diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-iio-lptimer-stm32 | 57 | ||||
| -rw-r--r-- | drivers/iio/counter/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/iio/counter/Makefile | 1 | ||||
| -rw-r--r-- | drivers/iio/counter/stm32-lptimer-cnt.c | 383 |
4 files changed, 450 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-lptimer-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-lptimer-stm32 new file mode 100644 index 000000000000..ad2cc63e4bf8 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-iio-lptimer-stm32 @@ -0,0 +1,57 @@ +What: /sys/bus/iio/devices/iio:deviceX/in_count0_preset +KernelVersion: 4.13 +Contact: fabrice.gasnier@st.com +Description: + Reading returns the current preset value. Writing sets the + preset value. Encoder counts continuously from 0 to preset + value, depending on direction (up/down). + +What: /sys/bus/iio/devices/iio:deviceX/in_count_quadrature_mode_available +KernelVersion: 4.13 +Contact: fabrice.gasnier@st.com +Description: + Reading returns the list possible quadrature modes. + +What: /sys/bus/iio/devices/iio:deviceX/in_count0_quadrature_mode +KernelVersion: 4.13 +Contact: fabrice.gasnier@st.com +Description: + Configure the device counter quadrature modes: + - non-quadrature: + Encoder IN1 input servers as the count input (up + direction). + - quadrature: + Encoder IN1 and IN2 inputs are mixed to get direction + and count. + +What: /sys/bus/iio/devices/iio:deviceX/in_count_polarity_available +KernelVersion: 4.13 +Contact: fabrice.gasnier@st.com +Description: + Reading returns the list possible active edges. + +What: /sys/bus/iio/devices/iio:deviceX/in_count0_polarity +KernelVersion: 4.13 +Contact: fabrice.gasnier@st.com +Description: + Configure the device encoder/counter active edge: + - rising-edge + - falling-edge + - both-edges + + In non-quadrature mode, device counts up on active edge. + In quadrature mode, encoder counting scenarios are as follows: + ---------------------------------------------------------------- + | Active | Level on | IN1 signal | IN2 signal | + | edge | opposite |------------------------------------------ + | | signal | Rising | Falling | Rising | Falling | + ---------------------------------------------------------------- + | Rising | High -> | Down | - | Up | - | + | edge | Low -> | Up | - | Down | - | + ---------------------------------------------------------------- + | Falling | High -> | - | Up | - | Down | + | edge | Low -> | - | Down | - | Up | + ---------------------------------------------------------------- + | Both | High -> | Down | Up | Up | Down | + | edges | Low -> | Up | Down | Down | Up | + ---------------------------------------------------------------- diff --git a/drivers/iio/counter/Kconfig b/drivers/iio/counter/Kconfig index b37e5fc03149..474e1ac4e7c0 100644 --- a/drivers/iio/counter/Kconfig +++ b/drivers/iio/counter/Kconfig @@ -21,4 +21,13 @@ config 104_QUAD_8 The base port addresses for the devices may be configured via the base array module parameter. +config STM32_LPTIMER_CNT + tristate "STM32 LP Timer encoder counter driver" + depends on MFD_STM32_LPTIMER || COMPILE_TEST + help + Select this option to enable STM32 Low-Power Timer quadrature encoder + and counter driver. + + To compile this driver as a module, choose M here: the + module will