From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753915AbaCaRgP (ORCPT ); Mon, 31 Mar 2014 13:36:15 -0400 Received: from top.free-electrons.com ([176.31.233.9]:47464 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752932AbaCaRgN (ORCPT ); Mon, 31 Mar 2014 13:36:13 -0400 Date: Mon, 31 Mar 2014 19:35:37 +0200 From: Maxime Ripard To: Alexandre Belloni Cc: Thierry Reding , linux-pwm@vger.kernel.org, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/4] pwm: Add Allwinner SoC support Message-ID: <20140331173537.GJ26751@lukather> References: <1396267649-18009-1-git-send-email-alexandre.belloni@free-electrons.com> <1396267649-18009-2-git-send-email-alexandre.belloni@free-electrons.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="wRtZRu2mMGBZ6YQ7" Content-Disposition: inline In-Reply-To: <1396267649-18009-2-git-send-email-alexandre.belloni@free-electrons.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --wRtZRu2mMGBZ6YQ7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Mar 31, 2014 at 02:07:26PM +0200, Alexandre Belloni wrote: > This adds a generic PWM framework driver for the PWM controller > found on Allwinner SoCs. >=20 > Signed-off-by: Alexandre Belloni > --- > drivers/pwm/Kconfig | 9 ++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-sunxi.c | 325 ++++++++++++++++++++++++++++++++++++++++++= ++++++ > 3 files changed, 335 insertions(+) > create mode 100644 drivers/pwm/pwm-sunxi.c >=20 > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > index 22f2f2857b82..f7381def0fd2 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -187,6 +187,15 @@ config PWM_SPEAR > To compile this driver as a module, choose M here: the module > will be called pwm-spear. > =20 > +config PWM_SUNXI > + tristate "Allwinner PWM support" > + depends on ARCH_SUNXI > + help > + Generic PWM framework driver for Allwinner SoCs. > + > + To compile this driver as a module, choose M here: the module > + will be called pwm-sunxi. > + > config PWM_TEGRA > tristate "NVIDIA Tegra PWM support" > depends on ARCH_TEGRA > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > index d8906ec69976..e110259b6c03 100644 > --- a/drivers/pwm/Makefile > +++ b/drivers/pwm/Makefile > @@ -16,6 +16,7 @@ obj-$(CONFIG_PWM_PXA) +=3D pwm-pxa.o > obj-$(CONFIG_PWM_RENESAS_TPU) +=3D pwm-renesas-tpu.o > obj-$(CONFIG_PWM_SAMSUNG) +=3D pwm-samsung.o > obj-$(CONFIG_PWM_SPEAR) +=3D pwm-spear.o > +obj-$(CONFIG_PWM_SUNXI) +=3D pwm-sunxi.o > obj-$(CONFIG_PWM_TEGRA) +=3D pwm-tegra.o > obj-$(CONFIG_PWM_TIECAP) +=3D pwm-tiecap.o > obj-$(CONFIG_PWM_TIEHRPWM) +=3D pwm-tiehrpwm.o > diff --git a/drivers/pwm/pwm-sunxi.c b/drivers/pwm/pwm-sunxi.c > new file mode 100644 > index 000000000000..be39abee0a24 > --- /dev/null > +++ b/drivers/pwm/pwm-sunxi.c > @@ -0,0 +1,325 @@ > +/* > + * Driver for Allwinner Pulse Width Modulation Controller > + * > + * Copyright (C) 2014 Alexandre Belloni > + * > + * Licensed under GPLv2. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define PWM_CTRL_REG 0x0 > + > +#define PWM_CH_PRD_BASE 0x4 > +#define PWM_CH_PRD_OFF 0x4 > +#define PWM_CH_PRD(x) (PWM_CH_PRD_BASE + PWM_CH_PRD_OFF * x) > + > +#define PWMCH_OFFSET 15 ^ That looks odd. > +#define PWM_PRESCAL_MASK (BIT(0)|BIT(1)|BIT(2)|BIT(3)) > +#define PWM_PRESCAL_OFF 0 > +#define PWM_EN BIT(4) > +#define PWM_ACT_STATE BIT(5) > +#define PWM_CLK_GATING BIT(6) > +#define PWM_MODE BIT(7) > +#define PWM_PULSE BIT(8) > +#define PWM_BYPASS BIT(9) > + > +#define PWM_RDY_BASE 28 > +#define PWM_RDY_OFF 1 > +#define PWM_RDY(x) BIT(PWM_RDY_BASE + PWM_RDY_OFF * x) > + > +#define PWM_PRD_ACT_MASK 0xFF > +#define PWM_PRD(x) (x << 16) > +#define PWM_PRD_MASK 0xFF > + > +#define BIT_CH(bit, chan) (bit << (chan * PWMCH_OFFSET)) > + > +u32 prescal_table[] =3D { 120, 180, 240, 360, 480, 0, 0, 0, > + 12000, 24000, 36000, 48000, 72000, > + 0, 0, 1 }; > + > +struct sunxi_pwm_data { > + bool has_rdy; > +}; > + > +struct sunxi_pwm_chip { > + struct pwm_chip chip; > + struct clk *clk; > + void __iomem *base; > + const struct sunxi_pwm_data *data; > +}; > + > +#define to_sunxi_pwm_chip(chip) container_of(chip, struct sunxi_pwm_chip= , chip) > + > +static inline u32 sunxi_pwm_readl(struct sunxi_pwm_chip *chip, > + unsigned long offset) > +{ > + return readl_relaxed(chip->base + offset); > +} > + > +static inline void sunxi_pwm_writel(struct sunxi_pwm_chip *chip, > + unsigned long offset, unsigned long val) > +{ > + writel_relaxed(val, chip->base + offset); > +} Do you have a reason to not use plain readl/writel? > +static int sunxi_pwm_config(struct pwm_chip *chip, struct pwm_device *pw= m, > + int duty_ns, int period_ns) > +{ > + struct sunxi_pwm_chip *sunxi_pwm =3D to_sunxi_pwm_chip(chip); > + u32 clk_rate, prd, dty; > + u64 div; > + u32 val, clk_gate; > + int i, ret; > + > + clk_rate =3D clk_get_rate(sunxi_pwm->clk); > + > + You can drop the extra line here. > + /* First, test without any divider */ > + i =3D PWM_PRESCAL_MASK; > + div =3D clk_rate * period_ns; > + do_div(div, 1000000000); > + if (div > PWM_PRD_MASK) { > + /* Then go up from the first divider */ > + for (i =3D 0; i < PWM_PRESCAL_MASK; i++) { > + if (!prescal_table[i]) > + continue; > + div =3D clk_rate / prescal_table[i]; > + div =3D div * period_ns; > + do_div(div, 1000000000); > + if (div <=3D PWM_PRD_MASK) > + break; > + } > + } > + > + if (div > PWM_PRD_MASK) { > + dev_err(chip->dev, "prescaler exceeds the maximum value\n"); > + return -EINVAL; > + } > + > + prd =3D div; > + div *=3D duty_ns; > + do_div(div, period_ns); > + dty =3D div; > + > + ret =3D clk_enable(sunxi_pwm->clk); > + if (ret) { > + dev_err(chip->dev, "failed to enable PWM clock\n"); > + return ret; > + } > + > + val =3D sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG); > + > + if (sunxi_pwm->data->has_rdy && (val & PWM_RDY(pwm->hwpwm))) > + return -EBUSY; clk_disable? And I'd rather use pm_runtime here. > + clk_gate =3D val & BIT_CH(PWM_CLK_GATING, pwm->hwpwm); > + val &=3D ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm); > + sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val); You probably can test clk_gate here to avoid a write if it's already disabled. > + val =3D sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG); > + val &=3D ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm); > + val |=3D i; > + sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val); > + > + sunxi_pwm_writel(sunxi_pwm, PWM_CH_PRD(pwm->hwpwm), dty | PWM_PRD(prd)); > + > + val =3D sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG); > + val |=3D clk_gate; > + sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val); And you can test it here too. > + clk_disable(sunxi_pwm->clk); > + return ret; return 0; ? > +} > + > +static int sunxi_pwm_set_polarity(struct pwm_chip *chip, struct pwm_devi= ce *pwm, > + enum pwm_polarity polarity) > +{ > + struct sunxi_pwm_chip *sunxi_pwm =3D to_sunxi_pwm_chip(chip); > + u32 val; > + int ret; > + > + val =3D sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG); > + > + if (polarity !