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References: <20210427093754.3000087-1-ikjn@chromium.org> <20210428040802.3266187-1-ikjn@chromium.org>
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From:   Hsin-Yi Wang <hsinyi@chromium.org>
Date:   Mon, 3 May 2021 18:04:48 +0800
Message-ID: <CAJMQK-gudmV9NWHKVccVMuAz1Nny5h686miRNVu4j7XowRr25Q@mail.gmail.com>
Subject: Re: [PATCH v2] power: supply: sbs-battery: cache constant string properties
To:     Ikjoon Jang <ikjn@chromium.org>
Cc:     Linux PM <linux-pm@vger.kernel.org>,
        Sebastian Reichel <sre@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>
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On Wed, Apr 28, 2021 at 12:08 PM Ikjoon Jang <ikjn@chromium.org> wrote:
>
> Currently sbs-battery supports three string properties -
> manufacturer, model_name, and chemistry. Buffers for those
> properties are currently defined as global variables.
>
> This patch moves those global variables into struct sbs_info
> and cache/reuse them as they are all constant values.
>
> Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
>

Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>

Test on a mt8183 krane device which uses sbs battery.

> ---
>
> Changes in v2:
> - change function name of sbs_get_battery_string_property()
>   to sbs_get_constant_string()
> - use cached string properties
> - use cached technology integer value in sbs_get_chemistry()
>
>  drivers/power/supply/sbs-battery.c | 140 +++++++++++++++++------------
>  1 file changed, 82 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/power/supply/sbs-battery.c b/drivers/power/supply/sbs-battery.c
> index 4bf92831cb06..414de9bc47bf 100644
> --- a/drivers/power/supply/sbs-battery.c
> +++ b/drivers/power/supply/sbs-battery.c
> @@ -188,6 +188,14 @@ static const enum power_supply_property sbs_properties[] = {
>  /* Supports special manufacturer commands from TI BQ20Z65 and BQ20Z75 IC. */
>  #define SBS_FLAGS_TI_BQ20ZX5           BIT(0)
>
> +static const enum power_supply_property string_properties[] = {
> +       POWER_SUPPLY_PROP_TECHNOLOGY,
> +       POWER_SUPPLY_PROP_MANUFACTURER,
> +       POWER_SUPPLY_PROP_MODEL_NAME,
> +};
> +
> +#define NR_STRING_BUFFERS      ARRAY_SIZE(string_properties)
> +
>  struct sbs_info {
>         struct i2c_client               *client;
>         struct power_supply             *power_supply;
> @@ -201,11 +209,22 @@ struct sbs_info {
>         struct delayed_work             work;
>         struct mutex                    mode_lock;
>         u32                             flags;
> +       int                             technology;
> +       char                            strings[NR_STRING_BUFFERS][I2C_SMBUS_BLOCK_MAX + 1];
>  };
>
> -static char model_name[I2C_SMBUS_BLOCK_MAX + 1];
> -static char manufacturer[I2C_SMBUS_BLOCK_MAX + 1];
> -static char chemistry[I2C_SMBUS_BLOCK_MAX + 1];
> +static char *sbs_get_string_buf(struct sbs_info *chip,
> +                               enum power_supply_property psp)
> +{
> +       int i = 0;
> +
> +       for (i = 0; i < NR_STRING_BUFFERS; i++)
> +               if (string_properties[i] == psp)
> +                       return chip->strings[i];
> +
> +       return ERR_PTR(-EINVAL);
> +}
> +
>  static bool force_load;
>
>  static int sbs_read_word_data(struct i2c_client *client, u8 address);
> @@ -639,17 +658,45 @@ static int sbs_get_battery_property(struct i2c_client *client,
>         return 0;
>  }
>
> -static int sbs_get_battery_string_property(struct i2c_client *client,
> -       int reg_offset, enum power_supply_property psp, char *val)
> +static int sbs_get_property_index(struct i2c_client *client,
> +       enum power_supply_property psp)
>  {
> -       s32 ret;
> +       int count;
> +
> +       for (count = 0; count < ARRAY_SIZE(sbs_data); count++)
> +               if (psp == sbs_data[count].psp)
> +                       return count;
>
> -       ret = sbs_read_string_data(client, sbs_data[reg_offset].addr, val);
> +       dev_warn(&client->dev,
> +               "%s: Invalid Property - %d\n", __func__, psp);
>
> -       if (ret < 0)
> -               return ret;
> +       return -EINVAL;
> +}
>
> -       return 0;
> +static const char *sbs_get_constant_string(struct sbs_info *chip,
> +                       enum power_supply_property psp)
> +{
> +       int ret;
> +       char *buf;
> +       u8 addr;
> +
> +       buf = sbs_get_string_buf(chip, psp);
> +       if (IS_ERR(buf))
> +               return buf;
> +
> +       if (!buf[0]) {
> +               ret = sbs_get_property_index(chip->client, psp);
> +               if (ret < 0)
> +                       return ERR_PTR(ret);
> +
> +               addr = sbs_data[ret].addr;
> +
> +               ret = sbs_read_string_data(chip->client, addr, buf);
> +               if (ret < 0)
> +                       return ERR_PTR(ret);
> +       }
> +
> +       return buf;
>  }
>
>  static void  sbs_unit_adjustment(struct i2c_client *client,
