RE: [PATCH v3 3/6] power: Add support for DA9150 Fuel-Gauge

[Opensource [Adam Thomson]]

On July 25, 2015 18:27, Sebastian Reichel wrote:

> Hi Adam,
> 
> The driver looks mostly fine. I have a few comments, though:
> 
> On Tue, Jul 07, 2015 at 05:34:19PM +0100, Adam Thomson wrote:
> > Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx>
> 
> Please add a short description to the commit message.
> 

Ok, I can add something. Didn't feel like it needed to be too descriptive, but
can make it a little more verbose.

> > [...]
> >
> > +config FG_DA9150
> 
> Please name the config entry BATTERY_DA9150 to be consistent with
> the other fuel gauges.
>

Ok no problem.

> > [...]
> >
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/of.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/slab.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/delay.h>
> > +#include <linux/power_supply.h>
> > +#include <linux/list.h>
> > +#include <asm/div64.h>
> > +#include <linux/mfd/da9150/core.h>
> > +#include <linux/mfd/da9150/registers.h>
> 
> I wonder if the "depends CHARGER_DA9150" in Kconfig should be
> "depends MFD_DA9150" instead.
> 

I did think about this, but it felt like it was a bit pointless having the
fuel-gauge driver without the charger driver, as they're intrinsically tied in
HW. I guess if you don't want the charging reporting but still wanted fuel-gauge
information then maybe. I don't mind making the change you mention as there
should be no functional impact.

> > [...]
> > +
> > +/* Power Supply attributes */
> > +static int da9150_fg_capacity(struct da9150_fg *fg,
> > +			      union power_supply_propval *val)
> > +{
> > +	da9150_fg_read_sync_start(fg);
> > +	val->intval = da9150_fg_read_attr(fg, DA9150_QIF_SOC_PCT,
> > +					  DA9150_QIF_SOC_PCT_SIZE);
> > +	da9150_fg_read_sync_end(fg);
> 
> Create a wrapper function for this. Reading a single value
> with sync guards is done multiple times.
> 
> da9150_fg_read_attr_sync(fg, ...) {
>     da9150_fg_read_sync_start(fg);
>     da9150_fg_read_attr(fg, ...);
>     da9150_fg_read_sync_end(fg);
> }
> 

Yep, fair point. Can add something for the single attribute accesses. 

> > +	if (val->intval > 100)
> > +		val->intval = 100;
> > +
> > +	return 0;
> > +}
> > +
> >
> > [...]
> > +					  DA9150_QIF_E_FG_STATUS_SIZE);
> > +
> > +	/* Handle warning/critical threhold events */
> > +	if ((DA9150_FG_IRQ_LOW_SOC_MASK | DA9150_FG_IRQ_HIGH_SOC_MASK)
> &
> > +	    e_fg_status)
> 
> Please make this (e_fg_status & CONSTANT_MASK).
>

Fine, not a problem.

