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Message-ID: <20130311122144.GA30159@roeck-us.net>
Date: Mon, 11 Mar 2013 05:21:44 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Naveen Krishna Chatradhi <ch.naveen@...sung.com>
Cc: linux-kernel@...r.kernel.org, lm-sensors@...sensors.org,
devicetree-discuss@...ts.ozlabs.org, khali@...ux-fr.org,
dianders@...omium.org, naveenkrishna.ch@...il.com,
dg77.kim@...sung.com
Subject: Re: [PATCH 1/2] hwmon: ntc: Add DT support to NTC thermistor driver
On Mon, Mar 11, 2013 at 07:39:46AM +0530, Naveen Krishna Chatradhi wrote:
> This patch adds the DT support to NTC driver to parse the
> platform data.
>
> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@...sung.com>
> ---
> drivers/hwmon/ntc_thermistor.c | 93 ++++++++++++++++++++++++++++++++--------
> 1 file changed, 75 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c
> index d92b237..cfedbd3 100644
> --- a/drivers/hwmon/ntc_thermistor.c
> +++ b/drivers/hwmon/ntc_thermistor.c
> @@ -26,6 +26,7 @@
> #include <linux/math64.h>
> #include <linux/platform_device.h>
> #include <linux/err.h>
> +#include <linux/of.h>
>
> #include <linux/platform_data/ntc_thermistor.h>
>
> @@ -37,6 +38,41 @@ struct ntc_compensation {
> unsigned int ohm;
> };
>
> +static const struct platform_device_id ntc_thermistor_id[] = {
> + { "ncp15wb473", TYPE_NCPXXWB473 },
> + { "ncp18wb473", TYPE_NCPXXWB473 },
> + { "ncp21wb473", TYPE_NCPXXWB473 },
> + { "ncp03wb473", TYPE_NCPXXWB473 },
> + { "ncp15wl333", TYPE_NCPXXWL333 },
> + { },
> +};
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id ntc_match[] = {
> + { .compatible = "ntc,ncp15wb473", .data = (void *)TYPE_NCPXXWB473 },
> + { .compatible = "ntc,ncp18wb473", .data = (void *)TYPE_NCPXXWB473 },
> + { .compatible = "ntc,ncp21wb473", .data = (void *)TYPE_NCPXXWB473 },
> + { .compatible = "ntc,ncp03wb473", .data = (void *)TYPE_NCPXXWB473 },
> + { .compatible = "ntc,ncp15wl333", .data = (void *)TYPE_NCPXXWL333 },
Better point to ntc_thermistor_id[TYPE_xxx]. See below.
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, ntc_match);
> +#endif
> +
> +/* Get NTC type either from device tree or platform data. */
> +static enum ntc_thermistor_type thermistor_get_type
> + (struct platform_device *pdev)
> +{
> + if (pdev->dev.of_node) {
> + const struct of_device_id *match;
> + match = of_match_node(of_match_ptr(ntc_match),
> + pdev->dev.of_node);
> + return (unsigned int)match->data;
> + }
> +
> + return platform_get_device_id(pdev)->driver_data;
> +}
> +
> /*
> * A compensation table should be sorted by the values of .ohm
> * in descending order.
> @@ -126,6 +162,27 @@ struct ntc_data {
> char name[PLATFORM_NAME_SIZE];
> };
>
> +#ifdef CONFIG_OF
Please merge the two CONFIG_OF blocks into one.
> +static void ntc_thermistor_parse_dt(struct ntc_thermistor_platform_data *pdata,
> + struct device_node *np)
> +{
> + of_property_read_u32(np, "pullup-uV", &pdata->pullup_uV);
> + of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm);
> + of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm);
> + if (of_find_property(np, "connected-positive", NULL))
> + pdata->connect = NTC_CONNECTED_POSITIVE;
> + else /* status change should be possible if not always on. */
> + pdata->connect = NTC_CONNECTED_GROUND;
> +}
> +#else
> +static void
> +static void ntc_thermistor_parse_dt(struct ntc_thermistor_platform_data *pdata,
> + struct device_node *np)
> +{
> + return;
Unnecessary return statement.
> +}
> +#endif
> +
> static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
> {
> if (divisor == 0 && dividend == 0)
> @@ -313,9 +370,19 @@ static const struct attribute_group ntc_attr_group = {
> static int ntc_thermistor_probe(struct platform_device *pdev)
> {
> struct ntc_data *data;
> - struct ntc_thermistor_platform_data *pdata = pdev->dev.platform_data;
> + struct device_node *np = pdev->dev.of_node;
> + struct ntc_thermistor_platform_data *pdata = NULL;
Unnecessary change. It doesn't hurt if pdata is initialized to non-NULL, and
initializing it to NULL is unnecessary anyway since it is always assigned below.
