Merge tag 'staging-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pull staging and IIO driver updates from Greg KH:
 "Here is the big staging/iio driver update for 5.4-rc1.

  Lots of churn here, with a few driver/filesystems moving out of
  staging finally:

     - erofs moved out of staging

     - greybus core code moved out of staging

  Along with that, a new filesytem has been added:

     - extfat

  to provide support for those devices requiring that filesystem (i.e.
  transfer devices to/from windows systems or printers)

  Other than that, there a number of new IIO drivers, and lots and lots
  and lots of staging driver cleanups and minor fixes as people continue
  to dig into those for easy changes.

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

* tag 'staging-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (453 commits)
  Staging: gasket: Use temporaries to reduce line length.
  Staging: octeon: Avoid several usecases of strcpy
  staging: vhciq_core: replace snprintf with scnprintf
  staging: wilc1000: avoid twice IRQ handler execution for each single interrupt
  staging: wilc1000: remove unused interrupt status handling code
  staging: fbtft: make several arrays static const, makes object smaller
  staging: rtl8188eu: make two arrays static const, makes object smaller
  staging: rtl8723bs: core: Remove Macro "IS_MAC_ADDRESS_BROADCAST"
  dt-bindings: anybus-controller: move to staging/ tree
  staging: emxx_udc: remove local TRUE/FALSE definition
  staging: wilc1000: look for rtc_clk clock
  staging: dt-bindings: wilc1000: add optional rtc_clk property
  staging: nvec: make use of devm_platform_ioremap_resource
  staging: exfat: drop unused function parameter
  Staging: exfat: Avoid use of strcpy
  staging: exfat: use integer constants
  staging: exfat: cleanup spacing for casts
  staging: exfat: cleanup spacing for operators
  staging: rtl8723bs: hal: remove redundant variable n
  staging: pi433: Fix typo in documentation
  ...

1 files changed, 135 insertions, 0 deletions

diff --git a/drivers/iio/potentiometer/max5432.c b/drivers/iio/potentiometer/max5432.c
new file mode 100644
index 000000000000..641b1821fdf6
--- /dev/null
+++ b/drivers/iio/potentiometer/max5432.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Maxim Integrated MAX5432-MAX5435 digital potentiometer driver
+ * Copyright (C) 2019 Martin Kaiser <martin@kaiser.cx>
+ *
+ * Datasheet:
+ * https://datasheets.maximintegrated.com/en/ds/MAX5432-MAX5435.pdf
+ */
+
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/limits.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+/* All chip variants have 32 wiper positions. */
+#define MAX5432_MAX_POS 31
+
+#define MAX5432_OHM_50K   (50  * 1000)
+#define MAX5432_OHM_100K  (100 * 1000)
+
+/* Update the volatile (currently active) setting. */
+#define MAX5432_CMD_VREG  0x11
+
+struct max5432_data {
+	struct i2c_client *client;
+	unsigned long ohm;
+};
+
+static const struct iio_chan_spec max5432_channels[] = {
+	{
+		.type = IIO_RESISTANCE,
+		.indexed = 1,
+		.output = 1,
+		.channel = 0,
+		.address = MAX5432_CMD_VREG,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+	}
+};
+
+static int max5432_read_raw(struct iio_dev *indio_dev,
+			struct iio_chan_spec const *chan,
+			int *val, int *val2, long mask)
+{
+	struct max5432_data *data = iio_priv(indio_dev);
+
+	if (mask != IIO_CHAN_INFO_SCALE)
+		return -EINVAL;
+
+	if (unlikely(data->ohm > INT_MAX))
+		return -ERANGE;
+
+	*val = data->ohm;
+	*val2 = MAX5432_MAX_POS;
+
+	return IIO_VAL_FRACTIONAL;
+}
+
+static int max5432_write_raw(struct iio_dev *indio_dev,
+			struct iio_chan_spec const *chan,
+			int val, int val2, long mask)
+{
+	struct max5432_data *data = iio_priv(indio_dev);
+	u8 data_byte;
+
+	if (mask != IIO_CHAN_INFO_RAW)
+		return -EINVAL;
+
+	if (val < 0 || val > MAX5432_MAX_POS)
+		return -EINVAL;
+
+	if (val2 != 0)
+		return -EINVAL;
+
+	/* Wiper position is in bits D7-D3. (D2-D0 are don't care bits.) */
+	data_byte = val << 3;
+	return i2c_smbus_write_byte_data(data->client, chan->address,
+			data_byte);
+}
+
+static const struct iio_info max5432_info = {
+	.read_raw = max5432_read_raw,
+	.write_raw = max5432_write_raw,
+};
+
+static int max5432_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct iio_dev *indio_dev;
+	struct max5432_data *data;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(struct max5432_data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, indio_dev);
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+	data->ohm = (unsigned long)of_device_get_match_data(dev);
+
+	indio_dev->dev.parent = dev;
+	indio_dev->info = &max5432_info;
+	indio_dev->channels = max5432_channels;
+	indio_dev->num_channels = ARRAY_SIZE(max5432_channels);
+	indio_dev->name = client->name;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id max5432_dt_ids[] = {
+	{ .compatible = "maxim,max5432", .data = (void *)MAX5432_OHM_50K  },
+	{ .compatible = "maxim,max5433", .data = (void *)MAX5432_OHM_100K },
+	{ .compatible = "maxim,max5434", .data = (void *)MAX5432_OHM_50K  },
+	{ .compatible = "maxim,max5435", .data = (void *)MAX5432_OHM_100K },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, max5432_dt_ids);
+
+static struct i2c_driver max5432_driver = {
+	.driver = {
+		.name = "max5432",
+		.of_match_table = of_match_ptr(max5432_dt_ids),
+	},
+	.probe = max5432_probe,
+};
+
+module_i2c_driver(max5432_driver);
+
+MODULE_AUTHOR("Martin Kaiser <martin@kaiser.cx>");
+MODULE_DESCRIPTION("max5432-max5435 digital potentiometers");
+MODULE_LICENSE("GPL v2");