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Date:   Sun, 14 Apr 2019 11:37:58 +0100
From:   Jonathan Cameron <jic23@kernel.org>
To:     Sebastian Reichel <sre@kernel.org>
Cc:     Artur Rojek <contact@artur-rojek.eu>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>, linux-pm@vger.kernel.org,
        linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Paul Cercueil <paul@crapouillou.net>
Subject: Re: [PATCH v2 4/4] power: supply: add Ingenic JZ47xx battery
 driver.
Message-ID: <20190414113758.07702982@archlinux>
In-Reply-To: <20190407165234.is66vmnjfc35jnho@earth.universe>
References: <20190323172809.14407-1-contact@artur-rojek.eu>
        <20190323172809.14407-4-contact@artur-rojek.eu>
        <20190324153137.04857cdf@archlinux>
        <20190407165234.is66vmnjfc35jnho@earth.universe>
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On Sun, 7 Apr 2019 18:52:34 +0200
Sebastian Reichel <sre@kernel.org> wrote:

> Hi,
> 
> On Sun, Mar 24, 2019 at 03:31:37PM +0000, Jonathan Cameron wrote:
> > On Sat, 23 Mar 2019 18:28:09 +0100
> > Artur Rojek <contact@artur-rojek.eu> wrote:
> >   
> > > Add a driver for battery present on Ingenic JZ47xx SoCs.
> > > 
> > > Signed-off-by: Artur Rojek <contact@artur-rojek.eu>  
> > The IIO parts look fine to me.
> > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > 
> > Sebastian, assuming you are happy with this version,  
> 
> The driver itself looks ok. I'm a bit unhappy, that we already have
> jz4740-battery. This driver is much cleaner, but does not yet seem
> to be ready to replace it. Artur Rojek what are your plans regarding
> to the existing driver? Is there currently work going on migrating
> JZ47xx to DT?
> 
> > do you have any preference for how we handle this series?
> > 
> > Probably needs one of us to do an immutable branch with just this
> > in it.  I'm happy to do so once all the relevant Acks etc are in
> > place, but don't mind if you want to!  
> 
> I suppose you could provide an immutable branch with just the first
> two patches in it. Then I can pull it and apply the power-supply
> patches on top.
Done. ib-jz47xx-battery-prereq branch of 
git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git

which is based on v5.0

I'll pull that into the togreg branch of iio.git shortly.

