| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * This file is part of STM32 DAC driver |
| * |
| * Copyright (C) 2017, STMicroelectronics - All Rights Reserved |
| * Authors: Amelie Delaunay <amelie.delaunay@st.com> |
| * Fabrice Gasnier <fabrice.gasnier@st.com> |
| */ |
| |
| #include <linux/bitfield.h> |
| #include <linux/delay.h> |
| #include <linux/iio/iio.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/platform_device.h> |
| #include <linux/pm_runtime.h> |
| |
| #include "stm32-dac-core.h" |
| |
| #define STM32_DAC_CHANNEL_1 1 |
| #define STM32_DAC_CHANNEL_2 2 |
| #define STM32_DAC_IS_CHAN_1(ch) ((ch) & STM32_DAC_CHANNEL_1) |
| |
| #define STM32_DAC_AUTO_SUSPEND_DELAY_MS 2000 |
| |
| /** |
| * struct stm32_dac - private data of DAC driver |
| * @common: reference to DAC common data |
| * @lock: lock to protect against potential races when reading |
| * and update CR, to keep it in sync with pm_runtime |
| */ |
| struct stm32_dac { |
| struct stm32_dac_common *common; |
| struct mutex lock; |
| }; |
| |
| static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel) |
| { |
| struct stm32_dac *dac = iio_priv(indio_dev); |
| u32 en, val; |
| int ret; |
| |
| ret = regmap_read(dac->common->regmap, STM32_DAC_CR, &val); |
| if (ret < 0) |
| return ret; |
| if (STM32_DAC_IS_CHAN_1(channel)) |
| en = FIELD_GET(STM32_DAC_CR_EN1, val); |
| else |
| en = FIELD_GET(STM32_DAC_CR_EN2, val); |
| |
| return !!en; |
| } |
| |
| static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch, |
| bool enable) |
| { |
| struct stm32_dac *dac = iio_priv(indio_dev); |
| struct device *dev = indio_dev->dev.parent; |
| u32 msk = STM32_DAC_IS_CHAN_1(ch) ? STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2; |
| u32 en = enable ? msk : 0; |
| int ret; |
| |
| /* already enabled / disabled ? */ |
| mutex_lock(&dac->lock); |
| ret = stm32_dac_is_enabled(indio_dev, ch); |
| if (ret < 0 || enable == !!ret) { |
| mutex_unlock(&dac->lock); |
| return ret < 0 ? ret : 0; |
| } |
| |
| if (enable) { |
| ret = pm_runtime_resume_and_get(dev); |
| if (ret < 0) { |
| mutex_unlock(&dac->lock); |
| return ret; |
| } |
| } |
| |
| ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en); |
| mutex_unlock(&dac->lock); |
| if (ret < 0) { |
| dev_err(&indio_dev->dev, "%s failed\n", en ? |
| "Enable" : "Disable"); |
| goto err_put_pm; |
| } |
| |
| /* |
| * When HFSEL is set, it is not allowed to write the DHRx register |
| * during 8 clock cycles after the ENx bit is set. It is not allowed |
| * to make software/hardware trigger during this period either. |
| */ |
| if (en && dac->common->hfsel) |
| udelay(1); |
| |
| if (!enable) { |
| pm_runtime_mark_last_busy(dev); |
| pm_runtime_put_autosuspend(dev); |
| } |
| |
| return 0; |
| |
| err_put_pm: |
| if (enable) { |
| pm_runtime_mark_last_busy(dev); |
| pm_runtime_put_autosuspend(dev); |
| } |
| |
| return ret; |
| } |
| |
| static int stm32_dac_get_value(struct stm32_dac *dac, int channel, int *val) |
| { |
| int ret; |
| |
| if (STM32_DAC_IS_CHAN_1(channel)) |
| ret = regmap_read(dac->common->regmap, STM32_DAC_DOR1, val); |
| else |
| ret = regmap_read(dac->common->regmap, STM32_DAC_DOR2, val); |
| |
| return ret ? ret : IIO_VAL_INT; |
| } |
| |
| static int stm32_dac_set_value(struct stm32_dac *dac, int channel, int val) |
| { |
| int ret; |
| |
| if (STM32_DAC_IS_CHAN_1(channel)) |
| ret = regmap_write(dac->common->regmap, STM32_DAC_DHR12R1, val); |
| else |
| ret = regmap_write(dac->common->regmap, STM32_DAC_DHR12R2, val); |
| |
| return ret; |
| } |
| |
| static int stm32_dac_read_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, |
| int *val, int *val2, long mask) |
| { |
