* [PATCH v6 1/2] dt-bindings: iio: adc: Add MAX1241 bindings
2020-04-01 18:51 [PATCH v6 0/2] Maxim MAX1241 driver Alexandru Lazar
@ 2020-04-01 18:51 ` Alexandru Lazar
2020-04-01 18:51 ` [PATCH v6 2/2] iio: adc: Add MAX1241 driver Alexandru Lazar
1 sibling, 0 replies; 7+ messages in thread
From: Alexandru Lazar @ 2020-04-01 18:51 UTC (permalink / raw)
To: linux-iio
Cc: devicetree, jic23, knaack.h, lars, pmeerw, robh+dt, mark.rutland,
Alexandru Lazar
Add device-tree bindings documentation for the MAX1241 device driver.
Signed-off-by: Alexandru Lazar <alazar@startmail.com>
---
.../bindings/iio/adc/maxim,max1241.yaml | 64 +++++++++++++++++++
1 file changed, 64 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/maxim,max1241.yaml
diff --git a/Documentation/devicetree/bindings/iio/adc/maxim,max1241.yaml b/Documentation/devicetree/bindings/iio/adc/maxim,max1241.yaml
new file mode 100644
index 000000000000..7da9e4153ac1
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/maxim,max1241.yaml
@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2020 Alexandru Lazar
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/maxim,max1241.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Maxim MAX1241 12-bit, single-channel analog to digital converter
+
+maintainers:
+ - Alexandru Lazar <alazar@startmail.com>
+
+description: |
+ Bindings for the max1241 12-bit, single-channel ADC device. Datasheet
+ can be found at:
+ https://datasheets.maximintegrated.com/en/ds/MAX1240-MAX1241.pdf
+
+properties:
+ compatible:
+ enum:
+ - maxim,max1241
+
+ reg:
+ maxItems: 1
+
+ vdd-supply:
+ description:
+ Device tree identifier of the regulator that powers the ADC.
+
+ vref-supply:
+ description:
+ Device tree identifier of the regulator that provides the external
+ reference voltage.
+ maxItems: 1
+
+ shutdown-gpios:
+ description:
+ GPIO spec for the GPIO pin connected to the ADC's /SHDN pin. If
+ specified, the /SHDN pin will be asserted between conversions,
+ thus enabling power-down mode.
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+ - vdd-supply
+ - vref-supply
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ adc@0 {
+ compatible = "maxim,max1241";
+ reg = <0>;
+ vdd-supply = <&adc_vdd>;
+ vref-supply = <&adc_vref>;
+ spi-max-frequency = <1000000>;
+ shutdown-gpios = <&gpio 26 1>;
+ };
+ };
--
2.20.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v6 2/2] iio: adc: Add MAX1241 driver
2020-04-01 18:51 [PATCH v6 0/2] Maxim MAX1241 driver Alexandru Lazar
2020-04-01 18:51 ` [PATCH v6 1/2] dt-bindings: iio: adc: Add MAX1241 bindings Alexandru Lazar
@ 2020-04-01 18:51 ` Alexandru Lazar
2020-04-02 18:45 ` Andy Shevchenko
1 sibling, 1 reply; 7+ messages in thread
From: Alexandru Lazar @ 2020-04-01 18:51 UTC (permalink / raw)
To: linux-iio
Cc: devicetree, jic23, knaack.h, lars, pmeerw, robh+dt, mark.rutland,
Alexandru Lazar, Alexandru Ardelean
Add driver for the Maxim MAX1241 12-bit, single-channel ADC.
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Alexandru Lazar <alazar@startmail.com>
---
drivers/iio/adc/Kconfig | 10 ++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/max1241.c | 227 ++++++++++++++++++++++++++++++++++++++
3 files changed, 238 insertions(+)
create mode 100644 drivers/iio/adc/max1241.c
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 5d8540b7b427..55f6462cd93f 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -566,6 +566,16 @@ config MAX1118
To compile this driver as a module, choose M here: the module will be
called max1118.
+config MAX1241
+ tristate "Maxim max1241 ADC driver"
+ depends on SPI_MASTER
+ help
+ Say yes here to build support for Maxim max1241 12-bit, single-channel
+ ADC.
+
+ To compile this driver as a module, choose M here: the module will be
+ called max1241.
+
config MAX1363
tristate "Maxim max1363 ADC driver"
depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index a1f1fbec0f87..37d6f17559dc 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_LTC2497) += ltc2497.o
obj-$(CONFIG_MAX1027) += max1027.o
obj-$(CONFIG_MAX11100) += max11100.o
obj-$(CONFIG_MAX1118) += max1118.o
+obj-$(CONFIG_MAX1241) += max1241.o
obj-$(CONFIG_MAX1363) += max1363.o
obj-$(CONFIG_MAX9611) += max9611.o
obj-$(CONFIG_MCP320X) += mcp320x.o
diff --git a/drivers/iio/adc/max1241.c b/drivers/iio/adc/max1241.c
new file mode 100644
index 000000000000..541939c7abca
--- /dev/null
+++ b/drivers/iio/adc/max1241.c
@@ -0,0 +1,227 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MAX1241 low-power, 12-bit serial ADC
+ *
+ * Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1240-MAX1241.pdf
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#define MAX1241_VAL_MASK GENMASK(11, 0)
+#define MAX1241_SHUTDOWN_DELAY_USEC 4
+
+enum max1241_id {
+ max1241,
+};
+
+struct max1241 {
+ struct spi_device *spi;
+ struct mutex lock;
+ struct regulator *vdd;
+ struct regulator *vref;
+ struct gpio_desc *shutdown;
+
+ __be16 data ____cacheline_aligned;
+};
+
+static const struct iio_chan_spec max1241_channels[] = {
+ {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .channel = 0,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ },
+};
+
+static int max1241_read(struct max1241 *adc)
+{
+ struct spi_transfer xfers[] = {
+ /*
+ * Begin conversion by bringing /CS low for at least
+ * tconv us.
