2012-10-27 15:05:17

by Francesco Lavra

[permalink] [raw]
Subject: Re: [PATCH 1/4] mfd: ab8500: add devicetree support for fuelgauge

On 10/25/2012 08:30 AM, Rajanikanth H.V wrote:
> From: "Rajanikanth H.V" <[email protected]>
>
> - This patch adds device tree support for fuelgauge driver
> - optimize bm devices platform_data usage and of_probe(...)
> Note: of_probe() routine for battery managed devices is made
> common across all bm drivers.
> - test status:
> - interrupt numbers assigned differs between legacy and FDT mode.
>
> Signed-off-by: Rajanikanth H.V <[email protected]>
[...]
> diff --git a/Documentation/devicetree/bindings/power_supply/ab8500/fg.txt b/Documentation/devicetree/bindings/power_supply/ab8500/fg.txt
> new file mode 100644
> index 0000000..28eaf35
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power_supply/ab8500/fg.txt
> @@ -0,0 +1,58 @@
> +=== AB8500 Fuel Gauge Driver ===
> +
> +AB8500 is a mixed signal multimedia and power management
> +device comprising: power and energy-management-module,
> +wall-charger, usb-charger, audio codec, general purpose adc,
> +tvout, clock management and sim card interface.
> +
> +Fuelgauge support is part of energy-management-modules, other
> +components of this module are:
> +main-charger, usb-combo-charger and battery-temperature-monitoring.
> +
> +The properties below describes the node for fuelgauge driver.
> +
> +Required Properties:
> +- compatible = This shall be: "stericsson,ab8500-fg"
> +- battery = Shall be battery specific information
> + Example:
> + ab8500_fg {
> + compatible = "stericsson,ab8500-fg";
> + battery = <&ab8500_battery>;
> + };
> +
> +dependent node:
> + ab8500_battery: ab8500_battery {
> + };
> + This node will provide information on 'thermistor interface' and
> + 'battery technology type' used.
> +
> +Properties of this node are:
> +thermistor-on-batctrl:
> + A boolean value indicating thermistor interface to battery
> +
> + Note:
> + 'btemp' and 'batctrl' are the pins interfaced for battery temperature
> + measurement, 'btemp' signal is used when NTC(negative temperature
> + coefficient) resister is interfaced external to battery whereas
> + 'batctrl' pin is used when NTC resister is internal to battery.
> +
> + Example:
> + ab8500_battery: ab8500_battery {
> + thermistor-on-batctrl;
> + };
> + indiactes: NTC resister is internal to battery, 'batctrl' is used

s/indiactes/indicates

[...]
> +int __devinit
> +bmdevs_of_probe(struct device *dev,
> + struct device_node *np,
> + struct abx500_bm_data **battery)
> +{
> + struct abx500_battery_type *btype;
> + struct device_node *np_bat_supply;
> + struct abx500_bm_data *bat;
> + const char *bat_tech;
> + int i, thermistor;
> +
> + *battery = &ab8500_bm_data;
> +
> + /* get phandle to 'battery-info' node */
> + np_bat_supply = of_parse_phandle(np, "battery", 0);
> + if (!np_bat_supply) {
> + dev_err(dev, "missing property battery\n");
> + return -EINVAL;
> + }
> + if (of_property_read_bool(np_bat_supply,
> + "thermistor-on-batctrl"))
> + thermistor = NTC_INTERNAL;
> + else
> + thermistor = NTC_EXTERNAL;
> +
> + bat = *battery;
> + if (thermistor == NTC_EXTERNAL) {
> + bat->n_btypes = 4;
> + bat->bat_type = bat_type_ext_thermistor;
> + bat->adc_therm = ABx500_ADC_THERM_BATTEMP;
> + }
> + bat_tech = of_get_property(np_bat_supply,
> + "stericsson,battery-type", NULL);
> + if (!bat_tech)
> + dev_warn(dev, "missing property battery-name/type\n");
> +
> + if (strncmp(bat_tech, "LION", 4) == 0) {

What if bat_tech is NULL?

[...]
> diff --git a/drivers/power/ab8500_fg.c b/drivers/power/ab8500_fg.c
> index bf02225..e117920 100644
> --- a/drivers/power/ab8500_fg.c
> +++ b/drivers/power/ab8500_fg.c
> @@ -22,15 +22,16 @@
> #include <linux/platform_device.h>
> #include <linux/power_supply.h>
> #include <linux/kobject.h>
> -#include <linux/mfd/abx500/ab8500.h>
> -#include <linux/mfd/abx500.h>
> #include <linux/slab.h>
> -#include <linux/mfd/abx500/ab8500-bm.h>
> #include <linux/delay.h>
> -#include <linux/mfd/abx500/ab8500-gpadc.h>
> -#include <linux/mfd/abx500.h>
> #include <linux/time.h>
> +#include <linux/of.h>
> #include <linux/completion.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/abx500.h>
> +#include <linux/mfd/abx500/ab8500.h>
> +#include <linux/mfd/abx500/ab8500-bm.h>
> +#include <linux/mfd/abx500/ab8500-gpadc.h>
>
> #define MILLI_TO_MICRO 1000
> #define FG_LSB_IN_MA 1627
> @@ -212,7 +213,6 @@ struct ab8500_fg {
> struct ab8500_fg_avg_cap avg_cap;
> struct ab8500 *parent;
> struct ab8500_gpadc *gpadc;
> - struct abx500_fg_platform_data *pdata;

pdata should be removed from the description of the struct members as well.

--
Francesco


2012-10-27 16:00:46

by Rajanikanth H.V

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Subject: Re: [PATCH 1/4] mfd: ab8500: add devicetree support for fuelgauge

On 27 October 2012 20:37, Francesco Lavra <[email protected]> wrote:
> On 10/25/2012 08:30 AM, Rajanikanth H.V wrote:
>> From: "Rajanikanth H.V" <[email protected]>
>> + bat_tech = of_get_property(np_bat_supply,
>> + "stericsson,battery-type", NULL);
>> + if (!bat_tech)
>> + dev_warn(dev, "missing property battery-name/type\n");
>> +
>> + if (strncmp(bat_tech, "LION", 4) == 0) {
>
> What if bat_tech is NULL?
It will be UNKNOWN

2012-10-27 16:16:51

by Francesco Lavra

[permalink] [raw]
Subject: Re: [PATCH 1/4] mfd: ab8500: add devicetree support for fuelgauge

On 10/27/2012 06:00 PM, Rajanikanth HV wrote:
> On 27 October 2012 20:37, Francesco Lavra <[email protected]> wrote:
>> On 10/25/2012 08:30 AM, Rajanikanth H.V wrote:
>>> From: "Rajanikanth H.V" <[email protected]>
>>> + bat_tech = of_get_property(np_bat_supply,
>>> + "stericsson,battery-type", NULL);
>>> + if (!bat_tech)
>>> + dev_warn(dev, "missing property battery-name/type\n");
>>> +
>>> + if (strncmp(bat_tech, "LION", 4) == 0) {
>>
>> What if bat_tech is NULL?
> It will be UNKNOWN

I wanted to draw your attention to the fact that if bat_tech is NULL you
are passing a NULL pointer to strncmp(), which is not good.
So you should assign a default value to bat_tech in case the battery
type property is not found in the DT, as below:

if (!bat_tech) {
dev_warn(dev, "missing property battery-name/type\n");
bat_tech = "UNKNOWN";
}

--
Francesco