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path: root/drivers/iio/dac/stm32-dac.c
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Diffstat (limited to 'drivers/iio/dac/stm32-dac.c')
-rw-r--r--drivers/iio/dac/stm32-dac.c334
1 files changed, 334 insertions, 0 deletions
diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c
new file mode 100644
index 000000000000..50f8ec091058
--- /dev/null
+++ b/drivers/iio/dac/stm32-dac.c
@@ -0,0 +1,334 @@
+/*
+ * 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>
+ *
+ * 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
+#define STM32_DAC_IS_CHAN_1(ch) ((ch) & STM32_DAC_CHANNEL_1)
+
+/**
+ * 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 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);
+ u32 msk = STM32_DAC_IS_CHAN_1(ch) ? STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2;
+ u32 en = enable ? msk : 0;
+ int ret;
+
+ ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev, "%s failed\n", en ?
+ "Enable" : "Disable");
+ 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 either.
+ */
+ if (en && dac->common->hfsel)
+ udelay(1);
+
+ return 0;
+}
+
+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,
+ .driver_module = THIS_MODULE,
+};
+
+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 sprintf(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", &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 st,dac-channel\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 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;
+
+ return devm_iio_device_register(&pdev->dev, indio_dev);
+}
+
+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,
+ .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.delaunay@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 DAC driver");
+MODULE_LICENSE("GPL v2");