On Tue, 12 Nov 2019 17:35:50 +0200
Beniamin Bia <beniamin....@analog.com> wrote:

> From: Michael Hennerich <michael.henner...@analog.com>
> 
> ADM1177 is a Hot Swap Controller and Digital Power Monitor with
> Soft Start Pin.
> 
> Datasheet:
> Link: 
> https://www.analog.com/media/en/technical-documentation/data-sheets/ADM1177.pdf
> 
> Signed-off-by: Michael Hennerich <michael.henner...@analog.com>
> Co-developed-by: Beniamin Bia <beniamin....@analog.com>
> Signed-off-by: Beniamin Bia <beniamin....@analog.com>

Hi Beniamin,

A couple immediate thoughts.

1. That cc list has some rather non obvious people on it.  Unless something
   fairly surprising is going on, probably better to cut it back a bit.

2. Why IIO?  Not entirely obvious to me.  From first glance this is definitely
   doing hardware monitoring.  If there is a reason there should be a clear
   statement here on why.

+CC Guenter and Jean as hwmon maintainers.

Whilst I'm here, a very quick review below.

> ---
>  drivers/iio/adc/Kconfig   |  12 ++
>  drivers/iio/adc/Makefile  |   1 +
>  drivers/iio/adc/adm1177.c | 257 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 270 insertions(+)
>  create mode 100644 drivers/iio/adc/adm1177.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 9554890a3200..4db8c6dcb595 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -228,6 +228,18 @@ config ASPEED_ADC
>         To compile this driver as a module, choose M here: the module will be
>         called aspeed_adc.
>  
> +config ADM1177
> +     tristate "Analog Devices ADM1177 Digital Power Monitor driver"
> +     depends on I2C
> +     help
> +       Say yes here to build support for Analog Devices:
> +       ADM1177 Hot Swap Controller and Digital Power Monitor
> +       with Soft Start Pin. Provides direct access
> +       via sysfs.
> +
> +       To compile this driver as a module, choose M here: the
> +       module will be called adm1177.
> +
>  config AT91_ADC
>       tristate "Atmel AT91 ADC"
>       depends on ARCH_AT91
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 5ecc481c2967..7899d6a158f3 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_AD7887) += ad7887.o
>  obj-$(CONFIG_AD7949) += ad7949.o
>  obj-$(CONFIG_AD799X) += ad799x.o
>  obj-$(CONFIG_ASPEED_ADC) += aspeed_adc.o
> +obj-$(CONFIG_ADM1177) += adm1177.o
>  obj-$(CONFIG_AT91_ADC) += at91_adc.o
>  obj-$(CONFIG_AT91_SAMA5D2_ADC) += at91-sama5d2_adc.o
>  obj-$(CONFIG_AXP20X_ADC) += axp20x_adc.o
> diff --git a/drivers/iio/adc/adm1177.c b/drivers/iio/adc/adm1177.c
> new file mode 100644
> index 000000000000..daec34566a65
> --- /dev/null
> +++ b/drivers/iio/adc/adm1177.c
> @@ -0,0 +1,257 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ADM1177 Hot Swap Controller and Digital Power Monitor with Soft Start Pin
> + *
> + * Copyright 2015-2019 Analog Devices Inc.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/slab.h>
> +#include <linux/sysfs.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/events.h>
> +
> +/*  Command Byte Operations */
> +#define ADM1177_CMD_V_CONT   BIT(0)
> +#define ADM1177_CMD_V_ONCE   BIT(1)
> +#define ADM1177_CMD_I_CONT   BIT(2)
> +#define ADM1177_CMD_I_ONCE   BIT(3)
> +#define ADM1177_CMD_VRANGE   BIT(4)
> +#define ADM1177_CMD_STATUS_RD        BIT(6)
> +
> +/* Extended Register */
> +#define ADM1177_REG_ALERT_EN 1
> +#define ADM1177_REG_ALERT_TH 2
> +#define ADM1177_REG_CONTROL  3
> +
> +/* ADM1177_REG_ALERT_EN */
> +#define ADM1177_EN_ADC_OC1   BIT(0)
> +#define ADM1177_EN_ADC_OC4   BIT(1)
> +#define ADM1177_EN_HS_ALERT  BIT(2)
> +#define ADM1177_EN_OFF_ALERT BIT(3)
> +#define ADM1177_CLEAR                BIT(4)
> +
> +/* ADM1177_REG_CONTROL */
> +#define ADM1177_SWOFF                BIT(0)
> +
> +#define ADM1177_BITS         12
> +
> +/**
> + * struct adm1177_state - driver instance specific data
> + * @client           pointer to i2c client
> + * @reg                      regulator info for the the power supply of the 
> device
> + * @command          internal control register
> + * @r_sense_uohm     current sense resistor value
> + * @alert_threshold_ua       current limit for shutdown
> + * @vrange_high              internal voltage divider
> + */
> +struct adm1177_state {
> +     struct i2c_client       *client;
> +     struct regulator        *reg;
> +     u8                      command;
> +     u32                     r_sense_uohm;
> +     u32                     alert_threshold_ua;
> +     bool                    vrange_high;
> +};
> +
> +static int adm1177_read(struct adm1177_state *st, u8 num, u8 *data)
> +{
> +     struct i2c_client *client = st->client;
> +     int ret = 0;
> +
> +     ret = i2c_master_recv(client, data, num);
> +     if (ret < 0) {
> +             dev_err(&client->dev, "I2C read error\n");
> +             return ret;
> +     }
> +
> +     return 0;
> +}
> +
> +static int adm1177_write_cmd(struct adm1177_state *st, u8 cmd)
> +{
> +     st->command = cmd;
> +     return i2c_smbus_write_byte(st->client, cmd);
> +}
> +
> +static int adm1177_write_reg(struct adm1177_state *st, u8 reg, u8 val)
> +{
> +     return i2c_smbus_write_byte_data(st->client, reg, val);

