[PATCH] rtc: abx80x: Implement procfs interface

[PATCH] rtc: abx80x: Implement procfs interface

[Marek Vasut]

Implement procfs interface for polling battery status of the RTC
via /proc/driver/rtc .

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
 drivers/rtc/rtc-abx80x.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
index 73830670a41f..4fab024fb508 100644
--- a/drivers/rtc/rtc-abx80x.c
+++ b/drivers/rtc/rtc-abx80x.c
@@ -78,6 +78,10 @@
 
 #define ABX8XX_REG_ID0		0x28
 
+#define ABX8XX_REG_ANA_STATUS	0x2f
+#define ABX8XX_ANA_BREFD	BIT(7)
+#define ABX8XX_ANA_BMIN		BIT(6)
+
 #define ABX8XX_REG_OUT_CTRL	0x30
 #define ABX8XX_OUT_CTRL_EXDS	BIT(4)
 
@@ -548,6 +552,25 @@ static int abx80x_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 	}
 }
 
+static int abx80x_proc(struct device *dev, struct seq_file *seq)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int status, tmp;
+
+	status = i2c_smbus_read_byte_data(client, ABX8XX_REG_ANA_STATUS);
+	if (status < 0)
+		return status;
+
+	if (status & ABX8XX_ANA_BREFD)
+		seq_printf(seq, "battery\t\t: ok\n");
+	else if (status & ABX8XX_ANA_BMIN)
+		seq_printf(seq, "battery\t\t: low\n");
+	else
+		seq_printf(seq, "battery\t\t: exhausted\n");
+
+	return 0;
+}
+
 static const struct rtc_class_ops abx80x_rtc_ops = {
 	.read_time	= abx80x_rtc_read_time,
 	.set_time	= abx80x_rtc_set_time,
@@ -555,6 +578,7 @@ static const struct rtc_class_ops abx80x_rtc_ops = {
 	.set_alarm	= abx80x_set_alarm,
 	.alarm_irq_enable = abx80x_alarm_irq_enable,
 	.ioctl		= abx80x_ioctl,
+	.proc		= abx80x_proc,
 };
 
 static int abx80x_dt_trickle_cfg(struct device_node *np)
-- 
2.20.1

Re: [PATCH] rtc: abx80x: Implement procfs interface

[Alexandre Belloni]

Hi Marek,

On 23/06/2019 14:08:54+0200, Marek Vasut wrote:
> Implement procfs interface for polling battery status of the RTC
> via /proc/driver/rtc .
> 

Please don't, this interface is deprecated and doesn't work well. Use
RTC_VL_READ instead.

> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> ---
>  drivers/rtc/rtc-abx80x.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
> index 73830670a41f..4fab024fb508 100644
> --- a/drivers/rtc/rtc-abx80x.c
> +++ b/drivers/rtc/rtc-abx80x.c
> @@ -78,6 +78,10 @@
>  
>  #define ABX8XX_REG_ID0		0x28
>  
> +#define ABX8XX_REG_ANA_STATUS	0x2f
> +#define ABX8XX_ANA_BREFD	BIT(7)
> +#define ABX8XX_ANA_BMIN		BIT(6)
> +
>  #define ABX8XX_REG_OUT_CTRL	0x30
>  #define ABX8XX_OUT_CTRL_EXDS	BIT(4)
>  
> @@ -548,6 +552,25 @@ static int abx80x_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
>  	}
>  }
>  
> +static int abx80x_proc(struct device *dev, struct seq_file *seq)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	int status, tmp;
> +
> +	status = i2c_smbus_read_byte_data(client, ABX8XX_REG_ANA_STATUS);
> +	if (status < 0)
> +		return status;
> +
> +	if (status & ABX8XX_ANA_BREFD)
> +		seq_printf(seq, "battery\t\t: ok\n");
> +	else if (status & ABX8XX_ANA_BMIN)
> +		seq_printf(seq, "battery\t\t: low\n");
> +	else
> +		seq_printf(seq, "battery\t\t: exhausted\n");
> +
> +	return 0;
> +}
> +
>  static const struct rtc_class_ops abx80x_rtc_ops = {
>  	.read_time	= abx80x_rtc_read_time,
>  	.set_time	= abx80x_rtc_set_time,
> @@ -555,6 +578,7 @@ static const struct rtc_class_ops abx80x_rtc_ops = {
>  	.set_alarm	= abx80x_set_alarm,
>  	.alarm_irq_enable = abx80x_alarm_irq_enable,
>  	.ioctl		= abx80x_ioctl,
> +	.proc		= abx80x_proc,
>  };
>  
>  static int abx80x_dt_trickle_cfg(struct device_node *np)
> -- 
> 2.20.1
> 

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

Re: [PATCH] rtc: abx80x: Implement procfs interface

[Marek Vasut]

On 6/23/19 2:38 PM, Alexandre Belloni wrote:
> Hi Marek,
> 
> On 23/06/2019 14:08:54+0200, Marek Vasut wrote:
>> Implement procfs interface for polling battery status of the RTC
>> via /proc/driver/rtc .
>>
> 
> Please don't, this interface is deprecated and doesn't work well. Use
> RTC_VL_READ instead.
That's already implemented, the procfs one isn't, but fine by me.

-- 
Best regards,
Marek Vasut

Re: [PATCH] rtc: abx80x: Implement procfs interface

[Marek Vasut]

On 6/23/19 3:20 PM, Marek Vasut wrote:
> On 6/23/19 2:38 PM, Alexandre Belloni wrote:
>> Hi Marek,
>>
>> On 23/06/2019 14:08:54+0200, Marek Vasut wrote:
>>> Implement procfs interface for polling battery status of the RTC
>>> via /proc/driver/rtc .
>>>
>>
>> Please don't, this interface is deprecated and doesn't work well. Use
>> RTC_VL_READ instead.
> That's already implemented, the procfs one isn't, but fine by me.

Oh, one more thing. The RTC_VL_READ only provides 1 bit of information,
the state of BLF bit (Battery low/failed IIRC). The procfs interface is
more verbose and provides explicit battery status (OK/low/exhausted). Is
there an ioctl for this too ?

-- 
Best regards,
Marek Vasut