Hi Sebastian,

On Wed, Dec 16, 2020 at 08:34:15AM -0800, Daisuke Nojiri wrote:
> This patch adds a driver for PCHG (Peripheral CHarGer). PCHG is a
> framework managing power supplies for peripheral devices.
> 
> This driver creates a sysfs node for each peripheral charge port:
> 
>       /sys/class/power_supply/PCHGn
> 
> where <n> is the index of a charge port.
> 
> For example, when a stylus is connected to a NFC/WLC port, the node
> prints:
> 
>       /sys/class/power_supply/PCHG0/
>               capacity=50
>               status=Charging
>               type=Wireless
> 
> Signed-off-by: Daisuke Nojiri <dnoj...@chromium.org>

This change seems reasonable to me. I've reviewed the cros_ec_commands header,
and it looks good.

Sebastian, do you have any comments on this? I can merge this through the
chrome/platform tree if we have your Acked-By.

Thanks,
Benson


> ---
> v1 -> v2
> * Separate mfd/cros_ec_dev.c
> * Make CONFIG_CHARGER_CROS_PCHG default to CONFIG_MFD_CROS_EC_DEV
> ---
> 
>  drivers/power/supply/Kconfig                  |  10 +
>  drivers/power/supply/Makefile                 |   1 +
>  .../power/supply/cros_peripheral_charger.c    | 346 ++++++++++++++++++
>  .../linux/platform_data/cros_ec_commands.h    |  48 +++
>  4 files changed, 405 insertions(+)
>  create mode 100644 drivers/power/supply/cros_peripheral_charger.c
> 
> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
> index eec646c568b7be..407f9fbbc2bb50 100644
> --- a/drivers/power/supply/Kconfig
> +++ b/drivers/power/supply/Kconfig
> @@ -714,6 +714,16 @@ config CHARGER_CROS_USBPD
>         what is connected to USB PD ports from the EC and converts
>         that into power_supply properties.
>  
> +config CHARGER_CROS_PCHG
> +     tristate "ChromeOS EC based peripheral charger"
> +     depends on MFD_CROS_EC_DEV
> +     default MFD_CROS_EC_DEV
> +     help
> +       Say Y here to enable ChromeOS EC based peripheral charge driver.
> +       This driver gets various information about the devices connected to
> +       the peripheral charge ports from the EC and converts that into
> +       power_supply properties.
> +
>  config CHARGER_SC2731
>       tristate "Spreadtrum SC2731 charger driver"
>       depends on MFD_SC27XX_PMIC || COMPILE_TEST
> diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
> index dd4b86318cd9bd..5263472a64809b 100644
> --- a/drivers/power/supply/Makefile
> +++ b/drivers/power/supply/Makefile
> @@ -91,6 +91,7 @@ obj-$(CONFIG_CHARGER_TPS65217)      += tps65217_charger.o
>  obj-$(CONFIG_AXP288_FUEL_GAUGE) += axp288_fuel_gauge.o
>  obj-$(CONFIG_AXP288_CHARGER) += axp288_charger.o
>  obj-$(CONFIG_CHARGER_CROS_USBPD)     += cros_usbpd-charger.o
> +obj-$(CONFIG_CHARGER_CROS_PCHG)      += cros_peripheral_charger.o
>  obj-$(CONFIG_CHARGER_SC2731) += sc2731_charger.o
>  obj-$(CONFIG_FUEL_GAUGE_SC27XX)      += sc27xx_fuel_gauge.o
>  obj-$(CONFIG_CHARGER_UCS1002)        += ucs1002_power.o
> diff --git a/drivers/power/supply/cros_peripheral_charger.c 
> b/drivers/power/supply/cros_peripheral_charger.c
> new file mode 100644
> index 00000000000000..db68d3b7c80f32
> --- /dev/null
> +++ b/drivers/power/supply/cros_peripheral_charger.c
> @@ -0,0 +1,346 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Power supply driver for ChromeOS EC based Peripheral Device Charger.
> + *
> + * Copyright 2020 Google LLC.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/notifier.h>
> +#include <linux/platform_data/cros_ec_commands.h>
> +#include <linux/platform_data/cros_ec_proto.h>
> +#include <linux/platform_device.h>
> +#include <linux/power_supply.h>
> +#include <linux/slab.h>
> +#include <linux/stringify.h>
> +#include <linux/types.h>
> +
> +#define DRV_NAME             "cros-ec-pchg"
> +#define PCHG_DIR_NAME                "PCHG%d"
> +#define PCHG_DIR_NAME_LENGTH sizeof("PCHG" __stringify(EC_PCHG_MAX_PORTS))
> +#define PCHG_CACHE_UPDATE_DELAY      msecs_to_jiffies(500)
> +
> +struct port_data {
> +     int port_number;
> +     char name[PCHG_DIR_NAME_LENGTH];
> +     struct power_supply *psy;
> +     struct power_supply_desc psy_desc;
> +     int psy_status;
> +     int battery_percentage;
> +     struct charger_data *charger;
