From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755357AbeARJma (ORCPT ); Thu, 18 Jan 2018 04:42:30 -0500 Received: from mail-wm0-f65.google.com ([74.125.82.65]:45409 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755005AbeARJm2 (ORCPT ); Thu, 18 Jan 2018 04:42:28 -0500 X-Google-Smtp-Source: ACJfBouMCKI3t1S57oOL4KYBf6uRhDgRv1+rKhiHdcZYneVx0E2jJ2oW2QTuv1ARbLRWukxb9h7CKQ== Subject: Re: [PATCH 3/6] backlight/pandora: Stop using BL_CORE_DRIVER1 To: DRI Development , LKML , Lee Jones , Jingoo Han , Daniel Vetter References: <20180117140159.27611-1-daniel.vetter@ffwll.ch> <20180117140159.27611-3-daniel.vetter@ffwll.ch> <7adf519b-68fa-e1c5-c001-68bf52f7e0b7@linaro.org> <20180117213819.GB2759@phenom.ffwll.local> From: Daniel Thompson Message-ID: <7f1630fc-c764-e0d9-07b4-541918ec2574@linaro.org> Date: Thu, 18 Jan 2018 09:42:24 +0000 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <20180117213819.GB2759@phenom.ffwll.local> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/01/18 21:38, Daniel Vetter wrote: > Thanks a lot for your comments. > > On Wed, Jan 17, 2018 at 04:47:41PM +0000, Daniel Thompson wrote: >> On 17/01/18 14:01, Daniel Vetter wrote: >>> Leaking driver internal tracking into the already massively confusing >>> backlight power tracking is really confusing. >>> >>> Stop that by allocating a tiny driver private data structure instead. >>> >>> Cc: Lee Jones >>> Cc: Daniel Thompson >>> Cc: Jingoo Han >>> Signed-off-by: Daniel Vetter >>> --- >>> drivers/video/backlight/pandora_bl.c | 26 +++++++++++++++++++------- >>> 1 file changed, 19 insertions(+), 7 deletions(-) >>> >>> diff --git a/drivers/video/backlight/pandora_bl.c b/drivers/video/backlight/pandora_bl.c >>> index a186bc677c7d..6bd159946a47 100644 >>> --- a/drivers/video/backlight/pandora_bl.c >>> +++ b/drivers/video/backlight/pandora_bl.c >>> @@ -35,11 +35,15 @@ >>> #define MAX_VALUE 63 >>> #define MAX_USER_VALUE (MAX_VALUE - MIN_VALUE) >>> -#define PANDORABL_WAS_OFF BL_CORE_DRIVER1 >>> +struct pandora_private { >>> + unsigned old_state; >>> +#define PANDORABL_WAS_OFF 1 >> >> Nit, but we using old_state like a bitfield so, BIT(0)? >> >> >>> +}; >>> static int pandora_backlight_update_status(struct backlight_device *bl) >>> { >>> int brightness = bl->props.brightness; >>> + struct pandora_private *priv = bl_get_data(bl); >>> u8 r; >>> if (bl->props.power != FB_BLANK_UNBLANK) >>> @@ -53,7 +57,7 @@ static int pandora_backlight_update_status(struct backlight_device *bl) >>> brightness = MAX_USER_VALUE; >>> if (brightness == 0) { >>> - if (bl->props.state & PANDORABL_WAS_OFF) >>> + if (priv->old_state & PANDORABL_WAS_OFF) >>> goto done; >>> /* first disable PWM0 output, then clock */ >>> @@ -66,7 +70,7 @@ static int pandora_backlight_update_status(struct backlight_device *bl) >>> goto done; >>> } >>> - if (bl->props.state & PANDORABL_WAS_OFF) { >>> + if (priv->old_state & PANDORABL_WAS_OFF) { >>> /* >>> * set PWM duty cycle to max. TPS61161 seems to use this >>> * to calibrate it's PWM sensitivity when it starts. >>> @@ -93,9 +97,9 @@ static int pandora_backlight_update_status(struct backlight_device *bl) >>> done: >>> if (brightness != 0) >>> - bl->props.state &= ~PANDORABL_WAS_OFF; >>> + priv->old_state 0; >>> else >>> - bl->props.state |= PANDORABL_WAS_OFF; >>> + priv->old_state = PANDORABL_WAS_OFF; >> >> Well, we were using it like a bitfield until this bit... > > I had a simple boolean first (because that's all we neeed), but that made > the code less readable. Should I s/1/true/ in the #define? The entire C99 > bool tends to be a bit a bikeshed sometimes :-) I'd prefer a simple boolean or just storing old_brightness directly in priv... it is only ever consumed as a boolean anyway. I'd have to say I'm not keen on #define true alongside the existing bitmask checks. However... I'm happy to leave that with you. Providing the spurious kfree() is removed then please feel free to repost with: Acked-by: Daniel Thompson Daniel. > >> >> >>> return 0; >>> } >>> @@ -109,15 +113,23 @@ static int pandora_backlight_probe(struct platform_device *pdev) >>> { >>> struct backlight_properties props; >>> struct backlight_device *bl; >>> + struct pandora_private *priv; >>> u8 r; >>> + priv = devm_kmalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); >>> + if (!priv) { >>> + dev_err(&pdev->dev, "failed to allocate driver private data\n"); >>> + return -ENOMEM; >>> + } >>> + >>> memset(&props, 0, sizeof(props)); >>> props.max_brightness = MAX_USER_VALUE; >>> props.type = BACKLIGHT_RAW; >>> bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, >>> - NULL, &pandora_backlight_ops, &props); >>> + priv, &pandora_backlight_ops, &props); >>> if (IS_ERR(bl)) { >>> dev_err(&pdev->dev, "failed to register backlight\n"); >>> + kfree(priv); >> >> Why can't we rely on devres for cleanup? > > Argh, I had kmalloc first and then changed to devm_kmalloc. The kfree here > needs to go indeed. > > Cheers, Daniel > >> >> >>> return PTR_ERR(bl); >>> } >>> @@ -126,7 +138,7 @@ static int pandora_backlight_probe(struct platform_device *pdev) >>> /* 64 cycle period, ON position 0 */ >>> twl_i2c_write_u8(TWL_MODULE_PWM, 0x80, TWL_PWM0_ON); >>> - bl->props.state |= PANDORABL_WAS_OFF; >>> + priv->old_state = PANDORABL_WAS_OFF; >>> bl->props.brightness = MAX_USER_VALUE; >>> backlight_update_status(bl); >>> >