| Message ID | 20220816211454.237751-9-ben.dooks@sifive.com |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | RFC on synpsys pwm driver changes | expand |
On Tue, Aug 16, 2022 at 10:14:52PM +0100, Ben Dooks wrote: > The dwc pwm controller can be used in non-PCI systems, so allow > either platform or OF based probing. > > Signed-off-by: Ben Dooks <ben.dooks@sifive.com> > --- > v4: > - split the of code out of the core > - moved the compile test code earlier > - fixed review comments > - used NS_PER_SEC > - use devm_clk_get_enabled > v3: > - changed compatible name > --- > drivers/pwm/Kconfig | 9 +++++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-dwc-of.c | 78 ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 88 insertions(+) > create mode 100644 drivers/pwm/pwm-dwc-of.c > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > index a9f1c554db2b..f1735653365f 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -192,6 +192,15 @@ config PWM_DWC_PCI > To compile this driver as a module, choose M here: the module > will be called pwm-dwc-pci. > > +config PWM_DWC_OF > + tristate "DesignWare PWM Controller (OF bus) > + depends on PWM_DWC && OF > + help > + PWM driver for Synopsys DWC PWM Controller on an OF bus. > + > + To compile this driver as a module, choose M here: the module > + will be called pwm-dwc-of. > + > 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 a70d36623129..d1fd1641f077 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-$(CONFIG_PWM_DWC_OF) += pwm-dwc-of.o > obj-$(CONFIG_PWM_DWC_PCI) += pwm-dwc-pci.o > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o > diff --git a/drivers/pwm/pwm-dwc-of.c b/drivers/pwm/pwm-dwc-of.c > new file mode 100644 > index 000000000000..d18fac287325 > --- /dev/null > +++ b/drivers/pwm/pwm-dwc-of.c > @@ -0,0 +1,78 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * DesignWare PWM Controller driver OF > + * > + * Copyright (C) 2022 SiFive, Inc. > + */ > + > +#include <linux/bitops.h> > +#include <linux/export.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/clk.h> > +#include <linux/platform_device.h> > +#include <linux/pm_runtime.h> > +#include <linux/pwm.h> > +#include <linux/io.h> > + > +#include "pwm-dwc.h" > + > +static int dwc_pwm_plat_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct dwc_pwm *dwc; > + int ret; > + > + dwc = dwc_pwm_alloc(dev); > + if (!dwc) > + return -ENOMEM; > + > + dwc->base = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(dwc->base)) > + return dev_err_probe(dev, PTR_ERR(dwc->base), > + "failed to map IO\n"); devm_platform_ioremap_resource() already emits an error message. > + > + dwc->clk = devm_clk_get_enabled(dev, "timer"); > + if (IS_ERR(dwc->clk)) > + return dev_err_probe(dev, PTR_ERR(dwc->clk), > + "failed to get timer clock\n"); > + > + clk_prepare_enable(dwc->clk); You don't need clk_prepare_enable() as you used devm_clk_get_enabled(). (Otherwise, when keeping clk_prepare_enable() you need to check the return value.) > + dwc->clk_ns = NSEC_PER_SEC / clk_get_rate(dwc->clk); I think I already pointed out this is non-optimal. Later you use clk_ns in __dwc_pwm_configure_timer(): tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, dwc->clk_ns); So what you really want here is: tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * clk_get_rate(dwc->clk), NSEC_PER_SEC); With for example clk_get_rate(dwc->clk) = 201171875 and duty_cycle = 4096 you now get clk_ns = 4 (while the exact value is 4.97087..), tmp = 1024, while the exact value is 824. So