Bindings for the TI ADS1298 medical ADC. This device is
typically used for ECG and similar measurements. Supports data
acquisition at configurable scale and sampling frequency.
The device has so many options for connecting stuff, at this
point the bindings aren't nearly complete but partial bindings
are better than no bindings at all.
Signed-off-by: Mike Looijmans <[email protected]>
Reviewed-by: Conor Dooley <[email protected]>
---
(no changes since v2)
Changes in v2:
Remove "clk" name
Add datasheet and "incomplete" note
.../bindings/iio/adc/ti,ads1298.yaml | 80 +++++++++++++++++++
1 file changed, 80 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,ads1298.yaml
diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads1298.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads1298.yaml
new file mode 100644
index 000000000000..bf5a43a81d59
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/ti,ads1298.yaml
@@ -0,0 +1,80 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/ti,ads1298.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments' ads1298 medical ADC chips
+
+description: |
+ Datasheet at: https://www.ti.com/product/ADS1298
+ Bindings for this chip aren't complete.
+
+maintainers:
+ - Mike Looijmans <[email protected]>
+
+properties:
+ compatible:
+ enum:
+ - ti,ads1298
+
+ reg:
+ maxItems: 1
+
+ spi-cpha: true
+
+ reset-gpios:
+ maxItems: 1
+
+ avdd-supply:
+ description:
+ Analog power supply, voltage between AVDD and AVSS. When providing a
+ symmetric +/- 2.5V, the regulator should report 5V.
+
+ vref-supply:
+ description:
+ Optional reference voltage. If omitted, internal reference is used,
+ which is 2.4V when analog supply is below 4.4V, 4V otherwise.
+
+ clocks:
+ description: Optional 2.048 MHz external source clock on CLK pin
+ maxItems: 1
+
+ interrupts:
+ description: Interrupt on DRDY pin, triggers on falling edge
+ maxItems: 1
+
+ label: true
+
+required:
+ - compatible
+ - reg
+ - avdd-supply
+ - interrupts
+
+allOf:
+ - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ #include <dt-bindings/interrupt-controller/irq.h>
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ adc@1 {
+ reg = <1>;
+ compatible = "ti,ads1298";
+ label = "ads1298-1-ecg";
+ avdd-supply = <®_iso_5v_a>;
+ clocks = <&clk_ads1298>;
+ interrupt-parent = <&gpio0>;
+ interrupts = <78 IRQ_TYPE_EDGE_FALLING>;
+ spi-max-frequency = <20000000>;
+ spi-cpha;
+ };
+ };
+...
--
2.34.1
Met vriendelijke groet / kind regards,
Mike Looijmans
System Expert
TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands
T: +31 (0) 499 33 69 69
E: [email protected]
W: http://www.topic.nl
Please consider the environment before printing this e-mail
Skeleton driver for the TI ADS1298 medical ADC. This device is
typically used for ECG and similar measurements. Supports data
acquisition at configurable scale and sampling frequency.
Signed-off-by: Mike Looijmans <[email protected]>
---
Changes in v6:
Use fsleep instead of udelay
Fix wrong error return as reported here:
https://lore.kernel.org/oe-kbuild-all/[email protected]/
Changes in v5:
Derive the name from the chip ID register
Fail probe if the ID is unknown
Interpret the number of channels (only tested the "8")
Changes in v4:
Explain rdata_xfer_busy better and remove post-decrement
Reset assert explanation and add cansleep
Additional style changes
Changes in v3:
Indentation fixups
Remove unused headers
Remove #define leftovers
Use devm_get_clk_optional_enabled
Use ilog2 instead of fls()-1
Magic "23" replaced
Explain the extra "0" in read/write register
use guard() from cleanup.h
use REGCACHE_MAPLE
Changes in v2:
Remove accidental "default y" in Kconfig
Indentation and similar cosmetic fixes
Magic numbers into constants
Short return paths in read_raw and write_raw
DMA buffer alignment
Bounce buffer is u32 instead of u8
Avoid races using claim_direct_mode
Check errors on all register accesses
Immediate SPI restart to reduce underruns
"name" is chip name, not unique
drivers/iio/adc/Kconfig | 11 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/ti-ads1298.c | 768 +++++++++++++++++++++++++++++++++++
3 files changed, 780 insertions(+)
create mode 100644 drivers/iio/adc/ti-ads1298.c
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 35f9867da12c..1d2d2eff15da 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1318,6 +1318,17 @@ config TI_ADS8688
This driver can also be built as a module. If so, the module will be
called ti-ads8688.
