Re: [PATCH v7 06/10] pwm: dwc: split pci out of core driver

From: Uwe Kleine-König
Date: Thu Feb 16 2023 - 16:31:10 EST

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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@xxxxxxxxxx>
> ---
> 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@xxxxxxxxxxxxxxx>
> + * Author: Raymond Tan <raymond.tan@xxxxxxxxx>
> + *
> + * 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@xxxxxxxxxxxxxxx>");
> +MODULE_AUTHOR("Raymond Tan <raymond.tan@xxxxxxxxx>");
> +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@xxxxxxxxxxxxxxx>
> * Author: Raymond Tan <raymond.tan@xxxxxxxxx>
> - *
> - * 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@xxxxxxxxxxxxxxx>");
> 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@xxxxxxxxxxxxxxx>
> + * Author: Raymond Tan <raymond.tan@xxxxxxxxx>
> + */
> +
> +#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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