=3D PWM_POLARITY_NORMAL) > + val &=3D ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm); > + else > + val |=3D BIT_CH(PWM_ACT_STATE, pwm->hwpwm); > + > + ret =3D clk_enable(sunxi_pwm->clk); Hmmm, this should probably be before you access the registers. > + if (ret) { > + dev_err(chip->dev, "failed to enable PWM clock\n"); > + return ret; > + } > + > + sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val); > + > + clk_disable(sunxi_pwm->clk); > + > + return 0; > +} > + > +static int sunxi_pwm_enable(struct pwm_chip *chip, struct pwm_device *pw= m) > +{ > + struct sunxi_pwm_chip *sunxi_pwm =3D to_sunxi_pwm_chip(chip); > + u32 val; > + int ret; > + > + ret =3D clk_enable(sunxi_pwm->clk); > + if (ret) { > + dev_err(chip->dev, "failed to enable PWM clock\n"); > + return ret; > + } > + > + val =3D sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG); > + val |=3D BIT_CH(PWM_EN, pwm->hwpwm); > + val |=3D BIT_CH(PWM_CLK_GATING, pwm->hwpwm); > + sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val); > + > + return 0; > +} > + > +static void sunxi_pwm_disable(struct pwm_chip *chip, struct pwm_device *= pwm) > +{ > + struct sunxi_pwm_chip *sunxi_pwm =3D to_sunxi_pwm_chip(chip); > + u32 val; > + > + val =3D sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG); > + val &=3D ~BIT_CH(PWM_EN, pwm->hwpwm); > + val &=3D ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm); > + sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val); > + > + clk_disable(sunxi_pwm->clk); > +} > + > +static const struct pwm_ops sunxi_pwm_ops =3D { > + .config =3D sunxi_pwm_config, > + .set_polarity =3D sunxi_pwm_set_polarity, > + .enable =3D sunxi_pwm_enable, > + .disable =3D sunxi_pwm_disable, > + .owner =3D THIS_MODULE, > +}; > + > +static const struct sunxi_pwm_data sunxi_pwm_data_v1 =3D { > + .has_rdy =3D false, > +}; > + > +static const struct sunxi_pwm_data sunxi_pwm_data_v2 =3D { > + .has_rdy =3D true, > +}; I'd prefer to see these structures named after the soc they're associated to. > +static const struct of_device_id sunxi_pwm_dt_ids[] =3D { > + { > + .compatible =3D "allwinner,sun4i-pwm", > + .data =3D &sunxi_pwm_data_v1, > + }, { > + .compatible =3D "allwinner,sun7i-pwm", > + .data =3D &sunxi_pwm_data_v2, > + }, { > + /* sentinel */ > + }, > +}; > +MODULE_DEVICE_TABLE(of, sunxi_pwm_dt_ids); > + > +static int sunxi_pwm_probe(struct platform_device *pdev) > +{ > + struct sunxi_pwm_chip *sunxi_pwm; > + struct resource *res; > + int ret; > + > + const struct of_device_id *match; > + > + match =3D of_match_device(sunxi_pwm_dt_ids, &pdev->dev); > + if (!match || !match->data) > + return -ENODEV; > + > + sunxi_pwm =3D devm_kzalloc(&pdev->dev, sizeof(*sunxi_pwm), GFP_KERNEL); > + if (!sunxi_pwm) > + return -ENOMEM; > + > + res =3D platform_get_resource(pdev, IORESOURCE_MEM, 0); > + sunxi_pwm->base =3D devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(sunxi_pwm->base)) > + return PTR_ERR(sunxi_pwm->base); > + > + sunxi_pwm->clk =3D devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(sunxi_pwm->clk)) > + return PTR_ERR(sunxi_pwm->clk); > + > + ret =3D clk_prepare(sunxi_pwm->clk); > + if (ret) { > + dev_err(&pdev->dev, "failed to prepare PWM clock\n"); > + return ret; > + } > + > + sunxi_pwm->chip.dev =3D &pdev->dev; > + sunxi_pwm->chip.ops =3D &sunxi_pwm_ops; > + > + if (pdev->dev.of_node) { Which will always happen if of_match_device succeeded. > + sunxi_pwm->chip.of_xlate =3D of_pwm_xlate_with_flags; > + sunxi_pwm->chip.of_pwm_n_cells =3D 3; > + } > + > + sunxi_pwm->chip.base =3D -1; > + sunxi_pwm->chip.npwm =3D 2; > + sunxi_pwm->data =3D match->data; > + > + /* By default, the polarity is inversed, set it to normal */ That comment should be after the clk_enable call. > + ret =3D clk_enable(sunxi_pwm->clk); > + if (ret) { > + dev_err(&pdev->dev, "failed to enable PWM clock\n"); > + goto unprepare_clk; > + } > + sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, > + BIT_CH(PWM_ACT_STATE, 0) | > + BIT_CH(PWM_ACT_STATE, 1)); > + clk_disable(sunxi_pwm->clk); > + > + ret =3D pwmchip_add(&sunxi_pwm->chip); > + if (ret < 0) { > + dev_err(&pdev->dev, "failed to add PWM chip %d\n", ret); > + goto unprepare_clk; > + } > + > + platform_set_drvdata(pdev, sunxi_pwm); > + > + You can drop the extra line. > + return ret; > + > +unprepare_clk: > + clk_unprepare(sunxi_pwm->clk); > + return ret; > +} > + > +static int sunxi_pwm_remove(struct platform_device *pdev) > +{ > + struct sunxi_pwm_chip *sunxi_pwm =3D platform_get_drvdata(pdev); > + > + clk_unprepare(sunxi_pwm->clk); > + > + return pwmchip_remove(&sunxi_pwm->chip); > +} > + > +static struct platform_driver sunxi_pwm_driver =3D { > + .driver =3D { > + .name =3D "sunxi-pwm", > + .of_match_table =3D of_match_ptr(sunxi_pwm_dt_ids), You can drop the of_match_ptr. CONFIG_OF is always selected, and you don't protect the definition of sunxi_pwm_dt_ids by an ifdef anyway. > + }, > + .probe =3D sunxi_pwm_probe, > + .remove =3D sunxi_pwm_remove, > +}; > +module_platform_driver(sunxi_pwm_driver); > + > +MODULE_ALIAS("platform:sunxi-pwm"); > +MODULE_AUTHOR("alexandre Belloni "= ); > +MODULE_DESCRIPTION("Allwinner PWM driver"); > +MODULE_LICENSE("GPL v2"); > --=20 > 1.8.3.2 >=20 Thanks! Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --wRtZRu2mMGBZ6YQ7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) iQIcBAEBAgAGBQJTOadoAAoJEBx+YmzsjxAgtxsP/35vkN1xFxtCv3OrMJVZztKX gj6aHsdiiz4kcN5iORUBFr50+930ZXRoha6w4DRXhmO2Xy+pzvOXvOI84CaXeBvQ n7PV/f+UDEOSOYwqUp9QQB4g+Qj6goD67D98C/6aQq+3HK3bmdu66gx0VZ2OvgWV hzueXstJgrq6HDUaiYC8R2BfoUnsPTHr3gaSTBkCtnTLDqz9Jt3i6REX12Qmue+a vcJVbf33Bt7oLfM5x6HQ43JtUK7vCH85iKF+7zY9D23REYUl7eS3AkyWgr8MrQ6F DMB/4gn4MKQwa4mxDPk64hIfMgYbOm48mIuuZTB3kys6VSLfvJg6pc/czc9j5iQD JMcGfKPPbpNEO5E9g0XTZa6Npu4VJ9PZvCfcbKNuwkrJJ5J5+QpFwoiUpZVaFj2z cyKy2jPqe5MAh0Kgpu4DrPbQG/D4BfqNlUvUS0JmYmaWp4c85NFFXWgufj2/T06c AXukojca91Z9t/B38ZKqEZl+w680nja3Id46vvwZ3CQr6porS+h2THRXdNeN7mLt 09cSthT1m5Wo93bDr3FbwxzX2BAVW6+6fX9fi06lWlWlmlw4OC7nPj7IdCnCTMMS CdFJ2ESJjTqaUoUAa9BvbRsONdsJ2RUqQSKbzrbcIzdJd4hU7Vgw+gqAouly4wLX BwgIoZKUf5ja5VHQXLfx =FXKv -----END PGP SIGNATURE----- --wRtZRu2mMGBZ6YQ7--