On 23.03.2017 12:28, Peter Meerwald-Stadler wrote:
On Thu, 23 Mar 2017, michael.hennerich@xxxxxxxxxx wrote:From: Michael Hennerich <michael.hennerich@xxxxxxxxxx>comments below
Hi Peter, Thanks for the review - comments inline.
Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx> --- .../devicetree/bindings/iio/adc/ltc2497.txt | 13 + MAINTAINERS | 1 + drivers/iio/adc/Kconfig | 11 + drivers/iio/adc/Makefile | 1 + drivers/iio/adc/ltc2497.c | 263 +++++++++++++++++++++ 5 files changed, 289 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/adc/ltc2497.txt create mode 100644 drivers/iio/adc/ltc2497.c diff --git a/Documentation/devicetree/bindings/iio/adc/ltc2497.txt b/Documentation/devicetree/bindings/iio/adc/ltc2497.txt new file mode 100644 index 0000000..c2829c19 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/adc/ltc2497.txt @@ -0,0 +1,13 @@ +* Linear Technology / Analog Devices LTC2497 ADC + +Required properties: + - compatible: Should be "lltc,ltc2497" + - reg: Should contain the ADC I2C address + - vref-supply: The regulator supply for ADC reference voltage + +Example: + ltc2497: adc@76 { + compatible = "lltc,ltc2497"; + reg = <0x76>; + vref-supply = <<c2497_reg>; + }; diff --git a/MAINTAINERS b/MAINTAINERS index a7d6f9a..173043c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -813,6 +813,7 @@ W: http://wiki.analog.com/ W: http://ez.analog.com/community/linux-device-drivers S: Supported F: drivers/iio/*/ad* +F: drivers/iio/adc/ltc2497* X: drivers/iio/*/adjd* F: drivers/staging/iio/*/ad* F: drivers/staging/iio/trigger/iio-trig-bfin-timer.c diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index 2268a6f..141cf4a 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -326,6 +326,17 @@ config LTC2485 To compile this driver as a module, choose M here: the module will be called ltc2485. +config LTC2497 + tristate "Linear Technology LTC2497 ADC driver" + depends on I2C + help + Say yes here to build support for Linear Technology LTC2497 + 16-Bit 8-/16-Channel Delta Sigma ADC. + Provides direct access via sysfsthe line "Provides..." should be removed I think, it confuses me at least
Sure I can remove - originally added to make checkpatch happy.
+ + To compile this driver as a module, choose M here: the module will be + called ltc2497. + config MAX1027 tristate "Maxim max1027 ADC driver" depends on SPI diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index 73dbe39..9d626b5 100644 --- a/drivers/iio/adc/Makefile +++ b/drivers/iio/adc/Makefile @@ -32,6 +32,7 @@ obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o obj-$(CONFIG_LTC2485) += ltc2485.o +obj-$(CONFIG_LTC2497) += ltc2497.o obj-$(CONFIG_MAX1027) += max1027.o obj-$(CONFIG_MAX11100) += max11100.o obj-$(CONFIG_MAX1363) += max1363.o diff --git a/drivers/iio/adc/ltc2497.c b/drivers/iio/adc/ltc2497.c new file mode 100644 index 0000000..0452715 --- /dev/null +++ b/drivers/iio/adc/ltc2497.c @@ -0,0 +1,263 @@ +/* + * ltc2497.c - Driver for Linear Technology LTC2497 ADC + * + * Copyright (C) 2017 Analog Devices Inc. + * + * Licensed under the GPL-2. + * + * Datasheet: http://cds.linear.com/docs/en/datasheet/2497fd.pdf + */ + +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/delay.h> +#include <linux/regulator/consumer.h> +#include <linux/of.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#define LTC2497_ENABLE 0xA0 +#define LTC2497_SGL (1 << 4) +#define LTC2497_DIFF (0 << 4) +#define LTC2497_SIGN (1 << 3) +#define LTC2497_CONFIG_DEFAULT LTC2497_ENABLE +#define LTC2497_CONVERSION_TIME_MS 150ULLis the ULL really needed?
Needed? - maybe not - but probably not wrong ktime_ms_delta() returns 64bit and we later do some comparisons...
+struct ltc2497_st { + struct i2c_client *client; + struct regulator *ref; + ktime_t time_prev; + u8 addr_prev; +}; + +static int ltc2497_wait_conv(struct ltc2497_st *st) +{ + s64 time_elapsed; + + time_elapsed = ktime_ms_delta(ktime_get(), st->time_prev); + + if (time_elapsed < LTC2497_CONVERSION_TIME_MS) { + /* delay if conversion time not passed + * since last read or write + */ + msleep(LTC2497_CONVERSION_TIME_MS - time_elapsed); + return 0; + } + + if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) { + /* We're in automatic mode - + * so the last reading is stil not outdated + */ + return 0; + } + + return -ETIMEDOUT; +} + +static int ltc2497_read(struct ltc2497_st *st, u8 address, int *val) +{ + struct i2c_client *client = st->client; + __be32 buf = 0; + int ret; + + ret = ltc2497_wait_conv(st); + if (ret < 0 || st->addr_prev != address) { + ret = i2c_smbus_write_byte(st->client, 0xA0 | address);use LTC2497_ENABLE instead of 0xa0
good catch.
