atombios_i2c.c

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/*
 * Copyright 2011 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: Alex Deucher
 *
 */
#include <drm/drmP.h>
#include <drm/radeon_drm.h>
#include "radeon.h"
#include "atom.h"

#define TARGET_HW_I2C_CLOCK 50

/* these are a limitation of ProcessI2cChannelTransaction not the hw */
#define ATOM_MAX_HW_I2C_WRITE 2
#define ATOM_MAX_HW_I2C_READ  255

static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
                 u8 slave_addr, u8 flags,
                 u8 *buf, u8 num)
{
    struct drm_device *dev = chan->dev;
    struct radeon_device *rdev = dev->dev_private;
    PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
    int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
    unsigned char *base;
    u16 out;

    memset(&args, 0, sizeof(args));

    base = (unsigned char *)rdev->mode_info.atom_context->scratch;

    if (flags & HW_I2C_WRITE) {
        if (num > ATOM_MAX_HW_I2C_WRITE) {
            DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 2)\n", num);
            return -EINVAL;
        }
        memcpy(&out, buf, num);
        args.lpI2CDataOut = cpu_to_le16(out);
    } else {
        if (num > ATOM_MAX_HW_I2C_READ) {
            DRM_ERROR("hw i2c: tried to read too many bytes (%d vs 255)\n", num);
            return -EINVAL;
        }
    }

    args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
    args.ucRegIndex = 0;
    args.ucTransBytes = num;
    args.ucSlaveAddr = slave_addr << 1;
    args.ucLineNumber = chan->rec.i2c_id;

    atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);

    /* error */
    if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
        DRM_DEBUG_KMS("hw_i2c error\n");
        return -EIO;
    }

    if (!(flags & HW_I2C_WRITE))
        memcpy(buf, base, num);

    return 0;
}

int radeon_atom_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
                struct i2c_msg *msgs, int num)
{
    struct radeon_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
    struct i2c_msg *p;
    int i, remaining, current_count, buffer_offset, max_bytes, ret;
    u8 buf = 0, flags;

    /* check for bus probe */
    p = &msgs[0];
    if ((num == 1) && (p->len == 0)) {
        ret = radeon_process_i2c_ch(i2c,
                        p->addr, HW_I2C_WRITE,
                        &buf, 1);
        if (ret)
            return ret;
        else
            return num;
    }

    for (i = 0; i < num; i++) {
        p = &msgs[i];
        remaining = p->len;
        buffer_offset = 0;
        /* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
        if (p->flags & I2C_M_RD) {
            max_bytes = ATOM_MAX_HW_I2C_READ;
            flags = HW_I2C_READ;
        } else {
            max_bytes = ATOM_MAX_HW_I2C_WRITE;
            flags = HW_I2C_WRITE;
        }
        while (remaining) {
            if (remaining > max_bytes)
                current_count = max_bytes;
            else
                current_count = remaining;
            ret = radeon_process_i2c_ch(i2c,
                            p->addr, flags,
                            &p->buf[buffer_offset], current_count);
            if (ret)
                return ret;
            remaining -= current_count;
            buffer_offset += current_count;
        }
    }

    return num;
}

u32 radeon_atom_hw_i2c_func(struct i2c_adapter *adap)
{
    return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}