Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752032AbbGMJFK (ORCPT ); Mon, 13 Jul 2015 05:05:10 -0400 Received: from mailgw01.mediatek.com ([210.61.82.183]:46357 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751947AbbGMJFG (ORCPT ); Mon, 13 Jul 2015 05:05:06 -0400 X-Listener-Flag: 11101 From: YH Huang To: Matthias Brugger , Mark Rutland , Thierry Reding CC: Rob Herring , Pawel Moll , , , , , , , Sascha Hauer , , YH Huang Subject: [PATCH v5 2/3] pwm: add MediaTek display PWM driver support Date: Mon, 13 Jul 2015 17:04:53 +0800 Message-ID: <1436778294-47635-3-git-send-email-yh.huang@mediatek.com> X-Mailer: git-send-email 1.8.1.1.dirty In-Reply-To: <1436778294-47635-1-git-send-email-yh.huang@mediatek.com> References: <1436778294-47635-1-git-send-email-yh.huang@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8916 Lines: 316 Add display PWM driver support to modify backlight for MT8173 and MT6595. The PWM has one channel to control the brightness of the display. When the (high_width / period) is closer to 1, the screen is brighter; otherwise, it is darker. Signed-off-by: YH Huang --- drivers/pwm/Kconfig | 10 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-mtk-disp.c | 256 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 267 insertions(+) create mode 100644 drivers/pwm/pwm-mtk-disp.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index b1541f4..f5b03a4 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -211,6 +211,16 @@ config PWM_LPSS_PLATFORM To compile this driver as a module, choose M here: the module will be called pwm-lpss-platform. +config PWM_MTK_DISP + tristate "MediaTek display PWM driver" + depends on ARCH_MEDIATEK || COMPILE_TEST + help + Generic PWM framework driver for MediaTek disp-pwm device. + The PWM is used to control the backlight brightness for display. + + To compile this driver as a module, choose M here: the module + will be called pwm-mtk-disp. + config PWM_MXS tristate "Freescale MXS PWM support" depends on ARCH_MXS && OF diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index ec50eb5..99c9e75 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -18,6 +18,7 @@ obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o obj-$(CONFIG_PWM_LPSS) += pwm-lpss.o obj-$(CONFIG_PWM_LPSS_PCI) += pwm-lpss-pci.o obj-$(CONFIG_PWM_LPSS_PLATFORM) += pwm-lpss-platform.o +obj-$(CONFIG_PWM_MTK_DISP) += pwm-mtk-disp.o obj-$(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-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c new file mode 100644 index 0000000..1f17cee --- /dev/null +++ b/drivers/pwm/pwm-mtk-disp.c @@ -0,0 +1,256 @@ +/* + * MediaTek display pulse-width-modulation controller driver. + * Copyright (c) 2015 MediaTek Inc. + * Author: YH Huang + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; 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 + +#define DISP_PWM_EN 0 +#define PWM_ENABLE_MASK BIT(0) + +#define DISP_PWM_COMMIT BIT(3) +#define PWM_COMMIT_MASK BIT(0) + +#define DISP_PWM_CON_0 BIT(4) +#define PWM_CLKDIV_SHIFT 16 +#define PWM_CLKDIV_MAX 0x3ff +#define PWM_CLKDIV_MASK (PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT) + +#define DISP_PWM_CON_1 0x14 +#define PWM_PERIOD_MASK 0xfff +/* Shift log2(PWM_PERIOD_MASK + 1) as divisor */ +#define PWM_PERIOD_BIT_SHIFT 12 + +#define PWM_HIGH_WIDTH_SHIFT 16 +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) + +struct mtk_disp_pwm { + struct pwm_chip chip; + struct device *dev; + struct clk *clk_main; + struct clk *clk_mm; + void __iomem *base; +}; + +static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip) +{ + return container_of(chip, struct mtk_disp_pwm, chip); +} + +static void mtk_disp_pwm_update_bits(void __iomem *address, u32 mask, u32 value) +{ + u32 val; + + val = readl(address); + val &= ~mask; + val |= value; + writel(val, address); +} + +static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip); + u64 div, rate; + u32 clk_div, period, high_width, value; + + /* + * Find period, high_width and clk_div to suit duty_ns and period_ns. + * Calculate proper div value to keep period value in the bound. + * + * period_ns = 10^9 * (clk_div + 1) * (period + 1) / PWM_CLK_RATE + * duty_ns = 10^9 * (clk_div + 1) * high_width / PWM_CLK_RATE + * + * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1 + * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) + */ + rate = clk_get_rate(mdp->clk_main); + clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >> + PWM_PERIOD_BIT_SHIFT; + if (clk_div > PWM_CLKDIV_MAX) + return -EINVAL; + + div = NSEC_PER_SEC * (clk_div + 1); + period = div64_u64(rate * period_ns, div); + if (period > 0) + period--; + + high_width = div64_u64(rate * duty_ns, div); + + mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_CON_0, + PWM_CLKDIV_MASK, clk_div << PWM_CLKDIV_SHIFT); + + value = period | (high_width << PWM_HIGH_WIDTH_SHIFT); + mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_CON_1, + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, value); + + mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_COMMIT, + PWM_COMMIT_MASK, 1); + mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_COMMIT, + PWM_COMMIT_MASK, 0); + + return 0; +} + +static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip); + + mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_EN, + PWM_ENABLE_MASK, 1); + + return 0; +} + +static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip); + + mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_EN, + PWM_ENABLE_MASK, 0); +} + +static const struct pwm_ops mtk_disp_pwm_ops = { + .config = mtk_disp_pwm_config, + .enable = mtk_disp_pwm_enable, + .disable = mtk_disp_pwm_disable, + .owner = THIS_MODULE, +}; + +static int mtk_disp_pwm_probe(struct platform_device *pdev) +{ + struct mtk_disp_pwm *mdp; + struct resource *r; + int ret; + + mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL); + if (!mdp) + return -ENOMEM; + + mdp->dev = &pdev->dev; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + mdp->base = devm_ioremap_resource(&pdev->dev, r); + if (IS_ERR(mdp->base)) + return PTR_ERR(mdp->base); + + mdp->clk_main = devm_clk_get(&pdev->dev, "main"); + if (IS_ERR(mdp->clk_main)) + return PTR_ERR(mdp->clk_main); + + mdp->clk_mm = devm_clk_get(&pdev->dev, "mm"); + if (IS_ERR(mdp->clk_mm)) + return PTR_ERR(mdp->clk_mm); + + ret = clk_prepare_enable(mdp->clk_main); + if (ret < 0) + return ret; + + ret = clk_prepare_enable(mdp->clk_mm); + if (ret < 0) + goto disable_clk_main; + + platform_set_drvdata(pdev, mdp); + + mdp->chip.dev = &pdev->dev; + mdp->chip.ops = &mtk_disp_pwm_ops; + mdp->chip.base = -1; + mdp->chip.npwm = 1; + + ret = pwmchip_add(&mdp->chip); + if (ret < 0) { + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); + goto disable_clk_mm; + } + + return 0; + +disable_clk_mm: + clk_disable_unprepare(mdp->clk_mm); +disable_clk_main: + clk_disable_unprepare(mdp->clk_main); + return ret; +} + +static int mtk_disp_pwm_remove(struct platform_device *pdev) +{ + struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev); + int ret = pwmchip_remove(&mdp->chip); + + clk_disable_unprepare(mdp->clk_main); + clk_disable_unprepare(mdp->clk_mm); + + return ret; +} + +static const struct of_device_id mtk_disp_pwm_of_match[] = { + { .compatible = "mediatek,mt8173-disp-pwm" }, + { .compatible = "mediatek,mt6595-disp-pwm" }, + { } +}; +MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match); + +#ifdef CONFIG_PM_SLEEP +static int mtk_disp_pwm_suspend(struct device *dev) +{ + struct mtk_disp_pwm *mdp = dev_get_drvdata(dev); + + clk_disable_unprepare(mdp->clk_main); + clk_disable_unprepare(mdp->clk_mm); + + return 0; +} + +static int mtk_disp_pwm_resume(struct device *dev) +{ + struct mtk_disp_pwm *mdp = dev_get_drvdata(dev); + int ret; + + ret = clk_prepare_enable(mdp->clk_main); + if (ret < 0) + return ret; + + ret = clk_prepare_enable(mdp->clk_mm); + if (ret < 0) { + clk_disable_unprepare(mdp->clk_main); + return ret; + } + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(mtk_disp_pwm_pm_ops, mtk_disp_pwm_suspend, + mtk_disp_pwm_resume); + +static struct platform_driver mtk_disp_pwm_driver = { + .driver = { + .name = "mediatek-disp-pwm", + .pm = &mtk_disp_pwm_pm_ops, + .of_match_table = mtk_disp_pwm_of_match, + }, + .probe = mtk_disp_pwm_probe, + .remove = mtk_disp_pwm_remove, +}; +module_platform_driver(mtk_disp_pwm_driver); + +MODULE_AUTHOR("YH Huang "); +MODULE_DESCRIPTION("MediaTek SoC display PWM driver"); +MODULE_LICENSE("GPL v2"); -- 1.8.1.1.dirty -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/