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SubjectRe: [PATCH v3 2/2] power_supply: platform/chrome: wilco_ec: Add charging config driver
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Hi Nick,


On 12/4/19 2:20, Nick Crews wrote:
> Add control of the charging algorithm used on Wilco devices.
> See Documentation/ABI/testing/sysfs-class-power-wilco for the
> userspace interface and other info.
>
> v3 changes:
> -Add this changelog
> -Fix commit message tags
> v2 changes:
> -Update Documentation to say KernelVersion 5.2
> -Update Documentation to explain Trickle mode better.
> -rename things from using *PCC* to *CHARGE*
> -Split up conversions between POWER_SUPPLY_PROP_CHARGE_TYPE values
> and Wilco EC codes
> -Use devm_ flavor of power_supply_register(), which simplifies things
> -Add extra error checking on property messages received from the EC
> -Fix bug in memcpy() calls in properties.c
> -Refactor fill_property_id()
> -Add valid input checks to charge_type
> -Properly convert charge_type when get()ting
>
> Signed-off-by: Nick Crews <ncrews@chromium.org>
> ---
> .../ABI/testing/sysfs-class-power-wilco | 30 +++

Oh, I see the doc now :-) I think that part of this documentation should be generic.

> drivers/platform/chrome/wilco_ec/Kconfig | 9 +
> drivers/platform/chrome/wilco_ec/Makefile | 2 +
> .../platform/chrome/wilco_ec/charge_config.c | 190 ++++++++++++++++++
> drivers/platform/chrome/wilco_ec/core.c | 14 ++
> drivers/platform/chrome/wilco_ec/properties.c | 134 ++++++++++++
> drivers/platform/chrome/wilco_ec/properties.h | 68 +++++++
> include/linux/platform_data/wilco-ec.h | 2 +
> 8 files changed, 449 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-class-power-wilco
> create mode 100644 drivers/platform/chrome/wilco_ec/charge_config.c
> create mode 100644 drivers/platform/chrome/wilco_ec/properties.c
> create mode 100644 drivers/platform/chrome/wilco_ec/properties.h
>
> diff --git a/Documentation/ABI/testing/sysfs-class-power-wilco b/Documentation/ABI/testing/sysfs-class-power-wilco
> new file mode 100644
> index 000000000000..7f3b01310476
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-power-wilco
> @@ -0,0 +1,30 @@
> +What: /sys/class/power_supply/wilco_charger/charge_type
> +Date: April 2019
> +KernelVersion: 5.2
> +Description:
> + What charging algorithm to use:
> +
> + Standard: Fully charges battery at a standard rate.
> + Adaptive: Battery settings adaptively optimized based on
> + typical battery usage pattern.
> + Fast: Battery charges over a shorter period.
> + Trickle: Extends battery lifespan, intended for users who
> + primarily use their Chromebook while connected to AC.
> + Custom: A low and high threshold percentage is specified.
> + Charging begins when level drops below
> + charge_control_start_threshold, and ceases when
> + level is above charge_control_end_threshold.
> +
> +What: /sys/class/power_supply/wilco_charger/charge_control_start_threshold
> +Date: April 2019
> +KernelVersion: 5.2
> +Description:
> + Used when charge_type="Custom", as described above. Measured in
> + percentages. The valid range is [50, 95].
> +
> +What: /sys/class/power_supply/wilco_charger/charge_control_end_threshold
> +Date: April 2019
> +KernelVersion: 5.2
> +Description:
> + Used when charge_type="Custom", as described above. Measured in
> + percentages. The valid range is [55, 100].
> diff --git a/drivers/platform/chrome/wilco_ec/Kconfig b/drivers/platform/chrome/wilco_ec/Kconfig
> index e09e4cebe9b4..1c427830bd57 100644
> --- a/drivers/platform/chrome/wilco_ec/Kconfig
> +++ b/drivers/platform/chrome/wilco_ec/Kconfig
> @@ -18,3 +18,12 @@ config WILCO_EC_DEBUGFS
> manipulation and allow for testing arbitrary commands. This
> interface is intended for debug only and will not be present
> on production devices.
> +
> +config WILCO_EC_CHARGE_CNTL
> + tristate "Enable charging control"
> + depends on WILCO_EC
> + help
> + If you say Y here, you get support to control the charging
> + routines performed by the Wilco Embedded Controller.