the idea is to add a clkrate member to the private driver struct, let it default to 100000000 for the pci case and use the line I suggested above. > + > + ret = devm_pwmchip_add(dev, &dwc->chip); > + if (ret) > + return ret; > + > + return 0; This is equivalent to return ret; > +} > + > +static int dwc_pwm_plat_remove(struct platform_device *pdev) > +{ > + struct dwc_pwm *dwc = platform_get_drvdata(pdev); > + > + clk_disable_unprepare(dwc->clk); > + return 0; > +} When dropping clk_prepare_enable() the .remove callback can go away, too. > + > +static const struct of_device_id dwc_pwm_dt_ids[] = { > + { .compatible = "snps,dw-apb-timers-pwm2" }, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, dwc_pwm_dt_ids); > + > +static struct platform_driver dwc_pwm_plat_driver = { > + .driver = { > + .name = "dwc-pwm", > + .of_match_table = dwc_pwm_dt_ids, > + }, > + .probe = dwc_pwm_plat_probe, > + .remove = dwc_pwm_plat_remove, > +}; > + > +module_platform_driver(dwc_pwm_plat_driver); > + > +MODULE_ALIAS("platform:dwc-pwm-of"); > +MODULE_AUTHOR("Ben Dooks <ben.dooks@sifive.com>"); > +MODULE_DESCRIPTION("DesignWare PWM Controller"); > +MODULE_LICENSE("GPL"); Best regards Uwe
Hello, On Tue, Aug 16, 2022 at 10:14:52PM +0100, Ben Dooks wrote: > The dwc pwm controller can be used in non-PCI systems, so allow > either platform or OF based probing. > > Signed-off-by: Ben Dooks <ben.dooks@sifive.com> > --- > v4: > - split the of code out of the core > - moved the compile test code earlier > - fixed review comments > - used NS_PER_SEC > - use devm_clk_get_enabled > v3: > - changed compatible name > --- > drivers/pwm/Kconfig | 9 +++++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-dwc-of.c | 78 ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 88 insertions(+) > create mode 100644 drivers/pwm/pwm-dwc-of.c > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > index a9f1c554db2b..f1735653365f 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -192,6 +192,15 @@ config PWM_DWC_PCI > To compile this driver as a module, choose M here: the module > will be called pwm-dwc-pci. > > +config PWM_DWC_OF > + tristate "DesignWare PWM Controller (OF bus) There is a missing " which results in: drivers/pwm/Kconfig:196:warning: multi-line strings not supported Best regards Uwe
On 15/09/2022 08:24, Uwe Kleine-König wrote: > Hello, > > On Tue, Aug 16, 2022 at 10:14:52PM +0100, Ben Dooks wrote: >> The dwc pwm controller can be used in non-PCI systems, so allow >> either platform or OF based probing. >> >> Signed-off-by: Ben Dooks <ben.dooks@sifive.com> >> --- >> v4: >> - split the of code out of the core >> - moved the compile test code earlier >> - fixed review comments >> - used NS_PER_SEC >> - use devm_clk_get_enabled >> v3: >> - changed compatible name >> --- >> drivers/pwm/Kconfig | 9 +++++ >> drivers/pwm/Makefile | 1 + >> drivers/pwm/pwm-dwc-of.c | 78 ++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 88 insertions(+) >> create mode 100644 drivers/pwm/pwm-dwc-of.c >> >> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig >> index a9f1c554db2b..f1735653365f 100644 >> --- a/drivers/pwm/Kconfig >> +++ b/drivers/pwm/Kconfig >> @@ -192,6 +192,15 @@ config PWM_DWC_PCI >> To compile this driver as a module, choose M here: the module >> will be called pwm-dwc-pci. >> >> +config PWM_DWC_OF >> + tristate "DesignWare PWM Controller (OF bus) > > There is a missing " which results in: > > drivers/pwm/Kconfig:196:warning: multi-line strings not supported > > Best regards > Uwe Thanks, fixed.
