Merge tag 'staging-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pull staging/IIO driver updates from Greg KH:
 "Here is the large set of staging and IIO driver changes for 5.8-rc1

  Nothing major, but a lot of new IIO drivers are included in here,
  along with other core iio cleanups and changes.

  On the staging driver front, again, nothing noticable. No new
  deletions or additions, just a ton of tiny cleanups all over the tree
  done by a lot of different people. Most coding style, but many actual
  real fixes and cleanups that are nice to see.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'staging-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (618 commits)
  staging: rtl8723bs: Use common packet header constants
  staging: sm750fb: Add names to proc_setBLANK args
  staging: most: usb: init return value in default path of switch/case expression
  staging: vchiq: Get rid of VCHIQ_SERVICE_OPENEND callback reason
  staging: vchiq: move vchiq_release_message() into vchiq
  staging: vchi: Get rid of C++ guards
  staging: vchi: Get rid of not implemented function declarations
  staging: vchi: Get rid of vchiq_status_to_vchi()
  staging: vchi: Get rid of vchi_service_set_option()
  staging: vchi: Merge vchi_msg_queue() into vchi_queue_kernel_message()
  staging: vchiq: Move copy callback handling into vchiq
  staging: vchi: Get rid of vchi_queue_user_message()
  staging: vchi: Get rid of vchi_service_destroy()
  staging: most: usb: use function sysfs_streq
  staging: most: usb: add missing put_device calls
  staging: most: usb: use correct error codes
  staging: most: usb: replace code to calculate array index
  staging: most: usb: don't use error path to exit function on success
  staging: most: usb: move allocation of URB out of critical section
  staging: most: usb: return 0 instead of variable
  ...

1 files changed, 227 insertions, 0 deletions

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");