Merge branch 'u-boot/master'

[people/ms/u-boot.git] / drivers / i2c / fsl_i2c.c

/*
 * Copyright 2006,2009 Freescale Semiconductor, Inc.
 *
 * 2012, Heiko Schocher, DENX Software Engineering, hs@denx.de.
 * Changes for multibus/multiadapter I2C support.
 *
 * 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.
 *
 * 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., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <command.h>
#include <i2c.h>                /* Functional interface */
#include <asm/io.h>
#include <asm/fsl_i2c.h>        /* HW definitions */

/* The maximum number of microseconds we will wait until another master has
 * released the bus.  If not defined in the board header file, then use a
 * generic value.
 */
#ifndef CONFIG_I2C_MBB_TIMEOUT
#define CONFIG_I2C_MBB_TIMEOUT  100000
#endif

/* The maximum number of microseconds we will wait for a read or write
 * operation to complete.  If not defined in the board header file, then use a
 * generic value.
 */
#ifndef CONFIG_I2C_TIMEOUT
#define CONFIG_I2C_TIMEOUT      10000
#endif

#define I2C_READ_BIT  1
#define I2C_WRITE_BIT 0

DECLARE_GLOBAL_DATA_PTR;

static const struct fsl_i2c *i2c_dev[2] = {
        (struct fsl_i2c *)(CONFIG_SYS_IMMR + CONFIG_SYS_FSL_I2C_OFFSET),
#ifdef CONFIG_SYS_FSL_I2C2_OFFSET
        (struct fsl_i2c *)(CONFIG_SYS_IMMR + CONFIG_SYS_FSL_I2C2_OFFSET)
#endif
};

/* I2C speed map for a DFSR value of 1 */

/*
 * Map I2C frequency dividers to FDR and DFSR values
 *
 * This structure is used to define the elements of a table that maps I2C
 * frequency divider (I2C clock rate divided by I2C bus speed) to a value to be
 * programmed into the Frequency Divider Ratio (FDR) and Digital Filter
 * Sampling Rate (DFSR) registers.
 *
 * The actual table should be defined in the board file, and it must be called
 * fsl_i2c_speed_map[].
 *
 * The last entry of the table must have a value of {-1, X}, where X is same
 * FDR/DFSR values as the second-to-last entry.  This guarantees that any
 * search through the array will always find a match.
 *
 * The values of the divider must be in increasing numerical order, i.e.
 * fsl_i2c_speed_map[x+1].divider > fsl_i2c_speed_map[x].divider.
 *
 * For this table, the values are based on a value of 1 for the DFSR
 * register.  See the application note AN2919 "Determining the I2C Frequency
 * Divider Ratio for SCL"
 *
 * ColdFire I2C frequency dividers for FDR values are different from
 * PowerPC. The protocol to use the I2C module is still the same.
 * A different table is defined and are based on MCF5xxx user manual.
 *
 */
static const struct {
        unsigned short divider;
        u8 fdr;
} fsl_i2c_speed_map[] = {
#ifdef __M68K__
        {20, 32}, {22, 33}, {24, 34}, {26, 35},
        {28, 0}, {28, 36}, {30, 1}, {32, 37},
        {34, 2}, {36, 38}, {40, 3}, {40, 39},
        {44, 4}, {48, 5}, {48, 40}, {56, 6},
        {56, 41}, {64, 42}, {68, 7}, {72, 43},
        {80, 8}, {80, 44}, {88, 9}, {96, 41},
        {104, 10}, {112, 42}, {128, 11}, {128, 43},
        {144, 12}, {160, 13}, {160, 48}, {192, 14},
        {192, 49}, {224, 50}, {240, 15}, {256, 51},
        {288, 16}, {320, 17}, {320, 52}, {384, 18},
        {384, 53}, {448, 54}, {480, 19}, {512, 55},
        {576, 20}, {640, 21}, {640, 56}, {768, 22},
        {768, 57}, {960, 23}, {896, 58}, {1024, 59},
        {1152, 24}, {1280, 25}, {1280, 60}, {1536, 26},
        {1536, 61}, {1792, 62}, {1920, 27}, {2048, 63},
        {2304, 28}, {2560, 29}, {3072, 30}, {3840, 31},
        {-1, 31}
#endif
};

/**
 * Set the I2C bus speed for a given I2C device
 *
 * @param dev: the I2C device
 * @i2c_clk: I2C bus clock frequency
 * @speed: the desired speed of the bus
 *
 * The I2C device must be stopped before calling this function.
 *
 * The return value is the actual bus speed that is set.
 */
static unsigned int set_i2c_bus_speed(const struct fsl_i2c *dev,
        unsigned int i2c_clk, unsigned int speed)
{
        unsigned short divider = min(i2c_clk / speed, (unsigned short) -1);

