On Fri, 16 Jun 2017, Fabrice Gasnier wrote: > STM32 Low Power Timer hardware block can be used for: > - PWM generation > - IIO trigger (in sync with PWM) > - IIO quadrature encoder counter > PWM and IIO timer configuration are mixed in the same registers so > we need a multi fonction driver to be able to share those registers. > > Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx> > --- > drivers/mfd/Kconfig | 15 ++++++ > drivers/mfd/Makefile | 1 + > drivers/mfd/stm32-lptimer.c | 110 ++++++++++++++++++++++++++++++++++++++ > include/linux/mfd/stm32-lptimer.h | 55 +++++++++++++++++++ > 4 files changed, 181 insertions(+) > create mode 100644 drivers/mfd/stm32-lptimer.c > create mode 100644 include/linux/mfd/stm32-lptimer.h > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig > index 3eb5c93..32c1f3f 100644 > --- a/drivers/mfd/Kconfig > +++ b/drivers/mfd/Kconfig > @@ -1683,6 +1683,21 @@ config MFD_STW481X > in various ST Microelectronics and ST-Ericsson embedded > Nomadik series. > > +config MFD_STM32_LPTIMER > + tristate "Support for STM32 low power timer" It think this should be "Low Power Timer" throughout. Or even "Low-Power Timer". You decide. > + depends on (ARCH_STM32 && OF) || COMPILE_TEST > + select MFD_CORE > + select REGMAP > + select REGMAP_MMIO > + select RESET_CONTROLLER > + help > + Select this option to enable STM32 low power timer driver > + used for PWM, IIO trigger, IIO encoder and counter. This driver "Counter" > + allows to share the resources between these drivers. "Shared resources are also dealt with here." Or similar. > + To compile this driver as a module, choose M here: the > + module will be called stm32-lptimer. > + > config MFD_STM32_TIMERS > tristate "Support for STM32 Timers" > depends on (ARCH_STM32 && OF) || COMPILE_TEST > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile > index c16bf1e..a5308d8 100644 > --- a/drivers/mfd/Makefile > +++ b/drivers/mfd/Makefile > @@ -219,5 +219,6 @@ obj-$(CONFIG_MFD_MT6397) += mt6397-core.o > obj-$(CONFIG_MFD_ALTERA_A10SR) += altera-a10sr.o > obj-$(CONFIG_MFD_SUN4I_GPADC) += sun4i-gpadc.o > > +obj-$(CONFIG_MFD_STM32_LPTIMER) += stm32-lptimer.o > obj-$(CONFIG_MFD_STM32_TIMERS) += stm32-timers.o > obj-$(CONFIG_MFD_MXS_LRADC) += mxs-lradc.o > diff --git a/drivers/mfd/stm32-lptimer.c b/drivers/mfd/stm32-lptimer.c > new file mode 100644 > index 0000000..fcfefa3 > --- /dev/null > +++ b/drivers/mfd/stm32-lptimer.c > @@ -0,0 +1,110 @@ > +/* > + * This file is part of STM32 low-power timer driver This is a separate driver. It isn't part of anything. "STM32 Low Power Timer parent driver". > + * Copyright (C) STMicroelectronics 2017 > + * > + * Author: Fabrice Gasnier <fabrice.gasnier@xxxxxx> '\n' here. > + * Inspired from: stm32-timers from Benjamin Gaignard "Inspired by Benjamin Gaignard's stm32-timers driver" > + * License terms: GNU General Public License (GPL), version 2 > + */ > + > +#include <linux/mfd/stm32-lptimer.h> > +#include <linux/module.h> > +#include <linux/of_platform.h> > +#include <linux/reset.h> > + > +static const struct regmap_config stm32_lptimer_regmap_cfg = { > + .reg_bits = 32, > + .val_bits = 32, > + .reg_stride = sizeof(u32), > + .max_register = 0x3fc, This should be defined. > +}; > + > +static int stm32_lptimer_detect_encoder(struct stm32_lptimer *ddata) > +{ > + u32 val, enc = STM32_LPTIM_ENC; Why have enc? Why not just use STM32_LPTIM_ENC? > + int ret; > + > + /* > + * Quadrature encoder mode bit can only be written and read back when > + * LP Timer supports is. "it" > + */ > + ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR, enc, enc); > + if (ret) > + return ret; '\n' here. > + ret = regmap_read(ddata->regmap, STM32_LPTIM_CFGR, &val); > + if (ret) > + return ret; '\n' here. > + ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR, enc, 0); > + if (ret) > + return ret; '\n' here. > + ddata->has_encoder = !!val; > + > + return 0; > +} > + > +static int