> + Further information can be found in
> + Documentation/ABI/testing/sysfs-class-power-wilco)
> diff --git a/drivers/platform/chrome/wilco_ec/Makefile b/drivers/platform/chrome/wilco_ec/Makefile
> index 063e7fb4ea17..7e980f56f793 100644
> --- a/drivers/platform/chrome/wilco_ec/Makefile
> +++ b/drivers/platform/chrome/wilco_ec/Makefile
> @@ -4,3 +4,5 @@ wilco_ec-objs := core.o mailbox.o
> obj-$(CONFIG_WILCO_EC) += wilco_ec.o
> wilco_ec_debugfs-objs := debugfs.o
> obj-$(CONFIG_WILCO_EC_DEBUGFS) += wilco_ec_debugfs.o
> +wilco_ec_charging-objs := charge_config.o properties.o
> +obj-$(CONFIG_WILCO_EC_CHARGE_CNTL) += wilco_ec_charging.o

Sebastian can correct me but I think this driver should go in
drivers/power/supply/ instead of platform (wilco-ec-charger?)

> diff --git a/drivers/platform/chrome/wilco_ec/charge_config.c b/drivers/platform/chrome/wilco_ec/charge_config.c
> new file mode 100644
> index 000000000000..7c41b847396d
> --- /dev/null
> +++ b/drivers/platform/chrome/wilco_ec/charge_config.c
> @@ -0,0 +1,190 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Charging control driver for the Wilco EC
> + *
> + * Copyright 2019 Google LLC
> + *
> + * See Documentation/ABI/testing/sysfs-class-power-wilco for
> + * userspace interface and other info.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/platform_data/wilco-ec.h>
> +#include <linux/power_supply.h>
> +
> +#include "properties.h"
> +
> +#define DRV_NAME "wilco-ec-charging"
> +
> +/* Property IDs and related EC constants */
> +#define PID_CHARGE_MODE 0x0710
> +#define PID_CHARGE_LOWER_LIMIT 0x0711
> +#define PID_CHARGE_UPPER_LIMIT 0x0712
> +
> +enum charge_mode {
> + CHARGE_MODE_STD = 1, /* Used for Standard */
> + CHARGE_MODE_EXP = 2, /* Express Charge, used for Fast */
> + CHARGE_MODE_AC = 3, /* Mostly AC use, used for Trickle */
> + CHARGE_MODE_AUTO = 4, /* Used for Adaptive */
> + CHARGE_MODE_CUSTOM = 5, /* Used for Custom */
> +};
> +
> +#define CHARGE_LOWER_LIMIT_MIN 50
> +#define CHARGE_LOWER_LIMIT_MAX 95
> +#define CHARGE_UPPER_LIMIT_MIN 55
> +#define CHARGE_UPPER_LIMIT_MAX 100
> +
> +/* Convert from POWER_SUPPLY_PROP_CHARGE_TYPE value to the EC's charge mode */
> +static enum charge_mode psp_val_to_charge_mode(int psp_val)
> +{
> + switch (psp_val) {
> + case (POWER_SUPPLY_CHARGE_TYPE_TRICKLE):
> + return CHARGE_MODE_AC;
> + case (POWER_SUPPLY_CHARGE_TYPE_FAST):
> + return CHARGE_MODE_EXP;
> + case (POWER_SUPPLY_CHARGE_TYPE_STANDARD):
> + return CHARGE_MODE_STD;
> + case (POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE):
> + return CHARGE_MODE_AUTO;
> + case (POWER_SUPPLY_CHARGE_TYPE_CUSTOM):
> + return CHARGE_MODE_CUSTOM;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +/* Convert from EC's charge mode to POWER_SUPPLY_PROP_CHARGE_TYPE value */
> +static int charge_mode_to_psp_val(enum charge_mode mode)
> +{
> + switch (mode) {
> + case (CHARGE_MODE_AC):
> + return POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
> + case (CHARGE_MODE_EXP):
> + return POWER_SUPPLY_CHARGE_TYPE_FAST;
> + case (CHARGE_MODE_STD):
> + return POWER_SUPPLY_CHARGE_TYPE_STANDARD;
> + case (CHARGE_MODE_AUTO):
> + return POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE;
> + case (CHARGE_MODE_CUSTOM):
> + return POWER_SUPPLY_CHARGE_TYPE_CUSTOM;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static enum power_supply_property wilco_charge_props[] = {
> + POWER_SUPPLY_PROP_CHARGE_TYPE,
> + POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD,
> + POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD,
> +};
> +
> +static int wilco_charge_get_property(struct power_supply *psy,
> + enum power_supply_property psp,
> + union power_supply_propval *val)
> +{
> + struct wilco_ec_device *ec = power_supply_get_drvdata(psy);
> + u32 property_id;
> + int ret;
> + u8 raw;
> +
> + switch (psp) {
> + case POWER_SUPPLY_PROP_CHARGE_TYPE:
> + property_id = PID_CHARGE_MODE;
> + break;
