Hi,
On Mon, Aug 16, 2021 at 01:52:44PM -0300, Bruno Meneguele wrote:
> The BQ24735 charger allows the user to set the watchdog timer delay between
> two consecutives ChargeCurrent or ChargeVoltage command writes, if the IC
> doesn't receive any command before the timeout happens, the charge is turned
> off.
>
> This patch adds the support to the user to change the default/POR value with
> four discrete values:
>
> 0 - disabled
> 1 - enabled, 44 sec
> 2 - enabled, 88 sec
> 3 - enabled, 175 sec (default at POR)
>
> These are the options supported in the ChargeOptions register bits 13&14.
>
> Also, this patch make one additional check when poll-interval is set by the
> user: if the interval set is greater than the WDT timeout it'll fail during
> the probe stage, preventing the user to set non-compatible values between
> the two options.
>
> Signed-off-by: Bruno Meneguele <bruno.meneguele@xxxxxxxxxxxxxx>
> ---
> Changelog:
> v3 - check wdt_timeout for the maximum and minimum available values
>
> drivers/power/supply/bq24735-charger.c | 54 ++++++++++++++++++++++++++
> include/linux/power/bq24735-charger.h | 1 +
> 2 files changed, 55 insertions(+)
>
> diff --git a/drivers/power/supply/bq24735-charger.c b/drivers/power/supply/bq24735-charger.c
> index 3ce36d09c017..7e8d0c23df9a 100644
> --- a/drivers/power/supply/bq24735-charger.c
> +++ b/drivers/power/supply/bq24735-charger.c
> @@ -45,6 +45,8 @@
> /* ChargeOptions bits of interest */
> #define BQ24735_CHARGE_OPT_CHG_DISABLE (1 << 0)
> #define BQ24735_CHARGE_OPT_AC_PRESENT (1 << 4)
> +#define BQ24735_CHARGE_OPT_WDT_OFFSET 13
> +#define BQ24735_CHARGE_OPT_WDT (3 << BQ24735_CHARGE_OPT_WDT_OFFSET)
>
> struct bq24735 {
> struct power_supply *charger;
> @@ -156,6 +158,20 @@ static int bq24735_config_charger(struct bq24735 *charger)
> }
> }
>
> + if (pdata->wdt_timeout >= 0 && pdata->wdt_timeout <= 3) {
wdt_timeout is unsigned and can't be smaller than 0.
> + value = pdata->wdt_timeout;
> +
> + ret = bq24735_update_word(charger->client, BQ24735_CHARGE_OPT,
> + BQ24735_CHARGE_OPT_WDT,
> + (value << BQ24735_CHARGE_OPT_WDT_OFFSET));
> + if (ret < 0) {
> + dev_err(&charger->client->dev,
> + "Failed to write watchdog timer: %d\n",
> + ret);
> + return ret;
> + }
> + }
> +
> return 0;
> }
>
> @@ -347,6 +363,23 @@ static struct bq24735_platform *bq24735_parse_dt_data(struct i2c_client *client)
> if (!ret)
> pdata->input_current = val;
>
> + ret = of_property_read_u32(np, "ti,wdt-timeout", &val);
> + if (!ret) {
> + if (val >= 0 && val <= 3) {
wdt_timeout is unsigned and can't be smaller than 0.
> + pdata->wdt_timeout = val;
> + } else {
> + dev_warn(&client->dev,
> + "Invalid value for ti,wdt-timeout: %d",
> + val);
> + }
> + } else {
> + /* Since 0 is a valid value (disabled), set something
> + * greater than the maximum limit accepted from the user to
> + * represent the "no change" state. */
> + pdata->wdt_timeout = 4;
> + }
> +
> +
> pdata->ext_control = of_property_read_bool(np, "ti,external-control");
>
> return pdata;
> @@ -476,6 +509,27 @@ static int bq24735_charger_probe(struct i2c_client *client,
> return 0;
> if (!charger->poll_interval)
> return 0;
> + if (charger->pdata->wdt_timeout > 0) {
> + int wdt_ms;
> +
> + switch (charger->pdata->wdt_timeout) {
> + case 1:
> + wdt_ms = 44000;
> + break;
> + case 2:
> + wdt_ms = 88000;
> + break;
> + case 3:
> + wdt_ms = 175000;
> + break;
> + }
wdt_ms is not initialized when wdt_timeout is not 1-3 resulting in undefined behaviour.
Also please create constants for the magic numbers, e.g.
#define BQ24735_WDT_OFF 0
#define BQ24735_WDT_44_SEC 1
#define BQ24735_WDT_88_SEC 2
#define BQ24735_WDT_175_SEC 3
#define BQ24735_WDT_INVALID 4
and use them throughout the code.
-- Sebastian
> +
> + if (charger->poll_interval > wdt_ms) {
> + dev_err(&client->dev,
> + "Poll interval greater than WDT timeout\n");
> + return -EINVAL;
> + }
> + }
>
> ret = devm_delayed_work_autocancel(&client->dev, &charger->poll,
> bq24735_poll);
> diff --git a/include/linux/power/bq24735-charger.h b/include/linux/power/bq24735-charger.h
> index 321dd009ce66..ce5a030ca111 100644
> --- a/include/linux/power/bq24735-charger.h
> +++ b/include/linux/power/bq24735-charger.h
> @@ -12,6 +12,7 @@ struct bq24735_platform {
> uint32_t charge_current;
> uint32_t charge_voltage;
> uint32_t input_current;
> + uint32_t wdt_timeout;
>
> const char *name;
>
> --
> 2.31.1
>
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