/*-
* Copyright (C) 2008 MARVELL INTERNATIONAL LTD.
* All rights reserved.
*
* Developed by Semihalf.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of MARVELL nor the names of contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Driver for the TWSI (aka I2C, aka IIC) bus controller found on Marvell
* and Allwinner SoCs. Supports master operation only, and works in polling mode.
*
* Calls to DELAY() are needed per Application Note AN-179 "TWSI Software
* Guidelines for Discovery(TM), Horizon (TM) and Feroceon(TM) Devices".
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/resource.h>
#include <machine/_inttypes.h>
#include <machine/bus.h>
#include <machine/resource.h>
#include <sys/rman.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/clk/clk.h>
#include <arm/mv/mvreg.h>
#include <arm/mv/mvvar.h>
#include <dev/iicbus/controller/twsi/twsi.h>
#include "iicbus_if.h"
#define MV_TWSI_NAME "twsi"
#define IICBUS_DEVNAME "iicbus"
#define TWSI_ADDR 0x00
#define TWSI_DATA 0x04
#define TWSI_CNTR 0x08
#define TWSI_XADDR 0x10
#define TWSI_STAT 0x0c
#define TWSI_BAUD_RATE 0x0c
#define TWSI_SRST 0x1c
#define TWSI_BAUD_RATE_RAW(C,M,N) ((C)/((10*(M+1))<<(N+1)))
#define TWSI_BAUD_RATE_SLOW 50000 /* 50kHz */
#define TWSI_BAUD_RATE_FAST 100000 /* 100kHz */
#define TWSI_DEBUG
#undef TWSI_DEBUG
#ifdef TWSI_DEBUG
#define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt,##args); } while (0)
#else
#define debugf(fmt, args...)
#endif
static phandle_t mv_twsi_get_node(device_t, device_t);
static int mv_twsi_probe(device_t);
static int mv_twsi_attach(device_t);
static struct ofw_compat_data compat_data[] = {
{ "mrvl,twsi", true },
{ "marvell,mv64xxx-i2c", true },
{ "marvell,mv78230-i2c", true },
{ NULL, false }
};
static device_method_t mv_twsi_methods[] = {
/* device interface */
DEVMETHOD(device_probe, mv_twsi_probe),
DEVMETHOD(device_attach, mv_twsi_attach),
/* ofw_bus interface */
DEVMETHOD(ofw_bus_get_node, mv_twsi_get_node),
DEVMETHOD_END
};
DEFINE_CLASS_1(twsi, mv_twsi_driver, mv_twsi_methods,
sizeof(struct twsi_softc), twsi_driver);
DRIVER_MODULE(twsi, simplebus, mv_twsi_driver, 0, 0);
DRIVER_MODULE(iicbus, twsi, iicbus_driver, 0, 0);
MODULE_DEPEND(twsi, iicbus, 1, 1, 1);
SIMPLEBUS_PNP_INFO(compat_data);
static phandle_t
mv_twsi_get_node(device_t bus, device_t dev)
{
/* Used by ofw_iicbus. */
return (ofw_bus_get_node(bus));
}
static int
mv_twsi_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
return (ENXIO);
device_set_desc(dev, "Marvell Integrated I2C Bus Controller");
return (BUS_PROBE_DEFAULT);
}
#define ABSSUB(a,b) (((a) > (b)) ? (a) - (b) : (b) - (a))
static void
mv_twsi_cal_baud_rate(struct twsi_softc *sc, const uint32_t target,
struct twsi_baud_rate *rate)
{
uint64_t clk;
uint32_t cur, diff, diff0;
int m, n, m0, n0;
/* Calculate baud rate. */
m0 = n0 = 4; /* Default values on reset */
diff0 = 0xffffffff;
clk_get_freq(sc->clk_core, &clk);
for (n = 0; n < 8; n++) {
for (m = 0; m < 16; m++) {
cur = TWSI_BAUD_RATE_RAW(clk,m,n);
diff = ABSSUB(target, cur);
if (diff < diff0) {
m0 = m;
n0 = n;
diff0 = diff;
}
}
}
rate->raw = TWSI_BAUD_RATE_RAW(clk, m0, n0);
rate->param = TWSI_BAUD_RATE_PARAM(m0, n0);
rate->m = m0;
rate->n = n0;
}
static int
mv_twsi_attach(device_t dev)
{
struct twsi_softc *sc;
int error;
sc = device_get_softc(dev);
sc->dev = dev;
/* Activate clock */
error = clk_get_by_ofw_index(dev, 0, 0, &sc->clk_core);
if (error != 0) {
device_printf(dev, "could not find core clock\n");
return (error);
}
error = clk_enable(sc->clk_core);
if (error != 0) {
device_printf(dev, "could not enable core clock\n");
return (error);
}
if (clk_get_by_ofw_index(dev, 0, 1, &sc->clk_reg) == 0) {
error = clk_enable(sc->clk_reg);
if (error != 0) {
device_printf(dev, "could not enable core clock\n");
return (error);
}
}
mv_twsi_cal_baud_rate(sc, TWSI_BAUD_RATE_SLOW, &sc->baud_rate[IIC_SLOW]);
mv_twsi_cal_baud_rate(sc, TWSI_BAUD_RATE_FAST, &sc->baud_rate[IIC_FAST]);
if (bootverbose)
device_printf(dev, "calculated baud rates are:\n"
" %" PRIu32 " kHz (M=%d, N=%d) for slow,\n"
" %" PRIu32 " kHz (M=%d, N=%d) for fast.\n",
sc->baud_rate[IIC_SLOW].raw / 1000,
sc->baud_rate[IIC_SLOW].m,
sc->baud_rate[IIC_SLOW].n,
sc->baud_rate[IIC_FAST].raw / 1000,
sc->baud_rate[IIC_FAST].m,
sc->baud_rate[IIC_FAST].n);
sc->reg_data = TWSI_DATA;
sc->reg_slave_addr = TWSI_ADDR;
sc->reg_slave_ext_addr = TWSI_XADDR;
sc->reg_control = TWSI_CNTR;
sc->reg_status = TWSI_STAT;
sc->reg_baud_rate = TWSI_BAUD_RATE;
sc->reg_soft_reset = TWSI_SRST;
return (twsi_attach(dev));
}