> + case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
> + property_id = PID_CHARGE_LOWER_LIMIT;
> + break;
> + case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
> + property_id = PID_CHARGE_UPPER_LIMIT;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + ret = wilco_ec_get_byte_property(ec, property_id, &raw);
> + if (ret < 0)
> + return ret;
> + if (property_id == PID_CHARGE_MODE) {
> + ret = charge_mode_to_psp_val(raw);
> + if (ret == -EINVAL)
> + return -EBADMSG;
> + raw = ret;
> + }
> + val->intval = raw;
> +
> + return 0;
> +}
> +
> +static int wilco_charge_set_property(struct power_supply *psy,
> + enum power_supply_property psp,
> + const union power_supply_propval *val)
> +{
> + struct wilco_ec_device *ec = power_supply_get_drvdata(psy);
> + enum charge_mode mode;
> +
> + switch (psp) {
> + case POWER_SUPPLY_PROP_CHARGE_TYPE:
> + mode = psp_val_to_charge_mode(val->intval);
> + if (mode == -EINVAL)
> + return -EINVAL;
> + return wilco_ec_set_byte_property(ec, PID_CHARGE_MODE, mode);
> + case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
> + if (val->intval < CHARGE_LOWER_LIMIT_MIN ||
> + val->intval > CHARGE_LOWER_LIMIT_MAX)
> + return -EINVAL;
> + return wilco_ec_set_byte_property(ec, PID_CHARGE_LOWER_LIMIT,
> + val->intval);
> + case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
> + if (val->intval < CHARGE_UPPER_LIMIT_MIN ||
> + val->intval > CHARGE_UPPER_LIMIT_MAX)
> + return -EINVAL;
> + return wilco_ec_set_byte_property(ec, PID_CHARGE_UPPER_LIMIT,
> + val->intval);
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int wilco_charge_property_is_writeable(struct power_supply *psy,
> + enum power_supply_property psp)
> +{
> + return 1;
> +}
> +
> +static const struct power_supply_desc wilco_ps_desc = {
> + .properties = wilco_charge_props,
> + .num_properties = ARRAY_SIZE(wilco_charge_props),
> + .get_property = wilco_charge_get_property,
> + .set_property = wilco_charge_set_property,
> + .property_is_writeable = wilco_charge_property_is_writeable,
> + .name = "wilco-charger",
> + .type = POWER_SUPPLY_TYPE_MAINS,
> +};
> +
> +static int wilco_charge_probe(struct platform_device *pdev)
> +{
> + struct wilco_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
> + struct power_supply_config psy_cfg = {};
> + struct power_supply *psy;
> +
> + psy_cfg.drv_data = ec;
> + psy = devm_power_supply_register(&pdev->dev, &wilco_ps_desc, &psy_cfg);
> + if (IS_ERR(psy))
> + return PTR_ERR(psy);
> +
> + return 0;
> +}
> +
> +static struct platform_driver wilco_charge_driver = {
> + .probe = wilco_charge_probe,
> + .driver = {
> + .name = DRV_NAME,
> + }
> +};
> +module_platform_driver(wilco_charge_driver);
> +
> +MODULE_ALIAS("platform:" DRV_NAME);
> +MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Wilco EC charge control driver");
> diff --git a/drivers/platform/chrome/wilco_ec/core.c b/drivers/platform/chrome/wilco_ec/core.c
> index 05e1e2be1c91..b6f3b061f37b 100644
> --- a/drivers/platform/chrome/wilco_ec/core.c
> +++ b/drivers/platform/chrome/wilco_ec/core.c
> @@ -89,8 +89,21 @@ static int wilco_ec_probe(struct platform_device *pdev)
> goto unregister_debugfs;
> }
>
> + /* Register child device to be found by charging config driver. */
> + ec->charging_pdev = platform_device_register_data(dev,
> + "wilco-ec-charging",
> + PLATFORM_DEVID_AUTO,
> + NULL, 0);
> + if (IS_ERR(ec->charging_pdev)) {
> + dev_err(dev, "Failed to create charging platform device\n");
> + ret = PTR_ERR(ec->charging_pdev);
> + goto unregister_rtc;
> + }
> +
> return 0;
>
> +unregister_rtc:
> + platform_device_unregister(ec->rtc_pdev);
> unregister_debugfs:
> if (ec->debugfs_pdev)
> platform_device_unregister(ec->debugfs_pdev);
> @@ -102,6 +115,7 @@ static int wilco_ec_remove(struct platform_device *pdev)
> {
> struct wilco_ec_device *ec = platform_get_drvdata(pdev);
>
> + platform_device_unregister(ec->charging_pdev);
