linux-kernel - Re: [PATCH v4 2/4] pmbus: core: add helpers for byte write and read modify write

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Message-ID: <542CCF1D.5090609@roeck-us.net>
Date:	Wed, 01 Oct 2014 21:05:49 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	atull@...nsource.altera.com, jdelvare@...e.de
CC:	lm-sensors@...sensors.org, lgirdwood@...il.com, broonie@...nel.org,
	robh+dt@...nel.org, pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	delicious.quinoa@...il.com, dinguyen@...nsource.altera.com,
	yvanderv@...nsource.altera.com
Subject: Re: [PATCH v4 2/4] pmbus: core: add helpers for byte write and read
 modify write

On 10/01/2014 12:05 PM, atull@...nsource.altera.com wrote:
> From: Alan Tull <atull@...nsource.altera.com>
>
> Add two helper functions:
>   * pmbus_write_byte_data  = paged byte write
>   * pmbus_update_byte_data = paged byte read/modify/write
>
> Signed-off-by: Alan Tull <atull@...nsource.altera.com>
> ---
>   drivers/hwmon/pmbus/pmbus_core.c |   31 +++++++++++++++++++++++++++++++
>   1 file changed, 31 insertions(+)
>
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 291d11f..d6c3701 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -253,6 +253,37 @@ int pmbus_read_byte_data(struct i2c_client *client, int page, u8 reg)
>   }
>   EXPORT_SYMBOL_GPL(pmbus_read_byte_data);
>
> +int pmbus_write_byte_data(struct i2c_client *client, int page, u8 reg, u8 value)
> +{
> +	int rv;
> +
> +	rv = pmbus_set_page(client, page);
> +	if (rv < 0)
> +		return rv;
> +
> +	return i2c_smbus_write_byte_data(client, reg, value);
> +}
> +EXPORT_SYMBOL_GPL(pmbus_write_byte_data);
> +
> +int pmbus_update_byte_data(struct i2c_client *client, int page, u8 reg,
> +			   u8 mask, u8 value)
> +{
> +	unsigned int tmp;
> +	int rv;
> +
> +	rv = pmbus_read_byte_data(client, page, reg);
> +	if (rv < 0)
> +		return rv;
> +
> +	tmp = (rv & ~mask) | (value & mask);
> +
> +	if (tmp != rv)
> +		rv = pmbus_write_byte_data(client, page, reg, tmp);
> +
> +	return rv;
> +}
> +EXPORT_SYMBOL_GPL(pmbus_update_byte_data);
> +
>   /*
>    * _pmbus_read_byte_data() is similar to pmbus_read_byte_data(), but checks if
>    * a device specific mapping function exists and calls it if necessary.
>

Results in:

drivers/hwmon/pmbus/pmbus_core.c:259:5: warning: symbol 'pmbus_write_byte_data' was not declared. Should it be static?
drivers/hwmon/pmbus/pmbus_core.c:271:5: warning: symbol 'pmbus_update_byte_data' was not declared. Should it be static?
drivers/hwmon/pmbus/pmbus_core.c:259:5: warning: no previous prototype for 'pmbus_write_byte_data' [-Wmissing-prototypes]
drivers/hwmon/pmbus/pmbus_core.c:271:5: warning: no previous prototype for 'pmbus_update_byte_data' [-Wmissing-prototypes]

No need to resubmit. I added a patch to un-export the functions
and merged patch 2 and 3 together in order to avoid a warning
after patch 2. We can always export the new helper functions
later if needed.

Guenter

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