> @@ -772,48 +819,34 @@ static int sbs_get_battery_serial_number(struct i2c_client *client,
>         return 0;
>  }
>
> -static int sbs_get_property_index(struct i2c_client *client,
> -       enum power_supply_property psp)
> -{
> -       int count;
> -       for (count = 0; count < ARRAY_SIZE(sbs_data); count++)
> -               if (psp == sbs_data[count].psp)
> -                       return count;
> -
> -       dev_warn(&client->dev,
> -               "%s: Invalid Property - %d\n", __func__, psp);
> -
> -       return -EINVAL;
> -}
> -
> -static int sbs_get_chemistry(struct i2c_client *client,
> +static int sbs_get_chemistry(struct sbs_info *chip,
>                 union power_supply_propval *val)
>  {
> -       enum power_supply_property psp = POWER_SUPPLY_PROP_TECHNOLOGY;
> -       int ret;
> +       const char *chemistry;
>
> -       ret = sbs_get_property_index(client, psp);
> -       if (ret < 0)
> -               return ret;
> +       if (chip->technology >= POWER_SUPPLY_TECHNOLOGY_UNKNOWN)
> +               return chip->technology;
>
> -       ret = sbs_get_battery_string_property(client, ret, psp,
> -                                             chemistry);
> -       if (ret < 0)
> -               return ret;
> +       chemistry = sbs_get_constant_string(chip, POWER_SUPPLY_PROP_TECHNOLOGY);
> +
> +       if (IS_ERR(chemistry))
> +               return PTR_ERR(chemistry);
>
>         if (!strncasecmp(chemistry, "LION", 4))
> -               val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
> +               chip->technology = POWER_SUPPLY_TECHNOLOGY_LION;
>         else if (!strncasecmp(chemistry, "LiP", 3))
> -               val->intval = POWER_SUPPLY_TECHNOLOGY_LIPO;
> +               chip->technology = POWER_SUPPLY_TECHNOLOGY_LIPO;
>         else if (!strncasecmp(chemistry, "NiCd", 4))
> -               val->intval = POWER_SUPPLY_TECHNOLOGY_NiCd;
> +               chip->technology = POWER_SUPPLY_TECHNOLOGY_NiCd;
>         else if (!strncasecmp(chemistry, "NiMH", 4))
> -               val->intval = POWER_SUPPLY_TECHNOLOGY_NiMH;
> +               chip->technology = POWER_SUPPLY_TECHNOLOGY_NiMH;
>         else
> -               val->intval = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
> +               chip->technology = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
>
> -       if (val->intval == POWER_SUPPLY_TECHNOLOGY_UNKNOWN)
> -               dev_warn(&client->dev, "Unknown chemistry: %s\n", chemistry);
> +       if (chip->technology == POWER_SUPPLY_TECHNOLOGY_UNKNOWN)
> +               dev_warn(&chip->client->dev, "Unknown chemistry: %s\n", chemistry);
> +
> +       val->intval = chip->technology;
>
>         return 0;
>  }
> @@ -857,6 +890,7 @@ static int sbs_get_property(struct power_supply *psy,
>         int ret = 0;
>         struct sbs_info *chip = power_supply_get_drvdata(psy);
>         struct i2c_client *client = chip->client;
> +       const char *str;
>
>         if (chip->gpio_detect) {
>                 ret = gpiod_get_value_cansleep(chip->gpio_detect);
> @@ -882,7 +916,7 @@ static int sbs_get_property(struct power_supply *psy,
>                 break;
>
>         case POWER_SUPPLY_PROP_TECHNOLOGY:
> -               ret = sbs_get_chemistry(client, val);
> +               ret = sbs_get_chemistry(chip, val);
>                 if (ret < 0)
>                         break;
>
> @@ -934,23 +968,12 @@ static int sbs_get_property(struct power_supply *psy,
>                 break;
>
>         case POWER_SUPPLY_PROP_MODEL_NAME:
> -               ret = sbs_get_property_index(client, psp);
> -               if (ret < 0)
> -                       break;
> -
> -               ret = sbs_get_battery_string_property(client, ret, psp,
> -                                                     model_name);
> -               val->strval = model_name;
> -               break;
> -
>         case POWER_SUPPLY_PROP_MANUFACTURER:
> -               ret = sbs_get_property_index(client, psp);
> -               if (ret < 0)
> -                       break;
> -
> -               ret = sbs_get_battery_string_property(client, ret, psp,
> -                                                     manufacturer);
> -               val->strval = manufacturer;
> +               str = sbs_get_constant_string(chip, psp);
> +               if (IS_ERR(str))
> +                       ret = PTR_ERR(str);
> +               else
> +                       val->strval = str;
>                 break;
>
>         case POWER_SUPPLY_PROP_MANUFACTURE_YEAR:
> @@ -1097,6 +1120,7 @@ static int sbs_probe(struct i2c_client *client)
>         psy_cfg.of_node = client->dev.of_node;
>         psy_cfg.drv_data = chip;
>         chip->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
> +       chip->technology = -1;
>         mutex_init(&chip->mode_lock);
>
>         /* use pdata if available, fall back to DT properties,
> --
> 2.31.1.498.g6c1eba8ee3d-goog
>