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Sat, 22 May 2021 21:35:42 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lkZHK-0007ik-LP; Sat, 22 May 2021 23:35:26 +0200 Received: from ukl by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1lkZHI-0002vl-F4; Sat, 22 May 2021 23:35:24 +0200 Date: Sat, 22 May 2021 23:35:24 +0200 From: Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= To: Baruch Siach Cc: Thierry Reding , Lee Jones , Andy Gross , Bjorn Andersson , Balaji Prakash J , Rob Herring , Robert Marko , devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 1/3] pwm: driver for qualcomm ipq6018 pwm block Message-ID: <20210522213524.lnb5bds5hvv2f2zi@pengutronix.de> References: <70ced827689b7ab35d8f3b07db8d9ccd1489e3e2.1621410526.git.baruch@tkos.co.il> MIME-Version: 1.0 In-Reply-To: <70ced827689b7ab35d8f3b07db8d9ccd1489e3e2.1621410526.git.baruch@tkos.co.il> X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210522_143539_979927_C64AE0C6 X-CRM114-Status: GOOD ( 47.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============4848722309929127424==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============4848722309929127424== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="x5ruvoykr2iiy6l3" Content-Disposition: inline --x5ruvoykr2iiy6l3 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello Baruch, On Wed, May 19, 2021 at 10:48:44AM +0300, Baruch Siach wrote: > Driver for the PWM block in Qualcomm IPQ6018 line of SoCs. Based on > driver from downstream Codeaurora kernel tree. Removed support for older > (V1) variants because I have no access to that hardware. >=20 > Tested on IPQ6010 based hardware. >=20 > Signed-off-by: Baruch Siach > --- > drivers/pwm/Kconfig | 12 ++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-ipq.c | 263 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 276 insertions(+) > create mode 100644 drivers/pwm/pwm-ipq.c >=20 > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > index 9a4f66ae8070..54ef62a27bdc 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -260,6 +260,18 @@ config PWM_INTEL_LGM > To compile this driver as a module, choose M here: the module > will be called pwm-intel-lgm. > =20 > +config PWM_IPQ > + tristate "IPQ PWM support" > + depends on ARCH_QCOM || COMPILE_TEST > + depends on HAVE_CLK && HAS_IOMEM > + help > + Generic PWM framework driver for IPQ PWM block which supports > + 4 pwm channels. Each of the these channels can be configured > + independent of each other. > + > + To compile this driver as a module, choose M here: the module > + will be called pwm-ipq. > + > config PWM_IQS620A > tristate "Azoteq IQS620A PWM support" > depends on MFD_IQS62X || COMPILE_TEST > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > index 6374d3b1d6f3..73eb955dea1d 100644 > --- a/drivers/pwm/Makefile > +++ b/drivers/pwm/Makefile > @@ -22,6 +22,7 @@ obj-$(CONFIG_PWM_IMX1) +=3D pwm-imx1.o > obj-$(CONFIG_PWM_IMX27) +=3D pwm-imx27.o > obj-$(CONFIG_PWM_IMX_TPM) +=3D pwm-imx-tpm.o > obj-$(CONFIG_PWM_INTEL_LGM) +=3D pwm-intel-lgm.o > +obj-$(CONFIG_PWM_IPQ) +=3D pwm-ipq.o > obj-$(CONFIG_PWM_IQS620A) +=3D pwm-iqs620a.o > obj-$(CONFIG_PWM_JZ4740) +=3D pwm-jz4740.o > obj-$(CONFIG_PWM_KEEMBAY) +=3D pwm-keembay.o > diff --git a/drivers/pwm/pwm-ipq.c b/drivers/pwm/pwm-ipq.c > new file mode 100644 > index 000000000000..885cf885fcf6 > --- /dev/null > +++ b/drivers/pwm/pwm-ipq.c > @@ -0,0 +1,263 @@ > +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 > +/* > + * Copyright (c) 2016-2017, 2020 The Linux Foundation. All rights reserv= ed. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define CLK_SRC_FREQ (100*1000*1000) > +#define MAX_PWM_DEVICES 4 > + > +/* The default period and duty cycle values to be configured. */ > +#define DEFAULT_PERIOD_NS 10 > +#define DEFAULT_DUTY_CYCLE_NS 5 These define's names are too generic. Please prefix them with your driver's name. > +/* > + * Enable bit is set to enable output toggling in pwm device. > + * Update bit is set to reflect the changed divider and high duration > + * values in register. > + */ > +#define PWM_ENABLE 0x80000000 > +#define PWM_UPDATE 0x40000000 > + > +/* The frequency range supported is 1Hz to 100MHz */ > +#define MIN_PERIOD_NS 10 > +#define MAX_PERIOD_NS 1000000000 > + > +/* > + * The max value specified for each field is based on the number of bits > + * in the pwm control register for that field > + */ > +#define MAX_PWM_CFG 0xFFFF > + > +#define PWM_CTRL_HI_SHIFT 16 > + > +#define PWM_CFG_REG0 0 /*PWM_DIV PWM_HI*/ > +#define PWM_CFG_REG1 1 /*ENABLE UPDATE PWM_PRE_DIV*/ > + > +struct ipq_pwm_chip { > + struct pwm_chip chip; > + struct clk *clk; > + void __iomem *mem; > +}; > + > +static struct ipq_pwm_chip *to_ipq_pwm_chip(struct pwm_chip *chip) > +{ > + return container_of(chip, struct ipq_pwm_chip, chip); > +} > + > +static unsigned ipq_pwm_reg_offset(struct pwm_device *pwm, unsigned reg) > +{ > + return ((pwm->hwpwm * 2) + reg) * 4; > +} > + > +static void config_div_and_duty(struct pwm_device *pwm, int pre_div, > + unsigned long long pwm_div, unsigned long period_ns, > + unsigned long long duty_ns) > +{ > + unsigned long hi_dur; > + unsigned long long quotient; > + unsigned long val =3D 0; > + struct ipq_pwm_chip *ipq_chip =3D to_ipq_pwm_chip(pwm->chip); > + > + /* > + * high duration =3D pwm duty * ( pwm div + 1) s/( /(/ > + * pwm duty =3D duty_ns / period_ns > + */ > + quotient =3D (pwm_div + 1) * duty_ns; > + do_div(quotient, period_ns); > + hi_dur =3D quotient; > + > + val |=3D ((hi_dur & MAX_PWM_CFG) << PWM_CTRL_HI_SHIFT); > + val |=3D (pwm_div & MAX_PWM_CFG); > + writel(val, ipq_chip->mem + ipq_pwm_reg_offset(pwm, PWM_CFG_REG0)); > + val =3D pre_div & MAX_PWM_CFG; > + writel(val, ipq_chip->mem + ipq_pwm_reg_offset(pwm, PWM_CFG_REG1)); > +} > + > +static int ipq_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) > +{ > + struct ipq_pwm_chip *ipq_chip =3D to_ipq_pwm_chip(pwm->chip); > + unsigned offset =3D ipq_pwm_reg_offset(pwm, PWM_CFG_REG1); > + unsigned long val; > + > + val =3D readl(ipq_chip->mem + offset); > + val |=3D (PWM_ENABLE | PWM_UPDATE); The parenthesis are not needed here. > + writel(val, ipq_chip->mem + offset); > + > + return 0; > +} > + > +static void ipq_pwm_disable(struct pwm_chip *chip, struct pwm_device *pw= m) > +{ > + struct ipq_pwm_chip *ipq_chip =3D to_ipq_pwm_chip(pwm->chip); > + unsigned offset =3D