> +     unsigned long last_update;
> +};
> +
> +struct charger_data {
> +     struct device *dev;
> +     struct cros_ec_dev *ec_dev;
> +     struct cros_ec_device *ec_device;
> +     int num_registered_psy;
> +     struct port_data *ports[EC_PCHG_MAX_PORTS];
> +     struct notifier_block notifier;
> +};
> +
> +static enum power_supply_property cros_pchg_props[] = {
> +     POWER_SUPPLY_PROP_STATUS,
> +     POWER_SUPPLY_PROP_CAPACITY,
> +     /*
> +      * todo: Add the following.
> +      *
> +      * POWER_SUPPLY_PROP_TECHNOLOGY,
> +      * POWER_SUPPLY_PROP_ERROR,
> +      * POWER_SUPPLY_PROP_SERIAL_NUMBER,
> +      *
> +      * POWER_SUPPLY_PROP_ONLINE can't be used because it indicates the
> +      * system is powered by AC.
> +      */
> +};
> +
> +static int cros_pchg_ec_command(const struct charger_data *charger,
> +                             unsigned int version,
> +                             unsigned int command,
> +                             const void *outdata,
> +                             unsigned int outsize,
> +                             void *indata,
> +                             unsigned int insize)
> +{
> +     struct cros_ec_dev *ec_dev = charger->ec_dev;
> +     struct cros_ec_command *msg;
> +     int ret;
> +
> +     msg = kzalloc(sizeof(*msg) + max(outsize, insize), GFP_KERNEL);
> +     if (!msg)
> +             return -ENOMEM;
> +
> +     msg->version = version;
> +     msg->command = ec_dev->cmd_offset + command;
> +     msg->outsize = outsize;
> +     msg->insize = insize;
> +
> +     if (outsize)
> +             memcpy(msg->data, outdata, outsize);
> +
> +     ret = cros_ec_cmd_xfer_status(charger->ec_device, msg);
> +     if (ret >= 0 && insize)
> +             memcpy(indata, msg->data, insize);
> +
> +     kfree(msg);
> +     return ret;
> +}
> +
> +static int cros_pchg_port_count(const struct charger_data *charger)
> +{
> +     struct ec_response_pchg_count rsp;
> +     int ret;
> +
> +     ret = cros_pchg_ec_command(charger, 0, EC_CMD_PCHG_COUNT,
> +                                NULL, 0, &rsp, sizeof(rsp));
> +     if (ret < 0) {
> +             dev_warn(charger->dev,
> +                      "Unable to get number or ports (err:%d)\n", ret);
> +             return ret;
> +     }
> +
> +     return rsp.port_count;
> +}
> +
> +static int cros_pchg_get_status(struct port_data *port)
> +{
> +     struct charger_data *charger = port->charger;
> +     struct ec_params_pchg req;
> +     struct ec_response_pchg rsp;
> +     struct device *dev = charger->dev;
> +     int ret;
> +
> +     req.port = port->port_number;
> +     ret = cros_pchg_ec_command(charger, 0, EC_CMD_PCHG,
> +                                &req, sizeof(req), &rsp, sizeof(rsp));
> +     if (ret < 0) {
> +             dev_err(dev, "Unable to get port.%d status (err:%d)\n",
> +                     port->port_number, ret);
> +             return ret;
> +     }
> +
> +     switch (rsp.state) {
> +     case PCHG_STATE_RESET:
> +     case PCHG_STATE_INITIALIZED:
> +     case PCHG_STATE_ENABLED:
> +     default:
> +             port->psy_status = POWER_SUPPLY_STATUS_UNKNOWN;
> +             port->battery_percentage = 0;
> +             break;
> +     case PCHG_STATE_DETECTED:
> +             port->psy_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
> +             port->battery_percentage = rsp.battery_percentage;
> +             break;
> +     case PCHG_STATE_CHARGING:
> +             port->psy_status = POWER_SUPPLY_STATUS_CHARGING;
> +             port->battery_percentage = rsp.battery_percentage;
> +             break;
> +     }
> +
> +     dev_dbg(dev,
> +             "Port %d: state=%d battery=%d%%\n",
> +             port->port_number, rsp.state, rsp.battery_percentage);
> +
> +     return 0;
> +}
> +
> +static int cros_pchg_get_port_status(struct port_data *port, bool ratelimit)
> +{
> +     int ret;
> +
> +     if (ratelimit &&
> +         time_is_after_jiffies(port->last_update + PCHG_CACHE_UPDATE_DELAY))
> +             return 0;
> +
> +     ret = cros_pchg_get_status(port);
> +     if (ret < 0)
> +             return ret;
> +
> +     port->last_update = jiffies;
> +
> +     return ret;