+config TI_ADS1298
+ tristate "Texas Instruments ADS1298"
+ depends on SPI
+ select IIO_BUFFER
+ help
+ If you say yes here you get support for Texas Instruments ADS1298
+ medical ADC chips
+
+ This driver can also be built as a module. If so, the module will be
+ called ti-ads1298.
+
config TI_ADS124S08
tristate "Texas Instruments ADS124S08"
depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index bee11d442af4..ff0e3633eded 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -117,6 +117,7 @@ obj-$(CONFIG_TI_ADS7924) += ti-ads7924.o
obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o
obj-$(CONFIG_TI_ADS8344) += ti-ads8344.o
obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
+obj-$(CONFIG_TI_ADS1298) += ti-ads1298.o
obj-$(CONFIG_TI_ADS124S08) += ti-ads124s08.o
obj-$(CONFIG_TI_ADS131E08) += ti-ads131e08.o
obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
diff --git a/drivers/iio/adc/ti-ads1298.c b/drivers/iio/adc/ti-ads1298.c
new file mode 100644
index 000000000000..257f8a49caad
--- /dev/null
+++ b/drivers/iio/adc/ti-ads1298.c
@@ -0,0 +1,768 @@
+// SPDX-License-Identifier: GPL-2.0
+/* TI ADS1298 chip family driver
+ * Copyright (C) 2023 - 2024 Topic Embedded Products
+ */
+
+#include <linux/bitfield.h>
+#include <linux/cleanup.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/log2.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/units.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/kfifo_buf.h>
+
+#include <asm/unaligned.h>
+
+/* Commands */
+#define ADS1298_CMD_WAKEUP 0x02
+#define ADS1298_CMD_STANDBY 0x04
+#define ADS1298_CMD_RESET 0x06
+#define ADS1298_CMD_START 0x08
+#define ADS1298_CMD_STOP 0x0a
+#define ADS1298_CMD_RDATAC 0x10
+#define ADS1298_CMD_SDATAC 0x11
+#define ADS1298_CMD_RDATA 0x12
+#define ADS1298_CMD_RREG 0x20
+#define ADS1298_CMD_WREG 0x40
+
+/* Registers */
+#define ADS1298_REG_ID 0x00
+#define ADS1298_MASK_ID_FAMILY GENMASK(7, 3)
+#define ADS1298_MASK_ID_CHANNELS GENMASK(2, 0)
+#define ADS1298_ID_FAMILY_ADS129X 0x90
+#define ADS1298_ID_FAMILY_ADS129XR 0xd0
+
+#define ADS1298_REG_CONFIG1 0x01
+#define ADS1298_MASK_CONFIG1_HR BIT(7)
+#define ADS1298_MASK_CONFIG1_DR GENMASK(2, 0)
+#define ADS1298_SHIFT_DR_HR 6
+#define ADS1298_SHIFT_DR_LP 7
+#define ADS1298_LOWEST_DR 0x06
+
+#define ADS1298_REG_CONFIG2 0x02
+#define ADS1298_MASK_CONFIG2_RESERVED BIT(6)
+#define ADS1298_MASK_CONFIG2_WCT_CHOP BIT(5)
+#define ADS1298_MASK_CONFIG2_INT_TEST BIT(4)
+#define ADS1298_MASK_CONFIG2_TEST_AMP BIT(2)
+#define ADS1298_MASK_CONFIG2_TEST_FREQ_DC GENMASK(1, 0)
+#define ADS1298_MASK_CONFIG2_TEST_FREQ_SLOW 0
+#define ADS1298_MASK_CONFIG2_TEST_FREQ_FAST BIT(0)
+
+#define ADS1298_REG_CONFIG3 0x03
+#define ADS1298_MASK_CONFIG3_PWR_REFBUF BIT(7)
+#define ADS1298_MASK_CONFIG3_RESERVED BIT(6)
+#define ADS1298_MASK_CONFIG3_VREF_4V BIT(5)
+
+#define ADS1298_REG_LOFF 0x04
+#define ADS1298_REG_CHnSET(n) (0x05 + n)
+#define ADS1298_MASK_CH_PD BIT(7)
+#define ADS1298_MASK_CH_PGA GENMASK(6, 4)
+#define ADS1298_MASK_CH_MUX GENMASK(2, 0)
+
+#define ADS1298_REG_LOFF_STATP 0x12
+#define ADS1298_REG_LOFF_STATN 0x13
+#define ADS1298_REG_CONFIG4 0x17
+#define ADS1298_MASK_CONFIG4_SINGLE_SHOT BIT(3)
+
+#define ADS1298_REG_WCT1 0x18
+#define ADS1298_REG_WCT2 0x19
+
+#define ADS1298_MAX_CHANNELS 8
+#define ADS1298_BITS_PER_SAMPLE 24
+#define ADS1298_CLK_RATE_HZ 2048000
+#define ADS1298_CLOCKS_TO_USECS(x) \
+ (DIV_ROUND_UP((x) * MICROHZ_PER_HZ, ADS1298_CLK_RATE_HZ))
+/*
+ * Read/write register commands require 4 clocks to decode, for speeds above
+ * 2x the clock rate, this would require extra time between the command byte and
+ * the data. Much simpler is to just limit the SPI transfer speed while doing
+ * register access.