ipq_pwm_reg_offset(pwm, PWM_CFG_REG1); > + unsigned long val; > + > + val =3D readl(ipq_chip->mem + offset); > + val |=3D PWM_UPDATE; What is the effect of this register bit? Does the output become inactive or does it freeze at state that happens to be emitted when the ENABLE bit is removed? > + val &=3D ~PWM_ENABLE; > + writel(val, ipq_chip->mem + offset); > +} > + > +static int ipq_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, > + int duty_ns, int period_ns) > +{ > + struct ipq_pwm_chip *ipq_chip =3D to_ipq_pwm_chip(chip); > + unsigned long freq; > + int pre_div, close_pre_div, close_pwm_div; > + int pwm_div; > + long long diff; > + unsigned long rate =3D clk_get_rate(ipq_chip->clk); > + unsigned long min_diff =3D rate; > + uint64_t fin_ps; > + > + if (period_ns > MAX_PERIOD_NS || period_ns < MIN_PERIOD_NS) { > + pr_err("PWM Frequency range supported is %dHz to %dHz\n" > + "Switching to default configuration values\n", > + (int)NSEC_PER_SEC / MAX_PERIOD_NS, > + (int)NSEC_PER_SEC / MIN_PERIOD_NS); > + period_ns =3D DEFAULT_PERIOD_NS; > + duty_ns =3D DEFAULT_DUTY_CYCLE_NS; > + pwm->state.period =3D period_ns; > + pwm->state.duty_cycle =3D duty_ns; > + } Please implement the biggest period not bigger than the requested period. That is do something like: if (period_ns < MIN_PERIOD_NS) return -ERANGE; if (period_ns > MAX_PERIOD_NS) period_ns =3D MAX_PERIOD_NS; > + > + /* freq in Hz for period in nano second*/ > + freq =3D NSEC_PER_SEC / period_ns; > + fin_ps =3D (uint64_t)NSEC_PER_SEC * 1000; > + do_div(fin_ps, rate); > + close_pre_div =3D MAX_PWM_CFG; > + close_pwm_div =3D MAX_PWM_CFG; > + > + ipq_pwm_disable(chip, pwm); This is necessary? > + for (pre_div =3D 0; pre_div <=3D MAX_PWM_CFG; pre_div++) { > + pwm_div =3D DIV_ROUND_CLOSEST_ULL((uint64_t)period_ns * 1000, > + fin_ps * (pre_div + 1)); > + pwm_div--; What if pwm_div was 0 before? (Didn't check if this can happen, maybe it doesn't with period_ns >=3D MIN_PERIOD_NS?) > + if (pwm_div <=3D MAX_PWM_CFG) { > + diff =3D (uint64_t)rate - ((uint64_t)freq * (pre_div + 1) * (pwm_div = + 1)); > + > + if (diff < 0) > + diff =3D -diff; > + if (!diff) { > + close_pre_div =3D pre_div; > + close_pwm_div =3D pwm_div; > + break; > + } > + if (diff < min_diff) { > + min_diff =3D diff; > + close_pre_div =3D pre_div; > + close_pwm_div =3D pwm_div; > + } As written above: Never pick a period bigger than the requested period. > + } > + } > + > + /* config divider values for the closest possible frequency */ > + config_div_and_duty(pwm, close_pre_div, close_pwm_div, > + period_ns, duty_ns); Please align follow up lines to the opening (. > + if (pwm->state.enabled) > + ipq_pwm_enable(chip, pwm); > + > + return 0; > +} > + > +static int ipq_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) > +{ > + pwm->state.period =3D DEFAULT_PERIOD_NS; > + pwm->state.duty_cycle =3D DEFAULT_DUTY_CYCLE_NS; > + > + ipq_pwm_config(chip, pwm, pwm->state.duty_cycle, pwm->state.period); =2Erequest is not supposed to modify the emitted wave form. > + > + return 0; > +} > + > +static void ipq_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) > +{ > + ipq_pwm_disable(chip, pwm); neither is .free. > +} > + > +static