cdce949.c

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/*
 * TI CDCE949 clock synthesizer driver
 *
 * Note: This implementation assumes an input of 27MHz to the CDCE.
 * This is by no means constrained by CDCE hardware although the datasheet
 * does use this as an example for all illustrations and more importantly:
 * that is the crystal input on boards it is currently used on.
 *
 * Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/module.h>

#include <mach/clock.h>
#include <mach/cdce949.h>

#include "clock.h"

static struct i2c_client *cdce_i2c_client;
static DEFINE_MUTEX(cdce_mutex);

/* CDCE register descriptor */
struct cdce_reg {
    u8  addr;
    u8  val;
};

/* Per-Output (Y1, Y2 etc.) frequency descriptor */
struct cdce_freq {
    /* Frequency in KHz */
    unsigned long frequency;
    /*
     * List of registers to program to obtain a particular frequency.
     * 0x0 in register address and value is the end of list marker.
     */
    struct cdce_reg *reglist;
};

#define CDCE_FREQ_TABLE_ENTRY(line, out)        \
{                           \
    .reglist    = cdce_y ##line## _ ##out,      \
    .frequency  = out,              \
}

/* List of CDCE outputs  */
struct cdce_output {
    /* List of frequencies on this output */
    struct cdce_freq *freq_table;
    /* Number of possible frequencies */
    int size;
};

/*
 * Finding out the values to program into CDCE949 registers for a particular
 * frequency output is not a simple calculation. Have a look at the datasheet
 * for the details. There is desktop software available to help users with
 * the calculations. Here, we just depend on the output of that software
 * (or hand calculations) instead trying to runtime calculate the register
 * values and inflicting misery on ourselves.
 */
static struct cdce_reg cdce_y1_148500[] = {
    { 0x13, 0x00 },
    /* program PLL1_0 multiplier */
    { 0x18, 0xaf },
    { 0x19, 0x50 },
    { 0x1a, 0x02 },
    { 0x1b, 0xc9 },
    /* program PLL1_11 multiplier */
    { 0x1c, 0x00 },
    { 0x1d, 0x40 },
    { 0x1e, 0x02 },
    { 0x1f, 0xc9 },
    /* output state selection */
    { 0x15, 0x00 },
    { 0x14, 0xef },
    /* switch MUX to PLL1 output */
    { 0x14, 0x6f },
    { 0x16, 0x06 },
    /* set P2DIV divider, P3DIV and input crystal */
    { 0x17, 0x06 },
    { 0x01, 0x00 },
    { 0x05, 0x48 },
    { 0x02, 0x80 },
    /* enable and disable PLL */
    { 0x02, 0xbc },
    { 0x03, 0x01 },
    { },
};

static struct cdce_reg cdce_y1_74250[] = {
    { 0x13, 0x00 },
    { 0x18, 0xaf },
    { 0x19, 0x50 },
    { 0x1a, 0x02 },
    { 0x1b, 0xc9 },
    { 0x1c, 0x00 },
    { 0x1d, 0x40 },
    { 0x1e, 0x02 },
    { 0x1f, 0xc9 },
    /* output state selection */
    { 0x15, 0x00 },
    { 0x14, 0xef },
    /* switch MUX to PLL1 output */
    { 0x14, 0x6f },
    { 0x16, 0x06 },
    /* set P2DIV divider, P3DIV and input crystal */
    { 0x17, 0x06 },
    { 0x01, 0x00 },
    { 0x05, 0x48 },
    { 0x02, 0x80 },
    /* enable and disable PLL */
    { 0x02, 0xbc },
    { 0x03, 0x02 },
    { },
};

static struct cdce_reg cdce_y1_27000[] = {
    { 0x13, 0x00 },
    { 0x18, 0x00 },
    { 0x19, 0x40 },
    { 0x1a, 0x02 },
    { 0x1b, 0x08 },
    { 0x1c, 0x00 },
    { 0x1d, 0x40 },
    { 0x1e, 0x02 },
    { 0x1f, 0x08 },
    { 0x15, 0x02 },
    { 0x14, 0xed },
    { 0x16, 0x01 },
    { 0x17, 0x01 },
    { 0x01, 0x00 },
    { 0x05, 0x50 },
    { 0x02, 0xb4 },
    { 0x03, 0x01 },
    { },
};