| struct stm32_dac *dac = iio_priv(indio_dev); |
| |
| switch (mask) { |
| case IIO_CHAN_INFO_RAW: |
| return stm32_dac_get_value(dac, chan->channel, val); |
| case IIO_CHAN_INFO_SCALE: |
| *val = dac->common->vref_mv; |
| *val2 = chan->scan_type.realbits; |
| return IIO_VAL_FRACTIONAL_LOG2; |
| default: |
| return -EINVAL; |
| } |
| } |
| |
| static int stm32_dac_write_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, |
| int val, int val2, long mask) |
| { |
| struct stm32_dac *dac = iio_priv(indio_dev); |
| |
| switch (mask) { |
| case IIO_CHAN_INFO_RAW: |
| return stm32_dac_set_value(dac, chan->channel, val); |
| default: |
| return -EINVAL; |
| } |
| } |
| |
| static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev, |
| unsigned reg, unsigned writeval, |
| unsigned *readval) |
| { |
| struct stm32_dac *dac = iio_priv(indio_dev); |
| |
| if (!readval) |
| return regmap_write(dac->common->regmap, reg, writeval); |
| else |
| return regmap_read(dac->common->regmap, reg, readval); |
| } |
| |
| static const struct iio_info stm32_dac_iio_info = { |
| .read_raw = stm32_dac_read_raw, |
| .write_raw = stm32_dac_write_raw, |
| .debugfs_reg_access = stm32_dac_debugfs_reg_access, |
| }; |
| |
| static const char * const stm32_dac_powerdown_modes[] = { |
| "three_state", |
| }; |
| |
| static int stm32_dac_get_powerdown_mode(struct iio_dev *indio_dev, |
| const struct iio_chan_spec *chan) |
| { |
| return 0; |
| } |
| |
| static int stm32_dac_set_powerdown_mode(struct iio_dev *indio_dev, |
| const struct iio_chan_spec *chan, |
| unsigned int type) |
| { |
| return 0; |
| } |
| |
| static ssize_t stm32_dac_read_powerdown(struct iio_dev *indio_dev, |
| uintptr_t private, |
| const struct iio_chan_spec *chan, |
| char *buf) |
| { |
| int ret = stm32_dac_is_enabled(indio_dev, chan->channel); |
| |
| if (ret < 0) |
| return ret; |
| |
| return sysfs_emit(buf, "%d\n", ret ? 0 : 1); |
| } |
| |
| static ssize_t stm32_dac_write_powerdown(struct iio_dev *indio_dev, |
| uintptr_t private, |
| const struct iio_chan_spec *chan, |
| const char *buf, size_t len) |
| { |
| bool powerdown; |
| int ret; |
| |
| ret = strtobool(buf, &powerdown); |
| if (ret) |
| return ret; |
| |
| ret = stm32_dac_set_enable_state(indio_dev, chan->channel, !powerdown); |
| if (ret) |
| return ret; |
| |
| return len; |
| } |
| |
| static const struct iio_enum stm32_dac_powerdown_mode_en = { |
| .items = stm32_dac_powerdown_modes, |
| .num_items = ARRAY_SIZE(stm32_dac_powerdown_modes), |
| .get = stm32_dac_get_powerdown_mode, |
| .set = stm32_dac_set_powerdown_mode, |
| }; |
| |
| static const struct iio_chan_spec_ext_info stm32_dac_ext_info[] = { |
| { |
| .name = "powerdown", |
| .read = stm32_dac_read_powerdown, |
| .write = stm32_dac_write_powerdown, |
| .shared = IIO_SEPARATE, |
| }, |
| IIO_ENUM("powerdown_mode", IIO_SEPARATE, &stm32_dac_powerdown_mode_en), |
| IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &stm32_dac_powerdown_mode_en), |
| {}, |
| }; |
| |
| #define STM32_DAC_CHANNEL(chan, name) { \ |
| .type = IIO_VOLTAGE, \ |
| .indexed = 1, \ |
| .output = 1, \ |
| .channel = chan, \ |
| .info_mask_separate = \ |
| BIT(IIO_CHAN_INFO_RAW) | \ |
| BIT(IIO_CHAN_INFO_SCALE), \ |
| /* scan_index is always 0 as num_channels is 1 */ \ |
| .scan_type = { \ |
| .sign = 'u', \ |
| .realbits = 12, \ |
| .storagebits = 16, \ |
| }, \ |
| .datasheet_name = name, \ |
| .ext_info = stm32_dac_ext_info \ |
| } |
| |
| static const struct iio_chan_spec stm32_dac_channels[] = { |
| STM32_DAC_CHANNEL(STM32_DAC_CHANNEL_1, "out1"), |
| STM32_DAC_CHANNEL(STM32_DAC_CHANNEL_2, "out2"), |
| }; |
| |
| static int stm32_dac_chan_of_init(struct iio_dev *indio_dev) |
| { |