+ */
+ {
+ .len = 0,
+ .delay.value = 8,
+ .delay.unit = SPI_DELAY_UNIT_USECS,
+ },
+ /*
+ * Then read two bytes of data in our RX buffer.
+ */
+ {
+ .rx_buf = &adc->data,
+ .len = 2,
+ },
+ };
+
+ return spi_sync_transfer(adc->spi, xfers, ARRAY_SIZE(xfers));
+}
+
+static int max1241_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ int ret, vref_uV;
+ struct max1241 *adc = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&adc->lock);
+
+ if (adc->shutdown) {
+ gpiod_set_value(adc->shutdown, 0);
+ udelay(MAX1241_SHUTDOWN_DELAY_USEC);
+ ret = max1241_read(adc);
+ gpiod_set_value(adc->shutdown, 1);
+ } else
+ ret = max1241_read(adc);
+
+ if (ret) {
+ mutex_unlock(&adc->lock);
+ return ret;
+ }
+
+ *val = (be16_to_cpu(adc->data) >> 3) & MAX1241_VAL_MASK;
+
+ mutex_unlock(&adc->lock);
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ vref_uV = regulator_get_voltage(adc->vref);
+
+ if (vref_uV < 0)
+ return vref_uV;
+
+ *val = vref_uV / 1000;
+ *val2 = 12;
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info max1241_info = {
+ .read_raw = max1241_read_raw,
+};
+
+static void max1241_disable_vdd_action(void *data)
+{
+ struct max1241 *adc = data;
+ struct device *dev = &adc->spi->dev;
+ int err;
+
+ err = regulator_disable(adc->vdd);
+ if (err)
+ dev_err(dev, "could not disable vdd regulator.\n");
+}
+
+static void max1241_disable_vref_action(void *data)
+{
+ struct max1241 *adc = data;
+ struct device *dev = &adc->spi->dev;
+ int err;
+
+ err = regulator_disable(adc->vref);
+ if (err)
+ dev_err(dev, "could not disable vref regulator.\n");
+}
+
+static int max1241_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+ struct iio_dev *indio_dev;
+ struct max1241 *adc;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ adc = iio_priv(indio_dev);
+ adc->spi = spi;
+ mutex_init(&adc->lock);
+
+ spi_set_drvdata(spi, indio_dev);
+
+ adc->vdd = devm_regulator_get(dev, "vdd");
+ if (IS_ERR(adc->vdd)) {
+ dev_err(dev, "failed to get vdd regulator\n");
+ return PTR_ERR(adc->vdd);
+ }
+
+ ret = regulator_enable(adc->vdd);
+ if (ret)
+ return ret;
+
+ ret = devm_add_action_or_reset(dev, max1241_disable_vdd_action, adc);
+ if (ret) {
+ dev_err(dev, "could not set up vdd regulator cleanup action\n");
+ return ret;
+ }
+
+ adc->vref = devm_regulator_get(dev, "vref");
+ if (IS_ERR(adc->vref)) {
+ dev_err(dev, "failed to get vref regulator\n");
+ return PTR_ERR(adc->vref);
+ }
+
+ ret = regulator_enable(adc->vref);
+ if (ret)
+ return ret;
+
+ ret = devm_add_action_or_reset(dev, max1241_disable_vref_action, adc);
+ if (ret) {
+ dev_err(dev, "could not set up vref regulator cleanup action\n");
+ return ret;
+ }
+
+ adc->shutdown = devm_gpiod_get_optional(dev, "shutdown",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(adc->shutdown))
+ return PTR_ERR(adc->shutdown);
+
+ if (adc->shutdown)
+ dev_dbg(dev, "shutdown pin passed, low-power mode enabled");
+ else
+ dev_dbg(dev, "no shutdown pin passed, low-power mode disabled");
+
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->dev.parent = dev;
+ indio_dev->info = &max1241_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = max1241_channels;
+ indio_dev->num_channels = ARRAY_SIZE(max1241_channels);
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct spi_device_id max1241_id[] = {
+ { "max1241", max1241 },
+ {}
+};
+
+static const struct of_device_id max1241_dt_ids[] = {
+ { .compatible = "maxim,max1241" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, max1241_dt_ids);
+
+static struct spi_driver max1241_spi_driver = {
+ .driver = {
+ .name = "max1241",
+ .of_match_table = max1241_dt_ids,
+ },
+ .probe = max1241_probe,
+ .id_table = max1241_id,
+};
+module_spi_driver(max1241_spi_driver);
+
+MODULE_AUTHOR("Alexandru Lazar <alazar@startmail.com>");
+MODULE_DESCRIPTION("MAX1241 ADC driver");
+MODULE_LICENSE("GPL v2");
--
2.20.1
^ permalink raw reply related [flat|nested] 7+ messages in thread