The subject should follow the standard subsystem subject scheme. E.g. in
this case "iio: adc: Add driver for ..."
On 03/23/2017 11:35 AM, michael.hennerich@xxxxxxxxxx wrote:
> From: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
Needs a commit message.
>
> 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"
Replace 'should' with 'must'. It won't work if it isn't.
> + - reg: Should contain the ADC I2C address
Same here.
> + - 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/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
That's the "Analog Devices LTC2497 ADC" now ;)
> + *
> + * 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>
Sorting alphabetically is preferred.
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define LTC2497_ENABLE 0xA0
> +#define LTC2497_SGL (1 << 4)
I'm sure 5 minutes after the patch has been applied somebody will send a
patch to replace this with BIT(4)
> +#define LTC2497_DIFF (0 << 4)
> +#define LTC2497_SIGN (1 << 3)
> +#define LTC2497_CONFIG_DEFAULT LTC2497_ENABLE
> +#define LTC2497_CONVERSION_TIME_MS 150ULL
> +
> +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);
Considering how long this sleeps msleep_interruptible() might be the better
choice.
> + 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;
transfer buffers must not be on the stack to avoid issues if the controller
should use DMA.
> + int ret;
> +
> + ret = ltc2497_wait_conv(st);
> + if (ret < 0 || st->addr_prev != address) {
> + ret = i2c_smbus_write_byte(st->client, 0xA0 | address);
> + 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);
> +
> + return ret;
> +}
[...]
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