        /*
         * We want to choose an FDR/DFSR that generates an I2C bus speed that
         * is equal to or lower than the requested speed.  That means that we
         * want the first divider that is equal to or greater than the
         * calculated divider.
         */
#ifdef __PPC__
        u8 dfsr, fdr = 0x31; /* Default if no FDR found */
        /* a, b and dfsr matches identifiers A,B and C respectively in AN2919 */
        unsigned short a, b, ga, gb;
        unsigned long c_div, est_div;

#ifdef CONFIG_FSL_I2C_CUSTOM_DFSR
        dfsr = CONFIG_FSL_I2C_CUSTOM_DFSR;
#else
        /* Condition 1: dfsr <= 50/T */
        dfsr = (5 * (i2c_clk / 1000)) / 100000;
#endif
#ifdef CONFIG_FSL_I2C_CUSTOM_FDR
        fdr = CONFIG_FSL_I2C_CUSTOM_FDR;
        speed = i2c_clk / divider; /* Fake something */
#else
        debug("Requested speed:%d, i2c_clk:%d\n", speed, i2c_clk);
        if (!dfsr)
                dfsr = 1;

        est_div = ~0;
        for (ga = 0x4, a = 10; a <= 30; ga++, a += 2) {
                for (gb = 0; gb < 8; gb++) {
                        b = 16 << gb;
                        c_div = b * (a + ((3*dfsr)/b)*2);
                        if ((c_div > divider) && (c_div < est_div)) {
                                unsigned short bin_gb, bin_ga;

                                est_div = c_div;
                                bin_gb = gb << 2;
                                bin_ga = (ga & 0x3) | ((ga & 0x4) << 3);
                                fdr = bin_gb | bin_ga;
                                speed = i2c_clk / est_div;
                                debug("FDR:0x%.2x, div:%ld, ga:0x%x, gb:0x%x, "
                                      "a:%d, b:%d, speed:%d\n",
                                      fdr, est_div, ga, gb, a, b, speed);
                                /* Condition 2 not accounted for */
                                debug("Tr <= %d ns\n",
                                      (b - 3 * dfsr) * 1000000 /
                                      (i2c_clk / 1000));
                        }
                }
                if (a == 20)
                        a += 2;
                if (a == 24)
                        a += 4;
        }
        debug("divider:%d, est_div:%ld, DFSR:%d\n", divider, est_div, dfsr);
        debug("FDR:0x%.2x, speed:%d\n", fdr, speed);
#endif
        writeb(dfsr, &dev->dfsrr);      /* set default filter */
        writeb(fdr, &dev->fdr);         /* set bus speed */
#else
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(fsl_i2c_speed_map); i++)
                if (fsl_i2c_speed_map[i].divider >= divider) {
                        u8 fdr;

                        fdr = fsl_i2c_speed_map[i].fdr;
                        speed = i2c_clk / fsl_i2c_speed_map[i].divider;
                        writeb(fdr, &dev->fdr);         /* set bus speed */

                        break;
                }
#endif
        return speed;
}

static unsigned int get_i2c_clock(int bus)
{
        if (bus)
                return gd->arch.i2c2_clk;       /* I2C2 clock */
        else
                return gd->arch.i2c1_clk;       /* I2C1 clock */
}

static int fsl_i2c_fixup(const struct fsl_i2c *dev)
{
        const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
        unsigned long long timeval = 0;
        int ret = -1;
        unsigned int flags = 0;

#ifdef CONFIG_SYS_FSL_ERRATUM_I2C_A004447
        unsigned int svr = get_svr();
        if ((SVR_SOC_VER(svr) == SVR_8548 && IS_SVR_REV(svr, 3, 1)) ||
            (SVR_REV(svr) <= CONFIG_SYS_FSL_A004447_SVR_REV))
                flags = I2C_CR_BIT6;
#endif

        writeb(I2C_CR_MEN | I2C_CR_MSTA, &dev->cr);

        timeval = get_ticks();
        while (!(readb(&dev->sr) & I2C_SR_MBB)) {
                if ((get_ticks() - timeval) > timeout)
                        goto err;
        }

        if (readb(&dev->sr) & I2C_SR_MAL) {
                /* SDA is stuck low */
                writeb(0, &dev->cr);
                udelay(100);
                writeb(I2C_CR_MSTA | flags, &dev->cr);
                writeb(I2C_CR_MEN | I2C_CR_MSTA | flags, &dev->cr);
        }

        readb(&dev->dr);

        timeval = get_ticks();
        while (!(readb(&dev->sr) & I2C_SR_MIF)) {
                if ((get_ticks() - timeval) > timeout)
                        goto err;
        }
        ret = 0;

err:
        writeb(I2C_CR_MEN | flags, &dev->cr);
        writeb(0, &dev->sr);
        udelay(100);

        return ret;
}

static void fsl_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
{
        const struct fsl_i2c *dev;
        const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
        unsigned long long timeval;

