linux-kernel - Re: [PATCH 3/3] hwmon: g672: add support for g761

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Date: Sat, 25 May 2024 12:47:23 +0200
From: Christian Marangi <ansuelsmth@...il.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: Jean Delvare <jdelvare@...e.com>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, linux-hwmon@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] hwmon: g672: add support for g761

On Sat, May 25, 2024 at 07:29:55AM -0700, Guenter Roeck wrote:
> On 5/25/24 03:29, Christian Marangi wrote:
> > Add support for g761 PWM Fan Controller.
> > 
> > The g761 is a copy of the g763 with the only difference of supporting
> > and internal clock. This can be configured with the gmt,internal-clock
> > property and in such case clock handling is skipped.
> > 
> 
> Do you happen to have a datasheet ? The datasheet is not available from GMT,
> making it impossible to validate the changes.
>

No datasheet, online there is only the first page that describe the
features.

This internal clock feature is the only difference to g763 and is
present in a downstream driver from a Asus ipq807x router.

I verified that all the regs match.

> > Signed-off-by: Christian Marangi <ansuelsmth@...il.com>
> > ---
> >   drivers/hwmon/g762.c | 23 ++++++++++++++++++++---
> >   1 file changed, 20 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/hwmon/g762.c b/drivers/hwmon/g762.c
> > index af1228708e25..1629a3141c11 100644
> > --- a/drivers/hwmon/g762.c
> > +++ b/drivers/hwmon/g762.c
> > @@ -69,6 +69,7 @@ enum g762_regs {
> >   #define G762_REG_FAN_CMD1_PWM_POLARITY  0x02 /* PWM polarity */
> >   #define G762_REG_FAN_CMD1_PULSE_PER_REV 0x01 /* pulse per fan revolution */
> > +#define G761_REG_FAN_CMD2_FAN_CLOCK     0x20 /* choose internal clock*/
> >   #define G762_REG_FAN_CMD2_GEAR_MODE_1   0x08 /* fan gear mode */
> >   #define G762_REG_FAN_CMD2_GEAR_MODE_0   0x04
> >   #define G762_REG_FAN_CMD2_FAN_STARTV_1  0x02 /* fan startup voltage */
> > @@ -115,6 +116,7 @@ enum g762_regs {
> >   struct g762_data {
> >   	struct i2c_client *client;
> > +	bool internal_clock;
> >   	struct clk *clk;
> >   	/* update mutex */
> > @@ -566,6 +568,7 @@ static int do_set_fan_startv(struct device *dev, unsigned long val)
> >   #ifdef CONFIG_OF
> >   static const struct of_device_id g762_dt_match[] = {
> > +	{ .compatible = "gmt,g761" },
> >   	{ .compatible = "gmt,g762" },
> >   	{ .compatible = "gmt,g763" },
> >   	{ },
> > @@ -597,6 +600,16 @@ static int g762_of_clock_enable(struct i2c_client *client)
> >   	if (!client->dev.of_node)
> >   		return 0;
> > +	data = i2c_get_clientdata(client);
> > +
> > +	/* Skip CLK detection and handling if we use internal clock */
> > +	data->internal_clock = of_property_read_bool(client->dev.of_node,
> > +						     "gmt,internal-clock");
> > +	if (data->internal_clock) {
> > +		do_set_clk_freq(&client->dev, 32768); > +		return 0;
> > +	}:
> > +
> >   	clk = of_clk_get(client->dev.of_node, 0);
> >   	if (IS_ERR(clk)) {
> >   		dev_err(&client->dev, "failed to get clock\n");
> > @@ -616,7 +629,6 @@ static int g762_of_clock_enable(struct i2c_client *client)
> >   		goto clk_unprep;
> >   	}
> > -	data = i2c_get_clientdata(client);
> >   	data->clk = clk;
> >   	ret = devm_add_action(&client->dev, g762_of_clock_disable, data);
> > @@ -1029,12 +1041,17 @@ static inline int g762_fan_init(struct device *dev)
> >   	if (IS_ERR(data))
> >   		return PTR_ERR(data);
> > +	if (data->internal_clock)
> > +		data->fan_cmd2 |= G761_REG_FAN_CMD2_FAN_CLOCK;
> > +
> 
> This and the property must only be accepted for G761.
>

Yes you are right. I limit this only in Documentation but as a failsafe
I should also verify this here. Will do in V2.

> >   	data->fan_cmd1 |= G762_REG_FAN_CMD1_DET_FAN_FAIL;
> >   	data->fan_cmd1 |= G762_REG_FAN_CMD1_DET_FAN_OOC;
> >   	data->valid = false;
> > -	return i2c_smbus_write_byte_data(data->client, G762_REG_FAN_CMD1,
> > -					 data->fan_cmd1);
> > +	return (i2c_smbus_write_byte_data(data->client, G762_REG_FAN_CMD1,
> > +					  data->fan_cmd1) |
> > +		i2c_smbus_write_byte_data(data->client, G762_REG_FAN_CMD2,
> > +					  data->fan_cmd2));
> 
> This is wrong. It would logically combine error codes, and execute
> the second write even after the first failed.
> 

Ok will change the thing. 

> >   }
> >   static int g762_probe(struct i2c_client *client)
> 

-- 
	Ansuel