Guenter Roeck <linux@roeck-us.net> wrote on 01/21/2017 12:11:21 PM:
> On 01/16/2017 01:13 PM, eajames.ibm@gmail.com wrote:
> > From: "Edward A. James" <eajames@us.ibm.com>
> >
> > Add functions to send SCOM operations over I2C bus. The BMC can
> > communicate with the Power8 host processor over I2C, but needs to use
SCOM
> > operations in order to access the OCC register space.
> >
> > Signed-off-by: Edward A. James <eajames@us.ibm.com>
> > Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> > ---
> >  drivers/hwmon/occ/occ_scom_i2c.c | 72 +++++++++++++++++++++++++++
> +++++++++++++
> >  drivers/hwmon/occ/occ_scom_i2c.h | 26 +++++++++++++++
> >  2 files changed, 98 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 0000000..8b4ca13
> > --- /dev/null
> > +++ b/drivers/hwmon/occ/occ_scom_i2c.c
> > @@ -0,0 +1,72 @@
> > +/*
> > + * occ_scom_i2c.c - hwmon OCC driver
> > + *
> > + * This file contains the functions for performing SCOM
> operations over I2C bus
> > + * to access the OCC.
> > + *
> > + * 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 "occ_scom_i2c.h"
> > +#include "scom.h"
> > +
> > +int occ_i2c_getscom(void *bus, u32 address, u64 *data)
> > +{
> > +   ssize_t rc;
> > +   u64 buf;
> > +   struct i2c_client *client = bus;
> > +
> > +   rc = i2c_master_send(client, (const char *)&address, sizeof(u32));
> > +   if (rc < 0)
> > +      return rc;
> > +   else if (rc != sizeof(u32))
> > +      return -EIO;
> > +
> > +   rc = i2c_master_recv(client, (char *)&buf, sizeof(u64));
> > +   if (rc < 0)
> > +      return rc;
> > +   else if (rc != sizeof(u64))
> > +      return -EIO;
> > +
> > +   *data = 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;
> > +
>
> Receive data is converted from be64 to host byte order, transmit
> data is sent as-is.
> Yet, if I recall correctly, some of the calling code passes in
> constants. Are you sure
> this works on both little and big endian systems ?

Not at all sure, no. I'll have another look at this. The constants aren't
an issue I believe, for putscom, as we don't modify data0/1. Maybe I'll
make
data0 and data1 const anyway, we shoulnd't be modifying those.

Thanks,
Eddie

>
> > +   rc = i2c_master_send(client, (const char *)buf, sizeof(u32) * 3);
> > +   if (rc < 0)
> > +      return rc;
> > +   else if (rc != sizeof(u32) * 3)
> > +      return -EIO;
> > +
> > +   return 0;
> > +}
> > +EXPORT_SYMBOL(occ_i2c_putscom);
> > +
> > +MODULE_AUTHOR("Eddie James <eajames@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 0000000..945739c
> > --- /dev/null
> > +++ b/drivers/hwmon/occ/occ_scom_i2c.h
> > @@ -0,0 +1,26 @@
> > +/*
> > + * occ_scom_i2c.h - hwmon OCC driver
> > + *
> > + * This file contains function protoypes for peforming SCOM
> operations over I2C
> > + * bus to access the OCC.
> > + *
> > + * 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.
> > + */
> > +
> > +#ifndef __OCC_SCOM_I2C_H__
> > +#define __OCC_SCOM_I2C_H__
> > +
> > +int occ_i2c_getscom(void *bus, u32 address, u64 *data);
> > +int occ_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1);
> > +
> > +#endif /* __OCC_SCOM_I2C_H__ */
> >
>