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[v8,0/3] Introduce Embedded Controller driver for Acer A500

Message ID 20201228160547.30562-1-digetx@gmail.com
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Series Introduce Embedded Controller driver for Acer A500 | expand

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Dmitry Osipenko Dec. 28, 2020, 4:05 p.m. UTC 
This series adds support for the Embedded Controller which is found on
Acer Iconia Tab A500 (Android tablet device).

The Embedded Controller is ENE KB930 and it's running firmware customized
for the A500. The firmware interface may be reused by some other sibling
Acer tablets, although none of those tablets are supported in upstream yet.

Changelog:

v8: - This series partially missed v5.11 kernel release, hence resending
      for v5.12.

      Please note that Thierry Reding already applied the v7 DT patch which
      added the EC node to the Acer A500 device-tree, this change presents
      in v5.11.

v7: - Improved MFD Kconfig entry by adding explicit dependency on OF and
      by rewording the help message, matching it to the other MFD drivers.

    - Improved comments in the code by removing unnecessary comments, adding
      necessary and rewording some others.

    - Added expressive defines for the command opcodes.

    - Fixed alphabet order of the MFD driver includes.

    - Removed unnecessary size checks which are already done by regmap core.

    - Renamed 'rmap' variable to 'regmap'.

v6: - Fixed dtschema-checker warning about a wrong indentation, reported
      by kernel bot for v5.

v5: - No changes. Re-sending again in order to check whether dtschema-bot
      warning is resolved now, which didn't happen in v4 because bot used
      older 5.9 kernel code base instead of 5.10.

v4: - No code changes. Added r-b from Rob Herring and Sebastian Reichel.
      Re-sending for 5.11.

    - The v3 of LED driver was applied by Pavel Machek and already presents
      in v5.10 kernel.

v3: - Rebased on a recent linux-next. Fixed new merge conflict and dropped
      "regmap: Use flexible sleep" patch because it's already applied.

v2: - Factored out KB930 device-tree binding into a separate file, like it
      was suggested by Lubomir Rintel.

    - Switched to use regmap API like it was suggested by Lubomir Rintel.

    - Added patch "regmap: Use flexible sleep" which allows not to hog
      CPU while LED is switching state.

    - Corrected MODULE_LICENSE to use "GPL" in all patches.

    - Corrected MFD driver Kconfig entry like it was suggested by
      Lubomir Rintel, it now depends on I2C.

    - Switched to use I2C probe_new() in the MFD driver.

    - Renamed the global pm_off variable, like it was suggested by
      Lubomir Rintel and Lee Jones.

    - Dropped serial number from the battery driver because I realized
      that it's not a battery serial, but a device serial.

    - Battery driver now uses dev_err_probe(), like it was suggested by
      Sebastian Reichel.

    - Dropped legacy LED_ON usage from the LED driver and renamed the
      LEDs, like it was suggested by Pavel Machek. I also checked whether
      LED-name customization via device-tree could be needed by other
      potentially compatible devices and it shouldn't be needed, anyways it
      won't be difficult to extend the code even if I'm wrong.


Dmitry Osipenko (3):
  dt-bindings: mfd: Add ENE KB930 Embedded Controller binding
  mfd: Add driver for Embedded Controller found on Acer Iconia Tab A500
  power: supply: Add battery gauge driver for Acer Iconia Tab A500

 .../devicetree/bindings/mfd/ene-kb930.yaml    |  65 ++++
 drivers/mfd/Kconfig                           |  11 +
 drivers/mfd/Makefile                          |   1 +
 drivers/mfd/acer-ec-a500.c                    | 202 ++++++++++++
 drivers/power/supply/Kconfig                  |   6 +
 drivers/power/supply/Makefile                 |   1 +
 drivers/power/supply/acer_a500_battery.c      | 297 ++++++++++++++++++
 7 files changed, 583 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/ene-kb930.yaml
 create mode 100644 drivers/mfd/acer-ec-a500.c
 create mode 100644 drivers/power/supply/acer_a500_battery.c

Comments

Dmitry Osipenko Jan. 12, 2021, 6:59 a.m. UTC | #1 
28.12.2020 19:05, Dmitry Osipenko пишет:
> This series adds support for the Embedded Controller which is found on
> Acer Iconia Tab A500 (Android tablet device).
> 
> The Embedded Controller is ENE KB930 and it's running firmware customized
> for the A500. The firmware interface may be reused by some other sibling
> Acer tablets, although none of those tablets are supported in upstream yet.
> 
> Changelog:
> 
> v8: - This series partially missed v5.11 kernel release, hence resending
>       for v5.12.