be called stm32-lptimer-cnt. endmenu diff --git a/drivers/iio/counter/Makefile b/drivers/iio/counter/Makefile index 007e88411648..1b9a896eb488 100644 --- a/drivers/iio/counter/Makefile +++ b/drivers/iio/counter/Makefile @@ -5,3 +5,4 @@ # When adding new entries keep the list in alphabetical order obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o +obj-$(CONFIG_STM32_LPTIMER_CNT) += stm32-lptimer-cnt.o diff --git a/drivers/iio/counter/stm32-lptimer-cnt.c b/drivers/iio/counter/stm32-lptimer-cnt.c new file mode 100644 index 000000000000..1c5909bb1605 --- /dev/null +++ b/drivers/iio/counter/stm32-lptimer-cnt.c @@ -0,0 +1,383 @@ +/* + * STM32 Low-Power Timer Encoder and Counter driver + * + * Copyright (C) STMicroelectronics 2017 + * + * Author: Fabrice Gasnier <fabrice.gasnier@st.com> + * + * Inspired by 104-quad-8 and stm32-timer-trigger drivers. + * + * License terms: GNU General Public License (GPL), version 2 + */ + +#include <linux/bitfield.h> +#include <linux/iio/iio.h> +#include <linux/mfd/stm32-lptimer.h> +#include <linux/module.h> +#include <linux/platform_device.h> + +struct stm32_lptim_cnt { + struct device *dev; + struct regmap *regmap; + struct clk *clk; + u32 preset; + u32 polarity; + u32 quadrature_mode; +}; + +static int stm32_lptim_is_enabled(struct stm32_lptim_cnt *priv) +{ + u32 val; + int ret; + + ret = regmap_read(priv->regmap, STM32_LPTIM_CR, &val); + if (ret) + return ret; + + return FIELD_GET(STM32_LPTIM_ENABLE, val); +} + +static int stm32_lptim_set_enable_state(struct stm32_lptim_cnt *priv, + int enable) +{ + int ret; + u32 val; + + val = FIELD_PREP(STM32_LPTIM_ENABLE, enable); + ret = regmap_write(priv->regmap, STM32_LPTIM_CR, val); + if (ret) + return ret; + + if (!enable) { + clk_disable(priv->clk); + return 0; + } + + /* LP timer must be enabled before writing CMP & ARR */ + ret = regmap_write(priv->regmap, STM32_LPTIM_ARR, priv->preset); + if (ret) + return ret; + + ret = regmap_write(priv->regmap, STM32_LPTIM_CMP, 0); + if (ret) + return ret; + + /* ensure CMP & ARR registers are properly written */ + ret = regmap_read_poll_timeout(priv->regmap, STM32_LPTIM_ISR, val, + (val & STM32_LPTIM_CMPOK_ARROK), + 100, 1000); + if (ret) + return ret; + + ret = regmap_write(priv->regmap, STM32_LPTIM_ICR, + STM32_LPTIM_CMPOKCF_ARROKCF); + if (ret) + return ret; + + ret = clk_enable(priv->clk); + if (ret) { + regmap_write(priv->regmap, STM32_LPTIM_CR, 0); + return ret; + } + + /* Start LP timer in continuous mode */ + return regmap_update_bits(priv->regmap, STM32_LPTIM_CR, + STM32_LPTIM_CNTSTRT, STM32_LPTIM_CNTSTRT); +} + +static int stm32_lptim_setup(struct stm32_lptim_cnt *priv, int enable) +{ + u32 mask = STM32_LPTIM_ENC | STM32_LPTIM_COUNTMODE | + STM32_LPTIM_CKPOL | STM32_LPTIM_PRESC; + u32 val; + + /* Setup LP timer encoder/counter and polarity, without prescaler */ + if (priv->quadrature_mode) + val = enable ? STM32_LPTIM_ENC : 0; + else + val = enable ? STM32_LPTIM_COUNTMODE : 0; + val |= FIELD_PREP(STM32_LPTIM_CKPOL, enable ? priv->polarity : 0); + + return regmap_update_bits(priv->regmap, STM32_LPTIM_CFGR, mask, val); +} + +static int stm32_lptim_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct stm32_lptim_cnt *priv = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_ENABLE: + if (val < 0 || val > 1) + return -EINVAL; + + /* Check nobody uses the timer, or already disabled/enabled */ + ret = stm32_lptim_is_enabled(priv); + if ((ret < 0) || (!ret && !val)) + return ret; + if (val && ret) + return -EBUSY; + + ret = stm32_lptim_setup(priv, val); + if (ret) + return ret; + return stm32_lptim_set_enable_state(priv, val); + + default: + return -EINVAL; + } +} + +static int stm32_lptim_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct stm32_lptim_cnt *priv = iio_priv(indio_dev); + u32 dat; + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = regmap_read(priv->regmap, STM32_LPTIM_CNT, &dat); + if (ret) + return ret; + *val = dat; + return IIO_VAL_INT; + + case IIO_CHAN_INFO_ENABLE: + ret = stm32_lptim_is_enabled(priv); + if (ret < 0) + return ret; + *val = ret; + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + /* Non-quadrature mode: scale = 1 */ + *val = 1; + *val2 = 0; + if (priv->quadrature_mode) { + /* + * Quadrature encoder mode: + * - both edges, quarter cycle, scale is 0.25 + * - either rising/falling edge scale is 0.5 + */ + if (priv->polarity > 1) + *val2 = 2; + else + *val2 = 1; + } + return IIO_VAL_FRACTIONAL_LOG2; + + default: + return -EINVAL; + } +} + +static const struct iio_info stm32_lptim_cnt_iio_info = { + .read_raw = stm32_lptim_read_raw, + .write_raw = stm32_lptim_write_raw, + .driver_module = THIS_MODULE, +}; + +static const char *const stm32_lptim_quadrature_modes[] = { + "non-quadrature", + "quadrature", +}; + +static int stm32_lptim_get_quadrature_mode(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct stm32_lptim_cnt *priv = iio_priv(indio_dev); + + return priv->quadrature_mode; +} + +static int stm32_lptim_set_quadrature_mode(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + unsigned int type) +{ + struct stm32_lptim_cnt *priv = iio_priv(indio_dev); + + if (stm32_lptim_is_enabled(priv)) + return -EBUSY; + + priv->quadrature_mode = type; + + return 0; +} + +static const struct iio_enum stm32_lptim_quadrature_mode_en = { + .items = stm32_lptim_quadrature_modes, + .num_items = ARRAY_SIZE(stm32_lptim_quadrature_modes), + .get = stm32_lptim_get_quadrature_mode, + .set = stm32_lptim_set_quadrature_mode, +}; + +static const char * const stm32_lptim_cnt_polarity[] = { + "rising-edge", "falling-edge", "both-edges", +}; + +static int stm32_lptim_cnt_get_polarity(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct stm32_lptim_cnt *priv = iio_priv(indio_dev); + + return priv->polarity; +} + +static int stm32_lptim_cnt_set_polarity(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + unsigned int type) +{ + struct stm32_lptim_cnt *priv = iio_priv(indio_dev); + + if (stm32_lptim_is_enabled(priv)) + return -EBUSY; + + priv->polarity = type; + + return 0; +} + +static const struct iio_enum stm32_lptim_cnt_polarity_en = { + .items = stm32_lptim_cnt_polarity, + .num_items = ARRAY_SIZE(stm32_lptim_cnt_polarity), + .get = stm32_lptim_cnt_get_polarity, + .set = stm32_lptim_cnt_set_polarity, +}; + +static ssize_t stm32_lptim_cnt_get_preset(struct iio_dev *indio_dev, + uintptr_t private, + const struct iio_chan_spec *chan, + char *buf) +{ + struct stm32_lptim_cnt *priv = iio_priv(indio_dev); + + return snprintf(buf, PAGE_SIZE, "%u\n", priv->preset); +} + +static ssize_t stm32_lptim_cnt_set_preset(struct iio_dev *indio_dev, + uintptr_t private, + const