On Mon, 22 Jul 2024 22:25:04 +0200 Pali Rohár <pali@xxxxxxxxxx> wrote: > On Monday 22 July 2024 20:41:32 Pali Rohár wrote: > > On Monday 22 July 2024 14:34:32 Andres Salomon wrote: > > > On Mon, 22 Jul 2024 09:18:45 +0200 > > > Pali Rohár <pali@xxxxxxxxxx> wrote: > > > > > > > On Sunday 21 July 2024 19:58:51 Andres Salomon wrote: > > > > > On Mon, 22 Jul 2024 01:40:37 +0200 > > > > > Pali Rohár <pali@xxxxxxxxxx> wrote: > > > > > > > > > > > On Sunday 21 July 2024 19:37:16 Andres Salomon wrote: > > > > > > > On Sun, 21 Jul 2024 11:02:38 +0200 > > > > > > > Pali Rohár <pali@xxxxxxxxxx> wrote: > > > > > > > > > > > > > > > On Saturday 20 July 2024 22:06:06 Andres Salomon wrote: > > > > > > > > > On Sat, 20 Jul 2024 11:55:07 +0200 > > > > > > > > > Pali Rohár <pali@xxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > > > On Saturday 20 July 2024 05:24:19 Andres Salomon wrote: > > > > > > > > > > > Thanks for the quick feedback! Responses below. > > > > > > > > > > > > > > > > > > > > > > On Sat, 20 Jul 2024 10:40:19 +0200 > > > > > > > > > > > Pali Rohár <pali@xxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > > > > > > > > > [...] > > > > > > > > > > > > > > > > > > > > + > > > > > > > > > > > > > +static void __init dell_battery_init(struct device *dev) > > > > > > > > > > > > > +{ > > > > > > > > > > > > > + enum battery_charging_mode current_mode = DELL_BAT_MODE_NONE; > > > > > > > > > > > > > + > > > > > > > > > > > > > + dell_battery_read_req(BAT_CUSTOM_MODE_TOKEN, (int *) ¤t_mode); > > > > > > > > > > > > > + if (current_mode != DELL_BAT_MODE_NONE) { > > > > > > > > > > > > > > > > > > > > > > > > I quite do not understand how is this code suppose to work. > > > > > > > > > > > > > > > > > > > > > > > > Why is there mix of custom kernel enum battery_charging_mode and return > > > > > > > > > > > > value from Dell's API? > > > > > > > > > > > > > > > > > > > > > > This is from the original patch from Dell; tbh, I'm not sure. It does > > > > > > > > > > > work, though. That is, current_mode ends up holding the correct value > > > > > > > > > > > based on what was previously set, even if the charging mode is set from > > > > > > > > > > > the BIOS. > > > > > > > > > > > > > > > > > > > > > > I just scanned through the libsmbios code to see what it's doing, and > > > > > > > > > > > it appears to loop through every charging mode to check if its active. > > > > > > > > > > > I'm not really sure that makes much more sense, so I'll try some more > > > > > > > > > > > tests. > > > > > > > > > > > > > > > > > > > > Keyboard backlight code (kbd_get_first_active_token_bit) is doing also > > > > > > > > > > this type scan. If I remember correctly, for every keyboard backlight > > > > > > > > > > token we just know the boolean value - if the token is set or not. > > > > > > > > > > > > > > > > > > > > It would really nice to see what (raw) value is returned by the > > > > > > > > > > dell_battery_read_req(token) function for every battery token and for > > > > > > > > > > every initial state. > > > > > > > > > > > > > > > > > > I checked this. The BIOS sets the mode value in every related token > > > > > > > > > location. I'm still not really sure what libsmbios is doing, but the > > > > > > > > > kernel code seems to arbitrarily choose one of the token locations > > > > > > > > > to read from. This makes sense to me