#ifdef CONFIG_SYS_I2C_INIT_BOARD
        /* Call board specific i2c bus reset routine before accessing the
         * environment, which might be in a chip on that bus. For details
         * about this problem see doc/I2C_Edge_Conditions.
        */
        i2c_init_board();
#endif
        dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];

        writeb(0, &dev->cr);            /* stop I2C controller */
        udelay(5);                      /* let it shutdown in peace */
        set_i2c_bus_speed(dev, get_i2c_clock(adap->hwadapnr), speed);
        writeb(slaveadd << 1, &dev->adr);/* write slave address */
        writeb(0x0, &dev->sr);          /* clear status register */
        writeb(I2C_CR_MEN, &dev->cr);   /* start I2C controller */

        timeval = get_ticks();
        while (readb(&dev->sr) & I2C_SR_MBB) {
                if ((get_ticks() - timeval) < timeout)
                        continue;

                if (fsl_i2c_fixup(dev))
                        debug("i2c_init: BUS#%d failed to init\n",
                              adap->hwadapnr);

                break;
        }

#ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT
        /* Call board specific i2c bus reset routine AFTER the bus has been
         * initialized. Use either this callpoint or i2c_init_board;
         * which is called before i2c_init operations.
         * For details about this problem see doc/I2C_Edge_Conditions.
        */
        i2c_board_late_init();
#endif
}

static int
i2c_wait4bus(struct i2c_adapter *adap)
{
        struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
        unsigned long long timeval = get_ticks();
        const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);

        while (readb(&dev->sr) & I2C_SR_MBB) {
                if ((get_ticks() - timeval) > timeout)
                        return -1;
        }

        return 0;
}

static __inline__ int
i2c_wait(struct i2c_adapter *adap, int write)
{
        u32 csr;
        unsigned long long timeval = get_ticks();
        const unsigned long long timeout = usec2ticks(CONFIG_I2C_TIMEOUT);
        struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];

        do {
                csr = readb(&dev->sr);
                if (!(csr & I2C_SR_MIF))
                        continue;
                /* Read again to allow register to stabilise */
                csr = readb(&dev->sr);

                writeb(0x0, &dev->sr);

                if (csr & I2C_SR_MAL) {
                        debug("i2c_wait: MAL\n");
                        return -1;
                }

                if (!(csr & I2C_SR_MCF))        {
                        debug("i2c_wait: unfinished\n");
                        return -1;
                }

                if (write == I2C_WRITE_BIT && (csr & I2C_SR_RXAK)) {
                        debug("i2c_wait: No RXACK\n");
                        return -1;
                }

                return 0;
        } while ((get_ticks() - timeval) < timeout);

        debug("i2c_wait: timed out\n");
        return -1;
}

static __inline__ int
i2c_write_addr(struct i2c_adapter *adap, u8 dev, u8 dir, int rsta)
{
        struct fsl_i2c *device = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];

        writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX
               | (rsta ? I2C_CR_RSTA : 0),
               &device->cr);

        writeb((dev << 1) | dir, &device->dr);

        if (i2c_wait(adap, I2C_WRITE_BIT) < 0)
                return 0;

        return 1;
}

static __inline__ int
__i2c_write(struct i2c_adapter *adap, u8 *data, int length)
{
        struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
        int i;

        for (i = 0; i < length; i++) {
                writeb(data[i], &dev->dr);

                if (i2c_wait(adap, I2C_WRITE_BIT) < 0)
                        break;
        }

        return i;
}

static __inline__ int
__i2c_read(struct i2c_adapter *adap, u8 *data, int length)
{
        struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
        int i;

        writeb(I2C_CR_MEN | I2C_CR_MSTA | ((length == 1) ? I2C_CR_TXAK : 0),
               &dev->cr);

        /* dummy read */
        readb(&dev->dr);

        for (i = 0; i < length; i++) {
                if (i2c_wait(adap, I2C_READ_BIT) < 0)
                        break;

                /* Generate ack on last next to last byte */
                if (i == length - 2)
                        writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_TXAK,
                               &dev->cr);

