From patchwork Mon Aug 28 10:04:09 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fabrice Gasnier X-Patchwork-Id: 9925113 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E924860375 for ; Mon, 28 Aug 2017 10:06:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D9822201BC for ; Mon, 28 Aug 2017 10:06:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CDDC127D16; Mon, 28 Aug 2017 10:06:13 +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=-2.6 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_LOW autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 0ABC328582 for ; Mon, 28 Aug 2017 10:06:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=rRA2DKmyUlyMZLwZwp1obnA+5BTfatT8NBZ2oU/qg4A=; b=ayC2B4YcPzwMSQ MLg6aQdF5n1nQARoaHYHMgyW2H97sdKFOsa04wNhLBCeQSO/Yc6COXd2At5vvLf2xLz9hN3aCO7IQ Ndc/XLrDJ5gBLviPM5DIPMgJfBa/9xWVS4bIGn6l61pFk7haVIAv25bWZLaKu6AA/QkaOW9hu4Hry Gor3E44XTmeBt9lu/VlrM9XZTxNLP50FQY4RS6k8FNFPMcayEZUbLswJbPHhblv3tAeyiYHvE4EeQ cVRTY+Yu6zj7G7r5UlJRcsY+r4yYnZnaBxRz0CT9pwFeSEK6+44cZt4fctOqNK8wzSpcTbLbgY7Y0 SiYy29u7YTsHtt8X/blw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1dmGvo-00078N-KO; Mon, 28 Aug 2017 10:06:08 +0000 Received: from mx07-00178001.pphosted.com ([62.209.51.94]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1dmGuq-0005Bt-86 for linux-arm-kernel@lists.infradead.org; Mon, 28 Aug 2017 10:05:16 +0000 Received: from pps.filterd (m0046037.ppops.net [127.0.0.1]) by mx07-.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v7SA4TDw028034; Mon, 28 Aug 2017 12:04:39 +0200 Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-.pphosted.com with ESMTP id 2cjxrqscsw-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT); Mon, 28 Aug 2017 12:04:39 +0200 Received: from zeta.dmz-eu.st.com (zeta.dmz-eu.st.com [164.129.230.9]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 7E55931; Mon, 28 Aug 2017 10:04:38 +0000 (GMT) Received: from Webmail-eu.st.com (sfhdag5node3.st.com [10.75.127.15]) by zeta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 5B2751FE8; Mon, 28 Aug 2017 10:04:38 +0000 (GMT) Received: from localhost (10.75.127.50) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1178.4; Mon, 28 Aug 2017 12:04:37 +0200 From: Fabrice Gasnier To: , , , , Subject: [RESEND PATCH v3 4/9] pwm: Add STM32 LPTimer PWM driver Date: Mon, 28 Aug 2017 12:04:09 +0200 Message-ID: <1503914654-19963-5-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1503914654-19963-1-git-send-email-fabrice.gasnier@st.com> References: <1503914654-19963-1-git-send-email-fabrice.gasnier@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.50] X-ClientProxiedBy: SFHDAG4NODE3.st.com (10.75.127.12) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-08-28_06:, , signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170828_030508_692364_DFE53039 X-CRM114-Status: GOOD ( 22.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, alexandre.torgue@st.com, linux-pwm@vger.kernel.org, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, vilhelm.gray@gmail.com, mcoquelin.stm32@gmail.com, fabrice.gasnier@st.com, linux-arm-kernel@lists.infradead.org, benjamin.gaignard@st.com Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Add support for single PWM channel on Low-Power Timer, that can be found on some STM32 platforms. Signed-off-by: Fabrice Gasnier Acked-by: Thierry Reding --- Changes in v3: - remove prescalers[] array, use power-of-2 presc directly - Update following Thierry's comments: - fix issue using FIELD_GET() macro - Add get_state() callback - remove some checks in probe - slight rework 'reenable' flag - use more common method to disable pwm in remove() Changes in v2: - s/Low Power/Low-Power - update few comment lines --- drivers/pwm/Kconfig | 10 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-stm32-lp.c | 246 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 257 insertions(+) create mode 100644 drivers/pwm/pwm-stm32-lp.