On 14/09/2022 17:47, Uwe Kleine-König wrote: > On Tue, Aug 16, 2022 at 10:14:52PM +0100, Ben Dooks wrote: >> The dwc pwm controller can be used in non-PCI systems, so allow >> either platform or OF based probing. >> >> Signed-off-by: Ben Dooks <ben.dooks@sifive.com> >> --- >> v4: >> - split the of code out of the core >> - moved the compile test code earlier >> - fixed review comments >> - used NS_PER_SEC >> - use devm_clk_get_enabled >> v3: >> - changed compatible name >> --- >> drivers/pwm/Kconfig | 9 +++++ >> drivers/pwm/Makefile | 1 + >> drivers/pwm/pwm-dwc-of.c | 78 ++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 88 insertions(+) >> create mode 100644 drivers/pwm/pwm-dwc-of.c >> >> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig >> index a9f1c554db2b..f1735653365f 100644 >> --- a/drivers/pwm/Kconfig >> +++ b/drivers/pwm/Kconfig >> @@ -192,6 +192,15 @@ config PWM_DWC_PCI >> To compile this driver as a module, choose M here: the module >> will be called pwm-dwc-pci. >> >> +config PWM_DWC_OF >> + tristate "DesignWare PWM Controller (OF bus) >> + depends on PWM_DWC && OF >> + help >> + PWM driver for Synopsys DWC PWM Controller on an OF bus. >> + >> + To compile this driver as a module, choose M here: the module >> + will be called pwm-dwc-of. >> + >> 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 a70d36623129..d1fd1641f077 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-$(CONFIG_PWM_DWC_OF) += pwm-dwc-of.o >> obj-$(CONFIG_PWM_DWC_PCI) += pwm-dwc-pci.o >> obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o >> obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o >> diff --git a/drivers/pwm/pwm-dwc-of.c b/drivers/pwm/pwm-dwc-of.c >> new file mode 100644 >> index 000000000000..d18fac287325 >> --- /dev/null >> +++ b/drivers/pwm/pwm-dwc-of.c >> @@ -0,0 +1,78 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * DesignWare PWM Controller driver OF >> + * >> + * Copyright (C) 2022 SiFive, Inc. >> + */ >> + >> +#include <linux/bitops.h> >> +#include <linux/export.h> >> +#include <linux/kernel.h> >> +#include <linux/module.h> >> +#include <linux/clk.h> >> +#include <linux/platform_device.h> >> +#include <linux/pm_runtime.h> >> +#include <linux/pwm.h> >> +#include <linux/io.h> >> + >> +#include "pwm-dwc.h" >> + >> +static int dwc_pwm_plat_probe(struct platform_device *pdev) >> +{ >> + struct device *dev = &pdev->dev; >> + struct dwc_pwm *dwc; >> + int ret; >> + >> + dwc = dwc_pwm_alloc(dev); >> + if (!dwc) >> + return -ENOMEM; >> + >> + dwc->base = devm_platform_ioremap_resource(pdev, 0); >> + if (IS_ERR(dwc->base)) >> + return dev_err_probe(dev, PTR_ERR(dwc->base), >> + "failed to map IO\n"); > > devm_platform_ioremap_resource() already emits an error message. ok, fixed >> + >> + dwc->clk = devm_clk_get_enabled(dev, "timer"); >> + if (IS_ERR(dwc->clk)) >> + return dev_err_probe(dev, PTR_ERR(dwc->clk), >> + "failed to get timer clock\n"); >> + >> + clk_prepare_enable(dwc->clk); > > You don't need clk_prepare_enable() as you used devm_clk_get_enabled(). > > (Otherwise, when keeping clk_prepare_enable() you need to check the > return value.) ok, fixed. I didn't notice that when changing to devm_ > >> + dwc->clk_ns = NSEC_PER_SEC / clk_get_rate(dwc->clk); > > I think I already pointed out this is non-optimal. > > Later you use clk_ns in __dwc_pwm_configure_timer(): > > tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, dwc->clk_ns); > > So what you really want here is: > > tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * clk_get_rate(dwc->clk), NSEC_PER_SEC); > > With for example clk_get_rate(dwc->clk) = 201171875 and duty_cycle = > 4096 you now get clk_ns = 4 (while the exact value is 4.97087..), tmp = > 1024, while the exact value is 824. > > So the idea is to add a clkrate member to the private driver struct, let > it default to 100000000 for the pci case and use the line I suggested > above. ok, will consider keeping the rate in hz and modifiying the pci version to use 10 * NSEC_PER_SEC for the rate. I've been trying to avoid changing the pci case, but I think for anything with a clk pointer we should be doing clk_get_rate in the calc code > >> + >> + ret = devm_pwmchip_add(dev, &dwc->chip); >> + if (ret) >> + return ret; >> + >> + return 