+ */
+#define ADS1298_SPI_BUS_SPEED_SLOW ADS1298_CLK_RATE_HZ
+/* For reading and writing registers, we need a 3-byte buffer */
+#define ADS1298_SPI_CMD_BUFFER_SIZE 3
+/* Outputs status word and 'n' 24-bit samples, plus the command byte */
+#define ADS1298_SPI_RDATA_BUFFER_SIZE(n) (((n) + 1) * 3 + 1)
+#define ADS1298_SPI_RDATA_BUFFER_SIZE_MAX \
+ ADS1298_SPI_RDATA_BUFFER_SIZE(ADS1298_MAX_CHANNELS)
+
+struct ads1298_private {
+ const struct ads1298_chip_info *chip_info;
+ struct spi_device *spi;
+ struct regulator *reg_avdd;
+ struct regulator *reg_vref;
+ struct clk *clk;
+ struct regmap *regmap;
+ struct completion completion;
+ struct iio_trigger *trig;
+ struct spi_transfer rdata_xfer;
+ struct spi_message rdata_msg;
+ spinlock_t irq_busy_lock; /* Handshake between SPI and DRDY irqs */
+ /*
+ * rdata_xfer_busy increments when a DRDY occurs and decrements when SPI
+ * completion is reported. Hence its meaning is:
+ * 0 = Waiting for DRDY interrupt
+ * 1 = SPI transfer in progress
+ * 2 = DRDY during SPI transfer, start another transfer on completion
+ * >2 = Multiple DRDY during transfer, lost rdata_xfer_busy - 2 samples
+ */
+ unsigned int rdata_xfer_busy;
+
+ /* Temporary storage for demuxing data after SPI transfer */
+ u32 bounce_buffer[ADS1298_MAX_CHANNELS];
+
+ /* For synchronous SPI exchanges (read/write registers) */
+ u8 cmd_buffer[ADS1298_SPI_CMD_BUFFER_SIZE] __aligned(IIO_DMA_MINALIGN);
+
+ /* Buffer used for incoming SPI data */
+ u8 rx_buffer[ADS1298_SPI_RDATA_BUFFER_SIZE_MAX];
+ /* Contains the RDATA command and zeroes to clock out */
+ u8 tx_buffer[ADS1298_SPI_RDATA_BUFFER_SIZE_MAX];
+};
+
+/* Three bytes per sample in RX buffer, starting at offset 4 */
+#define ADS1298_OFFSET_IN_RX_BUFFER(index) (3 * (index) + 4)
+
+#define ADS1298_CHAN(index) \
+{ \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = index, \
+ .address = ADS1298_OFFSET_IN_RX_BUFFER(index), \
+ .info_mask_separate = \
+ BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
+ .info_mask_shared_by_all = \
+ BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
+ .scan_index = index, \
+ .scan_type = { \
+ .sign = 's', \
+ .realbits = ADS1298_BITS_PER_SAMPLE, \
+ .storagebits = 32, \
+ .endianness = IIO_CPU, \
+ }, \
+}
+
+static const struct iio_chan_spec ads1298_channels[] = {
+ ADS1298_CHAN(0),
+ ADS1298_CHAN(1),
+ ADS1298_CHAN(2),
+ ADS1298_CHAN(3),
+ ADS1298_CHAN(4),
+ ADS1298_CHAN(5),
+ ADS1298_CHAN(6),
+ ADS1298_CHAN(7),
+};
+
+static int ads1298_write_cmd(struct ads1298_private *priv, u8 command)
+{
+ struct spi_transfer xfer = {
+ .tx_buf = priv->cmd_buffer,
+ .rx_buf = priv->cmd_buffer,
+ .len = 1,
+ .speed_hz = ADS1298_SPI_BUS_SPEED_SLOW,
+ .delay = {
+ .value = 2,
+ .unit = SPI_DELAY_UNIT_USECS,
+ },
+ };
+
+ priv->cmd_buffer[0] = command;
+
+ return spi_sync_transfer(priv->spi, &xfer, 1);
+}
+
+static int ads1298_read_one(struct ads1298_private *priv, int chan_index)
+{
+ int ret;
+
+ /* Enable the channel */
+ ret = regmap_update_bits(priv->regmap, ADS1298_REG_CHnSET(chan_index),
+ ADS1298_MASK_CH_PD, 0);
+ if (ret)
+ return ret;
+
+ /* Enable single-shot mode, so we don't need to send a STOP */
+ ret = regmap_update_bits(priv->regmap, ADS1298_REG_CONFIG4,
+ ADS1298_MASK_CONFIG4_SINGLE_SHOT,
+ ADS1298_MASK_CONFIG4_SINGLE_SHOT);