now. > > > > > > > > > > > > > > > > > > In the BIOS when I set the mode to "ExpressCharge", > > > > > > > > > this what I pulled for each token location: > > > > > > > > > > > > > > > > > > [ 5.704651] dell-laptop dell-laptop: BAT_CUSTOM_MODE_TOKEN value: 2 > > > > > > > > > [ 5.707015] dell-laptop dell-laptop: BAT_PRI_AC_MODE_TOKEN value: 2 > > > > > > > > > [ 5.709114] dell-laptop dell-laptop: BAT_ADAPTIVE_MODE_TOKEN value: 2 > > > > > > > > > [ 5.711041] dell-laptop dell-laptop: BAT_STANDARD_MODE_TOKEN value: 2 > > > > > > > > > [ 5.713705] dell-laptop dell-laptop: BAT_EXPRESS_MODE_TOKEN value: 2 > > > > > > > > > > > > > > > > > > Similar story when I set it to Custom (all were '5'), or Standard ('1'). > > > > > > > > > When I set it from linux as well, it changed all location values. > > > > > > > > > > > > > > > > Interesting... Anyway, I still think that the API could be similar to > > > > > > > > what is used in keyboard backlight. > > > > > > > > > > > > > > > > Could you please dump all information about each token? They are in > > > > > > > > struct calling_interface_token returned by dell_smbios_find_token. > > > > > > > > > > > > > > > > I'm interesting in tokenID, location and value. > > > > > > > > > > > > > > > > Ideally to compare what is in token->value and then in buffer.output[1] > > > > > > > > (in case dell_send_request does not fail). > > > > > > > > > > > > > > > > > > > > > Alright, here's what I see: > > > > > > > > > > > > > > [ 5.904775] dell_laptop: dell_battery_read_req: token requested: 0x343, tokenID=0x343, location=0x343, value=5 > > > > > > > [ 5.908675] dell_laptop: dell_battery_read_req: buffer.output[1]=3 > > > > > > > [ 5.908680] dell_laptop: dell_battery_init: BAT_CUSTOM_MODE_TOKEN value: 3 > > > > > > > [ 5.908682] dell_laptop: dell_battery_read_req: token requested: 0x341, tokenID=0x341, location=0x341, value=3 > > > > > > > [ 5.910922] dell_laptop: dell_battery_read_req: buffer.output[1]=3 > > > > > > > [ 5.910926] dell_laptop: dell_battery_init: BAT_PRI_AC_MODE_TOKEN value: 3 > > > > > > > [ 5.910928] dell_laptop: dell_battery_read_req: token requested: 0x342, tokenID=0x342, location=0x342, value=4 > > > > > > > [ 5.913042] dell_laptop: dell_battery_read_req: buffer.output[1]=3 > > > > > > > [ 5.913046] dell_laptop: dell_battery_init: BAT_ADAPTIVE_MODE_TOKEN value: 3 > > > > > > > [ 5.913048] dell_laptop: dell_battery_read_req: token requested: 0x346, tokenID=0x346, location=0x346, value=1 > > > > > > > [ 5.914996] dell_laptop: dell_battery_read_req: buffer.output[1]=3 > > > > > > > [ 5.914999] dell_laptop: dell_battery_init: BAT_STANDARD_MODE_TOKEN value: 3 > > > > > > > [ 5.915000] dell_laptop: dell_battery_read_req: token requested: 0x347, tokenID=0x347, location=0x347, value=2 > > > > > > > [ 5.916723] dell_laptop: dell_battery_read_req: buffer.output[1]=3 > > > > > > > [ 5.916724] dell_laptop: dell_battery_init: BAT_EXPRESS_MODE_TOKEN value: 3 > > > > > > > [ 5.916725] dell_laptop: dell_battery_read_req: token requested: 0x349, tokenID=0x349, location=0x349, value=65535 > > > > > > > [ 5.918727] dell_laptop: dell_battery_read_req: buffer.output[1]=65 > > > > > > > [ 5.918731] dell_laptop: dell_battery_init: BAT_CUSTOM_CHARGE_START value: 65 > > > > > > > [ 5.918734] dell_laptop: dell_battery_read_req: token requested: 0x34a, tokenID=0x34a, location=0x34a, value=65535 > > > > > > > [ 5.920864] dell_laptop: dell_battery_read_req: buffer.output[1]=85 > > > > > > > [ 5.920867] dell_laptop: dell_battery_init: BAT_CUSTOM_CHARGE_END value: 85 > > > > > > > > > > > > Perfect. And can you check dumps when the mode is set to some other than BAT_PRI_AC_MODE_TOKEN? > > > > > > > > > > Here's Express: > > > > > > > > > > [ 5.880090] dell_laptop: dell_battery_read_req: token requested: 0x343, tokenID=0x343, location=0x343, value=5 > > > > > [ 5.882011] dell_laptop: dell_battery_read_req: buffer.output[1]=2 > > > > > [ 5.882014] dell_laptop: dell_battery_init: BAT_CUSTOM_MODE_TOKEN value: 2 > > > > > [ 5.882016] dell_laptop: dell_battery_read_req: token requested: 0x341, tokenID=0x341, location=0x341, value=3 > > > > > [ 5.894513] dell_laptop: dell_battery_read_req: buffer.output[1]=2 > > > > > [ 5.894518] dell_laptop: dell_battery_init: BAT_PRI_AC_MODE_TOKEN value: 2 > > > > > [ 5.894520] dell_laptop: dell_battery_read_req: token requested: 0x342, tokenID=0x342, location=0x342, value=4 > > > > > [ 5.913870] dell_laptop: dell_battery_read_req: buffer.output[1]=2 > > > > > [ 5.913874] dell_laptop: dell_battery_init: BAT_ADAPTIVE_MODE_TOKEN value: 2 > > > > > [ 5.913875] dell_laptop: dell_battery_read_req: token requested: 0x346, tokenID=0x346, location=0x346, value=1 > > > > > [ 5.915622] dell_laptop: dell_battery_read_req: buffer.output[1]=2 > > > > > [ 5.915625] dell_laptop: dell_battery_init: BAT_STANDARD_MODE_TOKEN value: 2 > > > > > [ 5.915626] dell_laptop: dell_battery_read_req: token requested: 0x347, tokenID=0x347, location=0x347, value=2 > > > > > [ 5.917349] dell_laptop: dell_battery_read_req: buffer.output[1]=2 > > > > > [ 5.917351] dell_laptop: dell_battery_init: BAT_EXPRESS_MODE_TOKEN value: 2 > > > > > [ 5.917352] dell_laptop: dell_battery_read_req: token requested: 0x349, tokenID=0x349, location=0x349, value=65535 > > > > > [ 5.919068] dell_laptop: dell_battery_read_req: buffer.output[1]=65 > > > > > [ 5.919070] dell_laptop: dell_battery_init: BAT_CUSTOM_CHARGE_START value: 65 > > > > > [ 5.919071] dell_laptop: dell_battery_read_req: token requested: 0x34a, tokenID=0x34a, location=0x34a, value=65535 > > > > > [ 5.920780] dell_laptop: dell_battery_read_req: buffer.output[1]=85 > > > > > [ 5.920782] dell_laptop: dell_battery_init: BAT_CUSTOM_CHARGE_END value: 85 > > > > > > > > > > And here's Adaptive: > > > > > > > > > > [ 5.945319] dell_laptop: dell_battery_read_req: token requested: 0x343, tokenID=0x343, location=0x343, value=5 > > > > > [ 5.973685] dell_laptop: dell_battery_read_req: buffer.output[1]=4 > > > > > [ 5.973690] dell_laptop: dell_battery_init: BAT_CUSTOM_MODE_TOKEN value: 4 > > > > > [ 5.973692] dell_laptop: dell_battery_read_req: token requested: 0x341, tokenID=0x341, location=0x341, value=3 > > > > > [ 5.976533] dell_laptop: dell_battery_read_req: buffer.output[1]=4 > > > > > [ 5.976538] dell_laptop: dell_battery_init: BAT_PRI_AC_MODE_TOKEN value: 4 > > > > > [ 5.976540] dell_laptop: dell_battery_read_req: token requested: 0x342, tokenID=0x342, location=0x342, value=4 > > > > > [ 5.981013] dell_laptop: dell_battery_read_req: buffer.output[1]=4 > > > > > [ 5.981018] dell_laptop: dell_battery_init: BAT_ADAPTIVE_MODE_TOKEN value: 4 > > > > > [ 5.981020] dell_laptop: dell_battery_read_req: token requested: 0x346, tokenID=0x346, location=0x346, value=1 > > > > > [ 5.983474] dell_laptop: dell_battery_read_req: buffer.output[1]=4 > > > > > [ 5.983479] dell_laptop: dell_battery_init: BAT_STANDARD_MODE_TOKEN value: 4 > > > > > [ 5.983481] dell_laptop: dell_battery_read_req: token requested: 0x347, tokenID=0x347, location=0x347, value=2 > > > > > [ 5.985881] dell_laptop: dell_battery_read_req: buffer.output[1]=4 > > > > > [ 5.985885] dell_laptop: dell_battery_init: BAT_EXPRESS_MODE_TOKEN value: 4 > > > > > [ 5.985887] dell_laptop: dell_battery_read_req: token requested: 0x349, tokenID=0x349, location=0x349, value=65535 > > > > > [ 5.988332] dell_laptop: dell_battery_read_req: buffer.output[1]=65 > > > > > [ 5.988337] dell_laptop: dell_battery_init: BAT_CUSTOM_CHARGE_START value: 65 > > > > > [ 5.988339] dell_laptop: dell_battery_read_req: token requested: 0x34a, tokenID=0x34a, location=0x34a, value=65535 > > > > > [ 5.990769] dell_laptop: dell_battery_read_req: buffer.output[1]=85 > > > > > [ 5.990774] dell_laptop: dell_battery_init: BAT_CUSTOM_CHARGE_END value: 85 > > > > > > > > > > > > > > > > > > > > -- > > > > > I'm available for contract & employment work, see: > > > > > https://spindle.queued.net/~dilinger/resume-tech.pdf > > > > > > > > Nice! So it is exactly same as API of keyboard backlight tokens. Thanks. > > > > > > > > In dell_battery_write_req function you can drop second "val" argument > > > > and replace it by token->value. So the dell_fill_request call in that > > > > function would look like: > > > > > > > > dell_fill_request(&buffer, token->location, token->value, 0, 0); > > > > > > > > > Well, except that we use dell_battery_write_req for writing the charge > > > start/end values as well (in dell_battery_custom_set). Those can't be > > > obtained from token->value. > > > > > > We could have two separate functions for that, or set 'val' to a > > > sentinel value (0) that, if detected, we set val=token->value. I'm > > > still not really understanding the point, though. > > > > I think that two separate functions would be needed. One which set > > battery mode (enum) and which set custom thresholds. > > > > > > > > > > And then you can mimic the usage as it is done in keyboard backlight > > > > functions (kbd_get_first_active_token_bit). > > > > > > > > If you do not know what I mean then later (today or tomorrow) I can > > > > write code example of the functionality. > > > > > > Sorry, I still don't understand what the goal is here. Is the goal to > > > not pull from a random location to determine the current charging mode? > > > Is the goal to determine what charging modes are currently supported > > > (and if so, I don't see how)? Is the goal to avoid having the kernel > > > hardcode a list of enums that the BIOS might have different values > > > for? Is the goal to merge the keyboard backlight and battery setting > > > functions? > > > > Avoid having the kernel hardcoded values for enums which SMBIOS > > provides. Future (or maybe also older) modes may have different enum > > values. So we should use what SMBIOS provides to us. > > > > Also to determinate which charging modes are supported by the current HW > > configuration. If BIOS does not support some mode or does not allow to > > set some mode, kernel should not export this as supported option. > > > > If you do not see how to do it, please give me some time, I will send > > you an example. Going to look at it right now. > > > > Merging keyboard backlight and battery code is bonus, not