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

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:

quoted

Signed-off-by: Adam Thomson <redacted>

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.

quoted

[...]

+config FG_DA9150

Please name the config entry BATTERY_DA9150 to be consistent with
the other fuel gauges.

Ok no problem.

quoted

[...]

+#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.

quoted

[...]
+
+/* 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. 

quoted

+	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)

&

quoted

+	    e_fg_status)

Please make this (e_fg_status & CONSTANT_MASK).

Fine, not a problem.

quoted

+		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,

quoted

+			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.

quoted

+	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");

quoted

+		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");

quoted

+		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.

quoted

+	power_supply_unregister(fg->battery);
+
+	return 0;
+}

[...]

+
+MODULE_DESCRIPTION("Fuel-Gauge Driver for DA9150");
+MODULE_AUTHOR("Adam Thomson

[off-list ref]");

quoted

+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?