Message-ID: <20230216213054.lge6ugeay3uxh2ye@pengutronix.de>
Date:   Thu, 16 Feb 2023 22:30:54 +0100
From:   Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To:     Ben Dooks <ben.dooks@...ive.com>
Cc:     linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, Lee Jones <lee.jones@...aro.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Greentime Hu <greentime.hu@...ive.com>,
        jarkko.nikula@...ux.intel.com,
        William Salmon <william.salmon@...ive.com>,
        Jude Onyenegecha <jude.onyenegecha@...ive.com>
Subject: Re: [PATCH v7 06/10] pwm: dwc: split pci out of core driver

Hello,

On Fri, Dec 23, 2022 at 03:38:16PM +0000, Ben Dooks wrote:
> Moving towards adding non-pci support for the driver, move the pci
> parts out of the core into their own module. This is partly due to
> the module_driver() code only being allowed once in a module and also
> to avoid a number of #ifdef if we build a single file in a system
> without pci support.
> 
> Signed-off-by: Ben Dooks <ben.dooks@...ive.com>
> ---
> v7:
>  - re-order kconfig to make dwc core be selected by PCI driver
> v6:
>  - put DWC_PERIOD_NS back to avoid bisect issues
> v4:
>  - removed DWC_PERIOD_NS as not needed
> ---
>  drivers/pwm/Kconfig       |  17 +++-
>  drivers/pwm/Makefile      |   1 +
>  drivers/pwm/pwm-dwc-pci.c | 133 ++++++++++++++++++++++++++++++++
>  drivers/pwm/pwm-dwc.c     | 158 +-------------------------------------
>  drivers/pwm/pwm-dwc.h     |  58 ++++++++++++++
>  5 files changed, 209 insertions(+), 158 deletions(-)
>  create mode 100644 drivers/pwm/pwm-dwc-pci.c
>  create mode 100644 drivers/pwm/pwm-dwc.h
> 
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 3f3c53af4a56..8c5ef388a981 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -174,16 +174,25 @@ config PWM_CROS_EC
>  	  PWM driver for exposing a PWM attached to the ChromeOS Embedded
>  	  Controller.
>  
> -config PWM_DWC
> -	tristate "DesignWare PWM Controller"
> -	depends on PCI || COMPILE_TEST

You're loosing COMPILE_TEST here, as it's not present for the new
PWM_DWC.

