linux-kernel - Re: [PATCH v5 1/2] hwmon: (adt7475) Added attenuator bypass support

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Message-ID: <d8d1e0db-6e2d-8523-923a-df6c6dca0e89@roeck-us.net>
Date:   Thu, 23 Jan 2020 20:55:59 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Logan Shaw <logan.shaw@...iedtelesis.co.nz>, jdelvare@...e.com,
        robh+dt@...nel.org
Cc:     linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, Joshua.Scott@...iedtelesis.co.nz,
        Chris.Packham@...iedtelesis.co.nz
Subject: Re: [PATCH v5 1/2] hwmon: (adt7475) Added attenuator bypass support

On 1/23/20 2:05 PM, Logan Shaw wrote:
> Added support for reading DTS properties to set attenuators on
> device probe for the ADT7473, ADT7475, ADT7476, and ADT7490.
> 
> Signed-off-by: Logan Shaw <logan.shaw@...iedtelesis.co.nz>
> ---
> ---
>   drivers/hwmon/adt7475.c | 68 +++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 68 insertions(+)
> 
> diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
> index 6c64d50c9aae..8afc5a89ec92 100644
> --- a/drivers/hwmon/adt7475.c
> +++ b/drivers/hwmon/adt7475.c
> @@ -19,6 +19,7 @@
>   #include <linux/hwmon-vid.h>
>   #include <linux/err.h>
>   #include <linux/jiffies.h>
> +#include <linux/of.h>
>   #include <linux/util_macros.h>
>   
>   /* Indexes for the sysfs hooks */
> @@ -1457,6 +1458,70 @@ static int adt7475_update_limits(struct i2c_client *client)
>   	return 0;
>   }
>   
> +/**

I am still at loss why you think it would make sense to mark those
comments for the kernel documentation. This doesn't have value outside
this driver.

> + * Sets or clears the given bit in the config depending on the value of the
> + * given dts property. Non-zero value sets, zero value clears. No change if
> + * the property is absent.
> + */
> +static void modify_config(const struct i2c_client *client, char *property,
> +				u8 *config, u8 bit_index)
> +{
> +	u32 prop_value = 0;
> +	int ret = of_property_read_u32(client->dev.of_node, property,
> +					&prop_value);
> +
> +	if (!ret) {
> +		if (prop_value)
> +			*config |= (1 << bit_index);
> +		else
> +			*config &= ~(1 << bit_index);
> +	}
> +}
> +
> +/**
> + * Configures the attenuator bypasses for voltage inputs, depening on
> + * properties in the dts.
> +.*
> + * The adt7473 and adt7475 only support bypassing in1.
> + *
> + * Returns a negative error code if there was an error writing to the register.
> + */
> +static int load_attenuators(const struct i2c_client *client, int chip,
> +				u8 *config2, u8 *config4)
> +{
> +	u8 conf_copy;
> +	int ret = 0;

Unnecessary assignment.

> +
> +	if (chip == adt7476 || chip == adt7490) {
> +		conf_copy = *config4;
> +
> +		modify_config(client, "bypass-attenuator-in0", &conf_copy, 4);
> +		modify_config(client, "bypass-attenuator-in1", &conf_copy, 5);
> +		modify_config(client, "bypass-attenuator-in3", &conf_copy, 6);
> +		modify_config(client, "bypass-attenuator-in4", &conf_copy, 7);
> +
> +		ret = i2c_smbus_write_byte_data(client, REG_CONFIG4,
> +			conf_copy);
> +		if (ret < 0)
> +			return ret;
> +
> +		*config4 = conf_copy;
> +	} else if (chip == adt7473 || chip == adt7475) {
> +		conf_copy = *config2;
> +
> +		modify_config(client, "bypass-attenuator-in1", &conf_copy, 5);
> +
> +		ret = i2c_smbus_write_byte_data(client, REG_CONFIG2,
> +			conf_copy);
> +		if (ret < 0)
> +			return ret;
> +
> +		*config2 = conf_copy;
> +	}
> +
> +	return 0;
> +}
> +
>   static int adt7475_probe(struct i2c_client *client,
>   			 const struct i2c_device_id *id)
>   {
> @@ -1546,6 +1611,9 @@ static int adt7475_probe(struct i2c_client *client,
>   
>   	/* Voltage attenuators can be bypassed, globally or individually */
>   	config2 = adt7475_read(REG_CONFIG2);
> +	if (load_attenuators(client, chip, &config2, &(data->config4)) < 0)
> +		dev_warn(&client->dev, "Error setting bypass attenuators\n");
> +
>   	if (config2 & CONFIG2_ATTN) {
>   		data->bypass_attn = (0x3 << 3) | 0x3;
>   	} else {
> 
CHECK: Alignment should match open parenthesis
#45: FILE: drivers/hwmon/adt7475.c:1467:
+static void modify_config(const struct i2c_client *client, char *property,
+				u8 *config, u8 bit_index)

CHECK: Alignment should match open parenthesis
#68: FILE: drivers/hwmon/adt7475.c:1490:
+static int load_attenuators(const struct i2c_client *client, int chip,
+				u8 *config2, u8 *config4)

CHECK: Alignment should match open parenthesis
#82: FILE: drivers/hwmon/adt7475.c:1504:
+		ret = i2c_smbus_write_byte_data(client, REG_CONFIG4,
+			conf_copy);

CHECK: Alignment should match open parenthesis
#93: FILE: drivers/hwmon/adt7475.c:1515:
+		ret = i2c_smbus_write_byte_data(client, REG_CONFIG2,
+			conf_copy);

CHECK: Unnecessary parentheses around data->config4
#110: FILE: drivers/hwmon/adt7475.c:1614:
+	if (load_attenuators(client, chip, &config2, &(data->config4)) < 0)

None of those is beneficial. Please fix.

Thanks,
Guenter