+ if (ret)
+ return ret;
+
+ reinit_completion(&priv->completion);
+
+ ret = ads1298_write_cmd(priv, ADS1298_CMD_START);
+ if (ret < 0) {
+ dev_err(&priv->spi->dev, "CMD_START error: %d\n", ret);
+ return ret;
+ }
+
+ /* Cannot take longer than 40ms (250Hz) */
+ ret = wait_for_completion_timeout(&priv->completion, msecs_to_jiffies(50));
+ if (!ret)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int ads1298_get_samp_freq(struct ads1298_private *priv, int *val)
+{
+ unsigned long rate;
+ unsigned int cfg;
+ int ret;
+
+ ret = regmap_read(priv->regmap, ADS1298_REG_CONFIG1, &cfg);
+ if (ret)
+ return ret;
+
+ if (priv->clk)
+ rate = clk_get_rate(priv->clk);
+ else
+ rate = ADS1298_CLK_RATE_HZ;
+ if (!rate)
+ return -EINVAL;
+
+ /* Data rate shift depends on HR/LP mode */
+ if (cfg & ADS1298_MASK_CONFIG1_HR)
+ rate >>= ADS1298_SHIFT_DR_HR;
+ else
+ rate >>= ADS1298_SHIFT_DR_LP;
+
+ *val = rate >> (cfg & ADS1298_MASK_CONFIG1_DR);
+
+ return IIO_VAL_INT;
+}
+
+static int ads1298_set_samp_freq(struct ads1298_private *priv, int val)
+{
+ unsigned long rate;
+ unsigned int factor;
+ unsigned int cfg;
+
+ if (priv->clk)
+ rate = clk_get_rate(priv->clk);
+ else
+ rate = ADS1298_CLK_RATE_HZ;
+ if (!rate)
+ return -EINVAL;
+
+ factor = (rate >> ADS1298_SHIFT_DR_HR) / val;
+ if (factor >= BIT(ADS1298_SHIFT_DR_LP))
+ cfg = ADS1298_LOWEST_DR;
+ else if (factor)
+ cfg = ADS1298_MASK_CONFIG1_HR | ilog2(factor); /* Use HR mode */
+ else
+ cfg = ADS1298_MASK_CONFIG1_HR; /* Fastest possible */
+
+ return regmap_update_bits(priv->regmap, ADS1298_REG_CONFIG1,
+ ADS1298_MASK_CONFIG1_HR | ADS1298_MASK_CONFIG1_DR,
+ cfg);
+}
+
+static const u8 ads1298_pga_settings[] = { 6, 1, 2, 3, 4, 8, 12 };
+
+static int ads1298_get_scale(struct ads1298_private *priv,
+ int channel, int *val, int *val2)
+{
+ int ret;
+ unsigned int regval;
+ u8 gain;
+
+ if (priv->reg_vref) {
+ ret = regulator_get_voltage(priv->reg_vref);
+ if (ret < 0)
+ return ret;
+
+ *val = ret / MILLI; /* Convert to millivolts */
+ } else {
+ ret = regmap_read(priv->regmap, ADS1298_REG_CONFIG3, ®val);
+ if (ret)
+ return ret;
+
+ /* Refererence in millivolts */
+ *val = regval & ADS1298_MASK_CONFIG3_VREF_4V ? 4000 : 2400;
+ }
+
+ ret = regmap_read(priv->regmap, ADS1298_REG_CHnSET(channel), ®val);
+ if (ret)
+ return ret;
+
+ gain = ads1298_pga_settings[FIELD_GET(ADS1298_MASK_CH_PGA, regval)];
+ *val /= gain; /* Full scale is VREF / gain */
+
+ *val2 = ADS1298_BITS_PER_SAMPLE - 1; /* Signed, hence the -1 */
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+}
+
+static int ads1298_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct ads1298_private *priv = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;
+
+ ret = ads1298_read_one(priv, chan->scan_index);
+
+ iio_device_release_direct_mode(indio_dev);
+
+ if (ret)
+ return ret;
+
+ *val = sign_extend32(get_unaligned_be24(priv->rx_buffer + chan->address),
+ ADS1298_BITS_PER_SAMPLE - 1);
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ return ads1298_get_scale(priv, chan->channel, val, val2);
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ return ads1298_get_samp_freq(priv, val);
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ ret = regmap_read(priv->regmap, ADS1298_REG_CONFIG1, val);
