Re: [PATCH v2 2/2] rtc: nuvoton: Compatible with NCT3015Y-R and NCT3018Y-R

Dear Paul,

Thank you for your comments.
The replies are as follows.

Thanks.
Best regard,
Mia

On Aug 10, 2023, at 4:16 PM, Paul Menzel [off-list ref] wrote:

Dear Mia,


Thank you for your patch.

It’d be great if you made the commit message summary/title more specific. Maybe:

Add support for NCT3015Y-R

Am 09.08.23 um 11:51 schrieb Mia Lin:

An introduction what the NCT3015Y-R is and listing the differences to NCT3018Y-R would be nice.

[Mia] I will add more detail. Thank you for your comments.

quoted

- 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.

Why? This also looks unrelated to the NCT3015Y-R support. Could you factor it out into separate patch?

[Mia] The NCT3015Y-R and NCT3018Y-R use the same datasheet but have different topologies.
Therefore, the settings here are to set according to different models to match the behavior of each chip.

quoted

- Use DT compatible to check the chip matches or not.

Could you please add the datasheet name and revision?

[Mia] Use DT compatible to check does not make sense. I will remove it.

quoted

Signed-off-by: Mia Lin <redacted>
---
drivers/rtc/rtc-nct3018y.c | 88 +++++++++++++++++++++++++++++++++-----
1 file changed, 78 insertions(+), 10 deletions(-)

diff --git a/drivers/rtc/rtc-nct3018y.c b/drivers/rtc/rtc-nct3018y.c
index a4e3f924837e..edc73be3ab59 100644
--- a/drivers/rtc/rtc-nct3018y.c
+++ b/drivers/rtc/rtc-nct3018y.c

@@ -7,6 +7,7 @@

#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/of_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>

@@ -23,6 +24,7 @@

#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)

@@ -37,6 +39,20 @@

#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_NCT3015Y    0x01
+#define NCT3018Y_REG_PART_NCT3018Y    0x02
+
+struct rtc_data {
+    u8 part_number;
+};
+
+static const struct rtc_data nct3015y_rtc_data = {
+    .part_number = NCT3018Y_REG_PART_NCT3015Y,
+};
+
+static const struct rtc_data nct3018y_rtc_data = {
+    .part_number = NCT3018Y_REG_PART_NCT3018Y,
+};
struct nct3018y {
 struct rtc_device *rtc;

@@ -52,7 +68,7 @@ static int nct3018y_set_alarm_mode(struct i2c_client *client, bool on)
   dev_dbg(&client->dev, "%s:on:%d\n", __func__, on);
-    flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
+    flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
 if (flags < 0) {
     dev_dbg(&client->dev,
         "Failed to read NCT3018Y_REG_CTRL\n");

@@ -109,8 +125,10 @@ static int nct3018y_get_alarm_mode(struct i2c_client *client, unsigned char *ala
     *alarm_flag = flags & NCT3018Y_BIT_AF;
 }
-    dev_dbg(&client->dev, "%s:alarm_enable:%x alarm_flag:%x\n",
-        __func__, *alarm_enable, *alarm_flag);
+    if (alarm_enable && alarm_flag) {
+        dev_dbg(&client->dev, "%s:alarm_enable:%x alarm_flag:%x\n",
+            __func__, *alarm_enable, *alarm_flag);
+    }

The two hunks look like unrelated fixes. It’d be great, if you factored those out into a separate patch.

[Mia] I will factor it out into a separate patch.

quoted

   return 0;
}

@@ -178,7 +196,30 @@ static int nct3018y_rtc_set_time(struct device *dev, struct rtc_time *tm)

{
 struct i2c_client *client = to_i2c_client(dev);
 unsigned char buf[4] = {0};
-    int err;
+    int err, part_num, flags, restore_flags = 0;

Why is err now initialized to 0?

[Mia] I will refine it.

quoted

+    part_num = i2c_smbus_read_byte_data(client, NCT3018Y_REG_PART);
+    if (part_num < 0) {
+        dev_dbg(&client->dev, "%s: read error\n", __func__);
+        return part_num;
+    }
+
+    flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
+    if (flags < 0) {
+        dev_dbg(&client->dev, "%s: read error\n", __func__);

Could you make these distinct error messages, so users are able to pinpoint the correct location right away? (Or does `dev_dbg` already provide that information? Maybe the line? (Also more cases below.)

[Mia] I will refine error messages. Thank you.

quoted

+        return flags;
+    }
+
+    /* Check and set TWO bit */
+    if ((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 +253,18 @@ static int nct3018y_rtc_set_time(struct device *dev, struct rtc_time *tm)
     return -EIO;
 }
+    /* Restore TWO bit */
+    if (restore_flags) {
+        if (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;

}

@@ -456,6 +509,7 @@ static int nct3018y_probe(struct i2c_client *client)

{
 struct nct3018y *nct3018y;
 int err, flags;
+    const struct rtc_data *data = of_device_get_match_data(&client->dev);
   if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
                  I2C_FUNC_SMBUS_BYTE |

@@ -479,11 +533,24 @@ 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;
+    flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_PART);
+    if (flags < 0) {
+        dev_dbg(&client->dev, "%s: read error\n", __func__);
+        return flags;
+    } else if (flags & NCT3018Y_REG_PART_NCT3018Y) {
+        if (!(flags & data->part_number))
+            dev_warn(&client->dev, "%s: part_num=0x%x but NCT3018Y_REG_PART=0x%x\n",
+                 __func__, data->part_number, flags);
+        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;
+        }
+    } else if (flags & NCT3018Y_REG_PART_NCT3015Y) {
+        if (!(flags & data->part_number))
+            dev_warn(&client->dev, "%s: part_num=0x%x but NCT3018Y_REG_PART=0x%x\n",
+                 __func__, data->part_number, flags);
 }
   flags = 0;

@@ -530,7 +597,8 @@ static const struct i2c_device_id nct3018y_id[] = {

MODULE_DEVICE_TABLE(i2c, nct3018y_id);
static const struct of_device_id nct3018y_of_match[] = {
-    { .compatible = "nuvoton,nct3018y" },
+    { .compatible = "nuvoton,nct3015y", .data = &nct3015y_rtc_data },
+    { .compatible = "nuvoton,nct3018y", .data = &nct3018y_rtc_data },
 {}
};
MODULE_DEVICE_TABLE(of, nct3018y_of_match);

Kind regards,

Paul