| Message ID | 20220816211454.237751-1-ben.dooks@sifive.com |
|---|---|
| Headers | show |
| Series | RFC on synpsys pwm driver changes | expand |
Hello, On Tue, Aug 16, 2022 at 10:14:46PM +0100, Ben Dooks wrote: > Allow dwc driver to be built with COMPILE_TEST should allow > better coverage when build testing. > > Signed-off-by: Ben Dooks <ben.dooks@sifive.com> Very welcome, so: Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Thanks Uwe
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
On Tue, Aug 16, 2022 at 10:14:53PM +0100, Ben Dooks wrote: > Add snps,pwm-number property to indicate if the block does not have > all 8 of the PWM blocks. > > Not sure if this should be a general PWM property consider optional > for all PWM types, so have added a specific one here (there is only > one other controller with a property for PWM count at the moment) > > Signed-off-by: Ben Dooks <ben.dooks@sifive.com> > --- > drivers/pwm/pwm-dwc-of.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/pwm/pwm-dwc-of.c b/drivers/pwm/pwm-dwc-of.c > index d18fac287325..65c7e6621bba 100644 > --- a/drivers/pwm/pwm-dwc-of.c > +++ b/drivers/pwm/pwm-dwc-of.c > @@ -21,12 +21,20 @@ static int dwc_pwm_plat_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > struct dwc_pwm *dwc; > + u32 nr_pwm; > int ret; > > dwc = dwc_pwm_alloc(dev); > if (!dwc) > return -ENOMEM; > > + if (!device_property_read_u32(dev, "snps,pwm-number", &nr_pwm)) { > + if (nr_pwm > DWC_TIMERS_TOTAL) > + dev_err(dev, "too many PWMs specified (%d)\n", nr_pwm); Maybe dev_err(dev, "too many PWMs specified (%d), falling back to " #DWC_TIMERS_TOTAL "\n", nr_pwm); to make it obvious the error doesn't prevent probing the device. Or you believe the dtb and use whatever it specifies. > + else > + dwc->chip.npwm = nr_pwm; > + } > + > dwc->base = devm_platform_ioremap_resource(pdev, 0); > if (IS_ERR(dwc->base)) > return dev_err_probe(dev, PTR_ERR(dwc->base), 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.
Hello Thierry, On Tue, Aug 16, 2022 at 10:14:46PM +0100, Ben Dooks wrote: > Allow dwc driver to be built with COMPILE_TEST should allow > better coverage when build testing. > > Signed-off-by: Ben Dooks <ben.dooks@sifive.com> You marked this patch as "changes requested" without feedback. This patch is part of a bigger series, but makes sense to be applied stand alone, too. Ditto for patch #3 IMHO. Best regards Uwe
New version of the pwm timers patch, hopefully all review comments are sorted out, however I have not had time to fully test this and I do not have a PCI system to test it on either. The series has been moved around a bit to try to get some of the simpler changes in before splitting and to make the OF driver a single addition. v4: - split pci and of into new modules - fixup review comments - fix typos in dt-bindings v3: - change the compatible name - squash down pwm count patch - fixup patch naming v2: - fix #pwm-cells count to be 3 - fix indetation - merge the two clock patches - add HAS_IOMEM as a config dependency Ben Dooks (10): dt-bindings: pwm: Document Synopsys DesignWare snps,pwm-dw-apb-timers-pwm2 pwm: dwc: allow driver to be built with COMPILE_TEST pwm: dwc: change &pci->dev to dev in probe pwm: dwc: move memory alloc to own function pwm: dwc: use devm_pwmchip_add pwm: dwc: split pci out of core driver pwm: dwc: make timer clock configurable pwm: dwc: add of/platform support pwm: dwc: add snps,pwm-number to limit pwm count pwm: dwc: add PWM bit unset in get_state call .../bindings/pwm/snps,dw-apb-timers-pwm2.yaml | 69 ++++++ drivers/pwm/Kconfig | 24 ++- drivers/pwm/Makefile | 2 + drivers/pwm/pwm-dwc-of.c | 86 ++++++++ drivers/pwm/pwm-dwc-pci.c | 134 ++++++++++++ drivers/pwm/pwm-dwc.c | 197 +++--------------- drivers/pwm/pwm-dwc.h | 60 ++++++ 7 files changed, 402 insertions(+), 170 deletions(-) create mode 100644 Documentation/devicetree/bindings/pwm/snps,dw-apb-timers-pwm2.yaml create mode 100644 drivers/pwm/pwm-dwc-of.c create mode 100644 drivers/pwm/pwm-dwc-pci.c create mode 100644 drivers/pwm/pwm-dwc.h