required. > > But I thought that it would be easier to build a new code from common > > blocks. > > Here is very quick & hacky example of what I mean (completely untested): > > --- dell-laptop.c > +++ dell-laptop.c > @@ -353,6 +353,105 @@ static const struct dmi_system_id dell_q > { } > }; > > +static int dell_read_token_value(u16 tokenid, u32 *value) > +{ > + struct calling_interface_buffer buffer; > + struct calling_interface_token *token; > + int ret; > + > + token = dell_smbios_find_token(tokenid); > + if (!token) > + return -ENODEV; > + > + dell_fill_request(&buffer, token->location, 0, 0, 0); > + ret = dell_send_request(&buffer, CLASS_TOKEN_READ, SELECT_TOKEN_STD); > + if (ret) > + return ret; > + > + *value = buffer.output[1]; > + return 0; > +} > + > +static int dell_write_token_value(u16 tokenid, u32 value) > +{ > + struct calling_interface_buffer buffer; > + struct calling_interface_token *token; > + > + token = dell_smbios_find_token(type); > + if (!token) > + return -ENODEV; > + > + dell_fill_request(&buffer, token->location, value, 0, 0); > + return dell_send_request(&buffer, CLASS_TOKEN_WRITE, SELECT_TOKEN_STD); > +} > + I did things a bit differently here. I created a function dell_send_request_by_token_loc() that is available to be reused by all the code that sends packets to token->location. This is available for kbd_{g,s}et_token_bit(), micmute_led_set(), and mute_led_set() to use, but I'd rather do that in a separate patch. +static int dell_send_request_by_token_loc(struct calling_interface_buffer *buffer, + u16 class, u16 select, int type, + int val) +{ + struct calling_interface_token *token; + + token = dell_smbios_find_token(type); + if (!token) + return -ENODEV; + + if (val <= 0) + val = token->value; + + dell_fill_request(buffer, token->location, val, 0, 0); + return dell_send_request(buffer, class, select); +} + +static int dell_battery_set_mode(const int type) +{ + struct calling_interface_buffer buffer; + + /* 0 means use the value from the token */ + return dell_send_request_by_token_loc(&buffer, CLASS_TOKEN_WRITE, + SELECT_TOKEN_STD, type, 0); +} + +static int dell_battery_read(const int type) +{ + struct calling_interface_buffer buffer; + int err; + + err = dell_send_request_by_token_loc(&buffer, CLASS_TOKEN_READ, + SELECT_TOKEN_STD, type, 0); + if (err) + return err; + + return buffer.output[1]; +} > +static int dell_is_enum_token_active(u16 tokenid) > +{ > + struct calling_interface_buffer buffer; > + struct calling_interface_token *token; > + int ret; > + > + token = dell_smbios_find_token(tokenid); > + if (!token) > + return -EINVAL; > + > + if (token->value == (u16)-1) > + return -EINVAL; > + > + dell_fill_request(&buffer, token->location, 0, 0, 0); > + ret = dell_send_request(&buffer, CLASS_TOKEN_READ, SELECT_TOKEN_STD); > + if (ret) > + return ret; > + > + return (buffer.output[1] == token->value); > +} > + Okay, I incorporated this, but using the above helper functions: +static bool dell_battery_mode_is_active(const int type) +{ + struct calling_interface_token *token; + + token = dell_smbios_find_token(type); + if (!token) + return false; + + return token->value == dell_battery_read(type); +} It will look up the token twice, but this only happens once on it (and I'm realizing now that it can be marked __init). > +static int dell_activate_enum_token(u16 tokenid) > +{ > + struct calling_interface_buffer