Thanks,

Jonathan

> 
> -- Sebastian
> 
> > Thanks,
> > 
> > Jonathan
> >   
> > > ---
> > > 
> > > Changes:
> > > 
> > > v2: - rework the return logic in ingenic_battery_get_property,
> > >     - make index offsets point forward in ingenic_battery_set_scale,
> > >     - fix spacing around scale_raw[best_idx + 1]
> > > 
> > >  drivers/power/supply/Kconfig           |  11 ++
> > >  drivers/power/supply/Makefile          |   1 +
> > >  drivers/power/supply/ingenic-battery.c | 180 +++++++++++++++++++++++++
> > >  3 files changed, 192 insertions(+)
> > >  create mode 100644 drivers/power/supply/ingenic-battery.c
> > > 
> > > diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
> > > index e901b9879e7e..9bfb1637ec28 100644
> > > --- a/drivers/power/supply/Kconfig
> > > +++ b/drivers/power/supply/Kconfig
> > > @@ -169,6 +169,17 @@ config BATTERY_COLLIE
> > >  	  Say Y to enable support for the battery on the Sharp Zaurus
> > >  	  SL-5500 (collie) models.
> > >  
> > > +config BATTERY_INGENIC
> > > +	tristate "Ingenic JZ47xx SoCs battery driver"
> > > +	depends on MIPS || COMPILE_TEST
> > > +	depends on INGENIC_ADC
> > > +	help
> > > +	  Choose this option if you want to monitor battery status on
> > > +	  Ingenic JZ47xx SoC based devices.
> > > +
> > > +	  This driver can also be built as a module. If so, the module will be
> > > +	  called ingenic-battery.
> > > +
> > >  config BATTERY_IPAQ_MICRO
> > >  	tristate "iPAQ Atmel Micro ASIC battery driver"
> > >  	depends on MFD_IPAQ_MICRO
> > > diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
> > > index b731c2a9b695..9e2c481d0187 100644
> > > --- a/drivers/power/supply/Makefile
> > > +++ b/drivers/power/supply/Makefile
> > > @@ -34,6 +34,7 @@ obj-$(CONFIG_BATTERY_PMU)	+= pmu_battery.o
> > >  obj-$(CONFIG_BATTERY_OLPC)	+= olpc_battery.o
> > >  obj-$(CONFIG_BATTERY_TOSA)	+= tosa_battery.o
> > >  obj-$(CONFIG_BATTERY_COLLIE)	+= collie_battery.o
> > > +obj-$(CONFIG_BATTERY_INGENIC)	+= ingenic-battery.o
> > >  obj-$(CONFIG_BATTERY_IPAQ_MICRO) += ipaq_micro_battery.o
> > >  obj-$(CONFIG_BATTERY_WM97XX)	+= wm97xx_battery.o
> > >  obj-$(CONFIG_BATTERY_SBS)	+= sbs-battery.o
> > > diff --git a/drivers/power/supply/ingenic-battery.c b/drivers/power/supply/ingenic-battery.c
> > > new file mode 100644
> > > index 000000000000..822aee1c7b64
> > > --- /dev/null
> > > +++ b/drivers/power/supply/ingenic-battery.c
> > > @@ -0,0 +1,180 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Battery driver for the Ingenic JZ47xx SoCs
> > > + * Copyright (c) 2019 Artur Rojek <contact@artur-rojek.eu>
> > > + *
> > > + * based on drivers/power/supply/jz4740-battery.c
> > > + */
> > > +
> > > +#include <linux/iio/consumer.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/power_supply.h>
> > > +#include <linux/property.h>
> > > +
> > > +struct ingenic_battery {
> > > +	struct device *dev;
> > > +	struct iio_channel *channel;
> > > +	struct power_supply_desc desc;
> > > +	struct power_supply *battery;
> > > +	struct power_supply_battery_info info;
> > > +};
> > > +
> > > +static int ingenic_battery_get_property(struct power_supply *psy,
> > > +					enum power_supply_property psp,
> > > +					union power_supply_propval *val)
> > > +{
> > > +	struct ingenic_battery *bat = power_supply_get_drvdata(psy);
> > > +	struct power_supply_battery_info *info = &bat->info;
> > > +	int ret;
> > > +
> > > +	switch (psp) {
> > > +	case POWER_SUPPLY_PROP_HEALTH:
> > > +		ret = iio_read_channel_processed(bat->channel, &val->intval);
> > > +		val->intval *= 1000;
> > > +		if (val->intval < info->voltage_min_design_uv)
> > > +			val->intval = POWER_SUPPLY_HEALTH_DEAD;
> > > +		else if (val->intval > info->voltage_max_design_uv)
> > > +			val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
> > > +		else
> > > +			val->intval = POWER_SUPPLY_HEALTH_GOOD;
> > > +		return ret;
> > > +	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> > > +		ret = iio_read_channel_processed(bat->channel, &val->intval);
> > > +		val->intval *= 1000;
> > > +		return ret;
> > > +	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
> > > +		val->intval = info->voltage_min_design_uv;
> > > +		return 0;
> > > +	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
> > > +		val->intval = info->voltage_max_design_uv;
> > > +		return 0;
> > > +	default:
> > > +		return -EINVAL;
> > > +	};
> > > +}
> > > +
> > > +/* Set the most appropriate IIO channel voltage reference scale