+ if (ret)
+ return ret;
+
+ *val = 16 << (*val & ADS1298_MASK_CONFIG1_DR);
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ads1298_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int val,
+ int val2, long mask)
+{
+ struct ads1298_private *priv = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ return ads1298_set_samp_freq(priv, val);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ads1298_reg_write(void *context, unsigned int reg, unsigned int val)
+{
+ struct ads1298_private *priv = context;
+ struct spi_transfer reg_write_xfer = {
+ .tx_buf = priv->cmd_buffer,
+ .rx_buf = priv->cmd_buffer,
+ .len = 3,
+ .speed_hz = ADS1298_SPI_BUS_SPEED_SLOW,
+ .delay = {
+ .value = 2,
+ .unit = SPI_DELAY_UNIT_USECS,
+ },
+ };
+
+ priv->cmd_buffer[0] = ADS1298_CMD_WREG | reg;
+ priv->cmd_buffer[1] = 0; /* Number of registers to be written - 1 */
+ priv->cmd_buffer[2] = val;
+
+ return spi_sync_transfer(priv->spi, ®_write_xfer, 1);
+}
+
+static int ads1298_reg_read(void *context, unsigned int reg, unsigned int *val)
+{
+ struct ads1298_private *priv = context;
+ struct spi_transfer reg_read_xfer = {
+ .tx_buf = priv->cmd_buffer,
+ .rx_buf = priv->cmd_buffer,
+ .len = 3,
+ .speed_hz = ADS1298_SPI_BUS_SPEED_SLOW,
+ .delay = {
+ .value = 2,
+ .unit = SPI_DELAY_UNIT_USECS,
+ },
+ };
+ int ret;
+
+ priv->cmd_buffer[0] = ADS1298_CMD_RREG | reg;
+ priv->cmd_buffer[1] = 0; /* Number of registers to be read - 1 */
+ priv->cmd_buffer[2] = 0;
+
+ ret = spi_sync_transfer(priv->spi, ®_read_xfer, 1);
+ if (ret)
+ return ret;
+
+ *val = priv->cmd_buffer[2];
+
+ return 0;
+}
+
+static int ads1298_reg_access(struct iio_dev *indio_dev, unsigned int reg,
+ unsigned int writeval, unsigned int *readval)
+{
+ struct ads1298_private *priv = iio_priv(indio_dev);
+
+ if (readval)
+ return regmap_read(priv->regmap, reg, readval);
+
+ return regmap_write(priv->regmap, reg, writeval);
+}
+
+static void ads1298_rdata_unmark_busy(struct ads1298_private *priv)
+{
+ /* Notify we're no longer waiting for the SPI transfer to complete */
+ guard(spinlock_irqsave)(&priv->irq_busy_lock);
+ priv->rdata_xfer_busy = 0;
+}
+
+static int ads1298_update_scan_mode(struct iio_dev *indio_dev,
+ const unsigned long *scan_mask)
+{
+ struct ads1298_private *priv = iio_priv(indio_dev);
+ unsigned int val;
+ int ret;
+ int i;
+
+ /* Make the interrupt routines start with a clean slate */
+ ads1298_rdata_unmark_busy(priv);
+
+ /* Configure power-down bits to match scan mask */
+ for (i = 0; i < indio_dev->num_channels; i++) {
+ val = test_bit(i, scan_mask) ? 0 : ADS1298_MASK_CH_PD;
+ ret = regmap_update_bits(priv->regmap, ADS1298_REG_CHnSET(i),
+ ADS1298_MASK_CH_PD, val);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct iio_info ads1298_info = {
+ .read_raw = &ads1298_read_raw,
+ .write_raw = &ads1298_write_raw,
+ .update_scan_mode = &ads1298_update_scan_mode,
+ .debugfs_reg_access = &ads1298_reg_access,
+};
+
+static void ads1298_rdata_release_busy_or_restart(struct ads1298_private *priv)
+{
+ guard(spinlock_irqsave)(&priv->irq_busy_lock);
+
+ if (priv->rdata_xfer_busy > 1) {
+ /*
+ * DRDY interrupt occurred before SPI completion. Start a new
+ * SPI transaction now to retrieve the data that wasn't latched
+ * into the ADS1298 chip's transfer buffer yet.
