linux-kernel - Re: [PATCH 15/15] power: supply: olpc

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Message-ID: <CAHp75VepkJ2yy==rDO+WCrmj28_GDvin_3+MEnL7k0n4ZVP8QA@mail.gmail.com>
Date:   Fri, 19 Oct 2018 16:55:25 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Lubomir Rintel <lkundrak@...sk>
Cc:     Mark Brown <broonie@...nel.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        quozl@...top.org, Sebastian Reichel <sre@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Eric Miao <eric.y.miao@...il.com>,
        Haojian Zhuang <haojian.zhuang@...il.com>,
        Daniel Mack <daniel@...que.org>,
        Robert Jarzmik <robert.jarzmik@...e.fr>,
        linux-spi <linux-spi@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        devel@...verdev.osuosl.org, Linux PM <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 15/15] power: supply: olpc_battery: Add OLPC XO 1.75 support

On Wed, Oct 10, 2018 at 8:24 PM Lubomir Rintel <lkundrak@...sk> wrote:
>
> The battery and the protocol are essentially the same as OLPC XO 1.5,
> but the responses from the EC are LSB first.
>
> Signed-off-by: Lubomir Rintel <lkundrak@...sk>
> ---
>  drivers/power/supply/olpc_battery.c | 23 ++++++++++++++++++-----
>  1 file changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/power/supply/olpc_battery.c b/drivers/power/supply/olpc_battery.c
> index dde9863e5c4a..2adf33b9f641 100644
> --- a/drivers/power/supply/olpc_battery.c
> +++ b/drivers/power/supply/olpc_battery.c
> @@ -56,6 +56,7 @@ struct olpc_battery_data {
>         struct power_supply *olpc_bat;
>         char bat_serial[17];
>         int new_proto;
> +       int little_endian;
>  };
>
>  /*********************************************************************
> @@ -321,6 +322,14 @@ static int olpc_bat_get_voltage_max_design(union power_supply_propval *val)
>         return ret;
>  }
>
> +static s16 ecword_to_cpu(struct olpc_battery_data *data, u16 ec_byte)

ec_byte is misleading name. It's a 16-bit word. and since we called in
I/O accessor it as word, you may do the similar here.

And why result is s16 and not u16?

> +{
> +       if (data->little_endian)
> +               return le16_to_cpu(ec_byte);
> +       else
> +               return be16_to_cpu(ec_byte);

> +
>  /*********************************************************************
>   *             Battery properties
>   *********************************************************************/
> @@ -393,7 +402,7 @@ static int olpc_bat_get_property(struct power_supply *psy,
>                 if (ret)
>                         return ret;
>
> -               val->intval = (s16)be16_to_cpu(ec_word) * 9760L / 32;
> +               val->intval = ecword_to_cpu(data, ec_word) * 9760L / 32;
>                 break;
>         case POWER_SUPPLY_PROP_CURRENT_AVG:
>         case POWER_SUPPLY_PROP_CURRENT_NOW:
> @@ -401,7 +410,7 @@ static int olpc_bat_get_property(struct power_supply *psy,
>                 if (ret)
>                         return ret;
>
> -               val->intval = (s16)be16_to_cpu(ec_word) * 15625L / 120;
> +               val->intval = ecword_to_cpu(data, ec_word) * 15625L / 120;
>                 break;
>         case POWER_SUPPLY_PROP_CAPACITY:
>                 ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &ec_byte, 1);
> @@ -432,21 +441,21 @@ static int olpc_bat_get_property(struct power_supply *psy,
>                 if (ret)
>                         return ret;
>
> -               val->intval = (s16)be16_to_cpu(ec_word) * 10 / 256;
> +               val->intval = ecword_to_cpu(data, ec_word) * 10 / 256;
>                 break;
>         case POWER_SUPPLY_PROP_TEMP_AMBIENT:
>                 ret = olpc_ec_cmd(EC_AMB_TEMP, NULL, 0, (void *)&ec_word, 2);
>                 if (ret)
>                         return ret;
>
> -               val->intval = (int)be16_to_cpu(ec_word) * 10 / 256;
> +               val->intval = (int)ecword_to_cpu(data, ec_word) * 10 / 256;
>                 break;
>         case POWER_SUPPLY_PROP_CHARGE_COUNTER:
>                 ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);
>                 if (ret)
>                         return ret;
>
> -               val->intval = (s16)be16_to_cpu(ec_word) * 6250 / 15;
> +               val->intval = ecword_to_cpu(data, ec_word) * 6250 / 15;
>                 break;
>         case POWER_SUPPLY_PROP_SERIAL_NUMBER:
>                 ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);
> @@ -626,6 +635,10 @@ static int olpc_battery_probe(struct platform_device *pdev)
>         if (ecver[0] > 0x44) {
>                 /* XO 1 or 1.5 with a new EC firmware. */
>                 data->new_proto = 1;
> +       } else if (of_find_compatible_node(NULL, NULL, "olpc,xo1.75-ec")) {
> +               /* XO 1.75 */
> +               data->new_proto = 1;
> +               data->little_endian = 1;
>         } else if (ecver[0] < 0x44) {
>                 /*
>                  * We've seen a number of EC protocol changes; this driver
> --
> 2.19.0
>


-- 
With Best Regards,
Andy Shevchenko