From patchwork Mon Jul 6 17:53:47 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Walle X-Patchwork-Id: 11646359 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9573F739 for ; Mon, 6 Jul 2020 17:58:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75DB6206DF for ; Mon, 6 Jul 2020 17:58:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=walle.cc header.i=@walle.cc header.b="mg771PBZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729781AbgGFR6O (ORCPT ); Mon, 6 Jul 2020 13:58:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60014 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729718AbgGFR5g (ORCPT ); Mon, 6 Jul 2020 13:57:36 -0400 Received: from ssl.serverraum.org (ssl.serverraum.org [IPv6:2a01:4f8:151:8464::1:2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BED75C061794; Mon, 6 Jul 2020 10:57:35 -0700 (PDT) Received: from apollo.fritz.box (unknown [IPv6:2a02:810c:c200:2e91:6257:18ff:fec4:ca34]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id ABF0622FEB; Mon, 6 Jul 2020 19:57:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1594058254; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NHl1Tc7aOvXirXfgGGWl8EwtNqd6E5CLj8vfFb2yY3g=; b=mg771PBZKgAHlINc3ltwnUEF7MXmdgIPYHHgwI0osEyyLpUzsoJxvAXAb+FeW6RHvIYWXb 9a67BNfhvj4ssNhnZ1GemB9gehM/gtRNXj9lHcSZTcA0IyNyl/FTMbEayzJeTqq3Fo2vDW JpfZhOvjf2ql4v6LAMokTblogcFgusA= From: Michael Walle To: linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-pwm@vger.kernel.org, linux-watchdog@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Linus Walleij , Bartosz Golaszewski , Rob Herring , Jean Delvare , Guenter Roeck , Lee Jones , Thierry Reding , =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= , Wim Van Sebroeck , Shawn Guo , Li Yang , Thomas Gleixner , Jason Cooper , Marc Zyngier , Mark Brown , Greg Kroah-Hartman , Andy Shevchenko , Michael Walle Subject: [PATCH v5 07/13] pwm: add support for sl28cpld PWM controller Date: Mon, 6 Jul 2020 19:53:47 +0200 Message-Id: <20200706175353.16404-8-michael@walle.cc> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200706175353.16404-1-michael@walle.cc> References: <20200706175353.16404-1-michael@walle.cc> MIME-Version: 1.0 X-Spam: Yes Sender: linux-hwmon-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org Add support for the PWM controller of the sl28cpld board management controller. This is part of a multi-function device driver. The controller has one PWM channel and can just generate four distinct frequencies. Signed-off-by: Michael Walle --- Changes since v4: - update copyright year - remove #include , suggested by Andy. - make the pwm mode table look nicer, suggested by Lee. - use dev_get_drvdata(chip->dev) instead of container_of(), suggested by Lee. - use whole sentence in comments, suggested by Lee. - renamed the local "struct sl28cpld_pwm" variable to "priv" everywhere, suggested by Lee. - use pwm_{get,set}_relative_duty_cycle(), suggested by Andy. - make the comment about the 250Hz hardware limitation clearer - don't use "if (ret < 0)", but only "if (ret)", suggested by Andy. - don't use KBUID_MODNAME - remove comma in terminator line of the compatible strings list - remove the platform device table Changes since v3: - see cover letter drivers/pwm/Kconfig | 10 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-sl28cpld.c | 187 +++++++++++++++++++++++++++++++++++++ 3 files changed, 198 insertions(+) create mode 100644 drivers/pwm/pwm-sl28cpld.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 7dbcf6973d33..a0d50d70c3b9 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -428,6 +428,16 @@ config PWM_SIFIVE To compile this driver as a module, choose M here: the module will be called pwm-sifive. +config PWM_SL28CPLD + tristate "Kontron sl28cpld PWM support" + select MFD_SIMPLE_MFD_I2C + help + Generic PWM framework driver for board management controller + found on the Kontron sl28 CPLD. + + To compile this driver as a module, choose M here: the module + will be called pwm-sl28cpld. + config PWM_SPEAR tristate "STMicroelectronics SPEAr PWM support" depends on PLAT_SPEAR || COMPILE_TEST diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 2c2ba0a03557..cbdcd55d69ee 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -40,6 +40,7 @@ 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-$(CONFIG_PWM_SL28CPLD) += pwm-sl28cpld.o obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o obj-$(CONFIG_PWM_SPRD) += pwm-sprd.o obj-$(CONFIG_PWM_STI) += pwm-sti.o diff --git a/drivers/pwm/pwm-sl28cpld.c b/drivers/pwm/pwm-sl28cpld.c new file mode 100644 index 000000000000..8ee286b605bf --- /dev/null +++ b/drivers/pwm/pwm-sl28cpld.c @@ -0,0 +1,187 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * sl28cpld PWM driver + * + * Copyright 2020 Kontron Europe GmbH + */ + +#include +#include +#include +#include +#include +#include +#include + +/* + * PWM timer block registers. + */ +#define PWM_CTRL 0x00 +#define PWM_ENABLE BIT(7) +#define PWM_MODE_250HZ 0 +#define PWM_MODE_500HZ 1 +#define PWM_MODE_1KHZ 2 +#define PWM_MODE_2KHZ 3 +#define PWM_MODE_MASK GENMASK(1, 0) +#define PWM_CYCLE 0x01 +#define PWM_CYCLE_MAX 0x7f + +struct sl28cpld_pwm { + struct pwm_chip pwm_chip; + struct regmap *regmap; + u32 offset; +}; + +struct sl28cpld_pwm_periods { + u8 ctrl; + unsigned long duty_cycle; +}; + +struct sl28cpld_pwm_config { + unsigned long period_ns; + u8 max_duty_cycle; +}; + +static struct sl28cpld_pwm_config sl28cpld_pwm_config[] = { + [PWM_MODE_250HZ] = { .period_ns = 4000000, .max_duty_cycle = 0x80 }, + [PWM_MODE_500HZ] = { .period_ns = 2000000, .max_duty_cycle = 0x40 }, + [PWM_MODE_1KHZ] = { .period_ns = 1000000, .max_duty_cycle = 0x20 }, + [PWM_MODE_2KHZ] = { .period_ns = 500000, .max_duty_cycle = 0x10 }, +}; + +static void sl28cpld_pwm_get_state(struct pwm_chip *chip, + struct pwm_device *pwm, + struct pwm_state *state) +{ + struct sl28cpld_pwm *priv = dev_get_drvdata(chip->dev); + static struct sl28cpld_pwm_config *config; + unsigned int reg; + unsigned int mode; + + regmap_read(priv->regmap, priv->offset + PWM_CTRL, ®); + + state->enabled = reg & PWM_ENABLE; + + mode = FIELD_GET(PWM_MODE_MASK, reg); + config = &sl28cpld_pwm_config[mode]; + state->period = config->period_ns; + + regmap_read(priv->regmap, priv->offset + PWM_CYCLE, ®); + pwm_set_relative_duty_cycle(state, reg, config->max_duty_cycle); +} + +static int sl28cpld_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + struct sl28cpld_pwm *priv = dev_get_drvdata(chip->dev); + struct sl28cpld_pwm_config *config; + unsigned int cycle; + int ret; + int mode; + u8 ctrl; + + /* Get the configuration by comparing the period */ + for (mode = 0; mode < ARRAY_SIZE(sl28cpld_pwm_config); mode++) { + config = &sl28cpld_pwm_config[mode]; + if (state->period == config->period_ns) + break; + } + + if (mode == ARRAY_SIZE(sl28cpld_pwm_config)) + return -EINVAL; + + ctrl = FIELD_PREP(PWM_MODE_MASK, mode); + if (state->enabled) + ctrl |= PWM_ENABLE; + + cycle = pwm_get_relative_duty_cycle(state, config->max_duty_cycle); + + /* + * The hardware doesn't allow to set max_duty_cycle if the + * 250Hz mode is enabled, thus we have to trap that here. + * But because a 100% duty cycle is equal on all modes, i.e. + * it is just a "all-high" output, we trap any case with a + * 100% duty cycle and use the 500Hz mode. + */ + if (cycle == config->max_duty_cycle) { + ctrl &= ~PWM_MODE_MASK; + ctrl |= FIELD_PREP(PWM_MODE_MASK, PWM_MODE_500HZ); + cycle = PWM_CYCLE_MAX; + } + + ret = regmap_write(priv->regmap, priv->offset + PWM_CTRL, ctrl); + if (ret) + return ret; + + return regmap_write(priv->regmap, priv->offset + PWM_CYCLE, (u8)cycle); +} + +static const struct pwm_ops sl28cpld_pwm_ops = { + .apply = sl28cpld_pwm_apply, + .get_state = sl28cpld_pwm_get_state, + .owner = THIS_MODULE, +}; + +static int sl28cpld_pwm_probe(struct platform_device *pdev) +{ + struct sl28cpld_pwm *priv; + struct pwm_chip *chip; + int ret; + + if (!pdev->dev.parent) + return -ENODEV; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->regmap = dev_get_regmap(pdev->dev.parent, NULL); + if (!priv->regmap) + return -ENODEV; + + ret = device_property_read_u32(&pdev->dev, "reg", &priv->offset); + if (ret) + return -EINVAL; + + /* Initialize the pwm_chip structure */ + chip = &priv->pwm_chip; + chip->dev = &pdev->dev; + chip->ops = &sl28cpld_pwm_ops; + chip->base = -1; + chip->npwm = 1; + + ret = pwmchip_add(&priv->pwm_chip); + if (ret) + return ret; + + platform_set_drvdata(pdev, priv); + + return 0; +} + +static int sl28cpld_pwm_remove(struct platform_device *pdev) +{ + struct sl28cpld_pwm *priv = platform_get_drvdata(pdev); + + return pwmchip_remove(&priv->pwm_chip); +} + +static const struct of_device_id sl28cpld_pwm_of_match[] = { + { .compatible = "kontron,sl28cpld-pwm" }, + {} +}; +MODULE_DEVICE_TABLE(of, sl28cpld_pwm_of_match); + +static struct platform_driver sl28cpld_pwm_driver = { + .probe = sl28cpld_pwm_probe, + .remove = sl28cpld_pwm_remove, + .driver = { + .name = "sl28cpld-pwm", + .of_match_table = sl28cpld_pwm_of_match, + }, +}; +module_platform_driver(sl28cpld_pwm_driver); + +MODULE_DESCRIPTION("sl28cpld PWM Driver"); +MODULE_AUTHOR("Michael Walle "); +MODULE_LICENSE("GPL");