> +}
> +
> +static int cros_pchg_get_prop(struct power_supply *psy,
> +                           enum power_supply_property psp,
> +                           union power_supply_propval *val)
> +{
> +     struct port_data *port = power_supply_get_drvdata(psy);
> +
> +     switch (psp) {
> +     case POWER_SUPPLY_PROP_STATUS:
> +     case POWER_SUPPLY_PROP_CAPACITY:
> +             cros_pchg_get_port_status(port, true);
> +             break;
> +     default:
> +             break;
> +     }
> +
> +     switch (psp) {
> +     case POWER_SUPPLY_PROP_STATUS:
> +             val->intval = port->psy_status;
> +             break;
> +     case POWER_SUPPLY_PROP_CAPACITY:
> +             val->intval = port->battery_percentage;
> +             break;
> +     default:
> +             return -EINVAL;
> +     }
> +
> +     return 0;
> +}
> +
> +static int cros_pchg_event(const struct charger_data *charger,
> +                        unsigned long host_event)
> +{
> +     int i;
> +
> +     for (i = 0; i < charger->num_registered_psy; i++)
> +             cros_pchg_get_port_status(charger->ports[i], false);
> +
> +     return NOTIFY_OK;
> +}
> +
> +static u32 cros_get_device_event(const struct charger_data *charger)
> +{
> +     struct ec_params_device_event req;
> +     struct ec_response_device_event rsp;
> +     struct device *dev = charger->dev;
> +     int ret;
> +
> +     req.param = EC_DEVICE_EVENT_PARAM_GET_CURRENT_EVENTS;
> +     ret = cros_pchg_ec_command(charger, 0, EC_CMD_DEVICE_EVENT,
> +                                &req, sizeof(req), &rsp, sizeof(rsp));
> +     if (ret < 0) {
> +             dev_warn(dev, "Unable to get device events (err:%d)\n", ret);
> +             return 0;
> +     }
> +
> +     return rsp.event_mask;
> +}
> +
> +static int cros_ec_notify(struct notifier_block *nb,
> +                       unsigned long queued_during_suspend,
> +                       void *data)
> +{
> +     struct cros_ec_device *ec_dev = (struct cros_ec_device *)data;
> +     u32 host_event = cros_ec_get_host_event(ec_dev);
> +     struct charger_data *charger =
> +                     container_of(nb, struct charger_data, notifier);
> +     u32 device_event_mask;
> +
> +     if (!host_event)
> +             return NOTIFY_BAD;
> +
> +     if (!(host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_DEVICE)))
> +             return NOTIFY_DONE;
> +
> +     /*
> +      * todo: Retrieve device event mask in common place
> +      * (e.g. cros_ec_proto.c).
> +      */
> +     device_event_mask = cros_get_device_event(charger);
> +     if (!(device_event_mask & EC_DEVICE_EVENT_MASK(EC_DEVICE_EVENT_WLC)))
> +             return NOTIFY_DONE;
> +
> +     return cros_pchg_event(charger, host_event);
> +}
> +
> +static int cros_pchg_probe(struct platform_device *pdev)
> +{
> +     struct device *dev = &pdev->dev;
> +     struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
> +     struct cros_ec_device *ec_device = ec_dev->ec_dev;
> +     struct power_supply_desc *psy_desc;
> +     struct charger_data *charger;
> +     struct power_supply *psy;
> +     struct port_data *port;
> +     struct notifier_block *nb;
> +     int num_ports;
> +     int ret;
> +     int i;
> +
> +     charger = devm_kzalloc(dev, sizeof(*charger), GFP_KERNEL);
> +     if (!charger)
> +             return -ENOMEM;
> +
> +     charger->dev = dev;
> +     charger->ec_dev = ec_dev;
> +     charger->ec_device = ec_device;
> +
> +     ret = cros_pchg_port_count(charger);
> +     if (ret <= 0) {
> +             /*
> +              * This feature is enabled by the EC and the kernel driver is
> +              * included by default for CrOS devices. Don't need to be loud
> +              * since this error can be normal.
> +              */
> +             dev_info(dev, "No peripheral charge ports (err:%d)\n", ret);
> +             return -ENODEV;
> +     }
> +
> +     num_ports = ret;
> +     if (num_ports > EC_PCHG_MAX_PORTS) {
> +             dev_err(dev, "Too many peripheral charge ports (%d)\n",
> +                     num_ports);
> +             return -ENOBUFS;
> +     }
> +
> +     dev_info(dev, "%d peripheral charge ports found\n", num_ports);
