From patchwork Mon Jul 20 15:32:04 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris BREZILLON X-Patchwork-Id: 6828851 Return-Path: X-Original-To: patchwork-linux-fbdev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 90E999F7B4 for ; Mon, 20 Jul 2015 15:33:30 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8851320451 for ; Mon, 20 Jul 2015 15:33:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5951E205E9 for ; Mon, 20 Jul 2015 15:33:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932361AbbGTPcT (ORCPT ); Mon, 20 Jul 2015 11:32:19 -0400 Received: from down.free-electrons.com ([37.187.137.238]:56238 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932280AbbGTPcR (ORCPT ); Mon, 20 Jul 2015 11:32:17 -0400 Received: by mail.free-electrons.com (Postfix, from userid 106) id 5F00F20BC; Mon, 20 Jul 2015 17:32:21 +0200 (CEST) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from localhost.localdomain (AToulouse-657-1-56-159.w82-125.abo.wanadoo.fr [82.125.234.159]) by mail.free-electrons.com (Postfix) with ESMTPSA id 5AF96A3A; Mon, 20 Jul 2015 17:32:20 +0200 (CEST) From: Boris Brezillon To: Thierry Reding , linux-pwm@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Bryan Wu , Richard Purdie , Jacek Anaszewski , linux-leds@vger.kernel.org, Heiko Stuebner , linux-rockchip@lists.infradead.org, Jingoo Han , Lee Jones , linux-fbdev@vger.kernel.org, Mark Brown , Liam Girdwood , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , Doug Anderson , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Maxime Ripard , Boris Brezillon Subject: [PATCH v2 07/10] pwm: add the core infrastructure to allow atomic update Date: Mon, 20 Jul 2015 17:32:04 +0200 Message-Id: <1437406327-6207-8-git-send-email-boris.brezillon@free-electrons.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1437406327-6207-1-git-send-email-boris.brezillon@free-electrons.com> References: <1437406327-6207-1-git-send-email-boris.brezillon@free-electrons.com> Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add an ->apply() method to the pwm_ops struct to allow PWM drivers to implement atomic update. This method will be preferred over the ->enable(), ->disable() and ->config() methods if available. Add the pwm_get_state(), pwm_get_default_state() and pwm_apply_state() functions for PWM users to be able to use the atomic update feature. Note that the pwm_apply_state() does not guarantee the atomicity of the update operation, it all depends on the availability and implementation of the ->apply() method. Signed-off-by: Boris Brezillon --- drivers/pwm/core.c | 142 +++++++++++++++++++++++++++++++++++++++++++++++----- include/linux/pwm.h | 28 +++++++++++ 2 files changed, 158 insertions(+), 12 deletions(-) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 236a8cf..4fe4703 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -46,6 +46,12 @@ static struct pwm_device *pwm_to_device(unsigned int pwm) return radix_tree_lookup(&pwm_tree, pwm); } +static void pwm_set_state(struct pwm_device *pwm, + const struct pwm_state *state) +{ + pwm->state = *state; +} + static int alloc_pwms(int pwm, unsigned int count) { unsigned int from = 0; @@ -222,6 +228,19 @@ void *pwm_get_chip_data(struct pwm_device *pwm) } EXPORT_SYMBOL_GPL(pwm_get_chip_data); +static bool pwm_ops_check(const struct pwm_ops *ops) +{ + /* driver supports legacy, non-atomic operation */ + if (ops->config && ops->enable && ops->disable) + return true; + + /* driver supports atomic operation */ + if (ops->apply) + return true; + + return false; +} + /** * pwmchip_add_with_polarity() - register a new PWM chip * @chip: the PWM chip to add @@ -238,8 +257,10 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip, unsigned int i; int ret; - if (!chip || !chip->dev || !chip->ops || !chip->ops->config || - !chip->ops->enable || !chip->ops->disable || !chip->npwm) + if (!chip || !chip->dev || !chip->ops || !chip->npwm) + return -EINVAL; + + if (!pwm_ops_check(chip->ops)) return -EINVAL; mutex_lock(&pwm_lock); @@ -430,7 +451,19 @@ int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns) return -EINVAL; - err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns); + if (pwm->chip->ops->apply) { + struct pwm_state state; + + pwm_get_state(pwm, &state); + state.period = period_ns; + state.duty_cycle = duty_ns; + + err = pwm->chip->ops->apply(pwm->chip, pwm, &state); + } else { + err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, + period_ns); + } + if (err) return err; @@ -455,6 +488,18 @@ int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity) if (!pwm || !pwm->chip->ops) return -EINVAL; + if (pwm->chip->ops->apply) { + struct pwm_state state; + + pwm_get_state(pwm, &state); + state.polarity = polarity; + err = pwm->chip->ops->apply(pwm->chip, pwm, &state); + if (!err) + pwm->state.polarity = polarity; + + return err; + } + if (!pwm->chip->ops->set_polarity) return -ENOSYS; @@ -477,17 +522,29 @@ EXPORT_SYMBOL_GPL(pwm_set_polarity); */ int pwm_enable(struct pwm_device *pwm) { - if (pwm && !pwm_is_enabled(pwm)) { - int err; + int err; - err = pwm->chip->ops->enable(pwm->chip, pwm); - if (!err) - pwm->state.enabled = true; + if (!pwm) + return -EINVAL; - return err; + if (pwm_is_enabled(pwm)) + return 0; + + if (pwm->chip->ops->apply) { + struct pwm_state state; + + pwm_get_state(pwm, &state); + state.enabled = true; + + err = pwm->chip->ops->apply(pwm->chip, pwm, &state); + } else { + err = pwm->chip->ops->enable(pwm->chip, pwm); } - return pwm ? 0 : -EINVAL; + if (!err) + pwm->state.enabled = true; + + return err; } EXPORT_SYMBOL_GPL(pwm_enable); @@ -497,13 +554,74 @@ EXPORT_SYMBOL_GPL(pwm_enable); */ void pwm_disable(struct pwm_device *pwm) { - if (pwm && pwm_is_enabled(pwm)) { + if (!pwm || !pwm_is_enabled(pwm)) + return; + + if (pwm->chip->ops->apply) { + struct pwm_state state; + + pwm_get_state(pwm, &state); + state.enabled = false; + + pwm->chip->ops->apply(pwm->chip, pwm, &state); + } else { pwm->chip->ops->disable(pwm->chip, pwm); - pwm->state.enabled = false; } + + pwm->state.enabled = false; } EXPORT_SYMBOL_GPL(pwm_disable); +/** + * pwm_apply_state() - atomically apply a new state to a PWM device + * @pwm: PWM device + * @state: new state to apply + */ +int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state) +{ + int err = 0; + + if (!pwm) + return -EINVAL; + + if (!memcmp(state, &pwm->state, sizeof(*state))) + return 0; + + if (pwm->chip->ops->apply) { + err = pwm->chip->ops->apply(pwm->chip, pwm, state); + if (!err) + pwm_set_state(pwm, state); + } else { + /* + * FIXME: restore the initial state in case of error. + */ + if (state->polarity != pwm->state.polarity) { + pwm_disable(pwm); + err = pwm_set_polarity(pwm, state->polarity); + if (err) + goto out; + } + + if (state->period != pwm->state.period || + state->duty_cycle != pwm->state.duty_cycle) { + err = pwm_config(pwm, state->period, state->duty_cycle); + if (err) + goto out; + } + + if (state->enabled != pwm->state.enabled) { + if (state->enabled) + err = pwm_enable(pwm); + else + pwm_disable(pwm); + } + } + +out: + return err; +} +EXPORT_SYMBOL_GPL(pwm_apply_state); + static struct pwm_chip *of_node_to_pwmchip(struct device_node *np) { struct pwm_chip *chip; diff --git a/include/linux/pwm.h b/include/linux/pwm.h index df78211..25f7bd1 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -160,6 +160,30 @@ static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) return pwm ? pwm->state.polarity : PWM_POLARITY_NORMAL; } +int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state); + +/** + * pwm_get_state() - retrieve the current PWM state + * @pwm: PWM device + * @state: state to fill with the current PWM state + */ +static inline void pwm_get_state(struct pwm_device *pwm, + struct pwm_state *state) +{ + *state = pwm->state; +} + +/** + * pwm_get_default_state() - retrieve the default PWM state + * @pwm: PWM device + * @state: state to fill with the default PWM state + */ +static inline void pwm_get_default_state(struct pwm_device *pwm, + struct pwm_state *state) +{ + *state = pwm->default_state; +} + /** * struct pwm_ops - PWM controller operations * @request: optional hook for requesting a PWM @@ -168,6 +192,7 @@ static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) * @set_polarity: configure the polarity of this PWM * @enable: enable PWM output toggling * @disable: disable PWM output toggling + * @apply: atomically apply a new PWM config * @reset_state: reset the current PWM state (pwm->state) to the actual * hardware state. This function is only called once per * PWM device when the PWM chip is registered. @@ -189,6 +214,9 @@ struct pwm_ops { struct pwm_device *pwm); void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm); + int (*apply)(struct pwm_chip *chip, + struct pwm_device *pwm, + const struct pwm_state *state); void (*reset_state)(struct pwm_chip *chip, struct pwm_device *pwm); #ifdef CONFIG_DEBUG_FS