> int ret = 0;
>
> + if (np) {
> + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> + if (!pdata)
> + return -ENOMEM;
> +
> + ntc_thermistor_parse_dt(pdata, np);
This compiles, but the resulting code would not work as the necessary fields
in pdata are not all filled out. So I think it would be better to merge the code
with the next patch, as both don't really work independently.
> + } else
> + pdata = pdev->dev.platform_data;
Not necessary if you keep above pre-initialization.
A better idea would be to move the devm_kzalloc into ntc_thermistor_parse_dt
and return a pointer to pdata from it. Then you would have
pdata = ntc_thermistor_parse_dt(np);
if (!pdata)
pdata = pdev->dev.platform_data;
The check for np == NULL could then also be in ntc_thermistor_parse_dt and only
be executed if CONFIG_OF is defined. This would make the code flow look much nicer.
> +
> if (!pdata) {
> dev_err(&pdev->dev, "No platform init data supplied.\n");
> return -ENODEV;
> @@ -353,9 +420,9 @@ static int ntc_thermistor_probe(struct platform_device *pdev)
> data->dev = &pdev->dev;
> data->pdev = pdev;
> data->pdata = pdata;
> - strlcpy(data->name, pdev->id_entry->name, sizeof(data->name));
> + strncpy(data->name, dev_name(&pdev->dev), PLATFORM_NAME_SIZE);
>
strlcpy is used to ensure 0 termination.
sizeof(data->name) is used to ensure object size.
You should introduce a variable such as pdev_id and either assign pdev->id_entry
or the result of the of function call to it. Other code does that for example
with
const struct of_device_id *of_id =
of_match_device(of_match_ptr(coda_dt_ids),
&pdev->dev);
const struct platform_device_id *pdev_id;
...
pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
and then just use pdev_id. Then you can use
strncpy(data->name, pdev_id->name, sizeof(data->name));
That requires to change .data in the of_device_id table to point to the
platform_device_id.
> - switch (pdev->id_entry->driver_data) {
> + switch (thermistor_get_type(pdev)) {
And then:
switch (pdev_id) {
> case TYPE_NCPXXWB473:
> data->comp = ncpXXwb473;
> data->n_comp = ARRAY_SIZE(ncpXXwb473);
> @@ -365,9 +432,8 @@ static int ntc_thermistor_probe(struct platform_device *pdev)
> data->n_comp = ARRAY_SIZE(ncpXXwl333);
> break;
> default:
> - dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n",
> - pdev->id_entry->driver_data,
> - pdev->id_entry->name);
> + dev_err(&pdev->dev, "Unknown device type: %u\n",
> + thermistor_get_type(pdev));
dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n",
pdev_id->driver_data,
pdev_id->name);
> return -EINVAL;
> }
>
> @@ -386,9 +452,8 @@ static int ntc_thermistor_probe(struct platform_device *pdev)
> goto err_after_sysfs;
> }
>
> - dev_info(&pdev->dev, "Thermistor %s:%d (type: %s/%lu) successfully probed.\n",
> - pdev->name, pdev->id, pdev->id_entry->name,
> - pdev->id_entry->driver_data);
> + dev_info(&pdev->dev, "Thermistor successfully probed.\n");
Same here again.
dev_info(&pdev->dev, "Thermistor %s:%d (type: %s/%lu) successfully probed.\n",
pdev->name, pdev->id, pdev_id->name,
pdev_id->driver_data);
Though I would change that to
dev_info(&pdev->dev, "Thermistor type %s successfully probed.\n",
pdev_id->name);
since the rest of the output is either redundant (name/id) or internal
(pdev_id->driver_data).
> +
> return 0;
> err_after_sysfs:
> sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
> @@ -406,19 +471,11 @@ static int ntc_thermistor_remove(struct platform_device *pdev)
> return 0;
> }
>
> -static const struct platform_device_id ntc_thermistor_id[] = {
> - { "ncp15wb473", TYPE_NCPXXWB473 },
> - { "ncp18wb473", TYPE_NCPXXWB473 },
> - { "ncp21wb473", TYPE_NCPXXWB473 },
> - { "ncp03wb473", TYPE_NCPXXWB473 },
> - { "ncp15wl333", TYPE_NCPXXWL333 },
> - { },
> -};
> -
> static struct platform_driver ntc_thermistor_driver = {
> .driver = {
> .name = "ntc-thermistor",
> .owner = THIS_MODULE,
> + .of_match_table = of_match_ptr(ntc_match),
> },
> .probe = ntc_thermistor_probe,
> .remove = ntc_thermistor_remove,
> --
> 1.7.9.5
>
>
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