+ */
+ spi_async(priv->spi, &priv->rdata_msg);
+ /*
+ * If more than one DRDY took place, there was an overrun. Since
+ * the sample is already lost, reset the counter to 1 so that
+ * we will wait for a DRDY interrupt after this SPI transaction.
+ */
+ priv->rdata_xfer_busy = 1;
+ } else {
+ /* No pending data, wait for DRDY */
+ priv->rdata_xfer_busy = 0;
+ }
+}
+
+/* Called from SPI completion interrupt handler */
+static void ads1298_rdata_complete(void *context)
+{
+ struct iio_dev *indio_dev = context;
+ struct ads1298_private *priv = iio_priv(indio_dev);
+ int scan_index;
+ u32 *bounce = priv->bounce_buffer;
+
+ if (!iio_buffer_enabled(indio_dev)) {
+ /*
+ * for a single transfer mode we're kept in direct_mode until
+ * completion, avoiding a race with buffered IO.
+ */
+ ads1298_rdata_unmark_busy(priv);
+ complete(&priv->completion);
+ return;
+ }
+
+ /* Demux the channel data into our bounce buffer */
+ for_each_set_bit(scan_index, indio_dev->active_scan_mask,
+ indio_dev->masklength) {
+ const struct iio_chan_spec *scan_chan =
+ &indio_dev->channels[scan_index];
+ const u8 *data = priv->rx_buffer + scan_chan->address;
+
+ *bounce++ = get_unaligned_be24(data);
+ }
+
+ /* rx_buffer can be overwritten from this point on */
+ ads1298_rdata_release_busy_or_restart(priv);
+
+ iio_push_to_buffers(indio_dev, priv->bounce_buffer);
+}
+
+static irqreturn_t ads1298_interrupt(int irq, void *dev_id)
+{
+ struct iio_dev *indio_dev = dev_id;
+ struct ads1298_private *priv = iio_priv(indio_dev);
+ unsigned int wasbusy;
+
+ guard(spinlock_irqsave)(&priv->irq_busy_lock);
+
+ wasbusy = priv->rdata_xfer_busy++;
+ /* When no SPI transfer in transit, start one now */
+ if (!wasbusy)
+ spi_async(priv->spi, &priv->rdata_msg);
+
+ return IRQ_HANDLED;
+};
+
+static int ads1298_buffer_postenable(struct iio_dev *indio_dev)
+{
+ struct ads1298_private *priv = iio_priv(indio_dev);
+ int ret;
+
+ /* Disable single-shot mode */
+ ret = regmap_update_bits(priv->regmap, ADS1298_REG_CONFIG4,
+ ADS1298_MASK_CONFIG4_SINGLE_SHOT, 0);
+ if (ret)
+ return ret;
+
+ return ads1298_write_cmd(priv, ADS1298_CMD_START);
+}
+
+static int ads1298_buffer_predisable(struct iio_dev *indio_dev)
+{
+ struct ads1298_private *priv = iio_priv(indio_dev);
+
+ return ads1298_write_cmd(priv, ADS1298_CMD_STOP);
+}
+
+static const struct iio_buffer_setup_ops ads1298_setup_ops = {
+ .postenable = &ads1298_buffer_postenable,
+ .predisable = &ads1298_buffer_predisable,
+};
+
+static void ads1298_reg_disable(void *reg)
+{
+ regulator_disable(reg);
+}
+
+static const struct regmap_range ads1298_regmap_volatile_range[] = {
+ regmap_reg_range(ADS1298_REG_LOFF_STATP, ADS1298_REG_LOFF_STATN),
+};
+
+static const struct regmap_access_table ads1298_regmap_volatile = {
+ .yes_ranges = ads1298_regmap_volatile_range,
+ .n_yes_ranges = ARRAY_SIZE(ads1298_regmap_volatile_range),
+};
+
+static const struct regmap_config ads1298_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .reg_read = ads1298_reg_read,
+ .reg_write = ads1298_reg_write,
+ .max_register = ADS1298_REG_WCT2,
+ .volatile_table = &ads1298_regmap_volatile,
+ .cache_type = REGCACHE_MAPLE,
+};
+
+static int ads1298_init(struct iio_dev *indio_dev)
+{
+ struct ads1298_private *priv = iio_priv(indio_dev);
+ struct device *dev = &priv->spi->dev;
+ const char *suffix;
+ unsigned int val;
+ int ret;
+
