Date:   Wed, 7 Mar 2018 08:19:15 +0000
From:   Denis OSTERLAND <denis.osterland@...hl.com>
To:     "alexandre.belloni@...e-electrons.com" 
        <alexandre.belloni@...e-electrons.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "mgr@...gutronix.de" <mgr@...gutronix.de>,
        "m.grzeschik@...gutronix.de" <m.grzeschik@...gutronix.de>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "a.zummo@...ertech.it" <a.zummo@...ertech.it>,
        "linux@...ck-us.net" <linux@...ck-us.net>,
        "jdelvare@...e.com" <jdelvare@...e.com>,
        "linux-rtc@...r.kernel.org" <linux-rtc@...r.kernel.org>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>
Subject: Re: [PATCH v3 3/4] rtc: isl1208: add support for isl1219 with tamper
 detection

Am Dienstag, den 06.03.2018, 21:42 +0100 schrieb Alexandre Belloni:
> On 05/03/2018 at 10:43:52 +0000, Denis OSTERLAND wrote:
> > 
> > diff --git a/Documentation/devicetree/bindings/rtc/isil,isl1219.txt b/Documentation/devicetree/bindings/rtc/isil,isl1219.txt
> > new file mode 100644
> > index 0000000..7937c13
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/rtc/isil,isl1219.txt
> If you want that file to be reviewed by Rob (DT maintainer), you should
> probably separate it from that patch and copy his email. The bindings
> seem fine to me though.
OK
> 
> > 
> > diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c
> > index 1a2c38c..164371b 100644
> > --- a/drivers/rtc/rtc-isl1208.c
> > +++ b/drivers/rtc/rtc-isl1208.c
> > @@ -33,6 +33,7 @@
> >  #define ISL1208_REG_SR_ARST    (1<<7)	/* auto reset */
> >  #define ISL1208_REG_SR_XTOSCB  (1<<6)	/* crystal oscillator */
> >  #define ISL1208_REG_SR_WRTC    (1<<4)	/* write rtc */
> > +#define ISL1208_REG_SR_EVT     (1<<3)	/* event */
> >  #define ISL1208_REG_SR_ALM     (1<<2)	/* alarm */
> >  #define ISL1208_REG_SR_BAT     (1<<1)	/* battery */
> >  #define ISL1208_REG_SR_RTCF    (1<<0)	/* rtc fail */
> > @@ -57,8 +58,29 @@
> >  #define ISL1208_REG_USR2 0x13
> >  #define ISL1208_USR_SECTION_LEN 2
> > 
> > +/* event section */
> > +#define ISL1208_REG_SCT 0x14
> > +#define ISL1208_REG_MNT 0x15
> > +#define ISL1208_REG_HRT 0x16
> > +#define ISL1208_REG_DTT 0x17
> > +#define ISL1208_REG_MOT 0x18
> > +#define ISL1208_REG_YRT 0x19
> > +#define ISL1208_EVT_SECTION_LEN 6
> > +
> Because they are not available on ISL1208, maybe it would be better to
> prefix them with ISL1219.
I see. Yes, this would clarify that they are only available on isl1219.
Shall we rename isl1208_rtc_event_show_timestamp/isl1208_rtc_event_clear
to isl1219_rtc_event_show_timestamp/isl1219_rtc_event_clear, too?
> 
> > 
> > +
> > +	tv64.tv_sec = rtc_tm_to_time64(&tm);
> Why not using an unsigned long long directly here? time64_t is not the
> correct type.
Do you mean timespec64 is not the correct type here?
Then yes, sould be time64_t.
If you mean time64_t is not the correct type here,
then can you give me some detail why there is no rtc_tm_to_u64,
or something like that?
sprintf(buf, "%lld\n", rtc_tm_to_time64(&tm)) seems correct to me.
By the way, is it needed to check for seconds < 0 and return error?
> 
> > 
> > +
> > +	return sprintf(buf, "%lld\n", (long long) tv64.tv_sec);
> And this should become %llu
> 
> > 
> > +};
> > +
> > +static DEVICE_ATTR(timestamp0, 0640,
> Shouldn't the permissions be 644?