static struct cdce_freq cdce_y1_freqs[] = {
    CDCE_FREQ_TABLE_ENTRY(1, 148500),
    CDCE_FREQ_TABLE_ENTRY(1, 74250),
    CDCE_FREQ_TABLE_ENTRY(1, 27000),
};

static struct cdce_reg cdce_y5_13500[] = {
    { 0x27, 0x08 },
    { 0x28, 0x00 },
    { 0x29, 0x40 },
    { 0x2a, 0x02 },
    { 0x2b, 0x08 },
    { 0x24, 0x6f },
    { },
};

static struct cdce_reg cdce_y5_16875[] = {
    { 0x27, 0x08 },
    { 0x28, 0x9f },
    { 0x29, 0xb0 },
    { 0x2a, 0x02 },
    { 0x2b, 0x89 },
    { 0x24, 0x6f },
    { },
};

static struct cdce_reg cdce_y5_27000[] = {
    { 0x27, 0x04 },
    { 0x28, 0x00 },
    { 0x29, 0x40 },
    { 0x2a, 0x02 },
    { 0x2b, 0x08 },
    { 0x24, 0x6f },
    { },
};
static struct cdce_reg cdce_y5_54000[] = {
    { 0x27, 0x04 },
    { 0x28, 0xff },
    { 0x29, 0x80 },
    { 0x2a, 0x02 },
    { 0x2b, 0x07 },
    { 0x24, 0x6f },
    { },
};

static struct cdce_reg cdce_y5_81000[] = {
    { 0x27, 0x02 },
    { 0x28, 0xbf },
    { 0x29, 0xa0 },
    { 0x2a, 0x03 },
    { 0x2b, 0x0a },
    { 0x24, 0x6f },
    { },
};

static struct cdce_freq cdce_y5_freqs[] = {
    CDCE_FREQ_TABLE_ENTRY(5, 13500),
    CDCE_FREQ_TABLE_ENTRY(5, 16875),
    CDCE_FREQ_TABLE_ENTRY(5, 27000),
    CDCE_FREQ_TABLE_ENTRY(5, 54000),
    CDCE_FREQ_TABLE_ENTRY(5, 81000),
};


static struct cdce_output output_list[] = {
    [1] = { cdce_y1_freqs, ARRAY_SIZE(cdce_y1_freqs) },
    [5] = { cdce_y5_freqs, ARRAY_SIZE(cdce_y5_freqs) },
};

int cdce_set_rate(struct clk *clk, unsigned long rate)
{
    int i, ret = 0;
    struct cdce_freq *freq_table = output_list[clk->lpsc].freq_table;
    struct cdce_reg  *regs = NULL;

    if (!cdce_i2c_client)
        return -ENODEV;

    if (!freq_table)
        return -EINVAL;

    for (i = 0; i < output_list[clk->lpsc].size; i++) {
        if (freq_table[i].frequency == rate / 1000) {
            regs = freq_table[i].reglist;
            break;
        }
    }

    if (!regs)
        return -EINVAL;

    mutex_lock(&cdce_mutex);
    for (i = 0; regs[i].addr; i++) {
        ret = i2c_smbus_write_byte_data(cdce_i2c_client,
                    regs[i].addr | 0x80, regs[i].val);
        if (ret)
            break;
    }
    mutex_unlock(&cdce_mutex);

    if (!ret)
        clk->rate = rate;

    return ret;
}

static int cdce_probe(struct i2c_client *client,
                    const struct i2c_device_id *id)
{
    cdce_i2c_client = client;
    return 0;
}

static int __devexit cdce_remove(struct i2c_client *client)
{
    cdce_i2c_client = NULL;
    return 0;
}

static const struct i2c_device_id cdce_id[] = {
    {"cdce949", 0},
    {},
};
MODULE_DEVICE_TABLE(i2c, cdce_id);

static struct i2c_driver cdce_driver = {
    .driver = {
        .owner  = THIS_MODULE,
        .name   = "cdce949",
    },
    .probe      = cdce_probe,
    .remove     = __devexit_p(cdce_remove),
    .id_table   = cdce_id,
};

static int __init cdce_init(void)
{
    return i2c_add_driver(&cdce_driver);
}
subsys_initcall(cdce_init);

static void __exit cdce_exit(void)
{
    i2c_del_driver(&cdce_driver);
}
module_exit(cdce_exit);

MODULE_AUTHOR("Texas Instruments");
MODULE_DESCRIPTION("CDCE949 clock synthesizer driver");
MODULE_LICENSE("GPL v2");