On Fri, 31 Mar 2017, Fabrice Gasnier wrote: > Add support for STMicroelectronics STM32 DAC. It's a 12-bit, voltage > output digital-to-analog converter. It has two output channels, each > with its own converter. > It supports 8 bits or 12bits left/right aligned data format. Only > 12bits right-aligned is used here. It has built-in noise or > triangle waveform generator, and supports external triggers for > conversions. > Each channel can be used independently, with separate trigger, then > separate IIO devices are used to handle this. Core driver is intended > to share common resources such as clock, reset, reference voltage and > registers.
comments below > Signed-off-by: Fabrice Gasnier <fabrice.gasn...@st.com> > --- > drivers/iio/dac/Kconfig | 15 ++ > drivers/iio/dac/Makefile | 2 + > drivers/iio/dac/stm32-dac-core.c | 180 ++++++++++++++++++++++++ > drivers/iio/dac/stm32-dac-core.h | 51 +++++++ > drivers/iio/dac/stm32-dac.c | 296 > +++++++++++++++++++++++++++++++++++++++ > 5 files changed, 544 insertions(+) > create mode 100644 drivers/iio/dac/stm32-dac-core.c > create mode 100644 drivers/iio/dac/stm32-dac-core.h > create mode 100644 drivers/iio/dac/stm32-dac.c > > diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig > index d3084028..7198648 100644 > --- a/drivers/iio/dac/Kconfig > +++ b/drivers/iio/dac/Kconfig > @@ -274,6 +274,21 @@ config MCP4922 > To compile this driver as a module, choose M here: the module > will be called mcp4922. > > +config STM32_DAC > + tristate "STMicroelectronics STM32 DAC" > + depends on (ARCH_STM32 && OF) || COMPILE_TEST > + depends on REGULATOR > + select STM32_DAC_CORE > + help > + Say yes here to build support for STMicroelectronics STM32 Digital > + to Analog Converter (DAC). > + > + This driver can also be built as a module. If so, the module > + will be called stm32-dac. > + > +config STM32_DAC_CORE > + tristate > + > config VF610_DAC > tristate "Vybrid vf610 DAC driver" > depends on OF > diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile > index f01bf4a..afe8ae7 100644 > --- a/drivers/iio/dac/Makefile > +++ b/drivers/iio/dac/Makefile > @@ -29,4 +29,6 @@ obj-$(CONFIG_MAX517) += max517.o > obj-$(CONFIG_MAX5821) += max5821.o > obj-$(CONFIG_MCP4725) += mcp4725.o > obj-$(CONFIG_MCP4922) += mcp4922.o > +obj-$(CONFIG_STM32_DAC_CORE) += stm32-dac-core.o > +obj-$(CONFIG_STM32_DAC) += stm32-dac.o > obj-$(CONFIG_VF610_DAC) += vf610_dac.o > diff --git a/drivers/iio/dac/stm32-dac-core.c > b/drivers/iio/dac/stm32-dac-core.c > new file mode 100644 > index 0000000..75e4878 > --- /dev/null > +++ b/drivers/iio/dac/stm32-dac-core.c > @@ -0,0 +1,180 @@ > +/* > + * This file is part of STM32 DAC driver > + * > + * Copyright (C) 2017, STMicroelectronics - All Rights Reserved > + * Author: Fabrice Gasnier <fabrice.gasn...@st.com>. > + * > + * License type: GPLv2 > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms of the GNU General Public License version 2 as published > by > + * the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, but > + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY > + * or FITNESS FOR A PARTICULAR PURPOSE. > + * See the GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License along > with > + * this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > +#include <linux/clk.h> > +#include <linux/delay.h> > +#include <linux/module.h> > +#include <linux/of_platform.h> > +#include <linux/regulator/consumer.h> > +#include <linux/reset.h> > + > +#include "stm32-dac-core.h" > + > +/** > + * struct stm32_dac_priv - stm32 DAC core private data > + * @pclk: peripheral clock common for all DACs > + * @rst: peripheral reset control > + * @vref: regulator reference > + * @common: Common data for all DAC instances > + */ > +struct stm32_dac_priv { > + struct clk *pclk; > + struct reset_control *rst; > + struct regulator *vref; > + struct stm32_dac_common common; > +}; > + > +static struct stm32_dac_priv *to_stm32_dac_priv(struct stm32_dac_common *com) > +{ > + return container_of(com, struct stm32_dac_priv, common); > +} > + > +static const struct regmap_config stm32_dac_regmap_cfg = { > + .reg_bits = 32, > + .val_bits = 32, > + .reg_stride = sizeof(u32), > + .max_register = 0x3fc, > +}; > + > +static int stm32_dac_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct stm32_dac_priv *priv; > + struct regmap *regmap; > + struct resource *res; > + void __iomem *mmio; > + int ret; > + > + if (!dev->of_node) > + return -ENODEV; > + > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + mmio = devm_ioremap_resource(dev, res); > + if (IS_ERR(mmio)) > + return PTR_ERR(mmio); > + > + regmap = devm_regmap_init_mmio(dev, mmio, &stm32_dac_regmap_cfg); > + if (IS_ERR(regmap)) > + return PTR_ERR(regmap); > + priv->common.regmap = regmap; > + > + priv->vref = devm_regulator_get(dev, "vref"); > + if (IS_ERR(priv->vref)) { > + ret = PTR_ERR(priv->vref); > + dev_err(dev, "vref get failed, %d\n", ret); > + return ret; > + } > + > + ret = regulator_enable(priv->vref); > + if (ret < 0) { > + dev_err(dev, "vref enable failed\n"); > + return ret; > + } > + > + ret = regulator_get_voltage(priv->vref); > + if (ret < 0) { > + dev_err(dev, "vref get voltage failed, %d\n", ret); > + goto err_vref; > + } > + priv->common.vref_mv = ret / 1000; > + dev_dbg(dev, "vref+=%dmV\n", priv->common.vref_mv); > + > + priv->pclk = devm_clk_get(dev, "pclk"); > + if (IS_ERR(priv->pclk)) { > + ret = PTR_ERR(priv->pclk); > + dev_err(dev, "pclk get failed\n"); > + goto err_vref; > + } > + > + ret = clk_prepare_enable(priv->pclk); > + if (ret < 0) { > + dev_err(dev, "pclk enable failed\n"); > + goto err_vref; > + } > + > + priv->rst = devm_reset_control_get(dev, NULL); > + if (!IS_ERR(priv->rst)) { > + reset_control_assert(priv->rst); > + udelay(2); > + reset_control_deassert(priv->rst); > + } > + > + /* When clock speed is higher than 80MHz, set HFSEL */ > + priv->common.hfsel = (clk_get_rate(priv->pclk) > 80000000UL); > + ret = regmap_update_bits(regmap, STM32_DAC_CR, STM32H7_DAC_CR_HFSEL, > + priv->common.hfsel ? STM32H7_DAC_CR_HFSEL : 0); > + if (ret) > + goto err_pclk; > + > + platform_set_drvdata(pdev, &priv->common); > + > + ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, dev); > + if (ret < 0) { > + dev_err(dev, "failed to populate DT children\n"); > + goto err_pclk; > + } > + > + return 0; > + > +err_pclk: > + clk_disable_unprepare(priv->pclk); > +err_vref: > + regulator_disable(priv->vref); > + > + return ret; > +} > + > +static int stm32_dac_remove(struct platform_device *pdev) > +{ > + struct stm32_dac_common *common = platform_get_drvdata(pdev); > + struct stm32_dac_priv *priv = to_stm32_dac_priv(common); > + > + of_platform_depopulate(&pdev->dev); > + clk_disable_unprepare(priv->pclk); > + regulator_disable(priv->vref); > + > + return 0; > +} > + > +static const struct of_device_id stm32_dac_of_match[] = { > + { .compatible = "st,stm32h7-dac-core", }, > + {}, > +}; > +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-core", > + .of_match_table = stm32_dac_of_match, > + }, > +}; > +module_platform_driver(stm32_dac_driver); > + > +MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasn...