From e8924005b4e7964313536547d4b73406330be26d Mon Sep 17 00:00:00 2001 From: Fabrice Gasnier Date: Mon, 28 Aug 2017 12:04:07 +0200 Subject: [PATCH] mfd: Add STM32 LPTimer driver 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 Signed-off-by: Lee Jones --- drivers/mfd/Kconfig | 14 +++++ drivers/mfd/Makefile | 1 + drivers/mfd/stm32-lptimer.c | 107 ++++++++++++++++++++++++++++++++++++++ include/linux/mfd/stm32-lptimer.h | 62 ++++++++++++++++++++++ 4 files changed, 184 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 94ad2c1..fe76db9 100644 --- a/drivers/mfd/Kconfig +++ b/drivers/mfd/Kconfig @@ -1723,6 +1723,20 @@ config MFD_STW481X in various ST Microelectronics and ST-Ericsson embedded Nomadik series. +config MFD_STM32_LPTIMER + tristate "Support for STM32 Low-Power Timer" + depends on (ARCH_STM32 && OF) || COMPILE_TEST + select MFD_CORE + select REGMAP + select REGMAP_MMIO + help + Select this option to enable STM32 Low-Power Timer driver + used for PWM, IIO Trigger, IIO Encoder and Counter. Shared + resources are also dealt with here. + + 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 080793b..b80b1a3 100644 --- a/drivers/mfd/Makefile +++ b/drivers/mfd/Makefile @@ -221,5 +221,6 @@ 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..075330a --- /dev/null +++ b/drivers/mfd/stm32-lptimer.c @@ -0,0 +1,107 @@ +/* + * STM32 Low-Power Timer parent driver. + * + * Copyright (C) STMicroelectronics 2017 + * + * Author: Fabrice Gasnier + * + * Inspired by Benjamin Gaignard's stm32-timers driver + * + * License terms: GNU General Public License (GPL), version 2 + */ + +#include +#include +#include + +#define STM32_LPTIM_MAX_REGISTER 0x3fc + +static const struct regmap_config stm32_lptimer_regmap_cfg = { + .reg_bits = 32, + .val_bits = 32, + .reg_stride = sizeof(u32), + .max_register = STM32_LPTIM_MAX_REGISTER, +}; + +static int stm32_lptimer_detect_encoder(struct stm32_lptimer *ddata) +{ + u32 val; + int ret; + + /* + * Quadrature encoder mode bit can only be written and read back when + * Low-Power Timer supports it. + */ + ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR, + STM32_LPTIM_ENC, STM32_LPTIM_ENC); + if (ret) + return ret; + + ret = regmap_read(ddata->regmap, STM32_LPTIM_CFGR, &val); + if (ret) + return ret; + + ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR, + STM32_LPTIM_ENC, 0); + if (ret) + return ret; + + ddata->has_encoder = !!(val & STM32_LPTIM_ENC); + + return 0; +} + +static int stm32_lptimer_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct stm32_lptimer *ddata; + 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, "mux", mmio, + &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); + + 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", }, + {}, +}; +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 "); +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..77c7cf4 --- /dev/null +++ b/include/linux/mfd/stm32-lptimer.h @@ -0,0 +1,62 @@ +/* + * STM32 Low-Power Timer parent driver. + * + * Copyright (C) STMicroelectronics 2017 + * + * Author: Fabrice Gasnier + * + * Inspired by Benjamin Gaignard's stm32-timers driver + * + * License terms: GNU General Public License (GPL), version 2 + */ + +#ifndef _LINUX_STM32_LPTIMER_H_ +#define _LINUX_STM32_LPTIMER_H_ + +#include +#include + +#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 - STM32 Low-Power Timer data assigned by parent device + * @clk: clock reference for this instance + * @regmap: register map reference for this instance + * @has_encoder: indicates this Low-Power Timer supports encoder mode + */ +struct stm32_lptimer { + struct clk *clk; + struct regmap *regmap; + bool has_encoder; +}; + +#endif -- 2.7.4