On Wed, Nov 09, 2016 at 11:32:06AM -0800, Guenter Roeck wrote:
> On Wed, Nov 09, 2016 at 06:16:13PM +0100, Clemens Gruber wrote:
> > Support setting the reference voltage from the device tree.
> >
> > Signed-off-by: Clemens Gruber <[email protected]>
> > ---
> > drivers/hwmon/mcp3021.c | 46 ++++++++++++++++++++++++++++++++++++----------
> > 1 file changed, 36 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/hwmon/mcp3021.c b/drivers/hwmon/mcp3021.c
> > index 972444a..81f4b7f 100644
> > --- a/drivers/hwmon/mcp3021.c
> > +++ b/drivers/hwmon/mcp3021.c
> > @@ -4,6 +4,7 @@
> > * Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
> > * Author: Mingkai Hu <[email protected]>
> > * Reworked by Sven Schuchmann <[email protected]>
> > + * Copyright (C) 2016 Clemens Gruber <[email protected]>
>
> Sorry, I can't accept that for such a minor change. Feel free to add
> something like "devicetree support added by ...", if you like.
I understand, no problem. I'll use your suggestion then.
>
> > *
> > * This driver export the value of analog input voltage to sysfs, the
> > * voltage unit is mV. Through the sysfs interface, lm-sensors tool
> > @@ -22,11 +23,13 @@
> > #include <linux/i2c.h>
> > #include <linux/err.h>
> > #include <linux/device.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> >
> > -/* Vdd info */
> > +/* Vdd / reference voltage in millivolt */
> > #define MCP3021_VDD_MAX 5500
> > #define MCP3021_VDD_MIN 2700
> > -#define MCP3021_VDD_REF 3300
> > +#define MCP3021_VDD_DEFAULT 3300
>
> I don't really see the value of changing this, but if it makes you
> feel better at least make it MCP3021_VDD_REF_DEFAULT.
I changed it because all three defines are about the reference voltage,
not only the last one, which is just the default value.
Only changing the last one to MCP3021_VDD_REF_DEFAULT would not make it
less confusing.
Maybe replace MCP3021_VDD_ with MCP3021_VDD_REF_ for all three?
>
> >
> > /* output format */
> > #define MCP3021_SAR_SHIFT 2
> > @@ -47,7 +50,7 @@ enum chips {
> > */
> > struct mcp3021_data {
> > struct device *hwmon_dev;
> > - u32 vdd; /* device power supply */
> > + u32 vdd; /* supply and reference voltage in millivolt */
> > u16 sar_shift;
> > u16 sar_mask;
> > u8 output_res;
> > @@ -106,6 +109,7 @@ static int mcp3021_probe(struct i2c_client *client,
> > {
> > int err;
> > struct mcp3021_data *data = NULL;
> > + struct device_node *np = client->dev.of_node;
> >
> > if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> > return -ENODEV;
> > @@ -117,6 +121,21 @@ static int mcp3021_probe(struct i2c_client *client,
> >
> > i2c_set_clientdata(client, data);
> >
> > + if (np) {
> > + if (of_property_read_u32(np, "reference-voltage-microvolt",
> > + &data->vdd))
> > + data->vdd = MCP3021_VDD_DEFAULT;
> > + else
> > + data->vdd /= 1000;
>
> It would be slightly better to reverse the logic here to make the code easier
> to read.
>
> if (!of_property_read_u32(np, "reference-voltage-microvolt",
> &data->vdd))
> data->vdd /= 1000;
> else
> data->vdd = MCP3021_VDD_DEFAULT;
Yes, I'll change it.
>
> Not worth arguing about it, though, so feel free to keep it as is.
>
> > + } else {
> > + u32 *pdata = dev_get_platdata(&client->dev);
> > +
> > + if (pdata)
> > + data->vdd = *pdata;
> > + else
> > + data->vdd = MCP3021_VDD_DEFAULT;
> > + }
> > +
> > switch (id->driver_data) {
> > case mcp3021:
> > data->sar_shift = MCP3021_SAR_SHIFT;
> > @@ -129,15 +148,12 @@ static int mcp3021_probe(struct i2c_client *client,
> > data->sar_mask = MCP3221_SAR_MASK;
> > data->output_res = MCP3221_OUTPUT_RES;
> > break;
> > + default:
> > + return -ENODEV;
>
> Hmm ... that is really an unrelated change (nor is it really needed
> unless there is a bug in the code). Not worth arguing about it either,
> but please keep in mind that this is one of the things making life
> hard for maintainers.
I see, I'll remove it then.
Thank you for your feedback!
Clemens
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