On 22 September 2015 16:36:49 BST, Peter Rosin <peda@xxxxxxxxxxxxxx> wrote: >From: Peter Rosin <peda@xxxxxxxxxx> > >Add support for Microchip digital potentiometers and rheostats > MCP4531, MCP4532, MCP4551, MCP4552 > MCP4631, MCP4632, MCP4651, MCP4652 > >These are either single (45xx) or dual (46xx) wipers with either >129 (4x3x) or 257 (4x5x) steps, and configured either as >potentiometers (4xx1) or rheostats (4xx2). They all use i2c >client addresses of the 0101xxx form. > >Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22096b.pdf > >Signed-off-by: Peter Rosin <peda@xxxxxxxxxx> Mostly fine though I think you may have gone a bit too much for conciseness over clarity. Also the scale appears known so should be exposed to userspace. >--- > MAINTAINERS | 6 ++ > drivers/iio/Kconfig | 1 + > drivers/iio/Makefile | 1 + > drivers/iio/potentiometer/Kconfig | 20 ++++ > drivers/iio/potentiometer/Makefile | 6 ++ >drivers/iio/potentiometer/mcp4531.c | 196 >+++++++++++++++++++++++++++++++++++ > 6 files changed, 230 insertions(+) > create mode 100644 drivers/iio/potentiometer/Kconfig > create mode 100644 drivers/iio/potentiometer/Makefile > create mode 100644 drivers/iio/potentiometer/mcp4531.c > >diff --git a/MAINTAINERS b/MAINTAINERS >index b60e2b2369d2..27862156c7a7 100644 >--- a/MAINTAINERS >+++ b/MAINTAINERS >@@ -6600,6 +6600,12 @@ W: http://linuxtv.org > S: Maintained > F: drivers/media/radio/radio-maxiradio* > >+MCP4531 MICROCHIP DIGITAL POTENTIOMETER DRIVER >+M: Peter Rosin <peda@xxxxxxxxxx> >+L: linux-iio@xxxxxxxxxxxxxxx >+S: Maintained >+F: drivers/iio/potentiometer/mcp4531.c >+ > MEDIA DRIVERS FOR RENESAS - VSP1 > M: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > L: linux-media@xxxxxxxxxxxxxxx >diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig >index 4011effe4c05..7cc87f322655 100644 >--- a/drivers/iio/Kconfig >+++ b/drivers/iio/Kconfig >@@ -73,6 +73,7 @@ source "drivers/iio/orientation/Kconfig" > if IIO_TRIGGER > source "drivers/iio/trigger/Kconfig" > endif #IIO_TRIGGER >+source "drivers/iio/potentiometer/Kconfig" > source "drivers/iio/pressure/Kconfig" > source "drivers/iio/proximity/Kconfig" > source "drivers/iio/temperature/Kconfig" >diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile >index 698afc2d17ce..121c814e366b 100644 >--- a/drivers/iio/Makefile >+++ b/drivers/iio/Makefile >@@ -23,6 +23,7 @@ obj-y += imu/ > obj-y += light/ > obj-y += magnetometer/ > obj-y += orientation/ >+obj-y += potentiometer/ > obj-y += pressure/ > obj-y += proximity/ > obj-y += temperature/ >diff --git a/drivers/iio/potentiometer/Kconfig >b/drivers/iio/potentiometer/Kconfig >new file mode 100644 >index 000000000000..fd75db73e582 >--- /dev/null >+++ b/drivers/iio/potentiometer/Kconfig >@@ -0,0 +1,20 @@ >+# >+# Potentiometer drivers >+# >+# When adding new entries keep the list in alphabetical order >+ >+menu "Digital potentiometers" >+ >+config MCP4531 >+ tristate "Microchip MCP45xx/MCP46xx Digital Potentiometer driver" >+ depends on I2C >+ help >+ Say yes here to build support for the Microchip >+ MCP4531, MCP4532, MCP4551, MCP4552, >+ MCP4631, MCP4632, MCP4651, MCP4652 >+ digital potentiomenter chips. >+ >+ To compile this driver as a module, choose M here: the >+ module