> +config PWM_DWC_CORE
> +	tristate
>  	depends on HAS_IOMEM
>  	help
> -	  PWM driver for Synopsys DWC PWM Controller attached to a PCI bus.
> +	  PWM driver for Synopsys DWC PWM Controller.
>  
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called pwm-dwc.
>  
> +config PWM_DWC
> +	tristate "DesignWare PWM Controller (PCI bus)"
> +	depends on HAS_IOMEM && PCI
> +	select PWM_DWC_CORE
> +	help
> +	  PWM driver for Synopsys DWC PWM Controller attached to a PCI bus.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called pwm-dwc-pci.
> +
>  config PWM_EP93XX
>  	tristate "Cirrus Logic EP93xx PWM support"
>  	depends on ARCH_EP93XX || COMPILE_TEST
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 7bf1a29f02b8..a70d36623129 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -15,6 +15,7 @@ obj-$(CONFIG_PWM_CLPS711X)	+= pwm-clps711x.o
>  obj-$(CONFIG_PWM_CRC)		+= pwm-crc.o
>  obj-$(CONFIG_PWM_CROS_EC)	+= pwm-cros-ec.o
>  obj-$(CONFIG_PWM_DWC)		+= pwm-dwc.o
> +obj-$(CONFIG_PWM_DWC_PCI)	+= pwm-dwc-pci.o
>  obj-$(CONFIG_PWM_EP93XX)	+= pwm-ep93xx.o
>  obj-$(CONFIG_PWM_FSL_FTM)	+= pwm-fsl-ftm.o
>  obj-$(CONFIG_PWM_HIBVT)		+= pwm-hibvt.o
> diff --git a/drivers/pwm/pwm-dwc-pci.c b/drivers/pwm/pwm-dwc-pci.c
> new file mode 100644
> index 000000000000..2213d0e7f3c8
> --- /dev/null
> +++ b/drivers/pwm/pwm-dwc-pci.c
> @@ -0,0 +1,133 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * DesignWare PWM Controller driver (PCI part)
> + *
> + * Copyright (C) 2018-2020 Intel Corporation
> + *
> + * Author: Felipe Balbi (Intel)
> + * Author: Jarkko Nikula <jarkko.nikula@...ux.intel.com>
> + * Author: Raymond Tan <raymond.tan@...el.com>
> + *
> + * Limitations:
> + * - The hardware cannot generate a 0 % or 100 % duty cycle. Both high and low
> + *   periods are one or more input clock periods long.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/export.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/pwm.h>
> +
> +#include "pwm-dwc.h"
> +
> +static int dwc_pwm_probe(struct pci_dev *pci, const struct pci_device_id *id)
> +{
> +	struct device *dev = &pci->dev;
> +	struct dwc_pwm *dwc;
> +	int ret;
> +
> +	dwc = dwc_pwm_alloc(dev);
> +	if (!dwc)
> +		return -ENOMEM;
> +
> +	ret = pcim_enable_device(pci);
> +	if (ret) {
> +		dev_err(dev, "Failed to enable device (%pe)\n", ERR_PTR(ret));
> +		return ret;
> +	}
> +
> +	pci_set_master(pci);
> +
> +	ret = pcim_iomap_regions(pci, BIT(0), pci_name(pci));
> +	if (ret) {
> +		dev_err(dev, "Failed to iomap PCI BAR (%pe)\n", ERR_PTR(ret));
> +		return ret;
> +	}
> +
> +	dwc->base = pcim_iomap_table(pci)[0];
> +	if (!dwc->base) {
> +		dev_err(dev, "Base address missing\n");
> +		return -ENOMEM;
> +	}
> +
> +	ret = devm_pwmchip_add(dev, &dwc->chip);
> +	if (ret)
> +		return ret;
> +
> +	pm_runtime_put(dev);
> +	pm_runtime_allow(dev);
> +
> +	return 0;
> +}
> +
> +static void dwc_pwm_remove(struct pci_dev *pci)
> +{
> +	pm_runtime_forbid(&pci->dev);
> +	pm_runtime_get_noresume(&pci->dev);
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int dwc_pwm_suspend(struct device *dev)
> +{
> +	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
