tuner-i2c.h

Go to the documentation of this file.

/*
    tuner-i2c.h - i2c interface for different tuners

    Copyright (C) 2007 Michael Krufky ([email protected])

    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.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#ifndef __TUNER_I2C_H__
#define __TUNER_I2C_H__

#include <linux/i2c.h>
#include <linux/slab.h>

struct tuner_i2c_props {
    u8 addr;
    struct i2c_adapter *adap;

    /* used for tuner instance management */
    int count;
    char *name;
};

static inline int tuner_i2c_xfer_send(struct tuner_i2c_props *props, char *buf, int len)
{
    struct i2c_msg msg = { .addr = props->addr, .flags = 0,
                   .buf = buf, .len = len };
    int ret = i2c_transfer(props->adap, &msg, 1);

    return (ret == 1) ? len : ret;
}

static inline int tuner_i2c_xfer_recv(struct tuner_i2c_props *props, char *buf, int len)
{
    struct i2c_msg msg = { .addr = props->addr, .flags = I2C_M_RD,
                   .buf = buf, .len = len };
    int ret = i2c_transfer(props->adap, &msg, 1);

    return (ret == 1) ? len : ret;
}

static inline int tuner_i2c_xfer_send_recv(struct tuner_i2c_props *props,
                       char *obuf, int olen,
                       char *ibuf, int ilen)
{
    struct i2c_msg msg[2] = { { .addr = props->addr, .flags = 0,
                    .buf = obuf, .len = olen },
                  { .addr = props->addr, .flags = I2C_M_RD,
                    .buf = ibuf, .len = ilen } };
    int ret = i2c_transfer(props->adap, msg, 2);

    return (ret == 2) ? ilen : ret;
}

/* Callers must declare as a global for the module:
 *
 * static LIST_HEAD(hybrid_tuner_instance_list);
 *
 * hybrid_tuner_instance_list should be the third argument
 * passed into hybrid_tuner_request_state().
 *
 * state structure must contain the following:
 *
 *  struct list_head    hybrid_tuner_instance_list;
 *  struct tuner_i2c_props  i2c_props;
 *
 * hybrid_tuner_instance_list (both within state structure and globally)
 * is only required if the driver is using hybrid_tuner_request_state
 * and hybrid_tuner_release_state to manage state sharing between
 * multiple instances of hybrid tuners.
 */

#define tuner_printk(kernlvl, i2cprops, fmt, arg...) do {       \
    printk(kernlvl "%s %d-%04x: " fmt, i2cprops.name,       \
            i2cprops.adap ?                 \
                i2c_adapter_id(i2cprops.adap) : -1, \
            i2cprops.addr, ##arg);              \
     } while (0)

/* TO DO: convert all callers of these macros to pass in
 * struct tuner_i2c_props, then remove the macro wrappers */

#define __tuner_warn(i2cprops, fmt, arg...) do {            \
    tuner_printk(KERN_WARNING, i2cprops, fmt, ##arg);       \
    } while (0)

#define __tuner_info(i2cprops, fmt, arg...) do {            \
    tuner_printk(KERN_INFO, i2cprops, fmt, ##arg);          \
    } while (0)

#define __tuner_err(i2cprops, fmt, arg...) do {             \
    tuner_printk(KERN_ERR, i2cprops, fmt, ##arg);           \
    } while (0)

#define __tuner_dbg(i2cprops, fmt, arg...) do {             \
    if ((debug))                            \
        tuner_printk(KERN_DEBUG, i2cprops, fmt, ##arg);     \
    } while (0)

#define tuner_warn(fmt, arg...) __tuner_warn(priv->i2c_props, fmt, ##arg)
#define tuner_info(fmt, arg...) __tuner_info(priv->i2c_props, fmt, ##arg)
#define tuner_err(fmt, arg...) __tuner_err(priv->i2c_props, fmt, ##arg)
#define tuner_dbg(fmt, arg...) __tuner_dbg(priv->i2c_props, fmt, ##arg)

/****************************************************************************/

/* The return value of hybrid_tuner_request_state indicates the number of
 * instances using this tuner object.
 *
 * 0 - no instances, indicates an error - kzalloc must have failed
 *
 * 1 - one instance, indicates that the tuner object was created successfully
 *
 * 2 (or more) instances, indicates that an existing tuner object was found
 */

#define hybrid_tuner_request_state(type, state, list, i2cadap, i2caddr, devname)\
({                                  \
    int __ret = 0;                          \
    list_for_each_entry(state, &list, hybrid_tuner_instance_list) { \
        if (((i2cadap) && (state->i2c_props.adap)) &&       \
            ((i2c_adapter_id(state->i2c_props.adap) ==      \
              i2c_adapter_id(i2cadap)) &&           \
             (i2caddr == state->i2c_props.addr))) {     \
            __tuner_info(state->i2c_props,          \
                     "attaching existing instance\n");  \
            state->i2c_props.count++;           \
            __ret = state->i2c_props.count;         \
            break;                      \
        }                           \
    }                               \
    if (0 == __ret) {                       \
        state = kzalloc(sizeof(type), GFP_KERNEL);      \
        if (NULL == state)                  \
            goto __fail;                    \
        state->i2c_props.addr = i2caddr;            \
        state->i2c_props.adap = i2cadap;            \
        state->i2c_props.name = devname;            \
        __tuner_info(state->i2c_props,              \
                 "creating new instance\n");        \
        list_add_tail(&state->hybrid_tuner_instance_list, &list);\
        state->i2c_props.count++;               \
        __ret = state->i2c_props.count;             \
    }                               \
__fail:                                 \
    __ret;                              \
})

#define hybrid_tuner_release_state(state)               \
({                                  \
    int __ret;                          \
    state->i2c_props.count--;                   \
    __ret = state->i2c_props.count;                 \
    if (!state->i2c_props.count) {                  \
        __tuner_info(state->i2c_props, "destroying instance\n");\
        list_del(&state->hybrid_tuner_instance_list);       \
        kfree(state);                       \
    }                               \
    __ret;                              \
})

#define hybrid_tuner_report_instance_count(state)           \
({                                  \
    int __ret = 0;                          \
    if (state)                          \
        __ret = state->i2c_props.count;             \
    __ret;                              \
})

#endif /* __TUNER_I2C_H__ */