+ /* Device initializes into RDATAC mode, which we don't want */
+ ret = ads1298_write_cmd(priv, ADS1298_CMD_SDATAC);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(priv->regmap, ADS1298_REG_ID, &val);
+ if (ret)
+ return ret;
+
+ /* Fill in name and channel count based on what the chip told us */
+ indio_dev->num_channels = 4 + 2 * (val & ADS1298_MASK_ID_CHANNELS);
+ switch (val & ADS1298_MASK_ID_FAMILY) {
+ case ADS1298_ID_FAMILY_ADS129X:
+ suffix = "";
+ break;
+ case ADS1298_ID_FAMILY_ADS129XR:
+ suffix = "r";
+ break;
+ default:
+ return dev_err_probe(dev, -ENODEV, "Unknown ID: 0x%x\n", val);
+ }
+ indio_dev->name = devm_kasprintf(dev, GFP_KERNEL, "ads129%u%s",
+ indio_dev->num_channels, suffix);
+
+ /* Enable internal test signal, double amplitude, double frequency */
+ ret = regmap_write(priv->regmap, ADS1298_REG_CONFIG2,
+ ADS1298_MASK_CONFIG2_RESERVED |
+ ADS1298_MASK_CONFIG2_INT_TEST |
+ ADS1298_MASK_CONFIG2_TEST_AMP |
+ ADS1298_MASK_CONFIG2_TEST_FREQ_FAST);
+ if (ret)
+ return ret;
+
+ val = ADS1298_MASK_CONFIG3_RESERVED; /* Must write 1 always */
+ if (!priv->reg_vref) {
+ /* Enable internal reference */
+ val |= ADS1298_MASK_CONFIG3_PWR_REFBUF;
+ /* Use 4V VREF when power supply is at least 4.4V */
+ if (regulator_get_voltage(priv->reg_avdd) >= 4400000)
+ val |= ADS1298_MASK_CONFIG3_VREF_4V;
+ }
+ return regmap_write(priv->regmap, ADS1298_REG_CONFIG3, val);
+}
+
+static int ads1298_probe(struct spi_device *spi)
+{
+ struct ads1298_private *priv;
+ struct iio_dev *indio_dev;
+ struct device *dev = &spi->dev;
+ struct gpio_desc *reset_gpio;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ priv = iio_priv(indio_dev);
+
+ /* Reset to be asserted before enabling clock and power */
+ reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(reset_gpio))
+ return dev_err_probe(dev, PTR_ERR(reset_gpio), "Cannot get reset GPIO\n");
+
+ /* VREF can be supplied externally, otherwise use internal reference */
+ priv->reg_vref = devm_regulator_get_optional(dev, "vref");
+ if (IS_ERR(priv->reg_vref)) {
+ if (PTR_ERR(priv->reg_vref) != -ENODEV)
+ return dev_err_probe(dev, PTR_ERR(priv->reg_avdd),
+ "Failed to get vref regulator\n");
+
+ priv->reg_vref = NULL;
+ } else {
+ ret = regulator_enable(priv->reg_vref);
+ if (ret)
+ return ret;
+
+ ret = devm_add_action_or_reset(dev, ads1298_reg_disable, priv->reg_vref);
+ if (ret)
+ return ret;
+ }
+
+ priv->clk = devm_clk_get_optional_enabled(dev, "clk");
+ if (IS_ERR(priv->clk))
+ return dev_err_probe(dev, PTR_ERR(priv->clk), "Failed to get clk\n");
+
+ priv->reg_avdd = devm_regulator_get(dev, "avdd");
+ if (IS_ERR(priv->reg_avdd))
+ return dev_err_probe(dev, PTR_ERR(priv->reg_avdd),
+ "Failed to get avdd regulator\n");
+
+ ret = regulator_enable(priv->reg_avdd);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to enable avdd regulator\n");
+
+ ret = devm_add_action_or_reset(dev, ads1298_reg_disable, priv->reg_avdd);
+ if (ret)
+ return ret;
+
+ priv->spi = spi;
+ init_completion(&priv->completion);
+ spin_lock_init(&priv->irq_busy_lock);
+ priv->regmap = devm_regmap_init(dev, NULL, priv, &ads1298_regmap_config);
+ if (IS_ERR(priv->regmap))
+ return PTR_ERR(priv->regmap);
+
+ indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
+ indio_dev->channels = ads1298_channels;
+ indio_dev->info = &ads1298_info;
+
+ if (reset_gpio) {
+ /*
+ * Deassert reset now that clock and power are active.