> +	struct dwc_pwm *dwc = pci_get_drvdata(pdev);
> +	int i;
> +
> +	for (i = 0; i < DWC_TIMERS_TOTAL; i++) {
> +		if (dwc->chip.pwms[i].state.enabled) {
> +			dev_err(dev, "PWM %u in use by consumer (%s)\n",
> +				i, dwc->chip.pwms[i].label);
> +			return -EBUSY;
> +		}
> +		dwc->ctx[i].cnt = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT(i));
> +		dwc->ctx[i].cnt2 = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT2(i));
> +		dwc->ctx[i].ctrl = dwc_pwm_readl(dwc, DWC_TIM_CTRL(i));
> +	}
> +
> +	return 0;
> +}
> +
> +static int dwc_pwm_resume(struct device *dev)
> +{
> +	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
> +	struct dwc_pwm *dwc = pci_get_drvdata(pdev);
> +	int i;
> +
> +	for (i = 0; i < DWC_TIMERS_TOTAL; i++) {
> +		dwc_pwm_writel(dwc, dwc->ctx[i].cnt, DWC_TIM_LD_CNT(i));
> +		dwc_pwm_writel(dwc, dwc->ctx[i].cnt2, DWC_TIM_LD_CNT2(i));
> +		dwc_pwm_writel(dwc, dwc->ctx[i].ctrl, DWC_TIM_CTRL(i));
> +	}
> +
> +	return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(dwc_pwm_pm_ops, dwc_pwm_suspend, dwc_pwm_resume);
> +
> +static const struct pci_device_id dwc_pwm_id_table[] = {
> +	{ PCI_VDEVICE(INTEL, 0x4bb7) }, /* Elkhart Lake */
> +	{  }	/* Terminating Entry */
> +};
> +MODULE_DEVICE_TABLE(pci, dwc_pwm_id_table);
> +
> +static struct pci_driver dwc_pwm_driver = {
> +	.name = "pwm-dwc",
> +	.probe = dwc_pwm_probe,
> +	.remove = dwc_pwm_remove,
> +	.id_table = dwc_pwm_id_table,
> +	.driver = {
> +		.pm = &dwc_pwm_pm_ops,
> +	},
> +};
> +
> +module_pci_driver(dwc_pwm_driver);
> +
> +MODULE_AUTHOR("Felipe Balbi (Intel)");
> +MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@...ux.intel.com>");
> +MODULE_AUTHOR("Raymond Tan <raymond.tan@...el.com>");
> +MODULE_DESCRIPTION("DesignWare PWM Controller");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/pwm/pwm-dwc.c b/drivers/pwm/pwm-dwc.c
> index 56cde9da2c0e..90a8ae1252a1 100644
> --- a/drivers/pwm/pwm-dwc.c
> +++ b/drivers/pwm/pwm-dwc.c
> @@ -1,16 +1,12 @@
>  // SPDX-License-Identifier: GPL-2.0
>  /*
> - * DesignWare PWM Controller driver
> + * DesignWare PWM Controller driver core
>   *
>   * Copyright (C) 2018-2020 Intel Corporation
>   *
>   * Author: Felipe Balbi (Intel)
>   * Author: Jarkko Nikula <jarkko.nikula@...ux.intel.com>
>   * Author: Raymond Tan <raymond.tan@...el.com>
> - *
> - * Limitations:
> - * - The hardware cannot generate a 0 % or 100 % duty cycle. Both high and low
> - *   periods are one or more input clock periods long.
>   */
>  
>  #include <linux/bitops.h>
> @@ -21,51 +17,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/pwm.h>
>  
> -#define DWC_TIM_LD_CNT(n)	((n) * 0x14)
> -#define DWC_TIM_LD_CNT2(n)	(((n) * 4) + 0xb0)
> -#define DWC_TIM_CUR_VAL(n)	(((n) * 0x14) + 0x04)
> -#define DWC_TIM_CTRL(n)		(((n) * 0x14) + 0x08)
> -#define DWC_TIM_EOI(n)		(((n) * 0x14) + 0x0c)
> -#define DWC_TIM_INT_STS(n)	(((n) * 0x14) + 0x10)
> -
> -#define DWC_TIMERS_INT_STS	0xa0
> -#define DWC_TIMERS_EOI		0xa4
> -#define DWC_TIMERS_RAW_INT_STS	0xa8
> -#define DWC_TIMERS_COMP_VERSION	0xac
> -
> -#define DWC_TIMERS_TOTAL	8
> -#define DWC_CLK_PERIOD_NS	10
> -
> -/* Timer Control Register */
> -#define DWC_TIM_CTRL_EN		BIT(0)