> > +		da9150_fg_soc_event_config(fg);
> > +
> > +	/* Clear any FG IRQs */
> > +	da9150_fg_write_attr(fg, DA9150_QIF_E_FG_STATUS,
> > +			     DA9150_QIF_E_FG_STATUS_SIZE, e_fg_status);
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> >
> > [...]
> >
> > +static int da9150_fg_probe(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct da9150 *da9150 = dev_get_drvdata(dev->parent);
> > +	struct da9150_fg_pdata *fg_pdata = dev_get_platdata(dev);
> > +	struct da9150_fg *fg;
> > +	int ver, irq, ret;
> > +
> > +	fg = devm_kzalloc(dev, sizeof(*fg), GFP_KERNEL);
> > +	if (fg == NULL)
> > +		return -ENOMEM;
> > +
> > +	platform_set_drvdata(pdev, fg);
> > +	fg->da9150 = da9150;
> > +	fg->dev = dev;
> > +
> > +	mutex_init(&fg->io_lock);
> > +
> > +	/* Enable QIF */
> > +	da9150_set_bits(da9150, DA9150_CORE2WIRE_CTRL_A,
> DA9150_FG_QIF_EN_MASK,
> > +			DA9150_FG_QIF_EN_MASK);
> > +
> > +	fg->battery = power_supply_register(dev, &fg_desc, NULL);
> > +	if (IS_ERR(fg->battery)) {
> > +		ret = PTR_ERR(fg->battery);
> > +		return ret;
> > +	}
> 
> Please use devm_power_supply_register(...) to simplify the driver.
> 
> > +	ver = da9150_fg_read_attr(fg, DA9150_QIF_FW_MAIN_VER,
> > +				  DA9150_QIF_FW_MAIN_VER_SIZE);
> > +	dev_info(dev, "Version: 0x%x\n", ver);
> > +
> > +	/* Handle DT data if provided */
> > +	if (dev->of_node) {
> > +		fg_pdata = da9150_fg_dt_pdata(dev);
> > +		dev->platform_data = fg_pdata;
> > +	}
> > +
> > +	/* Handle any pdata provided */
> > +	if (fg_pdata) {
> > +		fg->interval = fg_pdata->update_interval;
> > +
> > +		if (fg_pdata->warn_soc_lvl > 100)
> > +			dev_warn(dev, "Invalid SOC warning level provided,
> Ignoring");
> > +		else
> > +			fg->warn_soc = fg_pdata->warn_soc_lvl;
> > +
> > +		if ((fg_pdata->crit_soc_lvl > 100) ||
> > +		    (fg_pdata->crit_soc_lvl >= fg_pdata->warn_soc_lvl))
> > +			dev_warn(dev, "Invalid SOC critical level provided,
> Ignoring");
> > +		else
> > +			fg->crit_soc = fg_pdata->crit_soc_lvl;
> > +
> > +
> > +	}
> > +
> > +	/* Configure initial SOC level events */
> > +	da9150_fg_soc_event_config(fg);
> > +
> > +	/*
> > +	 * If an interval period has been provided then setup repeating
> > +	 * work for reporting data updates.
> > +	 */
> > +	if (fg->interval) {
> > +		INIT_DELAYED_WORK(&fg->work, da9150_fg_work);
> > +		schedule_delayed_work(&fg->work,
> > +				      msecs_to_jiffies(fg->interval));
> > +	}
> > +
> > +	/* Register IRQ */
> > +	irq = platform_get_irq_byname(pdev, "FG");
> > +	ret = request_threaded_irq(irq, NULL, da9150_fg_irq, IRQF_ONESHOT, "FG",
> > +				   fg);
> > +	if (ret)
> > +		goto irq_fail;
> > +
> > +	return ret;
> > +
> > +irq_fail:
> > +	cancel_delayed_work(&fg->work);
> > +	power_supply_unregister(fg->battery);
> > +
> > +	return ret;
> > +}
> > +
> > +static int da9150_fg_remove(struct platform_device *pdev)
> > +{
> > +	struct da9150_fg *fg = platform_get_drvdata(pdev);
> > +	int irq;
> > +
> > +	irq = platform_get_irq_byname(pdev, "FG");
> > +	free_irq(irq, fg);
> > +
> > +	if (fg->interval)
> > +		cancel_delayed_work(&fg->work);
> 
> It looks like the order of irq freeing and canceling of the
> delayed work is not important. In that case I suggest switching
> to devm_request_threaded_irq(...).
> 

Yes, you're right. There's no ordering dependency. Will use devm.

> > +	power_supply_unregister(fg->battery);
> > +
> > +	return 0;
> > +}
> >
> > [...]
> >
> > +
> > +MODULE_DESCRIPTION("Fuel-Gauge Driver for DA9150");
> > +MODULE_AUTHOR("Adam Thomson
> <Adam.Thomson.Opensource@xxxxxxxxxxx>");
> > +MODULE_LICENSE("GPL");
> 
> MODULE_LICENSE("GPL v2");

If I do this then I need to update the file license disclaimer at the top, as
right now they match and are correct as far as I can tell. Is this change needed
and if so is this the intention for other drivers as well, just so I'm clear?