+ * Minimum reset pulsewidth is 2 clock cycles.
+ */
+ fsleep(ADS1298_CLOCKS_TO_USECS(2));
+ gpiod_set_value_cansleep(reset_gpio, 0);
+ } else {
+ ret = ads1298_write_cmd(priv, ADS1298_CMD_RESET);
+ if (ret)
+ return dev_err_probe(dev, ret, "RESET failed\n");
+ }
+ /* Wait 18 clock cycles for reset command to complete */
+ fsleep(ADS1298_CLOCKS_TO_USECS(18));
+
+ ret = ads1298_init(indio_dev);
+ if (ret)
+ return dev_err_probe(dev, ret, "Init failed\n");
+
+ priv->tx_buffer[0] = ADS1298_CMD_RDATA;
+ priv->rdata_xfer.tx_buf = priv->tx_buffer;
+ priv->rdata_xfer.rx_buf = priv->rx_buffer;
+ priv->rdata_xfer.len = ADS1298_SPI_RDATA_BUFFER_SIZE(indio_dev->num_channels);
+ /* Must keep CS low for 4 clocks */
+ priv->rdata_xfer.delay.value = 2;
+ priv->rdata_xfer.delay.unit = SPI_DELAY_UNIT_USECS;
+ spi_message_init_with_transfers(&priv->rdata_msg, &priv->rdata_xfer, 1);
+ priv->rdata_msg.complete = &ads1298_rdata_complete;
+ priv->rdata_msg.context = indio_dev;
+
+ ret = devm_request_irq(dev, spi->irq, &ads1298_interrupt,
+ IRQF_TRIGGER_FALLING, indio_dev->name,
+ indio_dev);
+ if (ret)
+ return ret;
+
+ ret = devm_iio_kfifo_buffer_setup(dev, indio_dev, &ads1298_setup_ops);
+ if (ret)
+ return ret;
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct spi_device_id ads1298_id[] = {
+ { "ads1298" },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, ads1298_id);
+
+static const struct of_device_id ads1298_of_table[] = {
+ { .compatible = "ti,ads1298" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ads1298_of_table);
+
+static struct spi_driver ads1298_driver = {
+ .driver = {
+ .name = "ads1298",
+ .of_match_table = ads1298_of_table,
+ },
+ .probe = ads1298_probe,
+ .id_table = ads1298_id,
+};
+module_spi_driver(ads1298_driver);
+
+MODULE_AUTHOR("Mike Looijmans <[email protected]>");
+MODULE_DESCRIPTION("TI ADS1298 ADC");
+MODULE_LICENSE("GPL");
--
2.34.1
Met vriendelijke groet / kind regards,
Mike Looijmans
System Expert
TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands
T: +31 (0) 499 33 69 69
E: [email protected]
W: http://www.topic.nl
Please consider the environment before printing this e-mail
On Mon, Feb 19, 2024 at 07:50:26AM +0100, Mike Looijmans wrote:
> Skeleton driver for the TI ADS1298 medical ADC. This device is
> typically used for ECG and similar measurements. Supports data
> acquisition at configurable scale and sampling frequency.
This version seems good enough,
Reviewed-by: Andy Shevchenko <[email protected]>
--
With Best Regards,
Andy Shevchenko
On Mon, 19 Feb 2024 14:27:57 +0200
Andy Shevchenko <[email protected]> wrote:
> On Mon, Feb 19, 2024 at 07:50:26AM +0100, Mike Looijmans wrote:
> > Skeleton driver for the TI ADS1298 medical ADC. This device is
> > typically used for ECG and similar measurements. Supports data
> > acquisition at configurable scale and sampling frequency.
>
> This version seems good enough,
> Reviewed-by: Andy Shevchenko <[email protected]>
>
I fixed up the PTR_ERR() thing directly on the tree and added Andy's
RB whilst there.