| struct device_node *np = indio_dev->dev.of_node; |
| unsigned int i; |
| u32 channel; |
| int ret; |
| |
| ret = of_property_read_u32(np, "reg", &channel); |
| if (ret) { |
| dev_err(&indio_dev->dev, "Failed to read reg property\n"); |
| return ret; |
| } |
| |
| for (i = 0; i < ARRAY_SIZE(stm32_dac_channels); i++) { |
| if (stm32_dac_channels[i].channel == channel) |
| break; |
| } |
| if (i >= ARRAY_SIZE(stm32_dac_channels)) { |
| dev_err(&indio_dev->dev, "Invalid reg property\n"); |
| return -EINVAL; |
| } |
| |
| indio_dev->channels = &stm32_dac_channels[i]; |
| /* |
| * Expose only one channel here, as they can be used independently, |
| * with separate trigger. Then separate IIO devices are instantiated |
| * to manage this. |
| */ |
| indio_dev->num_channels = 1; |
| |
| return 0; |
| }; |
| |
| static int stm32_dac_probe(struct platform_device *pdev) |
| { |
| struct device_node *np = pdev->dev.of_node; |
| struct device *dev = &pdev->dev; |
| struct iio_dev *indio_dev; |
| struct stm32_dac *dac; |
| int ret; |
| |
| if (!np) |
| return -ENODEV; |
| |
| indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac)); |
| if (!indio_dev) |
| return -ENOMEM; |
| platform_set_drvdata(pdev, indio_dev); |
| |
| dac = iio_priv(indio_dev); |
| dac->common = dev_get_drvdata(pdev->dev.parent); |
| indio_dev->name = dev_name(&pdev->dev); |
| indio_dev->dev.of_node = pdev->dev.of_node; |
| indio_dev->info = &stm32_dac_iio_info; |
| indio_dev->modes = INDIO_DIRECT_MODE; |
| |
| mutex_init(&dac->lock); |
| |
| ret = stm32_dac_chan_of_init(indio_dev); |
| if (ret < 0) |
| return ret; |
| |
| /* Get stm32-dac-core PM online */ |
| pm_runtime_get_noresume(dev); |
| pm_runtime_set_active(dev); |
| pm_runtime_set_autosuspend_delay(dev, STM32_DAC_AUTO_SUSPEND_DELAY_MS); |
| pm_runtime_use_autosuspend(dev); |
| pm_runtime_enable(dev); |
| |
| ret = iio_device_register(indio_dev); |
| if (ret) |
| goto err_pm_put; |
| |
| pm_runtime_mark_last_busy(dev); |
| pm_runtime_put_autosuspend(dev); |
| |
| return 0; |
| |
| err_pm_put: |
| pm_runtime_disable(dev); |
| pm_runtime_set_suspended(dev); |
| pm_runtime_put_noidle(dev); |
| |
| return ret; |
| } |
| |
| static int stm32_dac_remove(struct platform_device *pdev) |
| { |
| struct iio_dev *indio_dev = platform_get_drvdata(pdev); |
| |
| pm_runtime_get_sync(&pdev->dev); |
| iio_device_unregister(indio_dev); |
| pm_runtime_disable(&pdev->dev); |
| pm_runtime_set_suspended(&pdev->dev); |
| pm_runtime_put_noidle(&pdev->dev); |
| |
| return 0; |
| } |
| |
| static int stm32_dac_suspend(struct device *dev) |
| { |
| struct iio_dev *indio_dev = dev_get_drvdata(dev); |
| int channel = indio_dev->channels[0].channel; |
| int ret; |
| |
| /* Ensure DAC is disabled before suspend */ |
| ret = stm32_dac_is_enabled(indio_dev, channel); |
| if (ret) |
| return ret < 0 ? ret : -EBUSY; |
| |
| return pm_runtime_force_suspend(dev); |
| } |
| |
| static DEFINE_SIMPLE_DEV_PM_OPS(stm32_dac_pm_ops, stm32_dac_suspend, |
| pm_runtime_force_resume); |
| |
| static const struct of_device_id stm32_dac_of_match[] = { |
| { .compatible = "st,stm32-dac", }, |
| {}, |
| }; |
| MODULE_DEVICE_TABLE(of, stm32_dac_of_match); |
| |
| static struct platform_driver stm32_dac_driver = { |
| .probe = stm32_dac_probe, |
| .remove = stm32_dac_remove, |
| .driver = { |
| .name = "stm32-dac", |
| .of_match_table = stm32_dac_of_match, |
| .pm = pm_sleep_ptr(&stm32_dac_pm_ops), |
| }, |
| }; |
| module_platform_driver(stm32_dac_driver); |
| |
| MODULE_ALIAS("platform:stm32-dac"); |
| MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>"); |
| MODULE_DESCRIPTION("STMicroelectronics STM32 DAC driver"); |
| MODULE_LICENSE("GPL v2"); |