From patchwork Fri Jul 27 15:11:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Enric Balletbo i Serra X-Patchwork-Id: 10547281 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 250B714E0 for ; Fri, 27 Jul 2018 15:11:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 14D132BFE7 for ; Fri, 27 Jul 2018 15:11:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 12AAD2BFFE; Fri, 27 Jul 2018 15:11:40 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 51FBC2BFE7 for ; Fri, 27 Jul 2018 15:11:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388556AbeG0Qdx (ORCPT ); Fri, 27 Jul 2018 12:33:53 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:45542 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388563AbeG0Qdx (ORCPT ); Fri, 27 Jul 2018 12:33:53 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: eballetbo) with ESMTPSA id 44A4F2611B4 From: Enric Balletbo i Serra To: linux-kernel@vger.kernel.org Cc: kernel@collabora.com, cl@rock-chips.com, linux-pwm@vger.kernel.org, linux-fbdev@vger.kernel.org, Daniel Thompson , Thierry Reding , Bartlomiej Zolnierkiewicz , dri-devel@lists.freedesktop.org, Jingoo Han , Lee Jones Subject: [PATCH v2] backlight: pwm_bl: switch to using "atomic" PWM API Date: Fri, 27 Jul 2018 17:11:21 +0200 Message-Id: <20180727151121.12296-1-enric.balletbo@collabora.com> X-Mailer: git-send-email 2.18.0 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 The "atomic" API allows us to configure PWM period and duty_cycle and enable it in one call. The patch also moves the pwm_init_state just before any use of the pwm_state struct, this fixes a potential bug where pwm_get_state can be called before pwm_init_state. Signed-off-by: Enric Balletbo i Serra --- Changes in v2: - Do not force the PWM be off in the first call to pwm_apply_state. - Delayed applying the state until we know what the period is. - Removed pb->period as after the conversion is not needed. drivers/video/backlight/pwm_bl.c | 71 ++++++++++++++++++-------------- 1 file changed, 41 insertions(+), 30 deletions(-) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index bdfcc0a71db1..dd1cb29b5332 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -28,7 +28,6 @@ struct pwm_bl_data { struct pwm_device *pwm; struct device *dev; - unsigned int period; unsigned int lth_brightness; unsigned int *levels; bool enabled; @@ -46,7 +45,8 @@ struct pwm_bl_data { void (*exit)(struct device *); }; -static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness) +static void pwm_backlight_power_on(struct pwm_bl_data *pb, + struct pwm_state *state) { int err; @@ -57,7 +57,8 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness) if (err < 0) dev_err(pb->dev, "failed to enable power supply\n"); - pwm_enable(pb->pwm); + state->enabled = true; + pwm_apply_state(pb->pwm, state); if (pb->post_pwm_on_delay) msleep(pb->post_pwm_on_delay); @@ -70,6 +71,8 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness) static void pwm_backlight_power_off(struct pwm_bl_data *pb) { + struct pwm_state state; + if (!pb->enabled) return; @@ -79,8 +82,10 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb) if (pb->pwm_off_delay) msleep(pb->pwm_off_delay); - pwm_config(pb->pwm, 0, pb->period); - pwm_disable(pb->pwm); + pwm_get_state(pb->pwm, &state); + state.enabled = false; + state.duty_cycle = 0; + pwm_apply_state(pb->pwm, &state); regulator_disable(pb->power_supply); pb->enabled = false; @@ -89,14 +94,17 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb) static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness) { unsigned int lth = pb->lth_brightness; + struct pwm_state state; u64 duty_cycle; + pwm_get_state(pb->pwm, &state); + if (pb->levels) duty_cycle = pb->levels[brightness]; else duty_cycle = brightness; - duty_cycle *= pb->period - lth; + duty_cycle *= state.period - lth; do_div(duty_cycle, pb->scale); return duty_cycle + lth; @@ -106,6 +114,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl) { struct pwm_bl_data *pb = bl_get_data(bl); int brightness = bl->props.brightness; + struct pwm_state state; int duty_cycle; if (bl->props.power != FB_BLANK_UNBLANK || @@ -118,8 +127,12 @@ static int pwm_backlight_update_status(struct backlight_device *bl) if (brightness > 0) { duty_cycle = compute_duty_cycle(pb, brightness); - pwm_config(pb->pwm, duty_cycle, pb->period); - pwm_backlight_power_on(pb, brightness); + pwm_get_state(pb->pwm, &state); + state.duty_cycle = duty_cycle; + if (!state.enabled) + pwm_backlight_power_on(pb, &state); + else + pwm_apply_state(pb->pwm, &state); } else pwm_backlight_power_off(pb); @@ -447,7 +460,6 @@ static int pwm_backlight_probe(struct platform_device *pdev) struct device_node *node = pdev->dev.of_node; struct pwm_bl_data *pb; struct pwm_state state; - struct pwm_args pargs; unsigned int i; int ret; @@ -539,10 +551,26 @@ static int pwm_backlight_probe(struct platform_device *pdev) dev_dbg(&pdev->dev, "got pwm for backlight\n"); - if (!data->levels) { - /* Get the PWM period (in nanoseconds) */ - pwm_get_state(pb->pwm, &state); + /* Sync up PWM state. */ + pwm_init_state(pb->pwm, &state); + + /* + * The DT case will set the pwm_period_ns field to 0 and store the + * period, parsed from the DT, in the PWM device. For the non-DT case, + * set the period from platform data if it has not already been set + * via the PWM lookup table. + */ + if (!state.period && (data->pwm_period_ns > 0)) + state.period = data->pwm_period_ns; + ret = pwm_apply_state(pb->pwm, &state); + if (ret) { + dev_err(&pdev->dev, "failed to apply initial PWM state: %d\n", + ret); + goto err_alloc; + } + + if (!data->levels) { ret = pwm_backlight_brightness_default(&pdev->dev, data, state.period); if (ret < 0) { @@ -559,24 +587,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->levels = data->levels; } - /* - * FIXME: pwm_apply_args() should be removed when switching to - * the atomic PWM API. - */ - pwm_apply_args(pb->pwm); - - /* - * The DT case will set the pwm_period_ns field to 0 and store the - * period, parsed from the DT, in the PWM device. For the non-DT case, - * set the period from platform data if it has not already been set - * via the PWM lookup table. - */ - pwm_get_args(pb->pwm, &pargs); - pb->period = pargs.period; - if (!pb->period && (data->pwm_period_ns > 0)) - pb->period = data->pwm_period_ns; - - pb->lth_brightness = data->lth_brightness * (pb->period / pb->scale); + pb->lth_brightness = data->lth_brightness * (state.period / pb->scale); memset(&props, 0, sizeof(struct backlight_properties)); props.type = BACKLIGHT_RAW;