From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754612Ab3A2IRl (ORCPT ); Tue, 29 Jan 2013 03:17:41 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:40603 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754446Ab3A2IRi (ORCPT ); Tue, 29 Jan 2013 03:17:38 -0500 Message-ID: <51078580.2000808@ti.com> Date: Tue, 29 Jan 2013 09:17:04 +0100 From: Peter Ujfalusi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130115 Thunderbird/17.0.2 MIME-Version: 1.0 To: Thierry Reding CC: Richard Purdie , Grant Likely , Rob Landley , Florian Tobias Schandinat , Andrew Morton , , , , Subject: Re: [PATCH 1/4] pwm_backlight: Fix PWM levels support in non DT case References: <1358861996-27194-1-git-send-email-peter.ujfalusi@ti.com> <1358861996-27194-2-git-send-email-peter.ujfalusi@ti.com> <20130128210123.GA24673@avionic-0098.mockup.avionic-design.de> In-Reply-To: <20130128210123.GA24673@avionic-0098.mockup.avionic-design.de> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/28/2013 10:01 PM, Thierry Reding wrote: > On Tue, Jan 22, 2013 at 02:39:53PM +0100, Peter Ujfalusi wrote: >> It is expected that board files would have: >> static unsigned int bl_levels[] = { 0, 50, 100, 150, 200, 250, }; >> >> static struct platform_pwm_backlight_data bl_data = { >> .levels = bl_levels, >> .max_brightness = ARRAY_SIZE(bl_levels), >> .dft_brightness = 4, >> .pwm_period_ns = 7812500, >> }; >> >> In this case the max_brightness would be out of range in the levels array. >> Decrement the received max_brightness in every case (DT or non DT) when the >> levels has been provided. > > What's wrong with specifying .max_brightness = ARRAY_SIZE(bl_levels) - 1 > instead? There is nothing wrong with that either but IMHO it is more natural for board files to use just ARRAY_SIZE(bl_levels). In this way the handling of data->max_brightness among non DT and DT booted kernel is more uniform in the driver itself. Right now all board files are using only the .max_brightness to specify the maximum value, I could not find any users of .levels in the kernel. -- Péter