From patchwork Wed Nov 21 07:40:44 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: avinash philip X-Patchwork-Id: 1778761 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id DC3B93FC23 for ; Wed, 21 Nov 2012 07:42:41 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1Tb4vl-0007XZ-0D; Wed, 21 Nov 2012 07:41:11 +0000 Received: from comal.ext.ti.com ([198.47.26.152]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1Tb4vg-0007W9-6q for linux-arm-kernel@lists.infradead.org; Wed, 21 Nov 2012 07:41:05 +0000 Received: from dbdp20.itg.ti.com ([172.24.170.38]) by comal.ext.ti.com (8.13.7/8.13.7) with ESMTP id qAL7eum0029526; Wed, 21 Nov 2012 01:40:57 -0600 Received: from DBDE70.ent.ti.com (localhost [127.0.0.1]) by dbdp20.itg.ti.com (8.13.8/8.13.8) with ESMTP id qAL7eqVe011585; Wed, 21 Nov 2012 13:10:53 +0530 (IST) Received: from dbdp32.itg.ti.com (172.24.170.251) by dbde70.ent.ti.com (172.24.170.148) with Microsoft SMTP Server id 14.1.323.3; Wed, 21 Nov 2012 13:10:52 +0530 Received: from localhost.localdomain (dbdp20.itg.ti.com [172.24.170.38]) by dbdp32.itg.ti.com (8.13.8/8.13.8) with ESMTP id qAL7elmW019890; Wed, 21 Nov 2012 13:10:48 +0530 From: "Philip, Avinash" To: , , , Subject: [PATCH v3] pwm: Device tree support for PWM polarity. Date: Wed, 21 Nov 2012 13:10:44 +0530 Message-ID: <1353483644-32711-1-git-send-email-avinashphilip@ti.com> X-Mailer: git-send-email 1.7.0.4 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20121121_024104_967529_552530DB X-CRM114-Status: GOOD ( 13.54 ) X-Spam-Score: -4.6 (----) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-4.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [198.47.26.152 listed in list.dnswl.org] 3.0 KHOP_BIG_TO_CC Sent to 10+ recipients instaed of Bcc or a list -0.0 SPF_PASS SPF: sender matches SPF record -0.7 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: linux-doc@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, nsekhar@ti.com, linux-kernel@vger.kernel.org, gururaja.hebbar@ti.com, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Add support for encoding PWM properties in bit encoded form with of_pwm_xlate_with_flags() function support. Platforms require platform specific PWM properties has to populate in 3rd cell of the pwm-specifier and PWM driver should also set .of_xlate support with this function. Currently PWM property polarity encoded in bit position 0 of the third cell in pwm-specifier. Signed-off-by: Philip, Avinash Acked-by: Grant Likely --- Changes since v2: - Move PWM_SPEC_POLARITY to core.c - Remove dummy function Changes since v1: - of_pwm_xlate_with_flags function support added. - Documentation update :100644 100644 73ec962... 04b0dc4... M Documentation/devicetree/bindings/pwm/pwm.txt :100644 100644 f5acdaa... 780cb6b... M drivers/pwm/core.c :100644 100644 112b314... 6d661f3... M include/linux/pwm.h Documentation/devicetree/bindings/pwm/pwm.txt | 18 +++++++++++++-- drivers/pwm/core.c | 28 +++++++++++++++++++++++++ include/linux/pwm.h | 3 ++ 3 files changed, 46 insertions(+), 3 deletions(-) diff --git a/Documentation/devicetree/bindings/pwm/pwm.txt b/Documentation/devicetree/bindings/pwm/pwm.txt index 73ec962..04b0dc4 100644 --- a/Documentation/devicetree/bindings/pwm/pwm.txt +++ b/Documentation/devicetree/bindings/pwm/pwm.txt @@ -37,10 +37,22 @@ device: pwm-names = "backlight"; }; +Note that in the example above, specifying the "pwm-names" is redundant +because the name "backlight" would be used as fallback anyway. + pwm-specifier typically encodes the chip-relative PWM number and the PWM -period in nanoseconds. Note that in the example above, specifying the -"pwm-names" is redundant because the name "backlight" would be used as -fallback anyway. +period in nanoseconds. + +Optionally, the pwm-specifier can encode a number of flags in a third cell: +- bit 0: PWM signal polarity (0: normal polarity, 1: inverse polarity) + +Example with optional PWM specifier for inverse polarity + + bl: backlight { + pwms = <&pwm 0 5000000 1>; + pwm-names = "backlight"; + }; + 2) PWM controller nodes ----------------------- diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index f5acdaa..780cb6b 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -32,6 +32,9 @@ #define MAX_PWMS 1024 +/* flags in the third cell of the DT PWM specifier */ +#define PWM_SPEC_POLARITY (1 << 0) + static DEFINE_MUTEX(pwm_lookup_lock); static LIST_HEAD(pwm_lookup_list); static DEFINE_MUTEX(pwm_lock); @@ -129,6 +132,31 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) return 0; } +struct pwm_device * +of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) +{ + struct pwm_device *pwm; + + if (pc->of_pwm_n_cells < 3) + return ERR_PTR(-EINVAL); + + if (args->args[0] >= pc->npwm) + return ERR_PTR(-EINVAL); + + pwm = pwm_request_from_chip(pc, args->args[0], NULL); + if (IS_ERR(pwm)) + return pwm; + + pwm_set_period(pwm, args->args[1]); + + if (args->args[2] & PWM_SPEC_POLARITY) + pwm_set_polarity(pwm, PWM_POLARITY_INVERSED); + else + pwm_set_polarity(pwm, PWM_POLARITY_NORMAL); + + return pwm; +} + static struct pwm_device * of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) { diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 112b314..6d661f3 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -171,6 +171,9 @@ struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, unsigned int index, const char *label); +struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, + const struct of_phandle_args *args); + struct pwm_device *pwm_get(struct device *dev, const char *consumer); void pwm_put(struct pwm_device *pwm);