[RFC PATCH linux 4/9] hwmon: occ: Add I2C SCOM transport implementation

[Eddie James]

Hi Andrew,

Just a general comment on this one. I'm not sure it's worth having an
extra layer just to isolate these functions from the
p8_i2c_getscom/putscom. Those just do the address shift for P8. But
there's no situation where i2c is used that's not on the P8. So this
seems like unnecessary complexity to me. I'm not sure, just a thought.

Thanks,
Eddie

On Thu, Nov 10, 2016 at 10:12 PM, Andrew Jeffery <andrew at aj.id.au> wrote:
> The BMC queries the OCC on POWER8 chips with SCOMs over I2C.
>
> Signed-off-by: Andrew Jeffery <andrew at aj.id.au>
> ---
>  drivers/hwmon/occ/occ_scom_i2c.c | 68 ++++++++++++++++++++++++++++++++++++++++
>  drivers/hwmon/occ/occ_scom_i2c.h | 20 ++++++++++++
>  2 files changed, 88 insertions(+)
>  create mode 100644 drivers/hwmon/occ/occ_scom_i2c.c
>  create mode 100644 drivers/hwmon/occ/occ_scom_i2c.h
>
> diff --git a/drivers/hwmon/occ/occ_scom_i2c.c b/drivers/hwmon/occ/occ_scom_i2c.c
> new file mode 100644
> index 000000000000..b1a060331c4a
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ_scom_i2c.c
> @@ -0,0 +1,68 @@
> +/*
> + * occ_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/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +
> +#include "scom.h"
> +#include "occ_scom_i2c.h"
> +
> +#define OCC_I2C_NAME   "occ-p8-i2c"
> +
> +int occ_i2c_getscom(void *bus, u32 address, u8 *data, size_t offset)
> +{
> +       ssize_t rc;
> +       u64 buf;
> +       struct i2c_client *client = bus;
> +
> +       rc = i2c_master_send(client, (const char *)&address, sizeof(u32));
> +       if (rc != sizeof(u32))
> +               return -SCOM_WRITE_ERROR;
> +
> +       rc = i2c_master_recv(client, (char *)&buf, sizeof(u64));
> +       if (rc != sizeof(u64))
> +               return -SCOM_READ_ERROR;
> +
> +       *((u64 *)&data[offset]) = be64_to_cpu(buf);
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL(occ_i2c_getscom);
> +
> +int occ_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1)
> +{
> +       u32 buf[3];
> +       ssize_t rc;
> +       struct i2c_client *client = bus;
> +
> +       buf[0] = address;
> +       buf[1] = data1;
> +       buf[2] = data0;
> +
> +       rc = i2c_master_send(client, (const char *)buf, sizeof(u32) * 3);
> +       if (rc != sizeof(u32) * 3)
> +               return -SCOM_WRITE_ERROR;
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL(occ_i2c_putscom);
> +
> +MODULE_AUTHOR("Eddie James <eajames at us.ibm.com>");
> +MODULE_DESCRIPTION("I2C OCC SCOM transport");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/hwmon/occ/occ_scom_i2c.h b/drivers/hwmon/occ/occ_scom_i2c.h
> new file mode 100644
> index 000000000000..92225f4cd584
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ_scom_i2c.h
> @@ -0,0 +1,20 @@
> +/*
> + * occ_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.
> + */
> +
> +int occ_i2c_getscom(void *bus, u32 address, u8 *data, size_t offset);
> +int occ_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1);
> --
> 2.9.3
>