[RFC PATCH linux 6/9] hwmon: occ: Add hwmon implementation for the P8 OCC

[Eddie James]

Hi Andrew,

One comment on this one.

Thanks,
Eddie

On Thu, Nov 10, 2016 at 10:12 PM, Andrew Jeffery <andrew at aj.id.au> wrote:
> Signed-off-by: Andrew Jeffery <andrew at aj.id.au>
> ---
>  drivers/hwmon/occ/Kconfig      |  14 +++++
>  drivers/hwmon/occ/Makefile     |   1 +
>  drivers/hwmon/occ/occ_p8_i2c.c | 133 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 148 insertions(+)
>  create mode 100644 drivers/hwmon/occ/occ_p8_i2c.c
>
> diff --git a/drivers/hwmon/occ/Kconfig b/drivers/hwmon/occ/Kconfig
> index cdb64a71af6e..085e1f370c42 100644
> --- a/drivers/hwmon/occ/Kconfig
> +++ b/drivers/hwmon/occ/Kconfig
> @@ -13,3 +13,17 @@ menuconfig SENSORS_PPC_OCC
>
>           This driver can also be built as a module. If so, the module
>           will be called occ.
> +
> +if SENSORS_PPC_OCC
> +
> +config SENSORS_PPC_OCC_P8_I2C
> +       tristate "POWER8 OCC hwmon support"
> +       depends on I2C
> +       help
> +         Provide a hwmon sysfs interface for the POWER8 On-Chip Controller,
> +         exposing temperature, frequency and power measurements.
> +
> +         This driver can also be built as a module. If so, the module will be
> +         called occ-p8-i2c.
> +
> +endif
> diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
> index a6881f93067c..05a84e987127 100644
> --- a/drivers/hwmon/occ/Makefile
> +++ b/drivers/hwmon/occ/Makefile
> @@ -1 +1,2 @@
>  obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o occ_sysfs.o
> +obj-$(CONFIG_SENSORS_PPC_OCC_P8_I2C) += occ_scom_i2c.o occ_p8.o occ_p8_i2c.o
> diff --git a/drivers/hwmon/occ/occ_p8_i2c.c b/drivers/hwmon/occ/occ_p8_i2c.c
> new file mode 100644
> index 000000000000..1b66f302fe16
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ_p8_i2c.c
> @@ -0,0 +1,133 @@
> +/*
> + * occ_p8_i2c.c - hwmon OCC driver
> + *
> + * This file contains the i2c layer for accessing the OCC over i2c bus.
> + *
> + * Copyright 2016 IBM Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/i2c.h>
> +#include <linux/err.h>
> +#include <linux/of.h>
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +
> +#include "scom.h"
> +#include "occ_scom_i2c.h"
> +#include "occ_p8.h"
> +#include "occ_sysfs.h"
> +
> +#define OCC_I2C_NAME   "occ-p8-i2c"
> +
> +static char *caps_sensor_names[] = {
> +       "curr_powercap",
> +       "curr_powerreading",
> +       "norm_powercap",
> +       "max_powercap",
> +       "min_powercap",
> +       "user_powerlimit"
> +};

Does it make more sense to define this in the P8 callbacks code?

> +
> +int p8_i2c_getscom(void *bus, u32 address, u8 *data, size_t offset)
> +{
> +       /* P8 i2c slave requires address to be shifted by 1 */
> +       address = address << 1;
> +
> +       return occ_i2c_getscom(bus, address, data, offset);
> +}
> +
> +int p8_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1)
> +{
> +       /* P8 i2c slave requires address to be shifted by 1 */
> +       address = address << 1;
> +
> +       return occ_i2c_putscom(bus, address, data0, data1);
> +}
> +
> +static struct occ_bus_ops p8_bus_ops = {
> +       .getscom = p8_i2c_getscom,
> +       .putscom = p8_i2c_putscom,
> +};
> +
> +static struct occ_sysfs_config p8_sysfs_config = {
> +       .num_caps_fields = ARRAY_SIZE(caps_sensor_names),
> +       .caps_names = caps_sensor_names,
> +};

Same as above for this structure.

> +
> +static int occ_p8_probe(struct i2c_client *client,
> +                        const struct i2c_device_id *id)
> +{
> +       struct occ *occ;
> +       struct occ_sysfs *hwmon;
> +
> +       occ = occ_p8_start(&client->dev, client, p8_bus_ops);
> +       if (IS_ERR(occ))
> +               return PTR_ERR(occ);
> +
> +       hwmon = occ_sysfs_start(&client->dev, occ, &p8_sysfs_config);

I see why you defined those here. But I guess I don't see why
occ_sysfs_config has to be separate from occ_config structure. It
could be populated in occ_p8_start and then passed to occ_sysfs_start
here.

> +       if (IS_ERR(hwmon))
> +               return PTR_ERR(hwmon);
> +
> +       i2c_set_clientdata(client, hwmon);
> +
> +       return 0;
> +}
> +
> +static int occ_p8_remove(struct i2c_client *client)
> +{
> +       return occ_p8_stop(i2c_get_clientdata(client));
> +}
> +
> +/* used by old-style board info. */
> +static const struct i2c_device_id occ_ids[] = {
> +       { OCC_I2C_NAME, 0 },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(i2c, occ_ids);
> +
> +/* used by device table */
> +static const struct of_device_id occ_of_match[] = {
> +       { .compatible = "ibm,occ-p8-i2c" },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(of, occ_of_match);
> +
> +/*
> + * i2c-core uses i2c-detect() to detect device in below address list.
> + * If exists, address will be assigned to client.
> + * It is also possible to read address from device table.
> + */
> +static const unsigned short normal_i2c[] = {0x50, 0x51, I2C_CLIENT_END };
> +
> +static struct i2c_driver occ_p8_driver = {
> +       .class = I2C_CLASS_HWMON,
> +       .driver = {
> +               .name = OCC_I2C_NAME,
> +               .pm = NULL,
> +               .of_match_table = occ_of_match,
> +       },
> +       .probe = occ_p8_probe,
> +       .remove = occ_p8_remove,
> +       .id_table = occ_ids,
> +       .address_list = normal_i2c,
> +};
> +
> +module_i2c_driver(occ_p8_driver);
> +
> +MODULE_AUTHOR("Eddie James <eajames at us.ibm.com>");
> +MODULE_DESCRIPTION("BMC P8 OCC hwmon driver");
> +MODULE_LICENSE("GPL");
> --
> 2.9.3
>