> -#define DWC_TIM_CTRL_MODE	BIT(1)
> -#define DWC_TIM_CTRL_MODE_FREE	(0 << 1)
> -#define DWC_TIM_CTRL_MODE_USER	(1 << 1)
> -#define DWC_TIM_CTRL_INT_MASK	BIT(2)
> -#define DWC_TIM_CTRL_PWM	BIT(3)
> -
> -struct dwc_pwm_ctx {
> -	u32 cnt;
> -	u32 cnt2;
> -	u32 ctrl;
> -};
> -
> -struct dwc_pwm {
> -	struct pwm_chip chip;
> -	void __iomem *base;
> -	struct dwc_pwm_ctx ctx[DWC_TIMERS_TOTAL];
> -};
> -#define to_dwc_pwm(p)	(container_of((p), struct dwc_pwm, chip))
> -
> -static inline u32 dwc_pwm_readl(struct dwc_pwm *dwc, u32 offset)
> -{
> -	return readl(dwc->base + offset);
> -}
> -
> -static inline void dwc_pwm_writel(struct dwc_pwm *dwc, u32 value, u32 offset)
> -{
> -	writel(value, dwc->base + offset);
> -}
> +#include "pwm-dwc.h"
>  
>  static void __dwc_pwm_set_enable(struct dwc_pwm *dwc, int pwm, int enabled)
>  {
> @@ -196,7 +148,7 @@ static const struct pwm_ops dwc_pwm_ops = {
>  	.owner = THIS_MODULE,
>  };
>  
> -static struct dwc_pwm *dwc_pwm_alloc(struct device *dev)
> +struct dwc_pwm *dwc_pwm_alloc(struct device *dev)
>  {
>  	struct dwc_pwm *dwc;
>  
> @@ -211,109 +163,7 @@ static struct dwc_pwm *dwc_pwm_alloc(struct device *dev)
>  	dev_set_drvdata(dev, dwc);
>  	return dwc;
>  }
> -
> -static int dwc_pwm_probe(struct pci_dev *pci, const struct pci_device_id *id)
> -{
> -	struct device *dev = &pci->dev;
> -	struct dwc_pwm *dwc;
> -	int ret;
> -
> -	dwc = dwc_pwm_alloc(dev);
> -	if (!dwc)
> -		return -ENOMEM;
> -
> -	ret = pcim_enable_device(pci);
> -	if (ret) {
> -		dev_err(dev, "Failed to enable device (%pe)\n", ERR_PTR(ret));
> -		return ret;
> -	}
> -
> -	pci_set_master(pci);
> -
> -	ret = pcim_iomap_regions(pci, BIT(0), pci_name(pci));
> -	if (ret) {
> -		dev_err(dev, "Failed to iomap PCI BAR (%pe)\n", ERR_PTR(ret));
> -		return ret;
> -	}
> -
> -	dwc->base = pcim_iomap_table(pci)[0];
> -	if (!dwc->base) {
> -		dev_err(dev, "Base address missing\n");
> -		return -ENOMEM;
> -	}
> -
> -	ret = devm_pwmchip_add(dev, &dwc->chip);
> -	if (ret)
> -		return ret;
> -
> -	pm_runtime_put(dev);
> -	pm_runtime_allow(dev);
> -
> -	return 0;
> -}
> -
> -static void dwc_pwm_remove(struct pci_dev *pci)
> -{
> -	pm_runtime_forbid(&pci->dev);
> -	pm_runtime_get_noresume(&pci->dev);
> -}
> -
> -#ifdef CONFIG_PM_SLEEP
> -static int dwc_pwm_suspend(struct device *dev)
> -{
> -	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
> -	struct dwc_pwm *dwc = pci_get_drvdata(pdev);
> -	int i;
> -
> -	for (i = 0; i < DWC_TIMERS_TOTAL; i++) {
> -		if (dwc->chip.pwms[i].state.enabled) {
> -			dev_err(dev, "PWM %u in use by consumer (%s)\n",
> -				i, dwc->chip.pwms[i].label);
> -			return -EBUSY;
> -		}
> -		dwc->ctx[i].cnt = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT(i));
> -		dwc->ctx[i].cnt2 = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT2(i));
> -		dwc->ctx[i].ctrl = dwc_pwm_readl(dwc, DWC_TIM_CTRL(i));
> -	}
> -
> -	return 0;
> -}
> -
> -static int dwc_pwm_resume(struct device *dev)
> -{
> -	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
> -	struct dwc_pwm *dwc = pci_get_drvdata(pdev);
> -	int i;
> -
> -	for (i = 0; i < DWC_TIMERS_TOTAL; i++) {
> -		dwc_pwm_writel(dwc, dwc->ctx[i].cnt, DWC_TIM_LD_CNT(i));