These wrappers don't really add anything.  I'd just make the i2c
calls directly inline. They will be self explanatory.

> +}
> +
> +static int adm1177_read_raw(struct iio_dev *indio_dev,
> +                        struct iio_chan_spec const *chan,
> +                        int *val,
> +                        int *val2,
> +                        long mask)
> +{
> +     struct adm1177_state *st = iio_priv(indio_dev);
> +     u8 data[3];
> +
> +     switch (mask) {
> +     case IIO_CHAN_INFO_RAW:
> +             adm1177_read(st, 3, data);
> +             switch (chan->type) {
> +             case IIO_VOLTAGE:
> +                     *val = (data[0] << 4) | (data[2] >> 4);
> +                     return IIO_VAL_INT;
> +             case IIO_CURRENT:
> +                     *val = (data[1] << 4) | (data[2] & 0xF);
> +                     return IIO_VAL_INT;
> +             default:
> +                     return -EINVAL;
> +             }
> +
> +     case IIO_CHAN_INFO_SCALE:
> +             switch (chan->type) {
> +             case IIO_VOLTAGE:
> +                     if (st->command & ADM1177_CMD_VRANGE)
> +                             *val = 6650;
> +                     else
> +                             *val = 26350;
> +
> +                     *val2 = ADM1177_BITS;
> +                     return IIO_VAL_FRACTIONAL_LOG2;
> +             case IIO_CURRENT:
> +                     *val = 105840 / st->r_sense_uohm;
> +
> +                     *val2 = ADM1177_BITS;
> +                     return IIO_VAL_FRACTIONAL_LOG2;
> +             default:
> +                     return -EINVAL;
> +             }
> +     default:
> +             return -EINVAL;
> +     }
> +}
> +
> +static const struct iio_chan_spec adm1177_channels[] = {
> +     {
> +             .type = IIO_VOLTAGE,
> +             .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +                                   BIT(IIO_CHAN_INFO_SCALE),
> +             .indexed = 1,
> +             .channel = 0,
> +     },
> +     {
> +             .type = IIO_CURRENT,
> +             .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +                                   BIT(IIO_CHAN_INFO_SCALE),
> +             .indexed = 1,
> +             .channel = 0,
> +     },
> +};
> +
> +static const struct iio_info adm1177_info = {
> +     .read_raw = &adm1177_read_raw,
> +};

blank line here.

