From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9ECE1C7618F for ; Mon, 15 Jul 2019 09:47:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A24F20868 for ; Mon, 15 Jul 2019 09:47:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="soc+XYqr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729633AbfGOJrW (ORCPT ); Mon, 15 Jul 2019 05:47:22 -0400 Received: from lelv0143.ext.ti.com ([198.47.23.248]:36518 "EHLO lelv0143.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729257AbfGOJrW (ORCPT ); Mon, 15 Jul 2019 05:47:22 -0400 Received: from fllv0034.itg.ti.com ([10.64.40.246]) by lelv0143.ext.ti.com (8.15.2/8.15.2) with ESMTP id x6F9lBqe048982; Mon, 15 Jul 2019 04:47:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1563184031; bh=nsCbN9LXGkKl6cl+W3My4orVJKZBkvB5Iek+7zc89LA=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=soc+XYqrX6ZDIKzfnSbvExtZOfcT288ctZa2p4cB52aKsyU1yyucH/13+h7UcHZe8 H+UKU6hm+R1aG7rmRfxojjpC3ehzxg33cu6PRUU8EUz2LsfE6SXLnG9+euIPhISfws hDmswrrwMsitV6kCa6H0C9UDrzsWcLE+U1LVFwzU= Received: from DFLE114.ent.ti.com (dfle114.ent.ti.com [10.64.6.35]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id x6F9lBnw105365 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 15 Jul 2019 04:47:11 -0500 Received: from DFLE101.ent.ti.com (10.64.6.22) by DFLE114.ent.ti.com (10.64.6.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1713.5; Mon, 15 Jul 2019 04:47:10 -0500 Received: from fllv0039.itg.ti.com (10.64.41.19) by DFLE101.ent.ti.com (10.64.6.22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1713.5 via Frontend Transport; Mon, 15 Jul 2019 04:47:10 -0500 Received: from [10.250.97.31] (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id x6F9l8Uc080072; Mon, 15 Jul 2019 04:47:09 -0500 Subject: Re: [PATCH 1/2] leds: Add control of the voltage/current regulator to the LED core To: Daniel Thompson CC: Dan Murphy , , , , , , , References: <20190708103547.23528-1-jjhiblot@ti.com> <20190708103547.23528-2-jjhiblot@ti.com> <56d16260-ff82-3439-4c1f-2a3a1552bc7d@ti.com> <20190715092400.sedjumqkecglheyu@holly.lan> From: Jean-Jacques Hiblot Message-ID: <9c53f54f-d0d4-50d4-09da-34389085269a@ti.com> Date: Mon, 15 Jul 2019 11:47:08 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190715092400.sedjumqkecglheyu@holly.lan> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/07/2019 11:24, Daniel Thompson wrote: > On Mon, Jul 15, 2019 at 11:01:29AM +0200, Jean-Jacques Hiblot wrote: >> Hi Dan, >> >> On 12/07/2019 20:49, Dan Murphy wrote: >>> JJ >>> >>> On 7/8/19 5:35 AM, Jean-Jacques Hiblot wrote: >>>> A LED is usually powered by a voltage/current regulator. Let the LED >>>> core >>> Let the LED core know >>>> about it. This allows the LED core to turn on or off the power supply >>>> as needed. >>>> Signed-off-by: Jean-Jacques Hiblot >>>> --- >>>>   drivers/leds/led-class.c | 10 ++++++++ >>>>   drivers/leds/led-core.c  | 53 +++++++++++++++++++++++++++++++++++++--- >>>>   include/linux/leds.h     |  4 +++ >>>>   3 files changed, 64 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c >>>> index 4793e77808e2..e01b2d982564 100644 >>>> --- a/drivers/leds/led-class.c >>>> +++ b/drivers/leds/led-class.c >>>> @@ -17,6 +17,7 @@ >>>>   #include >>>>   #include >>>>   #include >>>> +#include >>> What if you move this to leds.h so core and class can both include it. >>> >>> >>>>   #include >>>>   #include "leds.h" >>>>   @@ -272,6 +273,15 @@ int of_led_classdev_register(struct device >>>> *parent, struct device_node *np, >>>>           dev_warn(parent, "Led %s renamed to %s due to name collision", >>>>                   