Hello Lee,

Could you please take a look at the MFD patch? If it's good to you, then
please apply this whole series via MFD tree.

Thanks in advance.
Lee Jones Jan. 14, 2021, 2:27 p.m. UTC | #2 
On Mon, 28 Dec 2020, Dmitry Osipenko wrote:

> Add binding document for the ENE KB930 Embedded Controller.

> 

> Reviewed-by: Rob Herring <robh@kernel.org>

> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>

> ---

>  .../devicetree/bindings/mfd/ene-kb930.yaml    | 65 +++++++++++++++++++

>  1 file changed, 65 insertions(+)

>  create mode 100644 Documentation/devicetree/bindings/mfd/ene-kb930.yaml


Applied, thanks.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog
Sebastian Reichel Jan. 14, 2021, 6:49 p.m. UTC | #3 
Hi,

On Mon, Dec 28, 2020 at 07:05:47PM +0300, Dmitry Osipenko wrote:
> This patch adds battery gauge driver for Acer Iconia Tab A500 device.
> The battery gauge function is provided via the Embedded Controller,
> which is found on the Acer A500.
> 
> Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---

Thanks, queued.

-- Sebastian

>  drivers/power/supply/Kconfig             |   6 +
>  drivers/power/supply/Makefile            |   1 +
>  drivers/power/supply/acer_a500_battery.c | 297 +++++++++++++++++++++++
>  3 files changed, 304 insertions(+)
>  create mode 100644 drivers/power/supply/acer_a500_battery.c
> 
> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
> index eec646c568b7..bc493173ddbc 100644
> --- a/drivers/power/supply/Kconfig
> +++ b/drivers/power/supply/Kconfig
> @@ -774,4 +774,10 @@ config RN5T618_POWER
>  	  This driver can also be built as a module. If so, the module will be
>  	  called rn5t618_power.
>  
> +config BATTERY_ACER_A500
> +	tristate "Acer Iconia Tab A500 battery driver"
> +	depends on MFD_ACER_A500_EC
> +	help
> +	  Say Y to include support for Acer Iconia Tab A500 battery fuel gauge.
> +
>  endif # POWER_SUPPLY
> diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
> index dd4b86318cd9..0607a3d64c0f 100644
> --- a/drivers/power/supply/Makefile
> +++ b/drivers/power/supply/Makefile
> @@ -98,3 +98,4 @@ obj-$(CONFIG_CHARGER_BD70528)	+= bd70528-charger.o
>  obj-$(CONFIG_CHARGER_BD99954)	+= bd99954-charger.o
>  obj-$(CONFIG_CHARGER_WILCO)	+= wilco-charger.o
>  obj-$(CONFIG_RN5T618_POWER)	+= rn5t618_power.o
> +obj-$(CONFIG_BATTERY_ACER_A500)	+= acer_a500_battery.o
> diff --git a/drivers/power/supply/acer_a500_battery.c b/drivers/power/supply/acer_a500_battery.c
> new file mode 100644
> index 000000000000..32a0bfcac08f
> --- /dev/null
> +++ b/drivers/power/supply/acer_a500_battery.c
> @@ -0,0 +1,297 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Battery driver for Acer Iconia Tab A500.
> + *
> + * Copyright 2020 GRATE-driver project.
> + *
> + * Based on downstream driver from Acer Inc.
> + * Based on NVIDIA Gas Gauge driver for SBS Compliant Batteries.
> + *
> + * Copyright (c) 2010, NVIDIA Corporation.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/power_supply.h>
> +#include <linux/regmap.h>
> +#include <linux/sched.h>
> +#include <linux/slab.h>
> +#include <linux/workqueue.h>
> +
> +enum {
> +	REG_CAPACITY,
> +	REG_VOLTAGE,
> +	REG_CURRENT,
> +	REG_DESIGN_CAPACITY,
> +	REG_TEMPERATURE,
> +};
> +
> +#define EC_DATA(_reg, _psp) {			\
> +	.psp = POWER_SUPPLY_PROP_ ## _psp,	\
> +	.reg = _reg,				\
> +}
> +
> +static const struct battery_register {
> +	enum power_supply_property psp;
> +	unsigned int reg;
> +} ec_data[] = {
> +	[REG_CAPACITY]		= EC_DATA(0x00, CAPACITY),
> +	[REG_VOLTAGE]		= EC_DATA(0x01, VOLTAGE_NOW),
> +	[REG_CURRENT]		= EC_DATA(0x03, CURRENT_NOW),