struct iio_chan_spec *chan, + const char *buf, size_t len) +{ + struct stm32_lptim_cnt *priv = iio_priv(indio_dev); + int ret; + + if (stm32_lptim_is_enabled(priv)) + return -EBUSY; + + ret = kstrtouint(buf, 0, &priv->preset); + if (ret) + return ret; + + if (priv->preset > STM32_LPTIM_MAX_ARR) + return -EINVAL; + + return len; +} + +/* LP timer with encoder */ +static const struct iio_chan_spec_ext_info stm32_lptim_enc_ext_info[] = { + { + .name = "preset", + .shared = IIO_SEPARATE, + .read = stm32_lptim_cnt_get_preset, + .write = stm32_lptim_cnt_set_preset, + }, + IIO_ENUM("polarity", IIO_SEPARATE, &stm32_lptim_cnt_polarity_en), + IIO_ENUM_AVAILABLE("polarity", &stm32_lptim_cnt_polarity_en), + IIO_ENUM("quadrature_mode", IIO_SEPARATE, + &stm32_lptim_quadrature_mode_en), + IIO_ENUM_AVAILABLE("quadrature_mode", &stm32_lptim_quadrature_mode_en), + {} +}; + +static const struct iio_chan_spec stm32_lptim_enc_channels = { + .type = IIO_COUNT, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_ENABLE) | + BIT(IIO_CHAN_INFO_SCALE), + .ext_info = stm32_lptim_enc_ext_info, + .indexed = 1, +}; + +/* LP timer without encoder (counter only) */ +static const struct iio_chan_spec_ext_info stm32_lptim_cnt_ext_info[] = { + { + .name = "preset", + .shared = IIO_SEPARATE, + .read = stm32_lptim_cnt_get_preset, + .write = stm32_lptim_cnt_set_preset, + }, + IIO_ENUM("polarity", IIO_SEPARATE, &stm32_lptim_cnt_polarity_en), + IIO_ENUM_AVAILABLE("polarity", &stm32_lptim_cnt_polarity_en), + {} +}; + +static const struct iio_chan_spec stm32_lptim_cnt_channels = { + .type = IIO_COUNT, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_ENABLE) | + BIT(IIO_CHAN_INFO_SCALE), + .ext_info = stm32_lptim_cnt_ext_info, + .indexed = 1, +}; + +static int stm32_lptim_cnt_probe(struct platform_device *pdev) +{ + struct stm32_lptimer *ddata = dev_get_drvdata(pdev->dev.parent); + struct stm32_lptim_cnt *priv; + struct iio_dev *indio_dev; + + if (IS_ERR_OR_NULL(ddata)) + return -EINVAL; + + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv)); + if (!indio_dev) + return -ENOMEM; + + priv = iio_priv(indio_dev); + priv->dev = &pdev->dev; + priv->regmap = ddata->regmap; + priv->clk = ddata->clk; + priv->preset = STM32_LPTIM_MAX_ARR; + + indio_dev->name = dev_name(&pdev->dev); + indio_dev->dev.parent = &pdev->dev; + indio_dev->dev.of_node = pdev->dev.of_node; + indio_dev->info = &stm32_lptim_cnt_iio_info; + if (ddata->has_encoder) + indio_dev->channels = &stm32_lptim_enc_channels; + else + indio_dev->channels = &stm32_lptim_cnt_channels; + indio_dev->num_channels = 1; + + platform_set_drvdata(pdev, priv); + + return devm_iio_device_register(&pdev->dev, indio_dev); +} + +static const struct of_device_id stm32_lptim_cnt_of_match[] = { + { .compatible = "st,stm32-lptimer-counter", }, + {}, +}; +MODULE_DEVICE_TABLE(of, stm32_lptim_cnt_of_match); + +static struct platform_driver stm32_lptim_cnt_driver = { + .probe = stm32_lptim_cnt_probe, + .driver = { + .name = "stm32-lptimer-counter", + .of_match_table = stm32_lptim_cnt_of_match, + }, +}; +module_platform_driver(stm32_lptim_cnt_driver); + +MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); +MODULE_ALIAS("platform:stm32-lptimer-counter"); +MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM counter driver"); +MODULE_LICENSE("GPL v2"); |