644 is OK
> 
> > 
> > +		isl1208_rtc_event_show_timestamp, isl1208_rtc_event_clear);
> > +
> >  static irqreturn_t
> >  isl1208_rtc_interrupt(int irq, void *data)
> >  {
> >  	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
> >  	struct i2c_client *client = data;
> > -	struct rtc_device *rtc = i2c_get_clientdata(client);
> > +	struct isl1208 *isl1208 = i2c_get_clientdata(client);
> >  	int handled = 0, sr, err;
> > 
> >  	/*
> > @@ -521,7 +609,7 @@ isl1208_rtc_interrupt(int irq, void *data)
> >  	if (sr & ISL1208_REG_SR_ALM) {
> >  		dev_dbg(&client->dev, "alarm!\n");
> > 
> > -		rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
> > +		rtc_update_irq(isl1208->rtc, 1, RTC_IRQF | RTC_AF);
> > 
> >  		/* Clear the alarm */
> >  		sr &= ~ISL1208_REG_SR_ALM;
> > @@ -538,6 +626,13 @@ isl1208_rtc_interrupt(int irq, void *data)
> >  			return err;
> >  	}
> > 
> > +	if (sr & ISL1208_REG_SR_EVT) {
> > +		sysfs_notify(&client->dev.kobj, NULL,
> > +			dev_attr_timestamp0.attr.name);
> > +		dev_warn(&client->dev, "event detected");
> > +		handled = 1;
> > +	}
> > +
> >  	return handled ? IRQ_HANDLED : IRQ_NONE;
> >  }
> > 
> > @@ -623,11 +718,23 @@ static const struct attribute_group isl1208_rtc_sysfs_files = {
> >  	.attrs	= isl1208_rtc_attrs,
> >  };
> > 
> > +static struct attribute *isl1219_rtc_attrs[] = {
> > +	&dev_attr_atrim.attr,
> > +	&dev_attr_dtrim.attr,
> > +	&dev_attr_usr.attr,
> > +	&dev_attr_timestamp0.attr,
> > +	NULL
> > +};
> > +
> > +static const struct attribute_group isl1219_rtc_sysfs_files = {
> > +	.attrs	= isl1219_rtc_attrs,
> > +};
> > +
> >  static int
> >  isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
> >  {
> >  	int rc = 0;
> > -	struct rtc_device *rtc;
> > +	struct isl1208 *isl1208;
> > 
> >  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> >  		return -ENODEV;
> > @@ -635,13 +742,18 @@ isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
> >  	if (isl1208_i2c_validate_client(client) < 0)
> >  		return -ENODEV;
> > 
> > -	rtc = devm_rtc_allocate_device(&client->dev);
> > -	if (IS_ERR(rtc))
> > -		return PTR_ERR(rtc);
> > +	isl1208 = devm_kzalloc(&client->dev, sizeof(struct isl1208),
> > +				GFP_KERNEL);
> > +	if (!isl1208)
> > +		return -ENOMEM;
> > 
> > -	rtc->ops = &isl1208_rtc_ops;
> > +	isl1208->rtc = devm_rtc_allocate_device(&client->dev);
> > +	if (IS_ERR(isl1208->rtc))
> > +		return PTR_ERR(isl1208->rtc);
> > 
> > -	i2c_set_clientdata(client, rtc);
> > +	isl1208->rtc->ops = &isl1208_rtc_ops;
> > +
> > +	i2c_set_clientdata(client, isl1208);
> > 
> >  	rc = isl1208_i2c_get_sr(client);
> >  	if (rc < 0) {
> > @@ -653,7 +765,18 @@ isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
> >  		dev_warn(&client->dev, "rtc power failure detected, "
> >  			 "please set clock.\n");
> > 
> > -	rc = sysfs_create_group(&client->dev.kobj, &isl1208_rtc_sysfs_files);
> > +	if (id->driver_data == TYPE_ISL1219) {
> > +		rc = i2c_smbus_write_byte_data(client, ISL1208_REG_09, 0x10);
> > +		if (rc < 0) {
> > +			dev_err(&client->dev, "could not enable tamper detection\n");
> > +			return rc;
> > +		}
> > +		isl1208->sysfs_files = &isl1219_rtc_sysfs_files;
> > +	} else {
> > +		isl1208->sysfs_files = &isl1208_rtc_sysfs_files;
> > +	}
> > +
> I don't think the whole isl1208 is necessary. You should probably use
> the .is_visible callback of isl1219_rtc_sysfs_files. This will make the
> changelog quite smaller.
> 
Well, I don´t know how to access i2c_device_id from kobject.
rtc_attr_is_visible shows how to convert kobject to device and rtc_device,
but how to do (id->driver_data == TYPE_ISL1219) here?
> > 
> > +	rc = sysfs_create_group(&client->dev.kobj, isl1208->sysfs_files);
> >  	if (rc)
> >  		return rc;
> > 
> > @@ -674,20 +797,23 @@ isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
> >  		}
> >  	}
> > 
> > -	return rtc_register_device(rtc);
> > +	return rtc_register_device(isl1208->rtc);
> >  }
> > 
> >  static int
> >  isl1208_remove(struct i2c_client *client)
> >  {
> > -	sysfs_remove_group(&client->dev.kobj, &isl1208_rtc_sysfs_files);
> > +	struct isl1208 *isl1208 = i2c_get_clientdata(client);
> > +
> > +	sysfs_remove_group(&client->dev.kobj, isl1208->sysfs_files);
> > 
> >  	return 0;
> >  }
> > 
> >  static const struct i2c_device_id isl1208_id[] = {
> > -	{ "isl1208", 0 },
> > -	{ "isl1218", 0 },
> > +	{ "isl1208", TYPE_ISL1208 },
> > +	{ "isl1218", TYPE_ISL1218 },
> > +	{ "isl1219", TYPE_ISL1219 },
> >  	{ }
> >  };
> >  MODULE_DEVICE_TABLE(i2c, isl1208_id);
> > --
> > 2.7.4
> > 
> > 
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