> platform_device_unregister(ec->rtc_pdev);
> if (ec->debugfs_pdev)
> platform_device_unregister(ec->debugfs_pdev);
> diff --git a/drivers/platform/chrome/wilco_ec/properties.c b/drivers/platform/chrome/wilco_ec/properties.c
> new file mode 100644
> index 000000000000..d74eb1208afd
> --- /dev/null
> +++ b/drivers/platform/chrome/wilco_ec/properties.c
> @@ -0,0 +1,134 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 Google LLC
> + */
> +
> +#include <linux/string.h>
> +#include "properties.h"
> +
> +struct ec_property_request {
> + u8 op;
> + u8 property_id[4];
> + u8 length;
> + u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
> +} __packed;
> +
> +struct ec_property_response {
> + u8 reserved[2];
> + u8 op;
> + u8 property_id[4];
> + u8 length;
> + u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
> +} __packed;
> +
> +static inline void fill_request_property_id(struct ec_property_request *rq,
> + u32 property_id)
> +{
> + rq->property_id[0] = property_id & 0xff;
> + rq->property_id[1] = (property_id >> 8) & 0xff;
> + rq->property_id[2] = (property_id >> 16) & 0xff;
> + rq->property_id[3] = (property_id >> 24) & 0xff;
> +}
> +
> +static int send_property_msg(struct wilco_ec_device *ec,
> + struct ec_property_request *rq,
> + struct ec_property_response *rs)
> +{
> + struct wilco_ec_message ec_msg;
> + int ret;
> +
> + memset(&ec_msg, 0, sizeof(ec_msg));
> + ec_msg.type = WILCO_EC_MSG_PROPERTY;
> + ec_msg.request_data = rq;
> + ec_msg.request_size = sizeof(*rq);
> + ec_msg.response_data = rs;
> + ec_msg.response_size = sizeof(*rs);
> + ret = wilco_ec_mailbox(ec, &ec_msg);
> + if (ret < 0)
> + return ret;
> +
> + if (rs->op != rq->op)
> + return -EBADMSG;
> + if (memcmp(rq->property_id, rs->property_id, sizeof(rs->property_id)))
> + return -EBADMSG;
> + if (rs->length > sizeof(rs->data))
> + return -EMSGSIZE;
> +
> + return 0;
> +}
> +
> +int wilco_ec_get_property(struct wilco_ec_device *ec,
> + struct ec_property_get_msg *prop_msg)
> +{
> + struct ec_property_request rq;
> + struct ec_property_response rs;
> + int ret;
> +
> + memset(&rq, 0, sizeof(rq));
> + rq.op = OP_GET;
> + fill_request_property_id(&rq, prop_msg->property_id);
> +
> + ret = send_property_msg(ec, &rq, &rs);
> + if (ret < 0)
> + return ret;
> +
> + prop_msg->length = rs.length;
> + memcpy(prop_msg->data, rs.data, rs.length);
> +
> + return 0;
> +}
> +
> +int wilco_ec_set_property(struct wilco_ec_device *ec,
> + struct ec_property_set_msg *prop_msg)
> +{
> + struct ec_property_request rq;
> + struct ec_property_response rs;
> + int ret;
> +
> + memset(&rq, 0, sizeof(rq));
> + rq.op = prop_msg->op;
> + fill_request_property_id(&rq, prop_msg->property_id);
> + rq.length = prop_msg->length;
> + memcpy(rq.data, prop_msg->data, prop_msg->length);
> +
> + ret = send_property_msg(ec, &rq, &rs);
> + if (ret < 0)
> + return ret;
> +
> + if (rs.length != prop_msg->length)
> + return -EBADMSG;
> +
> + return 0;
> +}
> +
> +int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id,
> + u8 *val)
> +{
> + struct ec_property_get_msg msg;
> + int ret;
> +
> + msg.property_id = property_id;
> + ret = wilco_ec_get_property(ec, &msg);
> + if (ret)
> + return ret;
> +
> + if (msg.length != 1)
> + return -EBADMSG;
> +
> + *val = msg.data[0];
> +
> + return 0;
> +}
> +
> +int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id,
> + u8 val)
> +{
> + struct ec_property_set_msg msg;
> +
> + msg.property_id = property_id;
> + msg.op = OP_SET;
> + msg.data[0] = val;
> + msg.length = 1;
> +
> + return wilco_ec_set_property(ec, &msg);
> +}
> diff --git a/drivers/platform/chrome/wilco_ec/properties.h b/drivers/platform/chrome/wilco_ec/properties.h
> new file mode 100644
> index 000000000000..da0bb3b869af
> --- /dev/null
> +++ b/drivers/platform/chrome/wilco_ec/properties.h
> @@ -0,0 +1,68 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Helper library for property access on the Wilco EC.