stm32_lptimer_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct stm32_lptimer *ddata; > + struct reset_control *rst; This looks quite a lot like 'ret'. Just use 'reset'. > + struct resource *res; > + void __iomem *mmio; > + int ret; > + > + ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); > + if (!ddata) > + return -ENOMEM; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + mmio = devm_ioremap_resource(dev, res); > + if (IS_ERR(mmio)) > + return PTR_ERR(mmio); > + > + ddata->regmap = devm_regmap_init_mmio_clk(dev, "int", mmio, Is that what the clock is called in the datasheet? > + &stm32_lptimer_regmap_cfg); > + if (IS_ERR(ddata->regmap)) > + return PTR_ERR(ddata->regmap); > + > + ddata->clk = devm_clk_get(dev, NULL); > + if (IS_ERR(ddata->clk)) > + return PTR_ERR(ddata->clk); > + > + rst = devm_reset_control_get_optional(dev, NULL); > + if (IS_ERR(rst)) > + return PTR_ERR(rst); > + > + if (rst) { > + reset_control_assert(rst); > + reset_control_deassert(rst); > + } This is odd. Please provide a comment as to why you're doing this. > + ret = stm32_lptimer_detect_encoder(ddata); > + if (ret) > + return ret; > + > + platform_set_drvdata(pdev, ddata); > + > + return devm_of_platform_populate(&pdev->dev); > +} > + > +static const struct of_device_id stm32_lptimer_of_match[] = { > + { .compatible = "st,stm32-lptimer", }, > + { /* end node */ }, No need for the comment. > +}; > +MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match); > + > +static struct platform_driver stm32_lptimer_driver = { > + .probe = stm32_lptimer_probe, > + .driver = { > + .name = "stm32-lptimer", > + .of_match_table = stm32_lptimer_of_match, > + }, > +}; > +module_platform_driver(stm32_lptimer_driver); > + > +MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@xxxxxx>"); > +MODULE_DESCRIPTION("STMicroelectronics STM32 Low Power Timer"); > +MODULE_ALIAS("platform:stm32-lptimer"); > +MODULE_LICENSE("GPL v2"); > diff --git a/include/linux/mfd/stm32-lptimer.h b/include/linux/mfd/stm32-lptimer.h > new file mode 100644 > index 0000000..72bc9be > --- /dev/null > +++ b/include/linux/mfd/stm32-lptimer.h > @@ -0,0 +1,55 @@ > +/* > + * This file is part of STM32 low-power timer driver > + * > + * Copyright (C) STMicroelectronics 2016 > + * > + * Author: Fabrice Gasnier <fabrice.gasnier@xxxxxx> > + * Inspired from: stm32-timers Same as the comments I provided for the *.c file above. > + * License terms: GNU General Public License (GPL), version 2 > + */ > + > +#ifndef _LINUX_STM32_LPTIMER_H_ > +#define _LINUX_STM32_LPTIMER_H_ > + > +#include <linux/clk.h> > +#include <linux/regmap.h> > + > +#define STM32_LPTIM_ISR 0x00 /* Interrupt and Status Reg */ > +#define STM32_LPTIM_ICR 0x04 /* Interrupt Clear Reg */ > +#define STM32_LPTIM_IER 0x08 /* Interrupt Enable Reg */ > +#define STM32_LPTIM_CFGR 0x0C /* Configuration Reg */ > +#define STM32_LPTIM_CR 0x10 /* Control Reg */ > +#define STM32_LPTIM_CMP 0x14 /* Compare Reg */ > +#define STM32_LPTIM_ARR 0x18 /* Autoreload Reg */ > +#define STM32_LPTIM_CNT 0x1C /* Counter Reg */ > + > +/* STM32_LPTIM_ISR - bit fields */ > +#define STM32_LPTIM_CMPOK_ARROK GENMASK(4, 3) > +#define STM32_LPTIM_ARROK BIT(4) > +#define STM32_LPTIM_CMPOK BIT(3) > + > +/* STM32_LPTIM_ICR - bit fields */ > +#define STM32_LPTIM_CMPOKCF_ARROKCF GENMASK(4, 3) > + > +/* STM32_LPTIM_CR - bit fields */ > +#define STM32_LPTIM_CNTSTRT BIT(2) > +#define STM32_LPTIM_ENABLE BIT(0) > + > +/* STM32_LPTIM_CFGR - bit fields */ > +#define STM32_LPTIM_ENC BIT(24) > +#define STM32_LPTIM_COUNTMODE BIT(23) > +#define STM32_LPTIM_WAVPOL BIT(21) > +#define STM32_LPTIM_PRESC GENMASK(11, 9) > +#define STM32_LPTIM_CKPOL GENMASK(2, 1) > + > +/* STM32_LPTIM_ARR */ > +#define STM32_LPTIM_MAX_ARR 0xFFFF > + > +struct stm32_lptimer { > + struct clk *clk; > + struct regmap *regmap; > + bool has_encoder; > +}; Please provide a kerneldoc type header for this struct. > +#endif -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html