+ if (ret < 0) + return ret; + st->addr_prev = address; + msleep(LTC2497_CONVERSION_TIME_MS); + } + ret = i2c_master_recv(client, (char *)&buf, 3); + if (ret < 0) { + dev_err(&client->dev, "i2c_master_recv failed\n"); + return ret; + } + st->time_prev = ktime_get(); + *val = (be32_to_cpu(buf) >> 14) - (1 << 17);what is the purpose of - (1 << 17)? maybe add a comment? I'd rather do it with bit operations that arithmetic
Well - this is for offset binary to signed conversion. I'll add a comment.
+ + return ret; +} + +static int ltc2497_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct ltc2497_st *st = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&indio_dev->mlock); + ret = ltc2497_read(st, chan->address, val); + mutex_unlock(&indio_dev->mlock); + if (ret < 0) + return ret; + + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + ret = regulator_get_voltage(st->ref); + if (ret < 0) + return ret; + + *val = ret / 1000; + *val2 = 17; + + return IIO_VAL_FRACTIONAL_LOG2; + + default: + return -EINVAL; + } +} + +#define LTC2497_CHAN(_chan, _addr) { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = (_chan), \ + .address = (_addr | (_chan / 2) | ((_chan & 1) ? LTC2497_SIGN : 0)), \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ +} + +#define LTC2497_CHAN_DIFF(_chan, _addr) { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \ + .channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\ + .address = (_addr | _chan), \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .differential = 1, \ +} + +static const struct iio_chan_spec ltc2497_channel[] = { + LTC2497_CHAN(0, LTC2497_SGL), + LTC2497_CHAN(1, LTC2497_SGL), + LTC2497_CHAN(2, LTC2497_SGL), + LTC2497_CHAN(3, LTC2497_SGL), + LTC2497_CHAN(4, LTC2497_SGL), + LTC2497_CHAN(5, LTC2497_SGL), + LTC2497_CHAN(6, LTC2497_SGL), + LTC2497_CHAN(7, LTC2497_SGL), + LTC2497_CHAN(8, LTC2497_SGL), + LTC2497_CHAN(9, LTC2497_SGL), + LTC2497_CHAN(10, LTC2497_SGL), + LTC2497_CHAN(11, LTC2497_SGL), + LTC2497_CHAN(12, LTC2497_SGL), + LTC2497_CHAN(13, LTC2497_SGL), + LTC2497_CHAN(14, LTC2497_SGL), + LTC2497_CHAN(15, LTC2497_SGL), + LTC2497_CHAN_DIFF(0, LTC2497_DIFF), + LTC2497_CHAN_DIFF(1, LTC2497_DIFF), + LTC2497_CHAN_DIFF(2, LTC2497_DIFF), + LTC2497_CHAN_DIFF(3, LTC2497_DIFF), + LTC2497_CHAN_DIFF(4, LTC2497_DIFF), + LTC2497_CHAN_DIFF(5, LTC2497_DIFF), + LTC2497_CHAN_DIFF(6, LTC2497_DIFF), + LTC2497_CHAN_DIFF(7, LTC2497_DIFF), + LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(2, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(3, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(4, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(5, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(6, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(7, LTC2497_DIFF | LTC2497_SIGN), +}; + +static const struct iio_info ltc2497_info = { + .read_raw = ltc2497_read_raw, + .driver_module = THIS_MODULE, +}; + +static int ltc2497_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct iio_dev *indio_dev; + struct ltc2497_st *st; + int ret; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | + I2C_FUNC_SMBUS_WRITE_BYTE)) + return -EOPNOTSUPP; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); + st->client = client; + + indio_dev->dev.parent = &client->dev; + indio_dev->name = id->name; + indio_dev->info = <c2497_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = ltc2497_channel; + indio_dev->num_channels = ARRAY_SIZE(ltc2497_channel); + + st->ref = devm_regulator_get(&client->dev, "vref"); + if (IS_ERR(st->ref)) + return PTR_ERR(st->ref); + + ret = regulator_enable(st->ref); + if (ret < 0) + return ret; + + ret = i2c_smbus_write_byte(st->client, LTC2497_CONFIG_DEFAULT); + if (ret < 0) + goto err_regulator_disable; + + st->addr_prev = LTC2497_CONFIG_DEFAULT; + st->time_prev = ktime_get(); + + ret = devm_iio_device_register(&client->dev, indio_dev);no devm_ since we have a non-empty _remove()?
ok
+ if (ret < 0) + goto err_regulator_disable; + + return 0; + +err_regulator_disable: + regulator_disable(st->ref); + + return ret; +} + +static int ltc2497_remove(struct i2c_client *client) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(client); + struct ltc2497_st *st = iio_priv(indio_dev); + + regulator_disable(st->ref); + + return 0; +} + +static const struct i2c_device_id ltc2497_id[] = { + { "ltc2497", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, ltc2497_id); + +static const struct of_device_id ltc2497_of_match[] = { + { .compatible = "lltc,ltc2497", }, + {}, +}; +MODULE_DEVICE_TABLE(of, ltc2497_of_match); + +static struct i2c_driver ltc2497_driver = { + .driver = { + .name = "ltc2497", + .of_match_table = of_match_ptr(ltc2497_of_match), + }, + .probe = ltc2497_probe, + .remove = ltc2497_remove, + .id_table = ltc2497_id, +}; +module_i2c_driver(ltc2497_driver); + +MODULE_AUTHOR("Michael Hennerich <michael.hennerich@xxxxxxxxxx>"); +MODULE_DESCRIPTION("Linear Technology LTC2497 ADC driver"); +MODULE_LICENSE("GPL v2");
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