> + *
> + * Copyright 2019 Google LLC
> + *
> + * A Property is typically a data item that is stored to NVRAM
> + * by the EC. Each of these data items has an index associated
> + * with it known as the Property ID (PID). Properties may have
> + * variable lengths, up to a max of WILCO_EC_PROPERTY_MAX_SIZE
> + * bytes. Properties can be simple integers, or they may be more
> + * complex binary data.
> + */
> +
> +#include <linux/platform_data/wilco-ec.h>
> +
> +#define WILCO_EC_PROPERTY_MAX_SIZE 4
> +
> +/*
> + * Properties are accessed with an subcommand, or "op". OP_GET
> + * requests the property from the EC. OP_SET and OP_SYNC do the
> + * exact same thing from our perspective: save a property. Only
> + * one of them works for a given property, so each property uses
> + * either OP_GET and OP_SET, or OP_GET and OP_SYNC.
> + */
> +enum get_set_sync_op {
> + OP_GET = 0,
> + OP_SET = 1,
> + OP_SYNC = 4
> +};
> +
> +/**
> + * struct ec_property_get_msg - Message to retrieve a property.
> + * @property_id: PID of property to retrieve.
> + * @length: number of bytes received, set by wilco_ec_get_property().
> + * @data: actual property data, set by wilco_ec_get_property().
> + */
> +struct ec_property_get_msg {
> + u32 property_id;
> + int length;
> + u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
> +};
> +
> +/**
> + * struct ec_property_set_msg - Message to save a property.
> + * @op: Which subcommand to use, either OP_SET or OP_SYNC
> + * @property_id: PID of property to save.
> + * @length: number of bytes to save, must not exceed WILCO_EC_PROPERTY_MAX_SIZE.
> + * @data: actual property data.
> + */
> +struct ec_property_set_msg {
> + enum get_set_sync_op op;
> + u32 property_id;
> + int length;
> + u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
> +};
> +
> +/* Both of these will return 0 on success, negative error code on failure */
> +int wilco_ec_get_property(struct wilco_ec_device *ec,
> + struct ec_property_get_msg *prop_msg);
> +int wilco_ec_set_property(struct wilco_ec_device *ec,
> + struct ec_property_set_msg *prop_msg);
> +
> +/* Both of these will return 0 on success, negative error code on failure */
> +int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id,
> + u8 *val);
> +int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id,
> + u8 val);
> diff --git a/include/linux/platform_data/wilco-ec.h b/include/linux/platform_data/wilco-ec.h
> index 1ff224793c99..4e7dce897500 100644
> --- a/include/linux/platform_data/wilco-ec.h
> +++ b/include/linux/platform_data/wilco-ec.h
> @@ -32,6 +32,7 @@
> * @data_size: Size of the data buffer used for EC communication.
> * @debugfs_pdev: The child platform_device used by the debugfs sub-driver.
> * @rtc_pdev: The child platform_device used by the RTC sub-driver.
> + * @charging_pdev: Child platform_device used by the charging config sub-driver.
> */
> struct wilco_ec_device {
> struct device *dev;
> @@ -43,6 +44,7 @@ struct wilco_ec_device {
> size_t data_size;
> struct platform_device *debugfs_pdev;
> struct platform_device *rtc_pdev;
> + struct platform_device *charging_pdev;
> };
>
> /**
>

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