led_cdev->name, dev_name(led_cdev->dev)); >>>>   +    led_cdev->regulator = devm_regulator_get(led_cdev->dev, "power"); >>> Is the regulator always going to be called power? >> Actually in the dts, that will be "power-supply". I lacked the imagination >> to come up with a better name. >> >> >> >>>> +    if (IS_ERR(led_cdev->regulator)) { >>>> +        dev_err(led_cdev->dev, "Cannot get the power supply for %s\n", >>>> +            led_cdev->name); >>>> +        device_unregister(led_cdev->dev); >>>> +        mutex_unlock(&led_cdev->led_access); >>>> +        return PTR_ERR(led_cdev->regulator); >>> This is listed as optional in the DT doc.  This appears to be required. >> The regulator core will provide a dummy regulator if none is given in the >> device tree. I would rather have an error in that case, but that is not how >> it works. > If you actively wanted to get -ENODEV back when there is no regulator > then you can use devm_regulator_get_optional() for that. > > However perhaps be careful what you wish for. If you use get_optional() > then you will have to sprinkle NULL or IS_ERR() checks everywhere. I'd > favour using the current approach! Thanks for the info. I think I'll use the get_optionnal(). That will add a bit of complexity, but it will avoid deferring some work in led_set_brightness_nopm() when it is not needed. JJ > > > Daniel. > >> >>> I prefer to keep it optional.  Many LED drivers are connected to fixed >>> non-managed supplies. >>> >>>> +    } >>>> + >>>>       if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) { >>>>           ret = led_add_brightness_hw_changed(led_cdev); >>>>           if (ret) { >>>> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c >>>> index 7107cd7e87cf..139de6b08cad 100644 >>>> --- a/drivers/leds/led-core.c >>>> +++ b/drivers/leds/led-core.c >>>> @@ -16,6 +16,7 @@ >>>>   #include >>>>   #include >>>>   #include "leds.h" >>>> +#include >>>>     DECLARE_RWSEM(leds_list_lock); >>>>   EXPORT_SYMBOL_GPL(leds_list_lock); >>>> @@ -23,6 +24,31 @@ EXPORT_SYMBOL_GPL(leds_list_lock); >>>>   LIST_HEAD(leds_list); >>>>   EXPORT_SYMBOL_GPL(leds_list); >>>>   +static bool __led_need_regulator_update(struct led_classdev >>>> *led_cdev, >>>> +                    int brightness) >>>> +{ >>>> +    bool new_regulator_state = (brightness != LED_OFF); >>>> + >>>> +    return led_cdev->regulator_state != new_regulator_state; >>>> +} >>>> + >>>> +static int __led_handle_regulator(struct led_classdev *led_cdev, >>>> +                int brightness) >>>> +{ >>>> +    if (__led_need_regulator_update(led_cdev, brightness)) { >>>> +        int ret; >>> Prefer to this to be moved up. >> ok >>>> + >>>> +        if (brightness != LED_OFF) >>>> +            ret = regulator_enable(led_cdev->regulator); >>>> +        else >>>> +            ret = regulator_disable(led_cdev->regulator); >>>> +        if (ret) >>>> +            return ret; >>> new line >>>> +        led_cdev->regulator_state = (brightness != LED_OFF); >>>> +    } >>>> +    return 0; >>>> +} >>>> + >>>>   static int __led_set_brightness(struct led_classdev *led_cdev, >>>>                   enum led_brightness value) >>>>   { >>>> @@ -80,6 +106,7 @@ static void led_timer_function(struct timer_list *t) >>>>       } >>>>         led_set_brightness_nosleep(led_cdev, brightness); >>>> +    __led_handle_regulator(led_cdev, brightness); >>> Again this seems to indicate that the regulator is a required property >>> for the LEDs >>> >>> This needs to be made optional.  