                /* Do not generate stop on last byte */
                if (i == length - 1)
                        writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX,
                               &dev->cr);

                data[i] = readb(&dev->dr);
        }

        return i;
}

static int
fsl_i2c_read(struct i2c_adapter *adap, u8 dev, uint addr, int alen, u8 *data,
             int length)
{
        struct fsl_i2c *device = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
        int i = -1; /* signal error */
        u8 *a = (u8*)&addr;
        int len = alen * -1;

        if (i2c_wait4bus(adap) < 0)
                return -1;

        /* To handle the need of I2C devices that require to write few bytes
         * (more than 4 bytes of address as in the case of else part)
         * of data before reading, Negative equivalent of length(bytes to write)
         * is passed, but used the +ve part of len for writing data
         */
        if (alen < 0) {
                /* Generate a START and send the Address and
                 * the Tx Bytes to the slave.
                 * "START: Address: Write bytes data[len]"
                 * IF part supports writing any number of bytes in contrast
                 * to the else part, which supports writing address offset
                 * of upto 4 bytes only.
                 * bytes that need to be written are passed in
                 * "data", which will eventually keep the data READ,
                 * after writing the len bytes out of it
                 */
                if (i2c_write_addr(adap, dev, I2C_WRITE_BIT, 0) != 0)
                        i = __i2c_write(adap, data, len);

                if (i != len)
                        return -1;

                if (length && i2c_write_addr(adap, dev, I2C_READ_BIT, 1) != 0)
                        i = __i2c_read(adap, data, length);
        } else {
                if ((!length || alen > 0) &&
                    i2c_write_addr(adap, dev, I2C_WRITE_BIT, 0) != 0  &&
                    __i2c_write(adap, &a[4 - alen], alen) == alen)
                        i = 0; /* No error so far */

                if (length &&
                    i2c_write_addr(adap, dev, I2C_READ_BIT, alen ? 1 : 0) != 0)
                        i = __i2c_read(adap, data, length);
        }

        writeb(I2C_CR_MEN, &device->cr);

        if (i2c_wait4bus(adap)) /* Wait until STOP */
                debug("i2c_read: wait4bus timed out\n");

        if (i == length)
            return 0;

        return -1;
}

static int
fsl_i2c_write(struct i2c_adapter *adap, u8 dev, uint addr, int alen,
              u8 *data, int length)
{
        struct fsl_i2c *device = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
        int i = -1; /* signal error */
        u8 *a = (u8*)&addr;

        if (i2c_wait4bus(adap) < 0)
                return -1;

        if (i2c_write_addr(adap, dev, I2C_WRITE_BIT, 0) != 0 &&
            __i2c_write(adap, &a[4 - alen], alen) == alen) {
                i = __i2c_write(adap, data, length);
        }

        writeb(I2C_CR_MEN, &device->cr);
        if (i2c_wait4bus(adap)) /* Wait until STOP */
                debug("i2c_write: wait4bus timed out\n");

        if (i == length)
            return 0;

        return -1;
}

static int
fsl_i2c_probe(struct i2c_adapter *adap, uchar chip)
{
        struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
        /* For unknow reason the controller will ACK when
         * probing for a slave with the same address, so skip
         * it.
         */
        if (chip == (readb(&dev->adr) >> 1))
                return -1;

        return fsl_i2c_read(adap, chip, 0, 0, NULL, 0);
}

static unsigned int fsl_i2c_set_bus_speed(struct i2c_adapter *adap,
                        unsigned int speed)
{
        struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];

        writeb(0, &dev->cr);            /* stop controller */
        set_i2c_bus_speed(dev, get_i2c_clock(adap->hwadapnr), speed);
        writeb(I2C_CR_MEN, &dev->cr);   /* start controller */

        return 0;
}

/*
 * Register fsl i2c adapters
 */
U_BOOT_I2C_ADAP_COMPLETE(fsl_0, fsl_i2c_init, fsl_i2c_probe, fsl_i2c_read,
                         fsl_i2c_write, fsl_i2c_set_bus_speed,
                         CONFIG_SYS_FSL_I2C_SPEED, CONFIG_SYS_FSL_I2C_SLAVE,
                         0)
#ifdef CONFIG_SYS_FSL_I2C2_OFFSET
U_BOOT_I2C_ADAP_COMPLETE(fsl_1, fsl_i2c_init, fsl_i2c_probe, fsl_i2c_read,
                         fsl_i2c_write, fsl_i2c_set_bus_speed,
                         CONFIG_SYS_FSL_I2C2_SPEED, CONFIG_SYS_FSL_I2C2_SLAVE,
                         1)
#endif