> +static void adm1177_remove(void *data)
> +{
> +     struct adm1177_state *st = data;
> +
> +     if (st->reg)
> +             regulator_disable(st->reg);

Probe and remove should be mirror images of each other.
As you have a mixture of managed and non managed calls that
isn't the case here.

devm_add_action_or_reset will sort this out for you if
used to turn off the regulator at the right point on removal.

> +}
> +
> +static int adm1177_probe(struct i2c_client *client,
> +                      const struct i2c_device_id *id)
> +{
> +     int ret;
> +     struct device_node *np;
> +     struct adm1177_state *st;
> +     struct iio_dev *indio_dev;
> +
> +     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;
> +
> +     np = client->dev.of_node;
> +
> +     st->reg = devm_regulator_get_optional(&client->dev, "vref");
> +     if (IS_ERR(st->reg)) {
> +             if (PTR_ERR(st->reg) == EPROBE_DEFER)
> +                     return -EPROBE_DEFER;
> +
> +             st->reg = NULL;
> +     } else {
> +             ret = regulator_enable(st->reg);
> +             if (ret)
> +                     return ret;
> +             ret = devm_add_action_or_reset(&client->dev, adm1177_remove,
> +                                            st);
> +             if (ret)
> +                     return ret;
> +     }
> +
> +     of_property_read_u32(np, "adi,r-sense-micro-ohms", &st->r_sense_uohm);
> +     of_property_read_u32(np, "adi,shutdown-threshold-microamp",
> +                          &st->alert_threshold_ua);
> +     st->vrange_high = of_property_read_bool(np,
> +                             "adi,vrange-high-enable");
> +     if (st->alert_threshold_ua) {
> +             unsigned int val;
> +
> +             val = (st->alert_threshold_ua * st->r_sense_uohm * 0xFF);
> +             val /= 105840000U;
> +             if (val > 0xFF) {
> +                     dev_err(&client->dev,
> +                             "Requested shutdown current %d uA above 
> limit\n",
> +                             st->alert_threshold_ua);
> +
> +                     val = 0xFF;
> +             }
> +             adm1177_write_reg(st, ADM1177_REG_ALERT_TH, val);
> +     }
> +
> +     adm1177_write_cmd(st, ADM1177_CMD_V_CONT |
> +                           ADM1177_CMD_I_CONT |
> +                           (st->vrange_high ? 0 : ADM1177_CMD_VRANGE));
> +
> +     indio_dev->name = id->name;
> +     indio_dev->channels = adm1177_channels;
> +     indio_dev->num_channels = ARRAY_SIZE(adm1177_channels);
> +
> +     indio_dev->dev.parent = &client->dev;
> +     indio_dev->info = &adm1177_info;
> +     indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +     return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +static const struct i2c_device_id adm1177_ids[] = {
> +     { "adm1177", 0 },
> +     {}
> +};
> +MODULE_DEVICE_TABLE(i2c, adm1177_ids);
> +
> +static const struct of_device_id adm1177_dt_ids[] = {
> +     { .compatible = "adi,adm1177" },
> +     {},
> +};
> +MODULE_DEVICE_TABLE(of, adm1177_dt_ids);
> +
> +static struct i2c_driver adm1177_driver = {
> +     .driver = {
> +             .name = "adm1177",
> +             .of_match_table = adm1177_dt_ids,
> +     },
> +     .probe = adm1177_probe,
> +     .id_table = adm1177_ids,
> +};
> +module_i2c_driver(adm1177_driver);
> +
> +MODULE_AUTHOR("Michael Hennerich <michael.henner...@analog.com>");
> +MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
> +MODULE_LICENSE("GPL v2");


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