buffer; > + struct calling_interface_token *token; > + int ret; > + > + token = dell_smbios_find_token(tokenid); > + if (!token) > + return -EINVAL; > + > + if (token->value == (u16)-1) > + return -EINVAL; > + > + dell_fill_request(&buffer, token->location, token->value, 0, 0); > + return dell_send_request(&buffer, CLASS_TOKEN_WRITE, SELECT_TOKEN_STD); > +} > + > +static u32 dell_get_supported_enum_tokens(const u16 *tokenids, u32 count) > +{ > + u32 supported_mask = 0; > + u32 i; > + > + for (i = 0; i < count; i++) { > + if (dell_smbios_find_token(tokenids[i])) > + supported_mask |= BIT(i); > + } > + > + return supported_mask; > +} > + > +static int dell_get_active_enum_token(const u16 *tokenids, u32 count, u32 supported_mask) > +{ > + int ret; > + u32 i; > + > + for (i = 0; i < count; i++) { > + if (!(supported_mask & BIT(i))) > + continue; > + ret = dell_is_enum_token_active(tokenids[i]); > + if (ret == 1) > + return i; > + } > + > + return -EINVAL; > +} Thanks, I incorporated and tested this code; though it only runs once during init, because I'm keeping the battery_cur_mode variable (see next section). +static u32 __init battery_get_supported_modes(void) +{ + u32 modes = 0; + int i; + + for (i = 0; i < ARRAY_SIZE(battery_modes); i++) { + if (dell_smbios_find_token(battery_modes[i].token)) + modes |= BIT(i); + } + + return modes; +} + +static int __init dell_battery_find_charging_mode(void) +{ + int i; + + battery_supported_modes = battery_get_supported_modes(); + for (i = 0; i < ARRAY_SIZE(battery_modes); i++) { + if (!(battery_supported_modes & BIT(i))) + continue; + if (dell_battery_mode_is_active(battery_modes[i].token)) + return battery_modes[i].token; + } + + return 0; +} > + > /* > * Derived from information in smbios-wireless-ctl: > * > @@ -2183,6 +2282,144 @@ static struct led_classdev mute_led_cdev > .default_trigger = "audio-mute", > }; > > +static const u16 battery_mode_tokens[] = { > + BAT_STANDARD_MODE_TOKEN, > + BAT_EXPRESS_MODE_TOKEN, > + BAT_PRI_AC_MODE_TOKEN, > + BAT_ADAPTIVE_MODE_TOKEN, > + BAT_CUSTOM_MODE_TOKEN, > +}; > + > +static const char * const battery_mode_names[] = { > + "standard", > + "express", > + "primarily_ac", > + "adaptive", > + "custom", > +}; > + > +static u32 battery_mode_token_mask; > + I merged the token and name lists. Also, is there any particular reason you dropped the current mode, preferring to read it from SMBIOS every time in the _show() callback? +static const struct { + int token; + const char *label; +} battery_modes[] = { + { BAT_STANDARD_MODE_TOKEN, "standard" }, + { BAT_EXPRESS_MODE_TOKEN, "express" }, + { BAT_PRI_AC_MODE_TOKEN, "primarily_ac" }, + { BAT_ADAPTIVE_MODE_TOKEN, "adaptive" }, + { BAT_CUSTOM_MODE_TOKEN, "custom" }, +}; +static u32 battery_supported_modes; +static int battery_cur_mode; + > +static int dell_battery_read_custom_charge(u16 token) > +{ > + u32 value; > + int ret; > + > + ret = dell_read_token_value(token, &value); > + if (ret) > + return ret; > + if (value > 100) > + return -EINVAL; > + return value; > +} > + > +#define CHARGE_START_MIN 50 > +#define CHARGE_START_MAX 95 > +#define CHARGE_END_MIN 55 > +#define CHARGE_END_MAX 100 > +#define CHARGE_MIN_DIFF 5 > + > +static int dell_battery_set_custom_charge_start(int val) > +{ > + int end; > + > + if (val < CHARGE_START_MIN) > + val = CHARGE_START_MIN; > + else if (val > CHARGE_START_MAX) > + val = CHARGE_START_MAX; > + > + end = dell_battery_get_custom_charge(BAT_CUSTOM_CHARGE_END); > + if (end < 0) > + return end; > + > + if (end - val < CHARGE_MIN_DIFF) > + val = end - CHARGE_MIN_DIFF; > + > + return dell_write_token_value(BAT_CUSTOM_CHARGE_START, val); > +} > + > +static int dell_battery_set_custom_charge_end(int val) > +{ > + int start; > + > + if (val < CHARGE_END_MIN) > + val = CHARGE_END_MIN; > + else if (val > CHARGE_END_MAX) > + val = CHARGE_END_MAX; > + > + start = dell_battery_get_custom_charge(BAT_CUSTOM_CHARGE_START); > + if (start < 0) > + return start; > + > + if (val - start < CHARGE_MIN_DIFF) > + val = start + CHARGE_MIN_DIFF; > + > + return dell_write_token_value(BAT_CUSTOM_CHARGE_END, val); > +} > + Good call, I split apart the start/end functions. It was originally much smaller and grew over time. :) > +static ssize_t charge_type_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + int active; > + ssize_t count; > + > + active = dell_get_active_enum_token(battery_mode_tokens, ARRAY_SIZE(battery_mode_tokens), battery_mode_token_mask); > + if (active < 0) > + return ret; > + > + for (count = 0, i = 0; i < ARRAY_SIZE(battery_mode_names); i++) { > + if (!(BIT(i) & battery_mode_token_mask)) > + continue; > + count += sysfs_emit_at(buf, count, i == active ? "[%s] " : "%s ", battery_mode_names[mode]); > + } > + > + /* convert the last space to a newline */ > + /* battery_mode_names is non-empty and battery_mode_token_mask is non-zero, so count is also non-zero */ > + count--; > + count += sysfs_emit_at(buf, count, "\n"); > + > + return count; > +} > + Again, I personally prefer keeping the currently active charging mode around as a variable: +static ssize_t charge_type_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + ssize_t count = 0; + int i; + + for (i = 0; i < ARRAY_SIZE(battery_modes); i++) { + if (!(battery_supported_modes & BIT(i))) + continue; + + count += sysfs_emit_at(buf, count, + battery_modes[i].token == battery_cur_mode ? "[%s] " : "%s ", + battery_modes[i].label); + } + + /* convert the last space to a newline */ + if (count > 0) + count--; + count += sysfs_emit_at(buf, count, "\n"); + + return count; +} > +static ssize_t charge_type_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t size) > +{ > + size_t i; > + int ret; > + > + for (i = 0; i < ARRAY_SIZE(battery_mode_names); i++) { > + if (sysfs_streq(battery_mode_names[i], buf)) > + break; > + } > + > + if (i >= ARRAY_SIZE(battery_mode_names)) > + return -EINVAL; > + > + if (!(BIT(i) & battery_mode_token_mask)) > + return -EINVAL; > + > + ret = dell_activate_enum_token(battery_mode_tokens[i]); > + if (ret) > + return ret; > + > + return size; > +} > + > +static void __init dell_battery_init(struct device *dev) > +{ > + battery_mode_token_mask = dell_get_supported_enum_tokens(battery_mode_tokens, ARRAY_SIZE(battery_mode_tokens)); > + if (battery_mode_token_mask != 0) > + battery_hook_register(&dell_battery_hook); > +} > + > +static void __exit dell_battery_exit(void) > +{ > + if (battery_mode_token_mask != 0) > + battery_hook_unregister(&dell_battery_hook); > +} > + > static int __init dell_init(void) > { > struct calling_interface_token *token; Let me know your thoughts, and I can send a V2 patch if you're okay with the code snippets I sent. -- I'm available for contract & employment work, see: https://spindle.queued.net/~dilinger/resume-tech.pdf