_time       = nct3018y_rtc_set_time,
> > +     .read_alarm     = nct3018y_rtc_read_alarm,
> > +     .set_alarm      = nct3018y_rtc_set_alarm,
> > +     .alarm_irq_enable = nct3018y_irq_enable,
> > +};
> > +
> > +static int nct3018y_probe(struct i2c_client *client,
> > +                       const struct i2c_device_id *id)
> > +{
> > +     struct nct3018y *nct3018y;
> > +     int err;
> > +     unsigned char buf;
> > +
> > +     if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
> > +             dev_err(&client->dev, "%s: ENODEV\n", __func__);
> > +             return -ENODEV;
> > +     }
> > +
> > +     nct3018y = devm_kzalloc(&client->dev, sizeof(struct nct3018y),
> > +                             GFP_KERNEL);
> > +     if (!nct3018y)
> > +             return -ENOMEM;
> > +
> > +     i2c_set_clientdata(client, nct3018y);
> > +     nct3018y->client = client;
> > +     device_set_wakeup_capable(&client->dev, 1);
> > +
> > +     err = nct3018y_read_block_data(client, NCT3018Y_REG_CTRL, 1, &buf);
> > +     if (err < 0) {
> > +             dev_err(&client->dev, "%s: read error\n", __func__);
> > +             return err;
> > +     } else if (buf & NCT3018Y_BIT_TWO) {
> > +             dev_dbg(&client->dev, "%s: NCT3018Y_BIT_TWO is :%ld\n",
> > +                     __func__, buf & NCT3018Y_BIT_TWO);
> > +     }
> > +
> > +     buf = 0 | NCT3018Y_BIT_TWO;
>
> This seems weird

Ok, I will modify it.

>
> > +     err = nct3018y_write_block_data(client, NCT3018Y_REG_CTRL, 1, &buf);
> > +     if (err < 0) {
> > +             dev_err(&client->dev, "%s: write fail, so ReadOnly\n", __func__);
> > +     } else {
> > +             buf = 0;
> > +             err = nct3018y_write_block_data(client, NCT3018Y_REG_ST, 1, &buf);
> > +             if (err < 0) {
> > +                     dev_err(&client->dev, "%s: write error\n", __func__);
> > +                     return err;
> > +             }
> > +     }
> > +
> > +     nct3018y->rtc = devm_rtc_allocate_device(&client->dev);
> > +     if (IS_ERR(nct3018y->rtc))
> > +             return PTR_ERR(nct3018y->rtc);
> > +
> > +     nct3018y->rtc->ops = &nct3018y_rtc_ops;
> > +     nct3018y->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
> > +     nct3018y->rtc->range_max = RTC_TIMESTAMP_END_2099;
> > +     nct3018y->rtc->set_start_time = true;
>
> Do you have a good reason to set set_start_time here?
>

Sorry, I am new here.
I just follow other drivers.
so you think I should not set set_start_time, right?

> > +
> > +     nct3018y->wakeup_host = devm_gpiod_get(&client->dev, "host-wakeup", GPIOD_IN);
> > +     if (IS_ERR(nct3018y->wakeup_host)) {
> > +             err = PTR_ERR(nct3018y->wakeup_host);
> > +             dev_err(&client->dev, "could not get host wakeup gpio: %d", err);
> > +             return err;
> > +     }
> > +     client->irq = gpiod_to_irq(nct3018y->wakeup_host);
>
> I don't get why you need that instead of using client->irq directly
> which is already parsed by the i2c core for you.
>

Ok, I will check it.

> > +
> > +     dev_dbg(&client->dev, "%s: client->irq:%d\n", __func__, client->irq);
> > +
> > +     if (client->irq > 0) {
> > +             err = devm_request_threaded_irq(&client->dev, client->irq,
> > +                             NULL, nct3018y_irq,
> > +                             IRQF_ONESHOT | IRQF_TRIGGER_FALLING,
> > +                             nct3018y_driver.driver.name, client);
> > +             if (err) {
> > +                     dev_err(&client->dev, "unable to request IRQ %d\n", client->irq);
> > +                     return err;
> > +             }
> > +     }
> > +
> > +     err = devm_rtc_register_device(nct3018y->rtc);
> > +     if (err)
> > +             return err;
> > +
>
> By reordering this part, you could simply return
> devm_rtc_register_device().

OK

>
> > +#ifdef CONFIG_COMMON_CLK
> > +     /* register clk in common clk framework */
> > +     nct3018y_clkout_register_clk(nct3018y);
> > +#endif
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct i2c_device_id nct3018y_id[] = {
> > +     { "nct3018y", 0 },
> > +     { }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, nct3018y_id);
> > +
> > +
> > +static const struct of_device_id nct3018y_of_match[] = {
> > +     { .compatible = "nuvoton,nct3018y" },
> > +     {}
> > +};
> > +MODULE_DEVICE_TABLE(of, nct3018y_of_match);
> > +
> > +static struct i2c_driver nct3018y_driver = {
> > +     .driver         = {
> > +             .name   = "rtc-nct3018y",
> > +             .of_match_table = of_match_ptr(nct3018y_of_match),
> > +     },
> > +     .probe          = nct3018y_probe,
> > +     .id_table       = nct3018y_id,
> > +};
> > +
> > +module_i2c_driver(nct3018y_driver);
> > +
> > +MODULE_AUTHOR("Medad CChien <ctcchien@...oton.com>");
> > +MODULE_DESCRIPTION("Nuvoton NCT3018Y RTC driver");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.17.1
> >
>
> --
> Alexandre Belloni, co-owner and COO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com

B.R.
Medad

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