@st.com>"); > +MODULE_DESCRIPTION("STMicroelectronics STM32 DAC core driver"); > +MODULE_LICENSE("GPL v2"); > +MODULE_ALIAS("platform:stm32-dac-core"); > diff --git a/drivers/iio/dac/stm32-dac-core.h > b/drivers/iio/dac/stm32-dac-core.h > new file mode 100644 > index 0000000..d3099f7 > --- /dev/null > +++ b/drivers/iio/dac/stm32-dac-core.h > @@ -0,0 +1,51 @@ > +/* > + * This file is part of STM32 DAC driver > + * > + * Copyright (C) 2017, STMicroelectronics - All Rights Reserved > + * Author: Fabrice Gasnier <fabrice.gasn...@st.com>. > + * > + * License type: GPLv2 > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms of the GNU General Public License version 2 as published > by > + * the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, but > + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY > + * or FITNESS FOR A PARTICULAR PURPOSE. > + * See the GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License along > with > + * this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > +#ifndef __STM32_DAC_CORE_H > +#define __STM32_DAC_CORE_H > + > +#include <linux/regmap.h> > + > +/* STM32 DAC registers */ > +#define STM32_DAC_CR 0x00 > +#define STM32_DAC_DHR12R1 0x08 > +#define STM32_DAC_DHR12R2 0x14 > +#define STM32_DAC_DOR1 0x2C > +#define STM32_DAC_DOR2 0x30 > + > +/* STM32_DAC_CR bit fields */ > +#define STM32_DAC_CR_EN1 BIT(0) > +#define STM32H7_DAC_CR_HFSEL BIT(15) > +#define STM32_DAC_CR_EN2 BIT(16) > + > +/** > + * struct stm32_dac_common - stm32 DAC driver common data (for all instances) > + * @regmap: DAC registers shared via regmap > + * @vref_mv: reference voltage (mv) > + * @hfsel: high speed bus clock probably better "high speed bus clock selected" > + */ > +struct stm32_dac_common { > + struct regmap *regmap; > + int vref_mv; > + bool hfsel; > +}; > + > +#endif > diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c > new file mode 100644 > index 0000000..ee9711d > --- /dev/null > +++ b/drivers/iio/dac/stm32-dac.c > @@ -0,0 +1,296 @@ > +/* > + * This file is part of STM32 DAC driver > + * > + * Copyright (C) 2017, STMicroelectronics - All Rights Reserved > + * Authors: Amelie Delaunay <amelie.delau...@st.com> > + * Fabrice Gasnier <fabrice.gasn...@st.com> > + * > + * License type: GPLv2 > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms of the GNU General Public License version 2 as published > by > + * the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, but > + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY > + * or FITNESS FOR A PARTICULAR PURPOSE. > + * See the GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License along > with > + * this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > +#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 "stm32-dac-core.h" > + > +#define STM32_DAC_CHANNEL_1 1 > +#define STM32_DAC_CHANNEL_2 2 > + > +/** > + * struct stm32_dac - private data of DAC driver > + * @common: reference to DAC common data > + */ > +struct stm32_dac { > + struct stm32_dac_common *common; > +}; > + > +static int stm32_dac_is_enabled(struct stm32_dac *dac, int channel) > +{ > + u32 en, val; > + int ret; > + > + ret = regmap_read(dac->common->regmap, STM32_DAC_CR, &val); > + if (ret < 0) > + return ret; > + if (channel == STM32_DAC_CHANNEL_1) > + en = FIELD_GET(STM32_DAC_CR_EN1, val); > + else > + en = FIELD_GET(STM32_DAC_CR_EN2, val); > + > + return !!en; > +} > + > +static int stm32_dac_enable(struct iio_dev *indio_dev, int channel) > +{ > + struct stm32_dac *dac = iio_priv(indio_dev); > + u32 en = (channel == STM32_DAC_CHANNEL_1) ? > + STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2; could #define a macro to select CR_EN1 or CR_EN2 depending on channel; to use here and above and below or maybe a table to select all the channel-specific constants indexed by channel > + int ret; > + > + ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, en, en); > + if (ret < 0) { > + dev_err(&indio_dev->dev, "Enable failed\n"); > + return ret; > + } > + > + /* > + * 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 neither. neither -> either > + */ > + if (dac->common->hfsel) > + udelay(1); > + > + return 0; > +} > + > +static int stm32_dac_disable(struct iio_dev *indio_dev, int channel) > +{ > + struct stm32_dac *dac = iio_priv(indio_dev); > + u32 en = (channel == STM32_DAC_CHANNEL_1) ? > + STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2; > + int ret; > + > + ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, en, 0); > + if (ret) > + dev_err(&indio_dev->dev, "Disable failed\n"); > + > + return ret; > +} > + > +static int stm32_dac_get_value(struct stm32_dac *dac, int channel, int *val) > +{ > + int ret; > + > + if (channel == STM32_DAC_CHANNEL_1) > + 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 (channel == STM32_DAC_CHANNEL_1) > + 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); > + int ret; > + > + 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; > + case IIO_CHAN_INFO_ENABLE: > + ret = stm32_dac_is_enabled(dac, chan->channel); > + if (ret < 0) > + return ret; > + *val = ret; > + return IIO_VAL_INT; > + 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); > + case IIO_CHAN_INFO_ENABLE: > + if (!!val) > + return stm32_dac_enable(indio_dev, chan->channel); > + else > + return stm32_dac_disable(indio_dev, chan->channel); > + 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, no & for functions (matter of taste) > + .write_raw = &stm32_dac_write_raw, > + .debugfs_reg_access = &stm32_dac_debugfs_reg_access, > + .driver_module = THIS_MODULE, > +}; > + > +#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_ENABLE) | \ > + BIT(IIO_CHAN_INFO_SCALE), \ > + .scan_type = { \ scan_type is no needed (yet) and scan_index is missing (or always 0 which becomes clear below, a comment may be helpful) > + .sign = 'u', \ > + .realbits = 12, \ > + .storagebits = 16, \ > + }, \ > + .datasheet_name = name, \ > +} > + > +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, "st,dac-channel", &channel); > + if (ret) { > + dev_err(&indio_dev->dev, "Failed to read st,dac-channel\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 st,dac-channel\n"); > + return -EINVAL; > + } > + > + indio_dev->channels = &stm32_dac_channels[i]; > + indio_dev->num_channels = 1; this is unusual, a comment would be helpful why not expose both channels? > + > + return 0; > +}; > + > +static int stm32_dac_probe(struct platform_device *pdev) > +{ > + struct device_node *np = pdev->dev.of_node; > + 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.parent = &pdev->dev; > + indio_dev->dev.of_node = pdev->dev.of_node; > + indio_dev->info = &stm32_dac_iio_info; > + indio_dev->modes = INDIO_DIRECT_MODE; > + > + ret = stm32_dac_chan_of_init(indio_dev); > + if (ret < 0) > + return ret; > + > + ret = iio_device_register(indio_dev); just return iio_device_register(); candidate for devm_ due to empty _remove() > + if (ret) > + return ret; > + > + return 0; > +} > + > +static int stm32_dac_remove(struct platform_device *pdev) > +{ > + struct iio_dev *indio_dev = platform_get_drvdata(pdev); > + > + iio_device_unregister(indio_dev); > + > + return 0; > +} > + > +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, > + }, > +}; > +module_platform_driver(stm32_dac_driver); > + > +MODULE_ALIAS("platform:stm32-dac"); > +MODULE_AUTHOR("Amelie Delaunay <amelie.delau...@st.com>"); > +MODULE_DESCRIPTION("STMicroelectronics STM32 DAC driver"); > +MODULE_LICENSE("GPL v2"); > -- Peter Meerwald-Stadler Mobile: +43 664 24 44 418