And the same comment through out for >>> every call. >>> >>> >>>>         /* Return in next iteration if led is in one-shot mode and >>>> we are in >>>>        * the final blink state so that the led is toggled each >>>> delay_on + >>>> @@ -115,6 +142,8 @@ static void set_brightness_delayed(struct >>>> work_struct *ws) >>>>       if (ret == -ENOTSUPP) >>>>           ret = __led_set_brightness_blocking(led_cdev, >>>>                       led_cdev->delayed_set_value); >>>> +    __led_handle_regulator(led_cdev, led_cdev->delayed_set_value); >>>> + >>>>       if (ret < 0 && >>>>           /* LED HW might have been unplugged, therefore don't warn */ >>>>           !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) && >>>> @@ -141,6 +170,7 @@ static void led_set_software_blink(struct >>>> led_classdev *led_cdev, >>>>       /* never on - just set to off */ >>>>       if (!delay_on) { >>>>           led_set_brightness_nosleep(led_cdev, LED_OFF); >>>> +        __led_handle_regulator(led_cdev, LED_OFF); >>>>           return; >>>>       } >>>>   @@ -148,6 +178,7 @@ static void led_set_software_blink(struct >>>> led_classdev *led_cdev, >>>>       if (!delay_off) { >>>>           led_set_brightness_nosleep(led_cdev, >>>>                          led_cdev->blink_brightness); >>>> +        __led_handle_regulator(led_cdev, led_cdev->blink_brightness); >>>>           return; >>>>       } >>>>   @@ -256,8 +287,14 @@ void led_set_brightness_nopm(struct >>>> led_classdev *led_cdev, >>>>                     enum led_brightness value) >>>>   { >>>>       /* Use brightness_set op if available, it is guaranteed not to >>>> sleep */ >>>> -    if (!__led_set_brightness(led_cdev, value)) >>>> -        return; >>>> +    if (!__led_set_brightness(led_cdev, value)) { >>>> +        /* >>>> +         * if regulator state doesn't need to be changed, that is all/ >>>> +         * Otherwise delegate the change to a work queue >>>> +         */ >>>> +        if (!__led_need_regulator_update(led_cdev, value)) >>>> +            return; >>>> +    } >>>>         /* If brightness setting can sleep, delegate it to a work >>>> queue task */ >>>>       led_cdev->delayed_set_value = value; >>>> @@ -280,6 +317,8 @@ EXPORT_SYMBOL_GPL(led_set_brightness_nosleep); >>>>   int led_set_brightness_sync(struct led_classdev *led_cdev, >>>>                   enum led_brightness value) >>>>   { >>>> +    int ret; >>>> + >>>>       if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) >>>>           return -EBUSY; >>>>   @@ -288,7 +327,15 @@ int led_set_brightness_sync(struct >>>> led_classdev *led_cdev, >>>>       if (led_cdev->flags & LED_SUSPENDED) >>>>           return 0; >>>>   -    return __led_set_brightness_blocking(led_cdev, >>>> led_cdev->brightness); >>>> +    ret = __led_set_brightness_blocking(led_cdev, >>>> led_cdev->brightness); >>>> +    if (ret) >>>> +        return ret; >>>> + >>>> +    ret = __led_handle_regulator(led_cdev, led_cdev->brightness); >>> Can't you just return here? >> ok >> >> >> thanks for the review >> >> JJ >> >>> Dan >>> >>>> +    if (ret) >>>> +        return ret; >>>> + >>>> +    return 0; >>>>   } >>>>   EXPORT_SYMBOL_GPL(led_set_brightness_sync); >>>>   diff --git a/include/linux/leds.h b/include/linux/leds.h >>>> index 9b2bf574a17a..bee8e3f8dddd 100644 >>>> --- a/include/linux/leds.h >>>> +++ b/include/linux/leds.h >>>> @@ -123,6 +123,10 @@ struct led_classdev { >>>>         /* Ensures consistent access to the LED Flash Class device */ >>>>       struct mutex        led_access; >>>> + >>>> +    /* regulator */ >>>> +    struct regulator    *regulator; >>>> +    bool            regulator_state; >>>>   }; >>>>     extern int of_led_classdev_register(struct device *parent,