> > > + * based on the battery's max voltage.
> > > + */
> > > +static int ingenic_battery_set_scale(struct ingenic_battery *bat)
> > > +{
> > > +	const int *scale_raw;
> > > +	int scale_len, scale_type, best_idx = -1, best_mV, max_raw, i, ret;
> > > +	u64 max_mV;
> > > +
> > > +	ret = iio_read_max_channel_raw(bat->channel, &max_raw);
> > > +	if (ret) {
> > > +		dev_err(bat->dev, "Unable to read max raw channel value\n");
> > > +		return ret;
> > > +	}
> > > +
> > > +	ret = iio_read_avail_channel_attribute(bat->channel, &scale_raw,
> > > +					       &scale_type, &scale_len,
> > > +					       IIO_CHAN_INFO_SCALE);
> > > +	if (ret < 0) {
> > > +		dev_err(bat->dev, "Unable to read channel avail scale\n");
> > > +		return ret;
> > > +	}
> > > +	if (ret != IIO_AVAIL_LIST || scale_type != IIO_VAL_FRACTIONAL_LOG2)
> > > +		return -EINVAL;
> > > +
> > > +	max_mV = bat->info.voltage_max_design_uv / 1000;
> > > +
> > > +	for (i = 0; i < scale_len; i += 2) {
> > > +		u64 scale_mV = (max_raw * scale_raw[i]) >> scale_raw[i + 1];
> > > +
> > > +		if (scale_mV < max_mV)
> > > +			continue;
> > > +
> > > +		if (best_idx >= 0 && scale_mV > best_mV)
> > > +			continue;
> > > +
> > > +		best_mV = scale_mV;
> > > +		best_idx = i;
> > > +	}
> > > +
> > > +	if (best_idx < 0) {
> > > +		dev_err(bat->dev, "Unable to find matching voltage scale\n");
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	return iio_write_channel_attribute(bat->channel,
> > > +					   scale_raw[best_idx],
> > > +					   scale_raw[best_idx + 1],
> > > +					   IIO_CHAN_INFO_SCALE);
> > > +}
> > > +
> > > +static enum power_supply_property ingenic_battery_properties[] = {
> > > +	POWER_SUPPLY_PROP_HEALTH,
> > > +	POWER_SUPPLY_PROP_VOLTAGE_NOW,
> > > +	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
> > > +	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
> > > +};
> > > +
> > > +static int ingenic_battery_probe(struct platform_device *pdev)
> > > +{
> > > +	struct device *dev = &pdev->dev;
> > > +	struct ingenic_battery *bat;
> > > +	struct power_supply_config psy_cfg = {};
> > > +	struct power_supply_desc *desc;
> > > +	int ret;
> > > +
> > > +	bat = devm_kzalloc(dev, sizeof(*bat), GFP_KERNEL);
> > > +	if (!bat)
> > > +		return -ENOMEM;
> > > +
> > > +	bat->dev = dev;
> > > +	bat->channel = devm_iio_channel_get(dev, "battery");
> > > +	if (IS_ERR(bat->channel))
> > > +		return PTR_ERR(bat->channel);
> > > +
> > > +	desc = &bat->desc;
> > > +	desc->name = "jz-battery";
> > > +	desc->type = POWER_SUPPLY_TYPE_BATTERY;
> > > +	desc->properties = ingenic_battery_properties;
> > > +	desc->num_properties = ARRAY_SIZE(ingenic_battery_properties);
> > > +	desc->get_property = ingenic_battery_get_property;
> > > +	psy_cfg.drv_data = bat;
> > > +	psy_cfg.of_node = dev->of_node;
> > > +
> > > +	bat->battery = devm_power_supply_register(dev, desc, &psy_cfg);
> > > +	if (IS_ERR(bat->battery)) {
> > > +		dev_err(dev, "Unable to register battery\n");
> > > +		return PTR_ERR(bat->battery);
> > > +	}
> > > +
> > > +	ret = power_supply_get_battery_info(bat->battery, &bat->info);
> > > +	if (ret) {
> > > +		dev_err(dev, "Unable to get battery info: %d\n", ret);
> > > +		return ret;
> > > +	}
> > > +	if (bat->info.voltage_min_design_uv < 0) {
> > > +		dev_err(dev, "Unable to get voltage min design\n");
> > > +		return bat->info.voltage_min_design_uv;
> > > +	}
> > > +	if (bat->info.voltage_max_design_uv < 0) {
> > > +		dev_err(dev, "Unable to get voltage max design\n");
> > > +		return bat->info.voltage_max_design_uv;
> > > +	}
> > > +
> > > +	return ingenic_battery_set_scale(bat);
> > > +}
> > > +
> > > +#ifdef CONFIG_OF
> > > +static const struct of_device_id ingenic_battery_of_match[] = {
> > > +	{ .compatible = "ingenic,jz4740-battery", },
> > > +	{ },
> > > +};
> > > +MODULE_DEVICE_TABLE(of, ingenic_battery_of_match);
> > > +#endif
> > > +
> > > +static struct platform_driver ingenic_battery_driver = {
> > > +	.driver = {
> > > +		.name = "ingenic-battery",
> > > +		.of_match_table = of_match_ptr(ingenic_battery_of_match),  
> > 
> > I guess we can be fairly sure no one will even user this with ACPI
> > (magic DT) bindings?  That would make this a rare case where the
> > of_match_pr protection and ifdef fun is still fine.
> > 
> >   
> > > +	},
> > > +	.probe = ingenic_battery_probe,
> > > +};
> > > +module_platform_driver(ingenic_battery_driver);  
> >