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 313c107..7cb982b 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -417,6 +417,16 @@ config PWM_STM32 To compile this driver as a module, choose M here: the module will be called pwm-stm32. +config PWM_STM32_LP + tristate "STMicroelectronics STM32 PWM LP" + depends on MFD_STM32_LPTIMER || COMPILE_TEST + help + Generic PWM framework driver for STMicroelectronics STM32 SoCs + with Low-Power Timer (LPTIM). + + To compile this driver as a module, choose M here: the module + will be called pwm-stm32-lp. + config PWM_STMPE bool "STMPE expander PWM export" depends on MFD_STMPE diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 93da1f7..a3a4bee 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -40,6 +40,7 @@ obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o obj-$(CONFIG_PWM_STI) += pwm-sti.o obj-$(CONFIG_PWM_STM32) += pwm-stm32.o +obj-$(CONFIG_PWM_STM32_LP) += pwm-stm32-lp.o obj-$(CONFIG_PWM_STMPE) += pwm-stmpe.o obj-$(CONFIG_PWM_SUN4I) += pwm-sun4i.o obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o diff --git a/drivers/pwm/pwm-stm32-lp.c b/drivers/pwm/pwm-stm32-lp.c new file mode 100644 index 0000000..9793b29 --- /dev/null +++ b/drivers/pwm/pwm-stm32-lp.c @@ -0,0 +1,246 @@ +/* + * STM32 Low-Power Timer PWM driver + * + * Copyright (C) STMicroelectronics 2017 + * + * Author: Gerald Baeza + * + * License terms: GNU General Public License (GPL), version 2 + * + * Inspired by Gerald Baeza's pwm-stm32 driver + */ + +#include +#include +#include +#include +#include +#include + +struct stm32_pwm_lp { + struct pwm_chip chip; + struct clk *clk; + struct regmap *regmap; +}; + +static inline struct stm32_pwm_lp *to_stm32_pwm_lp(struct pwm_chip *chip) +{ + return container_of(chip, struct stm32_pwm_lp, chip); +} + +/* STM32 Low-Power Timer is preceded by a configurable power-of-2 prescaler */ +#define STM32_LPTIM_MAX_PRESCALER 128 + +static int stm32_pwm_lp_apply(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct stm32_pwm_lp *priv = to_stm32_pwm_lp(chip); + unsigned long long prd, div, dty; + struct pwm_state cstate; + u32 val, mask, cfgr, presc = 0; + bool reenable; + int ret; + + pwm_get_state(pwm, &cstate); + reenable = !cstate.enabled; + + if (!state->enabled) { + if (cstate.enabled) { + /* Disable LP timer */ + ret = regmap_write(priv->regmap, STM32_LPTIM_CR, 0); + if (ret) + return ret; + /* disable clock to PWM counter */ + clk_disable(priv->clk); + } + return 0; + } + + /* Calculate the period and prescaler value */ + div = (unsigned long long)clk_get_rate(priv->clk) * state->period; + do_div(div, NSEC_PER_SEC); + prd = div; + while (div > STM32_LPTIM_MAX_ARR) { + presc++; + if ((1 << presc) > STM32_LPTIM_MAX_PRESCALER) { + dev_err(priv->chip.dev, "max prescaler exceeded\n"); + return -EINVAL; + } + div = prd >> presc; + } + prd = div; + + /* Calculate the duty cycle */ + dty = prd * state->duty_cycle; + do_div(dty, state->period); + + if (!cstate.enabled) { + /* enable clock to drive PWM counter */ + ret = clk_enable(priv->clk); + if (ret) + return ret; + } + + ret = regmap_read(priv->regmap, STM32_LPTIM_CFGR, &cfgr); + if (ret) + goto err; + + if ((FIELD_GET(STM32_LPTIM_PRESC, cfgr) != presc) || + (FIELD_GET(STM32_LPTIM_WAVPOL, cfgr) != state->polarity)) { + val = FIELD_PREP(STM32_LPTIM_PRESC, presc); + val |= FIELD_PREP(STM32_LPTIM_WAVPOL, state->polarity); + mask = STM32_LPTIM_PRESC | STM32_LPTIM_WAVPOL; + + /* Must disable LP timer to modify CFGR */ + reenable = true; + ret = regmap_write(priv->regmap, STM32_LPTIM_CR, 