From patchwork Fri Jan 11 08:22:44 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yash Shah X-Patchwork-Id: 1023436 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pwm-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=sifive.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=sifive.com header.i=@sifive.com header.b="HCjYH0E0"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43bbTv1GPfz9sLw for ; Fri, 11 Jan 2019 19:23:15 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730454AbfAKIXM (ORCPT ); Fri, 11 Jan 2019 03:23:12 -0500 Received: from mail-pg1-f193.google.com ([209.85.215.193]:38274 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730448AbfAKIXL (ORCPT ); Fri, 11 Jan 2019 03:23:11 -0500 Received: by mail-pg1-f193.google.com with SMTP id g189so6030955pgc.5 for ; Fri, 11 Jan 2019 00:23:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=9aUvpG6n9TjP6tya9JgTQ9MYcu5Ui/xdKtxpJsxUg8g=; b=HCjYH0E0CtR96Ikw3OrV6Gpe0rpqWrVpH97YfesNtf0hQGrkXXpRZV9o8xPW2XfCk9 YYGduzvAc+s3i8v/+EDe+vSdkMLpyCUhssdSGvTcIzlSexS5XlHCDzqOwOUNiop7fUbC ONJ6wy90b8y/VJQ4aHdSqWMtqw6WtLrwl9iwp1YMWe9hk9DuC1WhyghsWCBSaW1g+WQ3 fJ9Y7kDWV775ugVEgoRnjqglba7UgS1IoltXK7dDb/9Sf0YKnNQtTGPCdEFBkvhAr117 rAH9+eK/Ms4mfJ83W9oyQ3ZJK8308Xz2Cufe20vJWHTzrfHrko9Bc/JcKOCy7RRQvnLC YrNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=9aUvpG6n9TjP6tya9JgTQ9MYcu5Ui/xdKtxpJsxUg8g=; b=fAJd1Nbkv1jOuo34zGARYn6dZQltSLwefIQRzpm22bHq0iEMzTDFadATqLCCEtWJF6 cqOt+FC1SdsaHDvGPrkcScOHj9C2tx2EoVmkTAAWKX44Hu36PwLGEj96B31dI85TpUsC KJSR8thWSzKDXBc9TVGmdQOSScnX1xvxCOu4STNj8Y7Us7gW701FFBQppESriHNzh/Ua EcVM9QO8z3ITcWZV5QsrHNUtdSZxyRjYiSx0QBwJjT3kiLw2GCPpLDye1bstVDhy9+v9 K6ocYz3+t+MIXkIayG7nl2lnH5ercDFi7HBQgj86Zv7tkaticwB7WhRsivQ6rTWfMP+G tdtg== X-Gm-Message-State: AJcUukfStB6pOyE6wm7aXLsIhirJr0JmevC56Nc8vtH13gj8JKLboJMi tS5SEFPOguUrKrVfndq+Ys4yXA== X-Google-Smtp-Source: ALg8bN53HnJQn6VEgBpCvlqWtm6b9nPzJh7O8KAL1iIGXyxJtTNtOqLFRpNj4NfUkyjGDWhya3fXmw== X-Received: by 2002:a63:7418:: with SMTP id p24mr2432727pgc.196.1547194989900; Fri, 11 Jan 2019 00:23:09 -0800 (PST) Received: from buildserver-90.open-silicon.com ([114.143.65.226]) by smtp.googlemail.com with ESMTPSA id t87sm248422324pfk.122.2019.01.11.00.23.06 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 11 Jan 2019 00:23:09 -0800 (PST) From: Yash Shah To: palmer@sifive.com, linux-pwm@vger.kernel.org, linux-riscv@lists.infradead.org Cc: thierry.reding@gmail.com, robh+dt@kernel.org, mark.rutland@arm.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, sachin.ghadi@sifive.com, paul.walmsley@sifive.com, Yash Shah Subject: [PATCH 2/2] pwm: sifive: Add a driver for SiFive SoC PWM Date: Fri, 11 Jan 2019 13:52:44 +0530 Message-Id: <1547194964-16718-3-git-send-email-yash.shah@sifive.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1547194964-16718-1-git-send-email-yash.shah@sifive.com> References: <1547194964-16718-1-git-send-email-yash.shah@sifive.com> Sender: linux-pwm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org Adds a PWM driver for PWM chip present in SiFive's HiFive Unleashed SoC. Signed-off-by: Wesley W. Terpstra [Atish: Various fixes and code cleanup] Signed-off-by: Atish Patra Signed-off-by: Yash Shah Reviewed-by: Christoph Hellwig --- drivers/pwm/Kconfig | 10 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-sifive.c | 246 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 257 insertions(+) create mode 100644 drivers/pwm/pwm-sifive.