> -		dwc_pwm_writel(dwc, dwc->ctx[i].cnt2, DWC_TIM_LD_CNT2(i));
> -		dwc_pwm_writel(dwc, dwc->ctx[i].ctrl, DWC_TIM_CTRL(i));
> -	}
> -
> -	return 0;
> -}
> -#endif
> -
> -static SIMPLE_DEV_PM_OPS(dwc_pwm_pm_ops, dwc_pwm_suspend, dwc_pwm_resume);
> -
> -static const struct pci_device_id dwc_pwm_id_table[] = {
> -	{ PCI_VDEVICE(INTEL, 0x4bb7) }, /* Elkhart Lake */
> -	{  }	/* Terminating Entry */
> -};
> -MODULE_DEVICE_TABLE(pci, dwc_pwm_id_table);
> -
> -static struct pci_driver dwc_pwm_driver = {
> -	.name = "pwm-dwc",
> -	.probe = dwc_pwm_probe,
> -	.remove = dwc_pwm_remove,
> -	.id_table = dwc_pwm_id_table,
> -	.driver = {
> -		.pm = &dwc_pwm_pm_ops,
> -	},
> -};
> -
> -module_pci_driver(dwc_pwm_driver);
> +EXPORT_SYMBOL_GPL(dwc_pwm_alloc);
>  
>  MODULE_AUTHOR("Felipe Balbi (Intel)");
>  MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@...ux.intel.com>");
> diff --git a/drivers/pwm/pwm-dwc.h b/drivers/pwm/pwm-dwc.h
> new file mode 100644
> index 000000000000..68f98eb76152
> --- /dev/null
> +++ b/drivers/pwm/pwm-dwc.h
> @@ -0,0 +1,58 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * DesignWare PWM Controller driver
> + *
> + * Copyright (C) 2018-2020 Intel Corporation
> + *
> + * Author: Felipe Balbi (Intel)
> + * Author: Jarkko Nikula <jarkko.nikula@...ux.intel.com>
> + * Author: Raymond Tan <raymond.tan@...el.com>
> + */
> +
> +#define DWC_TIM_LD_CNT(n)	((n) * 0x14)
> +#define DWC_TIM_LD_CNT2(n)	(((n) * 4) + 0xb0)
> +#define DWC_TIM_CUR_VAL(n)	(((n) * 0x14) + 0x04)
> +#define DWC_TIM_CTRL(n)		(((n) * 0x14) + 0x08)
> +#define DWC_TIM_EOI(n)		(((n) * 0x14) + 0x0c)
> +#define DWC_TIM_INT_STS(n)	(((n) * 0x14) + 0x10)
> +
> +#define DWC_TIMERS_INT_STS	0xa0
> +#define DWC_TIMERS_EOI		0xa4
> +#define DWC_TIMERS_RAW_INT_STS	0xa8
> +#define DWC_TIMERS_COMP_VERSION	0xac
> +
> +#define DWC_TIMERS_TOTAL	8
> +#define DWC_CLK_PERIOD_NS	10
> +
> +/* Timer Control Register */
> +#define DWC_TIM_CTRL_EN		BIT(0)
> +#define DWC_TIM_CTRL_MODE	BIT(1)
> +#define DWC_TIM_CTRL_MODE_FREE	(0 << 1)
> +#define DWC_TIM_CTRL_MODE_USER	(1 << 1)
> +#define DWC_TIM_CTRL_INT_MASK	BIT(2)
> +#define DWC_TIM_CTRL_PWM	BIT(3)
> +
> +struct dwc_pwm_ctx {
> +	u32 cnt;
> +	u32 cnt2;
> +	u32 ctrl;
> +};
> +
> +struct dwc_pwm {
> +	struct pwm_chip chip;
> +	void __iomem *base;
> +	struct dwc_pwm_ctx ctx[DWC_TIMERS_TOTAL];
> +};
> +#define to_dwc_pwm(p)	(container_of((p), struct dwc_pwm, chip))
> +
> +static inline u32 dwc_pwm_readl(struct dwc_pwm *dwc, u32 offset)
> +{
> +	return readl(dwc->base + offset);
> +}
> +
> +static inline void dwc_pwm_writel(struct dwc_pwm *dwc, u32 value, u32 offset)
> +{
> +	writel(value, dwc->base + offset);
> +}
> +
> +extern struct dwc_pwm *dwc_pwm_alloc(struct device *dev);

If you respin this patch for the COMPILE_TEST issue I pointed out above,
would you mind using a module namespace?

That would work by adding e.g.

	#define DEFAULT_SYMBOL_NAMESPACE dwc-pwm

to drivers/pwm/pwm-dwc.c (before the includes) and

	MODULE_IMPORT_NS(dwc-pwm)

to drivers/pwm/pwm-dwc.h.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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