0); + if (ret) + goto err; + + ret = regmap_update_bits(priv->regmap, STM32_LPTIM_CFGR, mask, + val); + if (ret) + goto err; + } + + if (reenable) { + /* Must (re)enable LP timer to modify CMP & ARR */ + ret = regmap_write(priv->regmap, STM32_LPTIM_CR, + STM32_LPTIM_ENABLE); + if (ret) + goto err; + } + + ret = regmap_write(priv->regmap, STM32_LPTIM_ARR, prd - 1); + if (ret) + goto err; + + ret = regmap_write(priv->regmap, STM32_LPTIM_CMP, prd - (1 + dty)); + if (ret) + goto err; + + /* ensure CMP & ARR registers are properly written */ + ret = regmap_read_poll_timeout(priv->regmap, STM32_LPTIM_ISR, val, + (val & STM32_LPTIM_CMPOK_ARROK), + 100, 1000); + if (ret) { + dev_err(priv->chip.dev, "ARR/CMP registers write issue\n"); + goto err; + } + ret = regmap_write(priv->regmap, STM32_LPTIM_ICR, + STM32_LPTIM_CMPOKCF_ARROKCF); + if (ret) + goto err; + + if (reenable) { + /* Start LP timer in continuous mode */ + ret = regmap_update_bits(priv->regmap, STM32_LPTIM_CR, + STM32_LPTIM_CNTSTRT, + STM32_LPTIM_CNTSTRT); + if (ret) { + regmap_write(priv->regmap, STM32_LPTIM_CR, 0); + goto err; + } + } + + return 0; +err: + if (!cstate.enabled) + clk_disable(priv->clk); + + return ret; +} + +static void stm32_pwm_lp_get_state(struct pwm_chip *chip, + struct pwm_device *pwm, + struct pwm_state *state) +{ + struct stm32_pwm_lp *priv = to_stm32_pwm_lp(chip); + unsigned long rate = clk_get_rate(priv->clk); + u32 val, presc, prd; + u64 tmp; + + regmap_read(priv->regmap, STM32_LPTIM_CR, &val); + state->enabled = !!FIELD_GET(STM32_LPTIM_ENABLE, val); + /* Keep PWM counter clock refcount in sync with PWM initial state */ + if (state->enabled) + clk_enable(priv->clk); + + regmap_read(priv->regmap, STM32_LPTIM_CFGR, &val); + presc = FIELD_GET(STM32_LPTIM_PRESC, val); + state->polarity = FIELD_GET(STM32_LPTIM_WAVPOL, val); + + regmap_read(priv->regmap, STM32_LPTIM_ARR, &prd); + tmp = prd + 1; + tmp = (tmp << presc) * NSEC_PER_SEC; + state->period = DIV_ROUND_CLOSEST_ULL(tmp, rate); + + regmap_read(priv->regmap, STM32_LPTIM_CMP, &val); + tmp = prd - val; + tmp = (tmp << presc) * NSEC_PER_SEC; + state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, rate); +} + +static const struct pwm_ops stm32_pwm_lp_ops = { + .owner = THIS_MODULE, + .apply = stm32_pwm_lp_apply, + .get_state = stm32_pwm_lp_get_state, +}; + +static int stm32_pwm_lp_probe(struct platform_device *pdev) +{ + struct stm32_lptimer *ddata = dev_get_drvdata(pdev->dev.parent); + struct stm32_pwm_lp *priv; + int ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->regmap = ddata->regmap; + priv->clk = ddata->clk; + priv->chip.base = -1; + priv->chip.dev = &pdev->dev; + priv->chip.ops = &stm32_pwm_lp_ops; + priv->chip.npwm = 1; + + ret = pwmchip_add(&priv->chip); + if (ret < 0) + return ret; + + platform_set_drvdata(pdev, priv); + + return 0; +} + +static int stm32_pwm_lp_remove(struct platform_device *pdev) +{ + struct stm32_pwm_lp *priv = platform_get_drvdata(pdev); + unsigned int i; + + for (i = 0; i < priv->chip.npwm; i++) + if (pwm_is_enabled(&priv->chip.pwms[i])) + pwm_disable(&priv->chip.pwms[i]); + + return pwmchip_remove(&priv->chip); +} + +static const struct of_device_id stm32_pwm_lp_of_match[] = { + { .compatible = "st,stm32-pwm-lp", }, + {}, +}; +MODULE_DEVICE_TABLE(of, stm32_pwm_lp_of_match); + +static struct platform_driver stm32_pwm_lp_driver = { + .probe = stm32_pwm_lp_probe, + .remove = stm32_pwm_lp_remove, + .driver = { + .name = "stm32-pwm-lp", + .of_match_table = of_match_ptr(stm32_pwm_lp_of_match), + }, +}; +module_platform_driver(stm32_pwm_lp_driver); + +MODULE_ALIAS("platform:stm32-pwm-lp"); +MODULE_DESCRIPTION("STMicroelectronics STM32 PWM LP driver"); +MODULE_LICENSE("GPL v2");