From patchwork Thu Mar 20 14:04:23 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Chew, Chiau Ee" X-Patchwork-Id: 331994 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 7997F2C00A2 for ; Thu, 20 Mar 2014 17:02:24 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751280AbaCTGCX (ORCPT ); Thu, 20 Mar 2014 02:02:23 -0400 Received: from mga02.intel.com ([134.134.136.20]:13540 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751153AbaCTGCW (ORCPT ); Thu, 20 Mar 2014 02:02:22 -0400 Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP; 19 Mar 2014 23:02:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,692,1389772800"; d="scan'208";a="476176104" Received: from unknown (HELO localhost.png.intel.com) ([172.30.66.71]) by orsmga001.jf.intel.com with ESMTP; 19 Mar 2014 23:02:02 -0700 From: Chew Chiau Ee To: Thierry Reding Cc: Mika Westerberg , linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3] pwm: add support for Intel Low Power Subsystem PWM Date: Thu, 20 Mar 2014 22:04:23 +0800 Message-Id: <1395324263-4282-1-git-send-email-chiau.ee.chew@intel.com> X-Mailer: git-send-email 1.7.4.4 Sender: linux-pwm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org From: Mika Westerberg Add support for Intel Low Power I/O subsystem PWM controllers found on Intel BayTrail SoC. Signed-off-by: Mika Westerberg Signed-off-by: Chew, Kean Ho Signed-off-by: Chang, Rebecca Swee Fun Signed-off-by: Chew, Chiau Ee --- changelog v3: * check validity of clk_get_rate()'s return value before division * update MODULE_LICENSE()line drivers/pwm/Kconfig | 10 +++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-lpss.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 194 insertions(+), 0 deletions(-) create mode 100644 drivers/pwm/pwm-lpss.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 1445ba1..5b34ff2 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -138,6 +138,16 @@ config PWM_LPC32XX To compile this driver as a module, choose M here: the module will be called pwm-lpc32xx. +config PWM_LPSS + tristate "Intel LPSS PWM support" + depends on ACPI + help + Generic PWM framework driver for Intel Low Power Subsystem PWM + controller. + + To compile this driver as a module, choose M here: the module + will be called pwm-lpss. + config PWM_MXS tristate "Freescale MXS PWM support" depends on ARCH_MXS && OF diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 82f294e..e57d2c3 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -11,6 +11,7 @@ obj-$(CONFIG_PWM_IMX) += pwm-imx.o obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o obj-$(CONFIG_PWM_LP3943) += pwm-lp3943.o obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o +obj-$(CONFIG_PWM_LPSS) += pwm-lpss.o obj-$(CONFIG_PWM_MXS) += pwm-mxs.o obj-$(CONFIG_PWM_PCA9685) += pwm-pca9685.o obj-$(CONFIG_PWM_PUV3) += pwm-puv3.o diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c new file mode 100644 index 0000000..449e372 --- /dev/null +++ b/drivers/pwm/pwm-lpss.c @@ -0,0 +1,183 @@ +/* + * Intel Low Power Subsystem PWM controller driver + * + * Copyright (C) 2014, Intel Corporation + * Author: Mika Westerberg + * Author: Chew Kean Ho + * Author: Chang Rebecca Swee Fun + * Author: Chew Chiau Ee + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define PWM 0x00000000 +#define PWM_ENABLE BIT(31) +#define PWM_SW_UPDATE BIT(30) +#define PWM_BASE_UNIT_SHIFT 8 +#define PWM_BASE_UNIT_MASK 0x00ffff00 +#define PWM_ON_TIME_DIV_MASK 0x000000ff +#define PWM_DIVISION_CORRECTION 0x2 +#define PWM_LIMIT (0x8000 + PWM_DIVISION_CORRECTION) +#define NSECS_PER_SEC 1000000000UL + +struct pwm_lpss_chip { + struct pwm_chip chip; + void __iomem *regs; + struct clk *clk; +}; + +static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip) +{ + return container_of(chip, struct pwm_lpss_chip, chip); +} + +static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct pwm_lpss_chip *lpwm = to_lpwm(chip); + u8 on_time_div; + unsigned long c; + unsigned long long base_unit, freq = NSECS_PER_SEC; + u32 ctrl; + + do_div(freq, period_ns); + + /* The equation is: base_unit = ((freq / c) * 65536) + correction */ + base_unit = freq * 65536; + + c = clk_get_rate(lpwm->clk); + if (!c) + return -EINVAL; + + do_div(base_unit, c); + base_unit += PWM_DIVISION_CORRECTION; + if (base_unit > PWM_LIMIT) + return -EINVAL; + + if (duty_ns <= 0) + duty_ns = 1; + on_time_div = 255 - (255 * duty_ns / period_ns); + + ctrl = readl(lpwm->regs + PWM); + ctrl &= ~(PWM_BASE_UNIT_MASK | PWM_ON_TIME_DIV_MASK); + ctrl |= (u16) base_unit << PWM_BASE_UNIT_SHIFT; + ctrl |= on_time_div; + /* request PWM to update on next cycle */ + ctrl |= PWM_SW_UPDATE; + writel(ctrl, lpwm->regs + PWM); + + return 0; +} + +static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct pwm_lpss_chip *lpwm = to_lpwm(chip); + u32 ctrl; + int ret; + + ret = clk_prepare_enable(lpwm->clk); + if (ret) + return ret; + + ctrl = readl(lpwm->regs + PWM); + writel(ctrl | PWM_ENABLE, lpwm->regs + PWM); + + return 0; +} + +static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct pwm_lpss_chip *lpwm = to_lpwm(chip); + u32 ctrl; + + ctrl = readl(lpwm->regs + PWM); + writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM); + + clk_disable_unprepare(lpwm->clk); +} + +static const struct pwm_ops pwm_lpss_ops = { + .config = pwm_lpss_config, + .enable = pwm_lpss_enable, + .disable = pwm_lpss_disable, + .owner = THIS_MODULE, +}; + +static const struct acpi_device_id pwm_lpss_acpi_match[] = { + { "80860F09", 0 }, + { }, +}; +MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match); + +static int pwm_lpss_probe(struct platform_device *pdev) +{ + struct pwm_lpss_chip *lpwm; + struct resource *r; + int ret; + + lpwm = devm_kzalloc(&pdev->dev, sizeof(*lpwm), GFP_KERNEL); + if (!lpwm) + return -ENOMEM; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + lpwm->regs = devm_ioremap_resource(&pdev->dev, r); + if (IS_ERR(lpwm->regs)) + return PTR_ERR(lpwm->regs); + + lpwm->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(lpwm->clk)) { + dev_err(&pdev->dev, "failed to get PWM clock\n"); + return PTR_ERR(lpwm->clk); + } + + lpwm->chip.dev = &pdev->dev; + lpwm->chip.ops = &pwm_lpss_ops; + lpwm->chip.base = -1; + lpwm->chip.npwm = 1; + + ret = pwmchip_add(&lpwm->chip); + if (ret) { + dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret); + return ret; + } + + platform_set_drvdata(pdev, lpwm); + return 0; +} + +static int pwm_lpss_remove(struct platform_device *pdev) +{ + struct pwm_lpss_chip *lpwm = platform_get_drvdata(pdev); + u32 ctrl; + + ctrl = readl(lpwm->regs + PWM); + writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM); + + return pwmchip_remove(&lpwm->chip); +} + +static struct platform_driver pwm_lpss_driver = { + .driver = { + .name = "pwm-lpss", + .acpi_match_table = pwm_lpss_acpi_match, + }, + .probe = pwm_lpss_probe, + .remove = pwm_lpss_remove, +}; +module_platform_driver(pwm_lpss_driver); + +MODULE_DESCRIPTION("PWM driver for Intel LPSS"); +MODULE_AUTHOR("Mika Westerberg "); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:pwm-lpss");