> +	[REG_DESIGN_CAPACITY]	= EC_DATA(0x08, CHARGE_FULL_DESIGN),
> +	[REG_TEMPERATURE]	= EC_DATA(0x0a, TEMP),
> +};
> +
> +static const enum power_supply_property a500_battery_properties[] = {
> +	POWER_SUPPLY_PROP_CAPACITY,
> +	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
> +	POWER_SUPPLY_PROP_CURRENT_NOW,
> +	POWER_SUPPLY_PROP_PRESENT,
> +	POWER_SUPPLY_PROP_STATUS,
> +	POWER_SUPPLY_PROP_TECHNOLOGY,
> +	POWER_SUPPLY_PROP_TEMP,
> +	POWER_SUPPLY_PROP_VOLTAGE_NOW,
> +};
> +
> +struct a500_battery {
> +	struct delayed_work poll_work;
> +	struct power_supply *psy;
> +	struct regmap *regmap;
> +	unsigned int capacity;
> +};
> +
> +static bool a500_battery_update_capacity(struct a500_battery *bat)
> +{
> +	unsigned int capacity;
> +	int err;
> +
> +	err = regmap_read(bat->regmap, ec_data[REG_CAPACITY].reg, &capacity);
> +	if (err)
> +		return false;
> +
> +	/* capacity can be >100% even if max value is 100% */
> +	capacity = min(capacity, 100u);
> +
> +	if (bat->capacity != capacity) {
> +		bat->capacity = capacity;
> +		return true;
> +	}
> +
> +	return false;
> +}
> +
> +static int a500_battery_get_status(struct a500_battery *bat)
> +{
> +	if (bat->capacity < 100) {
> +		if (power_supply_am_i_supplied(bat->psy))
> +			return POWER_SUPPLY_STATUS_CHARGING;
> +		else
> +			return POWER_SUPPLY_STATUS_DISCHARGING;
> +	}
> +
> +	return POWER_SUPPLY_STATUS_FULL;
> +}
> +
> +static void a500_battery_unit_adjustment(struct device *dev,
> +					 enum power_supply_property psp,
> +					 union power_supply_propval *val)
> +{
> +	const unsigned int base_unit_conversion = 1000;
> +	const unsigned int temp_kelvin_to_celsius = 2731;
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
> +	case POWER_SUPPLY_PROP_CURRENT_NOW:
> +	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> +		val->intval *= base_unit_conversion;
> +		break;
> +
> +	case POWER_SUPPLY_PROP_TEMP:
> +		val->intval -= temp_kelvin_to_celsius;
> +		break;
> +
> +	case POWER_SUPPLY_PROP_PRESENT:
> +		val->intval = !!val->intval;
> +		break;
> +
> +	default:
> +		dev_dbg(dev,
> +			"%s: no need for unit conversion %d\n", __func__, psp);
> +	}
> +}
> +
> +static int a500_battery_get_ec_data_index(struct device *dev,
> +					  enum power_supply_property psp)
> +{
> +	unsigned int i;
> +
> +	/*
> +	 * DESIGN_CAPACITY register always returns a non-zero value if
> +	 * battery is connected and zero if disconnected, hence we'll use
> +	 * it for judging the battery presence.
> +	 */
> +	if (psp == POWER_SUPPLY_PROP_PRESENT)
> +		psp = POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN;
> +
> +	for (i = 0; i < ARRAY_SIZE(ec_data); i++)
> +		if (psp == ec_data[i].psp)
> +			return i;
> +
> +	dev_dbg(dev, "%s: invalid property %u\n", __func__, psp);
> +
> +	return -EINVAL;
> +}
> +
> +static int a500_battery_get_property(struct power_supply *psy,
> +				     enum power_supply_property psp,
> +				     union power_supply_propval *val)
> +{
> +	struct a500_battery *bat = power_supply_get_drvdata(psy);
> +	struct device *dev = psy->dev.parent;
> +	int ret = 0;
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_STATUS:
> +		val->intval = a500_battery_get_status(bat);
> +		break;
> +
> +	case POWER_SUPPLY_PROP_TECHNOLOGY:
> +		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
> +		break;
> +
> +	case POWER_SUPPLY_PROP_CAPACITY:
> +		a500_battery_update_capacity(bat);
> +		val->intval = bat->capacity;
> +		break;
> +
> +	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
> +	case POWER_SUPPLY_PROP_CURRENT_NOW:
> +	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> +	case POWER_SUPPLY_PROP_PRESENT:
> +	case POWER_SUPPLY_PROP_TEMP:
> +		ret = a500_battery_get_ec_data_index(dev, psp);
> +		if (ret < 0)
> +			break;
> +
> +		ret = regmap_read(bat->regmap, ec_data[ret].reg, &val->intval);
> +		break;
> +
> +	default:
> +		dev_err(dev, "%s: invalid property %u\n", __func__, psp);
> +		return -EINVAL;
> +	}
> +
> +	if (!ret) {
> +		/* convert units to match requirements of power supply class */
> +		a500_battery_unit_adjustment(dev, psp, val);
> +	}
> +
> +	dev_dbg(dev, "%s: property = %d, value = %x\n",
> +		__func__, psp, val->intval);
> +
> +	/* return NODATA for properties if battery not presents */
> +	if (ret)
> +		return -ENODATA;
> +
> +	return 0;
> +}
> +
> +static void a500_battery_poll_work(struct work_struct *work)
> +{
> +	struct a500_battery *bat;
> +	bool capacity_changed;
> +
> +	bat = container_of(work, struct a500_battery, poll_work.work);
> +	capacity_changed = a500_battery_update_capacity(bat);
> +
> +	if (capacity_changed)
> +		power_supply_changed(bat->psy);
> +
> +	/* continuously send uevent notification */
> +	schedule_delayed_work(&bat->poll_work, 30 * HZ);
> +}
> +
> +static const struct power_supply_desc a500_battery_desc = {
> +	.name = "ec-battery",
> +	.type = POWER_SUPPLY_TYPE_BATTERY,
> +	.properties = a500_battery_properties,
> +	.get_property = a500_battery_get_property,
> +	.num_properties = ARRAY_SIZE(a500_battery_properties),
> +	.external_power_changed = power_supply_changed,
> +};
> +
> +static int a500_battery_probe(struct platform_device *pdev)
> +{
> +	struct power_supply_config psy_cfg = {};
> +	struct a500_battery *bat;
> +
> +	bat = devm_kzalloc(&pdev->dev, sizeof(*bat), GFP_KERNEL);
> +	if (!bat)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, bat);
> +
> +	psy_cfg.of_node = pdev->dev.parent->of_node;
> +	psy_cfg.drv_data = bat;
> +
> +	bat->regmap = dev_get_regmap(pdev->dev.parent, "KB930");
> +	if (!bat->regmap)
> +		return -EINVAL;
> +
> +	bat->psy = devm_power_supply_register_no_ws(&pdev->dev,
> +						    &a500_battery_desc,
> +						    &psy_cfg);
> +	if (IS_ERR(bat->psy))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(bat->psy),
> +				     "failed to register battery\n");
> +
> +	INIT_DELAYED_WORK(&bat->poll_work, a500_battery_poll_work);
> +	schedule_delayed_work(&bat->poll_work, HZ);
> +
> +	return 0;
> +}
> +
> +static int a500_battery_remove(struct platform_device *pdev)
> +{
> +	struct a500_battery *bat = dev_get_drvdata(&pdev->dev);
> +
> +	cancel_delayed_work_sync(&bat->poll_work);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused a500_battery_suspend(struct device *dev)
> +{
> +	struct a500_battery *bat = dev_get_drvdata(dev);
> +
> +	cancel_delayed_work_sync(&bat->poll_work);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused a500_battery_resume(struct device *dev)
> +{
> +	struct a500_battery *bat = dev_get_drvdata(dev);
> +
> +	schedule_delayed_work(&bat->poll_work, HZ);
> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(a500_battery_pm_ops,
> +			 a500_battery_suspend, a500_battery_resume);
> +
> +static struct platform_driver a500_battery_driver = {
> +	.driver = {
> +		.name = "acer-a500-iconia-battery",
> +		.pm = &a500_battery_pm_ops,
> +	},
> +	.probe = a500_battery_probe,
> +	.remove = a500_battery_remove,
> +};
> +module_platform_driver(a500_battery_driver);
> +
> +MODULE_DESCRIPTION("Battery gauge driver for Acer Iconia Tab A500");
> +MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
> +MODULE_ALIAS("platform:acer-a500-iconia-battery");
> +MODULE_LICENSE("GPL");
> -- 
> 2.29.2
>