struct pwm_ops ipq_pwm_ops =3D { > + .request =3D ipq_pwm_request, > + .free =3D ipq_pwm_free, > + .config =3D ipq_pwm_config, > + .enable =3D ipq_pwm_enable, > + .disable =3D ipq_pwm_disable, Please implement .apply instead of .config/.enable/.disable. If you had enabled PWM_DEBUG during your tests you would have noticed yourself ... > + .owner =3D THIS_MODULE, > +}; > + > +static int ipq_pwm_probe(struct platform_device *pdev) > +{ > + struct ipq_pwm_chip *pwm; > + struct device *dev; > + int ret; > + > + dev =3D &pdev->dev; > + pwm =3D devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL); > + if (!pwm) { > + dev_err(dev, "failed to allocate memory\n"); You're not supposed to emit a message for -ENOMEM type errors. This is already loud enough. > + return -ENOMEM; > + } > + > + platform_set_drvdata(pdev, pwm); > + > + pwm->mem =3D devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(pwm->mem)) > + return PTR_ERR(pwm->mem); > + > + pwm->clk =3D devm_clk_get(dev, "core"); > + if (!IS_ERR(pwm->clk)) { If devm_clk_get() returns an error you should return an error, too. You might want to use devm_clk_get_optional(). > + ret =3D clk_set_rate(pwm->clk, CLK_SRC_FREQ); > + if (ret) > + return ret; > + ret =3D clk_prepare_enable(pwm->clk); > + if (ret) > + return ret; > + } > + > + pwm->chip.dev =3D dev; > + pwm->chip.ops =3D &ipq_pwm_ops; > + pwm->chip.npwm =3D MAX_PWM_DEVICES; > + > + ret =3D pwmchip_add(&pwm->chip); > + if (ret < 0) { > + dev_err(dev, "pwmchip_add() failed: %d\n", ret); > + return ret; return dev_err_probe(dev, ret, "...") please. And you have to disable the clock again. > + } > + > + return 0; > +} > + > +static int ipq_pwm_remove(struct platform_device *pdev) > +{ > + struct ipq_pwm_chip *pwm =3D platform_get_drvdata(pdev); > + > + return pwmchip_remove(&pwm->chip); Please ignore the return value of pwmchip_remove(). This is eventually changed to return void. > +} > + > +static const struct of_device_id pwm_ipq_dt_match[] =3D { > + { .compatible =3D "qcom,pwm-ipq6018", }, > + {} > +}; > +MODULE_DEVICE_TABLE(of, pwm_ipq_dt_match); > + > +static struct platform_driver ipq_pwm_driver =3D { > + .driver =3D { > + .name =3D "ipq-pwm", > + .owner =3D THIS_MODULE, > + .of_match_table =3D pwm_ipq_dt_match, > + }, > + .probe =3D ipq_pwm_probe, > + .remove =3D ipq_pwm_remove, > +}; > + > +module_platform_driver(ipq_pwm_driver); > + > +MODULE_LICENSE("Dual BSD/GPL"); Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig | Industrial Linux Solutions | https://www.pengutronix.de/ | --x5ruvoykr2iiy6l3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEfnIqFpAYrP8+dKQLwfwUeK3K7AkFAmCpeRcACgkQwfwUeK3K 7AkTOAgAkRtz7rA0+t4kUXIp/1GBcpf7PQwI2Dexau55OLafk77uOYR5zQ2JwlJG cv6cCRWO4rBfanooHR3hSIOmLZcuJ2PJH5zAUiotrTCxdBur+KT1dtHE5wcXxrbr w43NunARwz5eqgrlnSQPnO0Z4s6NdohNTURatx1Kkrx441zN4+JGjbNNIFFF7UdL 7lF+oo2Maaip3iuOBPoHhvxKV43YtrdHZH9mDfTvQdOBF422FvG14EJoetemb6s1 Jt3Jq7pijnBEqBsUp/I4pLG1HcmN+wEYVqxZI4cEIQJnFOkA1LRuAixuW6lM3zRo SSskrh+8a74qvx22/CffbYZ8BcQxxA== =Pdmk -----END PGP SIGNATURE----- --x5ruvoykr2iiy6l3-- --===============4848722309929127424== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============4848722309929127424==--