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

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Date: Sat, 25 May 2024 07:29:55 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Christian Marangi <ansuelsmth@...il.com>, 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 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.

> 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.

>   	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.

Guenter

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