Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964812AbbENOjm (ORCPT ); Thu, 14 May 2015 10:39:42 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:59379 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753269AbbENOjk (ORCPT ); Thu, 14 May 2015 10:39:40 -0400 X-Listener-Flag: 11101 Message-ID: <1431614352.15140.26.camel@mtksdaap41> Subject: Re: [PATCH 2/2] pwm: add Mediatek display PWM driver support From: YH Huang To: Matthias Brugger CC: Mark Rutland , Thierry Reding , Rob Herring , Pawel Moll , , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , srv_heupstream , , "Sascha Hauer" Date: Thu, 14 May 2015 22:39:12 +0800 In-Reply-To: References: <1431336382-13167-1-git-send-email-yh.huang@mediatek.com> <1431336382-13167-3-git-send-email-yh.huang@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9263 Lines: 246 On Tue, 2015-05-12 at 14:37 +0200, Matthias Brugger wrote: > Hi YH, > > 2015-05-11 11:26 GMT+02:00 YH Huang : > > Add display PWM driver support to modify backlight for MT8173/MT6595. > > > > Signed-off-by: YH Huang > > --- > > drivers/pwm/Kconfig | 9 ++ > > drivers/pwm/Makefile | 1 + > > drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 235 insertions(+) > > create mode 100644 drivers/pwm/pwm-disp-mediatek.c > > > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > > index b1541f4..9edbb5a 100644 > > --- a/drivers/pwm/Kconfig > > +++ b/drivers/pwm/Kconfig > > @@ -111,6 +111,15 @@ config PWM_CLPS711X > > To compile this driver as a module, choose M here: the module > > will be called pwm-clps711x. > > > > +config PWM_DISP_MEDIATEK > > + tristate "MEDIATEK display PWM driver" > > + depends on OF > > + help > > + Generic PWM framework driver for mediatek disp-pwm device. > > + > > + To compile this driver as a module, choose M here: the module > > + will be called pwm-disp-mediatek. > > + > > config PWM_EP93XX > > tristate "Cirrus Logic EP93xx PWM support" > > depends on ARCH_EP93XX > > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > > index ec50eb5..c5ff72a 100644 > > --- a/drivers/pwm/Makefile > > +++ b/drivers/pwm/Makefile > > @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o > > obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o > > obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o > > obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o > > +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o > > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > > obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o > > obj-$(CONFIG_PWM_IMG) += pwm-img.o > > diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c > > new file mode 100644 > > index 0000000..38293af > > --- /dev/null > > +++ b/drivers/pwm/pwm-disp-mediatek.c > > @@ -0,0 +1,225 @@ > > +/* > > + * 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_OFF (0x0) > > +#define PWM_ENABLE_SHIFT (0x0) > > +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) > > Get rid of the _SHIFT which are actually zero, it will make the code > more readable. > It seems unnecessary to add it and I will fix it. > > + > > +#define DISP_PWM_COMMIT_OFF (0x08) > > +#define PWM_COMMIT_SHIFT (0x0) > > +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) > > + > > +#define DISP_PWM_CON_0_OFF (0x10) > > +#define PWM_CLKDIV_SHIFT (0x10) > > +#define PWM_CLKDIV_MASK (0x3ff << PWM_CLKDIV_SHIFT) > > +#define PWM_CLKDIV_MAX (0x000003ff) > > + > > +#define DISP_PWM_CON_1_OFF (0x14) > > +#define PWM_PERIOD_SHIFT (0x0) > > +#define PWM_PERIOD_MASK (0xfff << PWM_PERIOD_SHIFT) > > +#define PWM_PERIOD_MAX (0x00000fff) > > +/* Shift log2(PWM_PERIOD_MAX + 1) as divisor */ > > +#define PWM_PERIOD_BIT_SHIFT 12 > > + > > +#define PWM_HIGH_WIDTH_SHIFT (0x10) > > +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) > > + > > +#define NUM_PWM 1 > > + > > +struct mtk_disp_pwm_chip { > > + struct pwm_chip chip; > > + struct device *dev; > > + struct clk *clk_main; > > + struct clk *clk_mm; > > + void __iomem *mmio_base; > > +}; > > + > > +static void mtk_disp_pwm_setting(void __iomem *address, u32 value, u32 mask) > > +{ > > + 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_chip *mpc; > > + u64 div, rate; > > + u32 clk_div, period, high_width, rem; > > + > > + /* > > + * 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 + 1) / 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)) - 1 > > + */ > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > + rate = clk_get_rate(mpc->clk_main); > > + clk_div = div_u64_rem(rate * period_ns, NSEC_PER_SEC, &rem) >> > > + PWM_PERIOD_BIT_SHIFT; > > You never use the remainder, so better use div_u64 to make the code cleaner. > OK. > > + if (clk_div > PWM_CLKDIV_MAX) > > + return -EINVAL; > > + > > + div = clk_div + 1; > > + period = div64_u64(rate * period_ns, NSEC_PER_SEC * div); > > + if (period > 0) > > + period--; > > + high_width = div64_u64(rate * duty_ns, NSEC_PER_SEC * div); > > + if (high_width > 0) > > + high_width--; > > + > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_0_OFF, > > + clk_div << PWM_CLKDIV_SHIFT, PWM_CLKDIV_MASK); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_1_OFF, > > + (period << PWM_PERIOD_SHIFT) | > > + (high_width << PWM_HIGH_WIDTH_SHIFT), > > + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK); > > + > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > > + 1 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > > + 0 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > > + > > + return 0; > > +} > > + > > +static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) > > +{ > > + struct mtk_disp_pwm_chip *mpc; > > + > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > > + 1 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > > + > > + return 0; > > +} > > + > > +static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) > > +{ > > + struct mtk_disp_pwm_chip *mpc; > > + > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > > + 0 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > > +} > > + > > +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_chip *pwm; > > + struct resource *r; > > + int ret; > > + > > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > > + if (!pwm) > > + return -ENOMEM; > > + > > + pwm->dev = &pdev->dev; > > + > > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); > > + if (IS_ERR(pwm->mmio_base)) > > + return PTR_ERR(pwm->mmio_base); > > + > > + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); > > + if (IS_ERR(pwm->clk_main)) > > + return PTR_ERR(pwm->clk_main); > > I prefer to have a newline after the if-then-ese block, which makes it > (at least for me) easier to read the code. > OK. > Thanks, > Matthias Thank for your suggestion. Regards, YH Huang -- 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/