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index a8f47df..3bcaf6a 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -380,6 +380,16 @@ config PWM_SAMSUNG To compile this driver as a module, choose M here: the module will be called pwm-samsung. +config PWM_SIFIVE + tristate "SiFive PWM support" + depends on OF + depends on COMMON_CLK + help + Generic PWM framework driver for SiFive SoCs. + + To compile this driver as a module, choose M here: the module + will be called pwm-sifive. + config PWM_SPEAR tristate "STMicroelectronics SPEAr PWM support" depends on PLAT_SPEAR diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 9c676a0..30089ca 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -37,6 +37,7 @@ obj-$(CONFIG_PWM_RCAR) += pwm-rcar.o obj-$(CONFIG_PWM_RENESAS_TPU) += pwm-renesas-tpu.o obj-$(CONFIG_PWM_ROCKCHIP) += pwm-rockchip.o obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o +obj-$(CONFIG_PWM_SIFIVE) += pwm-sifive.o obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o obj-$(CONFIG_PWM_STI) += pwm-sti.o obj-$(CONFIG_PWM_STM32) += pwm-stm32.o diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c new file mode 100644 index 0000000..7fee809 --- /dev/null +++ b/drivers/pwm/pwm-sifive.c @@ -0,0 +1,246 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2017-2018 SiFive + * For SiFive's PWM IP block documentation please refer Chapter 14 of + * Reference Manual : https://static.dev.sifive.com/FU540-C000-v1.0.pdf + */ +#include +#include +#include +#include +#include +#include + +/* Register offsets */ +#define REG_PWMCFG 0x0 +#define REG_PWMCOUNT 0x8 +#define REG_PWMS 0x10 +#define REG_PWMCMP0 0x20 + +/* PWMCFG fields */ +#define BIT_PWM_SCALE 0 +#define BIT_PWM_STICKY 8 +#define BIT_PWM_ZERO_ZMP 9 +#define BIT_PWM_DEGLITCH 10 +#define BIT_PWM_EN_ALWAYS 12 +#define BIT_PWM_EN_ONCE 13 +#define BIT_PWM0_CENTER 16 +#define BIT_PWM0_GANG 24 +#define BIT_PWM0_IP 28 + +#define SIZE_PWMCMP 4 +#define MASK_PWM_SCALE 0xf + +struct sifive_pwm_device { + struct pwm_chip chip; + struct notifier_block notifier; + struct clk *clk; + void __iomem *regs; + unsigned int approx_period; + unsigned int real_period; +}; + +static inline struct sifive_pwm_device *to_sifive_pwm_chip(struct pwm_chip *c) +{ + return container_of(c, struct sifive_pwm_device, chip); +} + +static void sifive_pwm_get_state(struct pwm_chip *chip, struct pwm_device *dev, + struct pwm_state *state) +{ + struct sifive_pwm_device *pwm = to_sifive_pwm_chip(chip); + u32 duty; + + duty = readl(pwm->regs + REG_PWMCMP0 + dev->hwpwm * SIZE_PWMCMP); + + state->period = pwm->real_period; + state->duty_cycle = ((u64)duty * pwm->real_period) >> 16; + state->polarity = PWM_POLARITY_INVERSED; + state->enabled = duty > 0; +} + +static int sifive_pwm_apply(struct pwm_chip *chip, struct pwm_device *dev, + struct pwm_state *state) +{ + struct sifive_pwm_device *pwm = to_sifive_pwm_chip(chip); + unsigned int duty_cycle; + u32 frac; + + if (state->polarity != PWM_POLARITY_INVERSED) + return -EINVAL; + + duty_cycle = state->duty_cycle; + if (!state->enabled) + duty_cycle = 0; + + frac = div_u64((u64)duty_cycle << 16, state->period); + frac = min(frac, 0xFFFFU); + + writel(frac, pwm->regs + REG_PWMCMP0 + dev->hwpwm * SIZE_PWMCMP); + + if (state->enabled) + sifive_pwm_get_state(chip, dev, state); + + return 0; +} + +static const struct pwm_ops sifive_pwm_ops = { + .get_state = sifive_pwm_get_state, + .apply = sifive_pwm_apply, + .owner = THIS_MODULE, +}; + +static struct pwm_device *sifive_pwm_xlate(struct pwm_chip *chip, + const struct of_phandle_args *args) +{ + struct sifive_pwm_device *pwm = to_sifive_pwm_chip(chip); + struct pwm_device *dev; + + if (args->args[0] >= chip->npwm) + return ERR_PTR(-EINVAL); + + dev = pwm_request_from_chip(chip, args->args[0], NULL); + if (IS_ERR(dev)) + return dev; + + /* The period cannot be changed on a per-PWM basis */ + dev->args.period = pwm->real_period; + dev->args.polarity = PWM_POLARITY_NORMAL; + if (args->args[1] & PWM_POLARITY_INVERSED) + dev->args.polarity = PWM_POLARITY_INVERSED; + + return dev; +} + +static void sifive_pwm_update_clock(struct sifive_pwm_device *pwm, + unsigned long rate) +{ + /* (1 << (16+scale)) * 10^9/rate = real_period */ + unsigned long scale_pow = (pwm->approx_period * (u64)rate) / 1000000000; + int scale = clamp(ilog2(scale_pow) - 16, 0, 0xf); + + writel((1 << BIT_PWM_EN_ALWAYS) | (scale << BIT_PWM_SCALE), + pwm->regs + REG_PWMCFG); + + /* As scale <= 15 the shift operation cannot overflow. */ + pwm->real_period = div64_ul(1000000000ULL << (16 + scale), rate); + dev_dbg(pwm->chip.dev, "New real_period = %u ns\n", pwm->real_period); +} + +static int sifive_pwm_clock_notifier(struct notifier_block *nb, + unsigned long event, void *data) +{ + struct clk_notifier_data *ndata = data; + struct sifive_pwm_device *pwm = + container_of(nb, struct sifive_pwm_device, notifier); + + if (event == POST_RATE_CHANGE) + sifive_pwm_update_clock(pwm, ndata->new_rate); + + return NOTIFY_OK; +} + +static int sifive_pwm_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *node = pdev->dev.of_node; + struct sifive_pwm_device *pwm; + struct pwm_chip *chip; + struct resource *res; + int ret; + + pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL); + if (!pwm) + return -ENOMEM; + + chip = &pwm->chip; + chip->dev = dev; + chip->ops = &sifive_pwm_ops; + chip->of_xlate = sifive_pwm_xlate; + chip->of_pwm_n_cells = 2; + chip->base = -1; + chip->npwm = 4; + + ret = of_property_read_u32(node, "sifive,approx-period-ns", + &pwm->approx_period); + if (ret < 0) { + dev_err(dev, "Unable to read sifive,approx-period from DTS\n"); + return ret; + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + pwm->regs = devm_ioremap_resource(dev, res); + if (IS_ERR(pwm->regs)) { + dev_err(dev, "Unable to map IO resources\n"); + return PTR_ERR(pwm->regs); + } + + pwm->clk = devm_clk_get(dev, NULL); + if (IS_ERR(pwm->clk)) { + if (PTR_ERR(pwm->clk) != -EPROBE_DEFER) + dev_err(dev, "Unable to find controller clock\n"); + return PTR_ERR(pwm->clk); + } + + ret = clk_prepare_enable(pwm->clk); + if (ret) { + dev_err(dev, "failed to enable clock for pwm: %d\n", ret); + return ret; + } + + /* Watch for changes to underlying clock frequency */ + pwm->notifier.notifier_call = sifive_pwm_clock_notifier; + ret = clk_notifier_register(pwm->clk, &pwm->notifier); + if (ret) { + dev_err(dev, "failed to register clock notifier: %d\n", ret); + clk_disable_unprepare(pwm->clk); + return ret; + } + + /* Initialize PWM config */ + sifive_pwm_update_clock(pwm, clk_get_rate(pwm->clk)); + + ret = pwmchip_add(chip); + if (ret < 0) { + dev_err(dev, "cannot register PWM: %d\n", ret); + clk_notifier_unregister(pwm->clk, &pwm->notifier); + clk_disable_unprepare(pwm->clk); + return ret; + } + + platform_set_drvdata(pdev, pwm); + dev_dbg(dev, "SiFive PWM chip registered %d PWMs\n", chip->npwm); + + return 0; +} + +static int sifive_pwm_remove(struct platform_device *dev) +{ + struct sifive_pwm_device *pwm = platform_get_drvdata(dev); + int ret; + + ret = pwmchip_remove(&pwm->chip); + clk_notifier_unregister(pwm->clk, &pwm->notifier); + clk_disable_unprepare(pwm->clk); + return ret; +} + +static const struct of_device_id sifive_pwm_of_match[] = { + { .compatible = "sifive,pwm0" }, + { .compatible = "sifive,fu540-c000-pwm" }, + {}, +}; +MODULE_DEVICE_TABLE(of, sifive_pwm_of_match); + +static struct platform_driver sifive_pwm_driver = { + .probe = sifive_pwm_probe, + .remove = sifive_pwm_remove, + .driver = { + .name = "pwm-sifive", + .of_match_table = sifive_pwm_of_match, + }, +}; +module_platform_driver(sifive_pwm_driver); + +MODULE_DESCRIPTION("SiFive PWM driver"); +MODULE_LICENSE("GPL v2");