Re: [PATCH v2] thermal: Add QPNP PMIC temperature alarm driver

[Kiran Padwal <kiran.padwal@smartplayin.com>]

On Thursday 25 September 2014 07:00 PM, Ivan T. Ivanov wrote:
> Add support for the temperature alarm peripheral found inside
> Qualcomm plug-and-play (QPNP) PMIC chips.  The temperature alarm
> peripheral outputs a pulse on an interrupt line whenever the
> thermal over temperature stage value changes.  Implement an ISR
> to manage this interrupt.
> 

<snip>

> + * This function updates the internal temp value based on the
> + * current thermal stage and threshold as well as the previous stage
> + */
> +static int qpnp_tm_update_temp_no_adc(struct qpnp_tm_chip *chip)
> +{
> +	unsigned int stage;
> +	int rc;
> +	u8 reg;
> +
> +	rc = qpnp_tm_read(chip, QPNP_TM_REG_STATUS, &reg);
> +	if (rc < 0)
> +		return rc;
> +
> +	stage = reg & STATUS_STAGE_MASK;

During compilation, getting a waring as below,

drivers/thermal/qpnp-temp-alarm.c: In function ‘qpnp_tm_update_temp_no_adc’:
drivers/thermal/qpnp-temp-alarm.c:135:8: warning: ‘reg’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  stage = reg & STATUS_STAGE_MASK;

> +
> +	if (stage > chip->stage) {
> +		/* increasing stage, use lower bound */
> +		chip->temp = (stage - 1) * TEMP_STAGE_STEP +
> +			     chip->thresh * TEMP_THRESH_STEP +
> +			     TEMP_STAGE_HYSTERESIS + TEMP_THRESH_MIN;
> +	} else if (stage < chip->stage) {
> +		/* decreasing stage, use upper bound */
> +		chip->temp = stage * TEMP_STAGE_STEP +
> +			     chip->thresh * TEMP_THRESH_STEP -
> +			     TEMP_STAGE_HYSTERESIS + TEMP_THRESH_MIN;
> +	}
> +
> +	chip->stage = stage;
> +
> +	return 0;
> +}
> +

<snip>

> +
> +#define QPNP_TM_PM_OPS	(&qpnp_tm_pm_ops)
> +#else
> +#define QPNP_TM_PM_OPS	NULL
> +#endif
> +
> +static struct of_device_id qpnp_tm_match_table[] = {

It must be static const struct of_device_id, because all OF functions handle it as const.

Thanks,
--Kiran

> +	{ .compatible = "qcom,spmi-temp-alarm" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, qpnp_tm_match_table);
> +
> +static struct platform_driver qpnp_tm_driver = {
> +	.driver = {
> +		.name = "spmi-temp-alarm",
> +		.of_match_table = qpnp_tm_match_table,
> +		.pm = QPNP_TM_PM_OPS,
> +	},
> +	.probe  = qpnp_tm_probe,
> +	.remove = qpnp_tm_remove,
> +};
> +module_platform_driver(qpnp_tm_driver);
> +
> +MODULE_ALIAS("platform:spmi-temp-alarm");
> +MODULE_DESCRIPTION("QPNP PMIC Temperature Alarm driver");
> +MODULE_LICENSE("GPL v2");
>