will be called mcp4531. >+ >+endmenu >diff --git a/drivers/iio/potentiometer/Makefile >b/drivers/iio/potentiometer/Makefile >new file mode 100644 >index 000000000000..8afe49227012 >--- /dev/null >+++ b/drivers/iio/potentiometer/Makefile >@@ -0,0 +1,6 @@ >+# >+# Makefile for industrial I/O potentiometer drivers >+# >+ >+# When adding new entries keep the list in alphabetical order >+obj-$(CONFIG_MCP4531) += mcp4531.o >diff --git a/drivers/iio/potentiometer/mcp4531.c >b/drivers/iio/potentiometer/mcp4531.c >new file mode 100644 >index 000000000000..04faf56dabe0 >--- /dev/null >+++ b/drivers/iio/potentiometer/mcp4531.c >@@ -0,0 +1,196 @@ >+/* >+ * Industrial I/O driver for Microchip digital potentiometers >+ * Copyright (c) 2015 Axentia Technologies AB >+ * Author: Peter Rosin <peda@xxxxxxxxxx> >+ * >+ * Datasheet: >http://www.microchip.com/downloads/en/DeviceDoc/22096b.pdf >+ * >+ * DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address >+ * mcp4531 1 129 5, 10, 50, 100 010111x >+ * mcp4532 1 129 5, 10, 50, 100 01011xx >+ * mcp4551 1 257 5, 10, 50, 100 010111x >+ * mcp4552 1 257 5, 10, 50, 100 01011xx >+ * mcp4631 2 129 5, 10, 50, 100 0101xxx >+ * mcp4632 2 129 5, 10, 50, 100 01011xx >+ * mcp4651 2 257 5, 10, 50, 100 0101xxx >+ * mcp4652 2 257 5, 10, 50, 100 01011xx >+ * >+ * 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. >+ */ >+ >+#include <linux/module.h> >+#include <linux/i2c.h> >+#include <linux/err.h> >+ >+#include <linux/iio/iio.h> >+ >+#define MCP4531_CONF(wipers, max_pos, uid) \ >+ ((((wipers) & 0xf) << 10) | \ >+ (((max_pos) & 0xf) << 6) | \ >+ ((uid) & 0x3f)) This strike me as harder to read than it need be. I think I would be clearer done By setting dev_id to an index into an array to static const structs with the various parts explicitly brought out as fields. Preferably assigned with c99 syntax for really easy reading :) >+ >+#define MCP4531_UID(conf) ((conf) & 0x3f) >+#define MCP4531_MAX_POS(conf) (((conf) >> 6) & 0xf) >+#define MCP4531_WIPERS(conf) (((conf) >> 10) & 0xf) >+ >+#define MCP4531_WRITE (0 << 2) >+#define MCP4531_INCR (1 << 2) >+#define MCP4531_DECR (2 << 2) >+#define MCP4531_READ (3 << 2) >+ >+#define MCP4531_WIPER_SHIFT (4) >+ >+enum mcp4531_devid { >+ MCP4531_ID = MCP4531_CONF(1, 7, 0), >+ MCP4532_ID = MCP4531_CONF(1, 7, 1), >+ MCP4551_ID = MCP4531_CONF(1, 8, 2), >+ MCP4552_ID = MCP4531_CONF(1, 8, 3), >+ MCP4631_ID = MCP4531_CONF(2, 7, 4), >+ MCP4632_ID = MCP4531_CONF(2, 7, 5), >+ MCP4651_ID = MCP4531_CONF(2, 8, 6), >+ MCP4652_ID = MCP4531_CONF(2, 8, 7), >+}; >+ >+struct mcp4531_data { >+ struct i2c_client *client; >+ unsigned int max_pos; >+ unsigned long devid; >+}; >+ >+#define MCP4531_CHANNEL(ch) { \ >+ .type = IIO_RESISTANCE, \ >+ .indexed = 1, \ >+ .output = 1, \ >+ .channel = (ch), \ >+ .address = (ch) << MCP4531_WIPER_SHIFT, \ Why not drop specifying address and use channel with the shift applied at call site? >+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ >+} >+ >+static const struct iio_chan_spec mcp4531_channels[] = { >+ MCP4531_CHANNEL(0), >+ MCP4531_CHANNEL(1), >+}; >+ >+static int mcp4531_get_value(struct iio_dev *indio_dev, >+ int address, int *val) >+{ >+ struct mcp4531_data *data = iio_priv(indio_dev); >+ s32 ret; >+ >+ ret = i2c_smbus_read_word_swapped(data->client, >+ MCP4531_READ | address); >+ if (ret < 0) >+ return ret; >+ *val = ret; >+ return 0; >+} >+ >+static int mcp4531_set_value(struct iio_dev *indio_dev, >+ int address, int val) >+{ >+ struct mcp4531_data *data = iio_priv(indio_dev); >+ >+ if (val >= data->max_pos || val < 0) >+ return -EINVAL; >+ >+ return i2c_smbus_write_byte_data(data->client, >+ MCP4531_WRITE | address | (val >> 8), >+ val & 0xff); >+} As each of these wrappers is so brief and only used once I would favour just merging them in where called. >+ >+static int mcp4531_read_raw(struct iio_dev *indio_dev, >+ struct iio_chan_spec const *chan, >+ int *val, int *val2, long mask) >+{ >+ int err; >+ >+ switch (mask) { >+ case IIO_CHAN_INFO_RAW: >+ err = mcp4531_get_value(indio_dev, chan->address, val); >+ if (err < 0) >+ return err; >+ return IIO_VAL_INT; >+ } No scale known? Be nice to relate to real world values. I gather this may need platform data of some type (can't open data sheet on phone for some reason) >+ >+ return -EINVAL; >+} >+ >+static int mcp4531_write_raw(struct iio_dev *indio_dev, >+ struct iio_chan_spec const *chan, >+ int val, int val2, long mask) >+{ >+ switch (mask) { >+ case IIO_CHAN_INFO_RAW: >+ return mcp4531_set_value(indio_dev, chan->address, val); >+ } >+ >+ return -EINVAL; >+} >+ >+static const struct iio_info mcp4531_info = { >+ .read_raw = mcp4531_read_raw, >+ .write_raw = mcp4531_write_raw, >+ .driver_module = THIS_MODULE, >+}; >+ >+static int mcp4531_probe(struct i2c_client *client, >+ const struct i2c_device_id *id) >+{ >+ struct device *dev = &client->dev; >+ unsigned long devid = id->driver_data; >+ struct mcp4531_data *data; >+ struct iio_dev *indio_dev; >+ >+ if (!i2c_check_functionality(client->adapter, >+ I2C_FUNC_SMBUS_WORD_DATA)) { >+ dev_err(dev, "SMBUS Word Data not supported\n"); >+ return -EIO; >+ } >+ >+ indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); >+ if (!indio_dev) >+ return -ENOMEM; >+ data = iio_priv(indio_dev); >+ i2c_set_clientdata(client, indio_dev); >+ data->client = client; >+ data->devid = devid; >+ >+ data->max_pos = (1 << MCP4531_MAX_POS(devid)) + 1; Derive at use site rather than here. >+ >+ indio_dev->dev.parent = dev; >+ indio_dev->info = &mcp4531_info; >+ indio_dev->channels = mcp4531_channels; >+ indio_dev->num_channels = MCP4531_WIPERS(devid); >+ indio_dev->name = client->name; >+ >+ return devm_iio_device_register(dev, indio_dev); >+} >+ >+static const struct i2c_device_id mcp4531_id[] = { >+ { "mcp4531", MCP4531_ID }, >+ { "mcp4532", MCP4532_ID }, >+ { "mcp4551", MCP4551_ID }, >+ { "mcp4552", MCP4552_ID }, >+ { "mcp4631", MCP4631_ID }, >+ { "mcp4632", MCP4632_ID }, >+ { "mcp4651", MCP4651_ID }, >+ { "mcp4652", MCP4652_ID }, >+ {} >+}; >+MODULE_DEVICE_TABLE(i2c, mcp4531_id); >+ >+static struct i2c_driver mcp4531_driver = { >+ .driver = { >+ .name = "mcp4531", >+ }, >+ .probe = mcp4531_probe, >+ .id_table = mcp4531_id, >+}; >+ >+module_i2c_driver(mcp4531_driver); >+ >+MODULE_AUTHOR("Peter Rosin <peda@xxxxxxxxxx>"); >+MODULE_DESCRIPTION("MCP4531 digital potentiometer"); >+MODULE_LICENSE("GPL"); -- Sent from my Android device with K-9 Mail. 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