Re: [PATCH 5/8] rtc: rx8010: don't use magic values for time buffer length

[Alexandre Belloni]

On 04/09/2020 17:21:13+0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski 
> 
> The time buffer len is used directly in this driver. For readability
> it's better to define a constant.
> 
> Signed-off-by: Bartosz Golaszewski 
> ---
>  drivers/rtc/rtc-rx8010.c | 13 -
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-rx8010.c b/drivers/rtc/rtc-rx8010.c
> index 67ff06a76629..f3bed7be2533 100644
> --- a/drivers/rtc/rtc-rx8010.c
> +++ b/drivers/rtc/rtc-rx8010.c
> @@ -48,6 +48,8 @@
>  
>  #define RX8010_ALARM_AE  BIT(7)
>  
> +#define RX8010_TIME_BUF_LEN  7
> +
>  static const struct i2c_device_id rx8010_id[] = {
>   { "rx8010", 0 },
>   { }
> @@ -108,7 +110,7 @@ static irqreturn_t rx8010_irq_1_handler(int irq, void 
> *dev_id)
>  static int rx8010_get_time(struct device *dev, struct rtc_time *dt)
>  {
>   struct rx8010_data *rx8010 = dev_get_drvdata(dev);
> - u8 date[7];

I'm usually fine with a magic value here...

> + u8 date[RX8010_TIME_BUF_LEN];
>   int flagreg, err;
>  
>   flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
> @@ -121,8 +123,8 @@ static int rx8010_get_time(struct device *dev, struct 
> rtc_time *dt)
>   }
>  
>   err = i2c_smbus_read_i2c_block_data(rx8010->client, RX8010_SEC,
> - 7, date);
> - if (err != 7)
> + RX8010_TIME_BUF_LEN, date);

..as long as sizeof(date) is used here.

Even better, you could have date[RX8010_YEAR - RX8010_SEC + 1] and then
use sizeof. Or also have #define RX8010_TIME_BUF_LEN (RX8010_YEAR -
RX8010_SEC + 1) which would be safer than 7.

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

[PATCH 5/8] rtc: rx8010: don't use magic values for time buffer length

[Bartosz Golaszewski]

From: Bartosz Golaszewski 

The time buffer len is used directly in this driver. For readability
it's better to define a constant.

Signed-off-by: Bartosz Golaszewski 
---
 drivers/rtc/rtc-rx8010.c | 13 -
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/rtc/rtc-rx8010.c b/drivers/rtc/rtc-rx8010.c
index 67ff06a76629..f3bed7be2533 100644
--- a/drivers/rtc/rtc-rx8010.c
+++ b/drivers/rtc/rtc-rx8010.c
@@ -48,6 +48,8 @@
 
 #define RX8010_ALARM_AEBIT(7)
 
+#define RX8010_TIME_BUF_LEN7
+
 static const struct i2c_device_id rx8010_id[] = {
{ "rx8010", 0 },
{ }
@@ -108,7 +110,7 @@ static irqreturn_t rx8010_irq_1_handler(int irq, void 
*dev_id)
 static int rx8010_get_time(struct device *dev, struct rtc_time *dt)
 {
struct rx8010_data *rx8010 = dev_get_drvdata(dev);
-   u8 date[7];
+   u8 date[RX8010_TIME_BUF_LEN];
int flagreg, err;
 
flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
@@ -121,8 +123,8 @@ static int rx8010_get_time(struct device *dev, struct 
rtc_time *dt)
}
 
err = i2c_smbus_read_i2c_block_data(rx8010->client, RX8010_SEC,
-   7, date);
-   if (err != 7)
+   RX8010_TIME_BUF_LEN, date);
+   if (err != RX8010_TIME_BUF_LEN)
return err < 0 ? err : -EIO;
 
dt->tm_sec = bcd2bin(date[RX8010_SEC - RX8010_SEC] & 0x7f);
@@ -139,7 +141,7 @@ static int rx8010_get_time(struct device *dev, struct 
rtc_time *dt)
 static int rx8010_set_time(struct device *dev, struct rtc_time *dt)
 {
struct rx8010_data *rx8010 = dev_get_drvdata(dev);
-   u8 date[7];
+   u8 date[RX8010_TIME_BUF_LEN];
int ctrl, flagreg, err;
 
if ((dt->tm_year < 100) || (dt->tm_year > 199))
@@ -164,7 +166,8 @@ static int rx8010_set_time(struct device *dev, struct 
rtc_time *dt)
date[RX8010_WDAY - RX8010_SEC] = bin2bcd(1 << dt->tm_wday);
 
err = i2c_smbus_write_i2c_block_data(rx8010->client,
-RX8010_SEC, 7, date);
+RX8010_SEC, RX8010_TIME_BUF_LEN,
+date);
if (err < 0)
return err;
 
-- 
2.26.1