On Mon, May 11, 2015 at 5:26 PM, YH Huang <yh.huang@xxxxxxxxxxxx> wrote: > Add display PWM driver support to modify backlight for MT8173/MT6595. > > Signed-off-by: YH Huang <yh.huang@xxxxxxxxxxxx> > --- > 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 <yh.huang@xxxxxxxxxxxx> > + * > + * 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 <linux/clk.h> > +#include <linux/err.h> > +#include <linux/io.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/pwm.h> > +#include <linux/platform_device.h> > +#include <linux/slab.h> > + > +#define DISP_PWM_EN_OFF (0x0) > +#define PWM_ENABLE_SHIFT (0x0) > +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) > + > +#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; > + 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); > + pwm->clk_mm = devm_clk_get(&pdev->dev, "mm"); > + if (IS_ERR(pwm->clk_mm)) > + return PTR_ERR(pwm->clk_mm); > + > + ret = clk_prepare_enable(pwm->clk_main); > + if (ret < 0) > + return ret; > + ret = clk_prepare_enable(pwm->clk_mm); > + if (ret < 0) { > + clk_disable_unprepare(pwm->clk_main); > + return ret; > + } > + > + platform_set_drvdata(pdev, pwm); > + > + pwm->chip.dev = &pdev->dev; > + pwm->chip.ops = &mtk_disp_pwm_ops; > + pwm->chip.base = -1; > + pwm->chip.npwm = NUM_PWM; > + > + ret = pwmchip_add(&pwm->chip); > + if (ret < 0) { > + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); > + return ret; > + } > + > + return 0; > +} > + > +static int mtk_disp_pwm_remove(struct platform_device *pdev) > +{ > + struct mtk_disp_pwm_chip *pc = platform_get_drvdata(pdev); > + > + if (WARN_ON(!pc)) > + return -ENODEV; > + > + clk_disable_unprepare(pc->clk_main); > + clk_disable_unprepare(pc->clk_mm); > + > + return pwmchip_remove(&pc->chip); > +} > + > +static const struct of_device_id mtk_disp_pwm_of_match[] = { > + { .compatible = "mediatek,mt6595-disp-pwm" }, Does this driver support the PWM in mt8173? If so, don't you need this, too: { .compatible = "mediatek,mt8173-disp-pwm" }, > + { } > +}; > + > +MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match); > + > +static struct platform_driver mtk_disp_pwm_driver = { > + .driver = { > + .name = "mediatek-disp-pwm", > + .owner = THIS_MODULE, > + .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 <yh.huang@xxxxxxxxxxxx>"); > +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@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html