0; > > This is equivalent to > > return ret; Will sort that out. >> +} >> + >> +static int dwc_pwm_plat_remove(struct platform_device *pdev) >> +{ >> + struct dwc_pwm *dwc = platform_get_drvdata(pdev); >> + >> + clk_disable_unprepare(dwc->clk); >> + return 0; >> +} > > When dropping clk_prepare_enable() the .remove callback can go away, > too. thanks, spotted that one a while ago. >> + >> +static const struct of_device_id dwc_pwm_dt_ids[] = { >> + { .compatible = "snps,dw-apb-timers-pwm2" }, >> + { }, >> +}; >> +MODULE_DEVICE_TABLE(of, dwc_pwm_dt_ids); >> + >> +static struct platform_driver dwc_pwm_plat_driver = { >> + .driver = { >> + .name = "dwc-pwm", >> + .of_match_table = dwc_pwm_dt_ids, >> + }, >> + .probe = dwc_pwm_plat_probe, >> + .remove = dwc_pwm_plat_remove, >> +}; >> + >> +module_platform_driver(dwc_pwm_plat_driver); >> + >> +MODULE_ALIAS("platform:dwc-pwm-of"); >> +MODULE_AUTHOR("Ben Dooks <ben.dooks@sifive.com>"); >> +MODULE_DESCRIPTION("DesignWare PWM Controller"); >> +MODULE_LICENSE("GPL"); > > Best regards > Uwe >
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index a9f1c554db2b..f1735653365f 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -192,6 +192,15 @@ config PWM_DWC_PCI To compile this driver as a module, choose M here: the module will be called pwm-dwc-pci. +config PWM_DWC_OF + tristate "DesignWare PWM Controller (OF bus) + depends on PWM_DWC && OF + help + PWM driver for Synopsys DWC PWM Controller on an OF bus. + + To compile this driver as a module, choose M here: the module + will be called pwm-dwc-of. + 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 a70d36623129..d1fd1641f077 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-$(CONFIG_PWM_DWC_OF) += pwm-dwc-of.o obj-$(CONFIG_PWM_DWC_PCI) += pwm-dwc-pci.o obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o diff --git a/drivers/pwm/pwm-dwc-of.c b/drivers/pwm/pwm-dwc-of.c new file mode 100644 index 000000000000..d18fac287325 --- /dev/null +++ b/drivers/pwm/pwm-dwc-of.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * DesignWare PWM Controller driver OF + * + * Copyright (C) 2022 SiFive, Inc. + */ + +#include <linux/bitops.h> +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/clk.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/pwm.h> +#include <linux/io.h> + +#include "pwm-dwc.h" + +static int dwc_pwm_plat_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct dwc_pwm *dwc; + int ret; + + dwc = dwc_pwm_alloc(dev); + if (!dwc) + return -ENOMEM; + + dwc->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(dwc->base)) + return dev_err_probe(dev, PTR_ERR(dwc->base), + "failed to map IO\n"); + + dwc->clk = devm_clk_get_enabled(dev, "timer"); + if (IS_ERR(dwc->clk)) + return dev_err_probe(dev, PTR_ERR(dwc->clk), + "failed to get timer clock\n"); + + clk_prepare_enable(dwc->clk); + dwc->clk_ns = NSEC_PER_SEC / clk_get_rate(dwc->clk); + + ret = devm_pwmchip_add(dev, &dwc->chip); + if (ret) + return ret; + + return 0; +} + +static int dwc_pwm_plat_remove(struct platform_device *pdev) +{ + struct dwc_pwm *dwc = platform_get_drvdata(pdev); + + clk_disable_unprepare(dwc->clk); + return 0; +} + +static const struct of_device_id dwc_pwm_dt_ids[] = { + { .compatible = "snps,dw-apb-timers-pwm2" }, + { }, +}; +MODULE_DEVICE_TABLE(of, dwc_pwm_dt_ids); + +static struct platform_driver dwc_pwm_plat_driver = { + .driver = { + .name = "dwc-pwm", + .of_match_table = dwc_pwm_dt_ids, + }, + .probe = dwc_pwm_plat_probe, + .remove = dwc_pwm_plat_remove, +}; + +module_platform_driver(dwc_pwm_plat_driver); + +MODULE_ALIAS("platform:dwc-pwm-of"); +MODULE_AUTHOR("Ben Dooks <ben.dooks@sifive.com>"); +MODULE_DESCRIPTION("DesignWare PWM Controller"); +MODULE_LICENSE("GPL");
The dwc pwm controller can be used in non-PCI systems, so allow either platform or OF based probing. Signed-off-by: Ben Dooks <ben.dooks@sifive.com> --- v4: - split the of code out of the core - moved the compile test code earlier - fixed review comments - used NS_PER_SEC - use devm_clk_get_enabled v3: - changed compatible name --- drivers/pwm/Kconfig | 9 +++++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-dwc-of.c | 78 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 88 insertions(+) create mode 100644 drivers/pwm/pwm-dwc-of.c