Re: [PATCH v4 4/4] platform/x86: dell-laptop: Use power_supply_charge_types_show/_parse() helpers

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Tue, 17 Dec 2024, Hans de Goede wrote:
> On 17-Dec-24 1:01 PM, Ilpo Järvinen wrote:
> > On Wed, 11 Dec 2024, Hans de Goede wrote:
> > 
> >> Make battery_modes a map between tokens and enum power_supply_charge_type
> >> values instead of between tokens and strings and use the new
> >> power_supply_charge_types_show/_parse() helpers for show()/store()
> >> to ensure that things are handled in the same way as in other drivers.
> >>
> >> This also changes battery_supported_modes to be a bitmap of charge-types
> >> (enum power_supply_charge_type values) rather then a bitmap of indices
> >> into battery_modes[].
> >>
> >> Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
> >> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> >> ---
> >>  drivers/platform/x86/dell/dell-laptop.c | 54 ++++++++++++-------------
> >>  1 file changed, 25 insertions(+), 29 deletions(-)
> >>
> >> diff --git a/drivers/platform/x86/dell/dell-laptop.c b/drivers/platform/x86/dell/dell-laptop.c
> >> index 5671bd0deee7..9a4cfcb8bbe0 100644
> >> --- a/drivers/platform/x86/dell/dell-laptop.c
> >> +++ b/drivers/platform/x86/dell/dell-laptop.c
> >> @@ -103,15 +103,15 @@ static bool mute_led_registered;
> >>  
> >>  struct battery_mode_info {
> >>  	int token;
> >> -	const char *label;
> >> +	enum power_supply_charge_type charge_type;
> >>  };
> >>  
> >>  static const struct battery_mode_info battery_modes[] = {
> >> -	{ BAT_PRI_AC_MODE_TOKEN,   "Trickle" },
> >> -	{ BAT_EXPRESS_MODE_TOKEN,  "Fast" },
> >> -	{ BAT_STANDARD_MODE_TOKEN, "Standard" },
> >> -	{ BAT_ADAPTIVE_MODE_TOKEN, "Adaptive" },
> >> -	{ BAT_CUSTOM_MODE_TOKEN,   "Custom" },
> >> +	{ BAT_PRI_AC_MODE_TOKEN,   POWER_SUPPLY_CHARGE_TYPE_TRICKLE },
> >> +	{ BAT_EXPRESS_MODE_TOKEN,  POWER_SUPPLY_CHARGE_TYPE_FAST },
> >> +	{ BAT_STANDARD_MODE_TOKEN, POWER_SUPPLY_CHARGE_TYPE_STANDARD },
> >> +	{ BAT_ADAPTIVE_MODE_TOKEN, POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE },
> >> +	{ BAT_CUSTOM_MODE_TOKEN,   POWER_SUPPLY_CHARGE_TYPE_CUSTOM },
> >>  };
> >>  static u32 battery_supported_modes;
> >>  
> >> @@ -2261,46 +2261,42 @@ static ssize_t charge_types_show(struct device *dev,
> >>  		struct device_attribute *attr,
> >>  		char *buf)
> >>  {
> >> -	ssize_t count = 0;
> >> +	enum power_supply_charge_type charge_type;
> >>  	int i;
> >>  
> >>  	for (i = 0; i < ARRAY_SIZE(battery_modes); i++) {
> >> -		bool active;
> >> +		charge_type = battery_modes[i].charge_type;
> >>  
> >> -		if (!(battery_supported_modes & BIT(i)))
> >> +		if (!(battery_supported_modes & BIT(charge_type)))
> >>  			continue;
> >>  
> >> -		active = dell_battery_mode_is_active(battery_modes[i].token);
> >> -		count += sysfs_emit_at(buf, count, active ? "[%s] " : "%s ",
> >> -				battery_modes[i].label);
> >> +		if (!dell_battery_mode_is_active(battery_modes[i].token))
> >> +			continue;
> >> +
> >> +		return power_supply_charge_types_show(dev, battery_supported_modes,
> >> +						      charge_type, buf);
> >>  	}
> >>  
> >> -	/* convert the last space to a newline */
> >> -	if (count > 0)
> >> -		count--;
> >> -	count += sysfs_emit_at(buf, count, "\n");
> >> -
> >> -	return count;
> >> +	/* No active mode found */
> >> +	return -EIO;
> >>  }
> >>  
> >>  static ssize_t charge_types_store(struct device *dev,
> >>  		struct device_attribute *attr,
> >>  		const char *buf, size_t size)
> >>  {
> >> -	bool matched = false;
> >> -	int err, i;
> >> +	int charge_type, err, i;
> >> +
> >> +	charge_type = power_supply_charge_types_parse(battery_supported_modes, buf);
> >> +	if (charge_type < 0)
> >> +		return charge_type;
> >>  
> >>  	for (i = 0; i < ARRAY_SIZE(battery_modes); i++) {
> >> -		if (!(battery_supported_modes & BIT(i)))
> >> -			continue;
> >> -
> >> -		if (sysfs_streq(battery_modes[i].label, buf)) {
> >> -			matched = true;
> >> +		if (battery_modes[i].charge_type == charge_type)
> >>  			break;
> >> -		}
> >>  	}
> >> -	if (!matched)
> >> -		return -EINVAL;
> >> +	if (i == ARRAY_SIZE(battery_modes))
> >> +		return -EIO;
> > 
> > Hi Hans,
> > 
> > Is this errno change helpful/correct?
> 
> power_supply_charge_types_parse() already checks that the user-input
> is one of the values advertised in the passed in battery_supported_modes,
> so when we loop to translate the enum power_supply_charge_type value
> returned by power_supply_charge_types_parse() then we should find
> a matching entry in battery_modes[] if not something is wrong at
> the driver level. So not -EINVAL, since this is a driver issue not
> a user input issue.
> 
> > There is zero I/O done before 
> > reaching this point, just input validation, so why does it return errno 
> > that is "I/O error"? If you want to differentiate from -EINVAL, I suggest 
> > using -ENOENT (but I personally think -EINVAL would be fine as well 
> > because it's still an invalid argument even if it passed one stage of 
> > the input checks).
> 
> -ENOENT instead of -EIO works for me.
> 
> Shall I send out a new version with that changed?
>
> Note that merging this requires the earlier patches from this
> series which have been merged into:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply.git/log/?h=for-next
> 
> so this either requires an immutable tag from Sebastian for you to merge,
> or this should be merged through Sebastian's tree.

Yes, please send a new version with -ENOENT as I was going to ask
Sebastian to take this patch but noticed this small errno thing while 
reading the patch one more time before acking it.

-- 
 i.