> +
> +     for (i = 0; i < num_ports; i++) {
> +             struct power_supply_config psy_cfg = {};
> +
> +             port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
> +             if (!port)
> +                     return -ENOMEM;
> +
> +             port->charger = charger;
> +             port->port_number = i;
> +             snprintf(port->name, sizeof(port->name), PCHG_DIR_NAME, i);
> +
> +             psy_desc = &port->psy_desc;
> +             psy_desc->name = port->name;
> +             psy_desc->type = POWER_SUPPLY_TYPE_WIRELESS;
> +             psy_desc->get_property = cros_pchg_get_prop;
> +             psy_desc->external_power_changed = NULL;
> +             psy_desc->properties = cros_pchg_props;
> +             psy_desc->num_properties = ARRAY_SIZE(cros_pchg_props);
> +             psy_cfg.drv_data = port;
> +
> +             psy = devm_power_supply_register_no_ws(dev, psy_desc, &psy_cfg);
> +             if (IS_ERR(psy)) {
> +                     dev_err(dev, "Failed to register power supply\n");
> +                     continue;
> +             }
> +             port->psy = psy;
> +
> +             charger->ports[charger->num_registered_psy++] = port;
> +     }
> +
> +     if (!charger->num_registered_psy)
> +             return -ENODEV;
> +
> +     nb = &charger->notifier;
> +     nb->notifier_call = cros_ec_notify;
> +     ret = blocking_notifier_chain_register(&ec_dev->ec_dev->event_notifier,
> +                                            nb);
> +     if (ret < 0)
> +             dev_err(dev, "Failed to register notifier (err:%d)\n", ret);
> +
> +     return 0;
> +}
> +
> +static struct platform_driver cros_pchg_driver = {
> +     .driver = {
> +             .name = DRV_NAME,
> +     },
> +     .probe = cros_pchg_probe
> +};
> +
> +module_platform_driver(cros_pchg_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("ChromeOS EC peripheral device charger");
> +MODULE_ALIAS("platform:" DRV_NAME);
> diff --git a/include/linux/platform_data/cros_ec_commands.h 
> b/include/linux/platform_data/cros_ec_commands.h
> index 58495127dfa656..c0f0a032c8beb6 100644
> --- a/include/linux/platform_data/cros_ec_commands.h
> +++ b/include/linux/platform_data/cros_ec_commands.h
> @@ -4225,6 +4225,7 @@ enum ec_device_event {
>       EC_DEVICE_EVENT_TRACKPAD,
>       EC_DEVICE_EVENT_DSP,
>       EC_DEVICE_EVENT_WIFI,
> +     EC_DEVICE_EVENT_WLC,
>  };
>  
>  enum ec_device_event_param {
> @@ -5456,6 +5457,53 @@ struct ec_response_rollback_info {
>  /* Issue AP reset */
>  #define EC_CMD_AP_RESET 0x0125
>  
> +/**
> + * Get the number of peripheral charge ports
> + */
> +#define EC_CMD_PCHG_COUNT 0x0134
> +
> +#define EC_PCHG_MAX_PORTS 8
> +
> +struct ec_response_pchg_count {
> +     uint8_t port_count;
> +} __ec_align1;
> +
> +/**
> + * Get the status of a peripheral charge port
> + */
> +#define EC_CMD_PCHG 0x0135
> +
> +struct ec_params_pchg {
> +     uint8_t port;
> +} __ec_align1;
> +
> +struct ec_response_pchg {
> +     uint32_t error; /* enum pchg_error */
> +     uint8_t state; /* enum pchg_state state */
> +     uint8_t battery_percentage;
> +} __ec_align2;
> +
> +enum pchg_state {
> +     /* Charger is reset and not initialized. */
> +     PCHG_STATE_RESET = 0,
> +     /* Charger is initialized or disabled. */
> +     PCHG_STATE_INITIALIZED,
> +     /* Charger is enabled and ready to detect a device. */
> +     PCHG_STATE_ENABLED,
> +     /* Device is detected in proximity. */
> +     PCHG_STATE_DETECTED,
> +     /* Device is being charged. */
> +     PCHG_STATE_CHARGING,
> +};
> +
> +#define EC_PCHG_STATE_TEXT { \
> +     [PCHG_STATE_RESET] = "RESET", \
> +     [PCHG_STATE_INITIALIZED] = "INITIALIZED", \
> +     [PCHG_STATE_ENABLED] = "ENABLED", \
> +     [PCHG_STATE_DETECTED] = "DETECTED", \
> +     [PCHG_STATE_CHARGING] = "CHARGING", \
> +     }
> +
>  
> /*****************************************************************************/
>  /* Locate peripheral chips
>   *
> -- 
> 2.29.2.684.gfbc64c5ab5-goog
> 

-- 
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
ble...@google.com
Chromium OS Project
ble...@chromium.org

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