From patchwork Tue Feb 4 19:51:40 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tim Kryger X-Patchwork-Id: 3578871 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 45EAD9F2E9 for ; Tue, 4 Feb 2014 19:55:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 096782017B for ; Tue, 4 Feb 2014 19:55:36 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2B040201B6 for ; Tue, 4 Feb 2014 19:55:34 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WAm4R-0002ua-DA; Tue, 04 Feb 2014 19:54:12 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WAm4B-0007pl-7W; Tue, 04 Feb 2014 19:53:55 +0000 Received: from mail-gw3-out.broadcom.com ([216.31.210.64]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WAm3V-0007gw-Mk for linux-arm-kernel@lists.infradead.org; Tue, 04 Feb 2014 19:53:16 +0000 X-IronPort-AV: E=Sophos;i="4.95,781,1384329600"; d="scan'208";a="12703089" Received: from irvexchcas06.broadcom.com (HELO IRVEXCHCAS06.corp.ad.broadcom.com) ([10.9.208.53]) by mail-gw3-out.broadcom.com with ESMTP; 04 Feb 2014 12:01:24 -0800 Received: from IRVEXCHSMTP2.corp.ad.broadcom.com (10.9.207.52) by IRVEXCHCAS06.corp.ad.broadcom.com (10.9.208.53) with Microsoft SMTP Server (TLS) id 14.3.174.1; Tue, 4 Feb 2014 11:52:47 -0800 Received: from mail-sj1-12.sj.broadcom.com (10.10.10.20) by IRVEXCHSMTP2.corp.ad.broadcom.com (10.9.207.52) with Microsoft SMTP Server id 14.3.174.1; Tue, 4 Feb 2014 11:52:47 -0800 Received: from mps-infra-lab3.broadcom.com (mps-infra-lab3.sj.broadcom.com [10.19.114.109]) by mail-sj1-12.sj.broadcom.com (Postfix) with ESMTP id 7696A207DF; Tue, 4 Feb 2014 11:52:45 -0800 (PST) Received: by mps-infra-lab3.broadcom.com (Postfix, from userid 1004) id 2FAC8458A2E; Tue, 4 Feb 2014 11:52:45 -0800 (PST) From: Tim Kryger To: Thierry Reding , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , "Kumar Gala" , Rob Landley , Christian Daudt , Grant Likely Subject: [PATCH v2 2/5] pwm: kona: Introduce Kona PWM controller support Date: Tue, 4 Feb 2014 11:51:40 -0800 Message-ID: <1391543503-14773-3-git-send-email-tim.kryger@linaro.org> X-Mailer: git-send-email 1.8.0.1 In-Reply-To: <1391543503-14773-1-git-send-email-tim.kryger@linaro.org> References: <1391543503-14773-1-git-send-email-tim.kryger@linaro.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140204_145314_026317_47B42EF7 X-CRM114-Status: GOOD ( 28.04 ) X-Spam-Score: -2.5 (--) Cc: Linux PWM List , Linux Doc List , Tim Kryger , Linux Kernel Mailing List , Device Tree List , Broadcom Kernel Feedback List , Linux ARM Kernel List X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.8 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add support for the six-channel Kona PWM controller found on Broadcom mobile SoCs like bcm281xx. Signed-off-by: Tim Kryger Reviewed-by: Alex Elder Reviewed-by: Markus Mayer --- drivers/pwm/Kconfig | 10 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-bcm-kona.c | 291 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 302 insertions(+) create mode 100644 drivers/pwm/pwm-bcm-kona.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 22f2f28..1fd42af 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -62,6 +62,16 @@ config PWM_ATMEL_TCB To compile this driver as a module, choose M here: the module will be called pwm-atmel-tcb. +config PWM_BCM_KONA + tristate "Kona PWM support" + depends on ARCH_BCM_MOBILE + default y + help + Generic PWM framework driver for Broadcom Kona PWM block. + + To compile this driver as a module, choose M here: the module + will be called pwm-bcm-kona. + config PWM_BFIN tristate "Blackfin PWM support" depends on BFIN_GPTIMERS diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index d8906ec..7413090 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -3,6 +3,7 @@ obj-$(CONFIG_PWM_SYSFS) += sysfs.o obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o +obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o obj-$(CONFIG_PWM_IMX) += pwm-imx.o diff --git a/drivers/pwm/pwm-bcm-kona.c b/drivers/pwm/pwm-bcm-kona.c new file mode 100644 index 0000000..631ec14 --- /dev/null +++ b/drivers/pwm/pwm-bcm-kona.c @@ -0,0 +1,291 @@ +/* + * Copyright (C) 2014 Broadcom Corporation + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation version 2. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define PWM_CONTROL_OFFSET (0x00000000) +#define PWM_CONTROL_SMOOTH_SHIFT(chan) (24 + (chan)) +#define PWM_CONTROL_TYPE_SHIFT(chan) (16 + (chan)) +#define PWM_CONTROL_POLARITY_SHIFT(chan) (8 + (chan)) +#define PWM_CONTROL_ENABLE_SHIFT(chan) (chan) + +#define PRESCALE_OFFSET (0x00000004) +#define PRESCALE_SHIFT(chan) ((chan) << 2) +#define PRESCALE_MASK(chan) (0x7 << PRESCALE_SHIFT(chan)) +#define PRESCALE_MIN (0x00000000) +#define PRESCALE_MAX (0x00000007) + +#define PERIOD_COUNT_OFFSET(chan) (0x00000008 + ((chan) << 3)) +#define PERIOD_COUNT_MIN (0x00000002) +#define PERIOD_COUNT_MAX (0x00ffffff) + +#define DUTY_CYCLE_HIGH_OFFSET(chan) (0x0000000c + ((chan) << 3)) +#define DUTY_CYCLE_HIGH_MIN (0x00000000) +#define DUTY_CYCLE_HIGH_MAX (0x00ffffff) + +struct kona_pwmc { + struct pwm_chip chip; + void __iomem *base; + struct clk *clk; +}; + +static void kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan) +{ + /* New settings take effect on rising edge of enable bit */ + unsigned long value = readl(kp->base + PWM_CONTROL_OFFSET); + + value &= ~(1 << PWM_CONTROL_ENABLE_SHIFT(chan)); + writel(value, kp->base + PWM_CONTROL_OFFSET); + + value |= (1 << PWM_CONTROL_ENABLE_SHIFT(chan)); + writel(value, kp->base + PWM_CONTROL_OFFSET); +} + +static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct kona_pwmc *kp = dev_get_drvdata(chip->dev); + u64 val, div, clk_rate; + unsigned long prescale = PRESCALE_MIN, pc, dc; + unsigned int value, chan = pwm->hwpwm; + + /* + * Find period count, duty count and prescale to suit duty_ns and + * period_ns. This is done according to formulas described below: + * + * period_ns = 10^9 * (PRESCALE + 1) * PC / PWM_CLK_RATE + * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE + * + * PC = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1)) + * DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1)) + */ + + clk_rate = clk_get_rate(kp->clk); + + /* There is polarity support in HW but it is easier to manage in SW */ + if (pwm->polarity == PWM_POLARITY_INVERSED) + duty_ns = period_ns - duty_ns; + + while (1) { + div = 1000000000; + div *= 1 + prescale; + val = clk_rate * period_ns; + pc = div64_u64(val, div); + val = clk_rate * duty_ns; + dc = div64_u64(val, div); + + /* If duty_ns or period_ns are not achievable then return */ + if (pc < PERIOD_COUNT_MIN || dc < DUTY_CYCLE_HIGH_MIN) + return -EINVAL; + + /* If pc and dc are in bounds, the calculation is done */ + if (pc <= PERIOD_COUNT_MAX && dc <= DUTY_CYCLE_HIGH_MAX) + break; + + /* Otherwise, increase prescale and recalculate pc and dc */ + if (++prescale > PRESCALE_MAX) + return -EINVAL; + } + + /* If the PWM channel is enabled, write the settings to the HW */ + if (test_bit(PWMF_ENABLED, &pwm->flags)) { + value = readl(kp->base + PRESCALE_OFFSET); + value &= ~PRESCALE_MASK(chan); + value |= prescale << PRESCALE_SHIFT(chan); + writel(value, kp->base + PRESCALE_OFFSET); + + writel(pc, kp->base + PERIOD_COUNT_OFFSET(chan)); + + writel(dc, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan)); + + kona_pwmc_apply_settings(kp, chan); + } + + return 0; +} + +static int kona_pwmc_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, + enum pwm_polarity polarity) +{ + /* + * The framework only allows the polarity to be changed when a PWM is + * disabled so no immediate action is required here. When a channel is + * enabled, the polarity gets handled as part of the re-config step. + */ + + return 0; +} + +static int kona_pwmc_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct kona_pwmc *kp = dev_get_drvdata(chip->dev); + int ret; + + /* + * The PWM framework does not clear the enable bit in the flags if an + * error is returned from a PWM driver's enable function so it must be + * cleared here if any trouble is encountered. + */ + + ret = clk_prepare_enable(kp->clk); + if (ret < 0) { + dev_err(chip->dev, "failed to enable clock: %d\n", ret); + clear_bit(PWMF_ENABLED, &pwm->flags); + return ret; + } + + ret = kona_pwmc_config(chip, pwm, pwm->duty_cycle, pwm->period); + if (ret < 0) { + clk_disable_unprepare(kp->clk); + clear_bit(PWMF_ENABLED, &pwm->flags); + return ret; + } + + return 0; +} + +static void kona_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct kona_pwmc *kp = dev_get_drvdata(chip->dev); + unsigned int chan = pwm->hwpwm; + + /* + * The "enable" bits in the control register only affect when settings + * start to take effect so the only real way to disable the PWM output + * is to program a zero duty cycle. + */ + + writel(0, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan)); + kona_pwmc_apply_settings(kp, chan); + + /* + * When the PWM clock is disabled, the output is pegged high or low + * depending on its state at that instant. To guarantee that the new + * settings have taken effect and the output is low a delay of 400ns is + * required. + */ + + ndelay(400); + + clk_disable_unprepare(kp->clk); +} + +static const struct pwm_ops kona_pwm_ops = { + .config = kona_pwmc_config, + .set_polarity = kona_pwmc_set_polarity, + .enable = kona_pwmc_enable, + .disable = kona_pwmc_disable, + .owner = THIS_MODULE, +}; + +static int kona_pwmc_probe(struct platform_device *pdev) +{ + struct kona_pwmc *kp; + struct resource *res; + unsigned int chan, value; + int ret = 0; + + kp = devm_kzalloc(&pdev->dev, sizeof(*kp), GFP_KERNEL); + if (kp == NULL) + return -ENOMEM; + + platform_set_drvdata(pdev, kp); + + kp->chip.dev = &pdev->dev; + kp->chip.ops = &kona_pwm_ops; + kp->chip.base = -1; + kp->chip.npwm = 6; + kp->chip.of_xlate = of_pwm_xlate_with_flags; + kp->chip.of_pwm_n_cells = 3; + kp->chip.can_sleep = true; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + kp->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(kp->base)) + return PTR_ERR(kp->base); + + kp->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(kp->clk)) { + dev_err(&pdev->dev, "failed to get clock: %ld\n", + PTR_ERR(kp->clk)); + return PTR_ERR(kp->clk); + } + + ret = clk_prepare_enable(kp->clk); + if (ret < 0) { + dev_err(&pdev->dev, "failed to enable clock: %d\n", ret); + return ret; + } + + /* Set smooth mode, push/pull, and normal polarity for all channels */ + for (value = 0, chan = 0; chan < kp->chip.npwm; chan++) { + value |= (1 << PWM_CONTROL_SMOOTH_SHIFT(chan)); + value |= (1 << PWM_CONTROL_TYPE_SHIFT(chan)); + value |= (1 << PWM_CONTROL_POLARITY_SHIFT(chan)); + } + writel(value, kp->base + PWM_CONTROL_OFFSET); + + clk_disable_unprepare(kp->clk); + + ret = pwmchip_add(&kp->chip); + if (ret < 0) + dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret); + + return ret; +} + +static int kona_pwmc_remove(struct platform_device *pdev) +{ + struct kona_pwmc *kp = platform_get_drvdata(pdev); + unsigned int chan; + + for (chan = 0; chan < kp->chip.npwm; chan++) + if (test_bit(PWMF_ENABLED, &kp->chip.pwms[chan].flags)) + clk_disable_unprepare(kp->clk); + + return pwmchip_remove(&kp->chip); +} + +static const struct of_device_id bcm_kona_pwmc_dt[] = { + { .compatible = "brcm,kona-pwm" }, + { }, +}; +MODULE_DEVICE_TABLE(of, bcm_kona_pwmc_dt); + +static struct platform_driver kona_pwmc_driver = { + + .driver = { + .name = "bcm-kona-pwm", + .of_match_table = bcm_kona_pwmc_dt, + }, + .probe = kona_pwmc_probe, + .remove = kona_pwmc_remove, +}; + +module_platform_driver(kona_pwmc_driver); + +MODULE_AUTHOR("Broadcom Corporation "); +MODULE_AUTHOR("Tim Kryger "); +MODULE_DESCRIPTION("Driver for Kona PWM controller"); +MODULE_LICENSE("GPL v2");