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/* $OpenBSD: mcp794xx.c,v 1.1 2019/09/06 09:38:19 patrick Exp $ */
/*
* Copyright (c) 2018 Mark Kettenis <kettenis@openbsd.org>
* Copyright (c) 2018 Patrick Wildt <patrick@blueri.se>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <dev/i2c/i2cvar.h>
#include <dev/clock_subr.h>
extern todr_chip_handle_t todr_handle;
#define MCP794XX_SC 0x00
#define MCP794XX_SC_ST (1 << 7)
#define MCP794XX_MN 0x01
#define MCP794XX_HR 0x02
#define MCP794XX_HR_PM (1 << 5)
#define MCP794XX_HR_12H (1 << 6)
#define MCP794XX_DW 0x03
#define MCP794XX_DW_VBATEN (1 << 3)
#define MCP794XX_DW_PWRFAIL (1 << 4)
#define MCP794XX_DW_OSCRUN (1 << 5)
#define MCP794XX_DT 0x04
#define MCP794XX_MO 0x05
#define MCP794XX_YR 0x06
#define MCP794XX_CR 0x07
#define MCP794XX_CR_EXTOSC (1 << 3)
#define MCP794XX_NRTC_REGS 7
struct mcprtc_softc {
struct device sc_dev;
i2c_tag_t sc_tag;
i2c_addr_t sc_addr;
int sc_extosc;
struct todr_chip_handle sc_todr;
};
int mcprtc_match(struct device *, void *, void *);
void mcprtc_attach(struct device *, struct device *, void *);
struct cfattach mcprtc_ca = {
sizeof(struct mcprtc_softc), mcprtc_match, mcprtc_attach
};
struct cfdriver mcprtc_cd = {
NULL, "mcprtc", DV_DULL
};
uint8_t mcprtc_reg_read(struct mcprtc_softc *, int);
void mcprtc_reg_write(struct mcprtc_softc *, int, uint8_t);
int mcprtc_clock_read(struct mcprtc_softc *, struct clock_ymdhms *);
int mcprtc_clock_write(struct mcprtc_softc *, struct clock_ymdhms *);
int mcprtc_gettime(struct todr_chip_handle *, struct timeval *);
int mcprtc_settime(struct todr_chip_handle *, struct timeval *);
int
mcprtc_match(struct device *parent, void *match, void *aux)
{
struct i2c_attach_args *ia = aux;
if (strcmp(ia->ia_name, "microchip,mcp7940x") == 0 ||
strcmp(ia->ia_name, "microchip,mcp7941x") == 0)
return 1;
return 0;
}
void
mcprtc_attach(struct device *parent, struct device *self, void *aux)
{
struct mcprtc_softc *sc = (struct mcprtc_softc *)self;
struct i2c_attach_args *ia = aux;
sc->sc_tag = ia->ia_tag;
sc->sc_addr = ia->ia_addr;
sc->sc_todr.cookie = sc;
sc->sc_todr.todr_gettime = mcprtc_gettime;
sc->sc_todr.todr_settime = mcprtc_settime;
printf("\n");
todr_handle = &sc->sc_todr;
}
int
mcprtc_gettime(struct todr_chip_handle *handle, struct timeval *tv)
{
struct mcprtc_softc *sc = handle->cookie;
struct clock_ymdhms dt;
int error;
error = mcprtc_clock_read(sc, &dt);
if (error)
return error;
if (dt.dt_sec > 59 || dt.dt_min > 59 || dt.dt_hour > 23 ||
dt.dt_day > 31 || dt.dt_day == 0 ||
dt.dt_mon > 12 || dt.dt_mon == 0 ||
dt.dt_year < POSIX_BASE_YEAR)
return EINVAL;
tv->tv_sec = clock_ymdhms_to_secs(&dt);
tv->tv_usec = 0;
return 0;
}
int
mcprtc_settime(struct todr_chip_handle *handle, struct timeval *tv)
{
struct mcprtc_softc *sc = handle->cookie;
struct clock_ymdhms dt;
clock_secs_to_ymdhms(tv->tv_sec, &dt);
return mcprtc_clock_write(sc, &dt);
}
uint8_t
mcprtc_reg_read(struct mcprtc_softc *sc, int reg)
{
uint8_t cmd = reg;
uint8_t val;
int error;
iic_acquire_bus(sc->sc_tag, I2C_F_POLL);
error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
&cmd, sizeof cmd, &val, sizeof val, I2C_F_POLL);
iic_release_bus(sc->sc_tag, I2C_F_POLL);
if (error) {
printf("%s: can't read register 0x%02x\n",
sc->sc_dev.dv_xname, reg);
val = 0xff;
}
return val;
}
void
mcprtc_reg_write(struct mcprtc_softc *sc, int reg, uint8_t val)
{
uint8_t cmd = reg;
int error;
iic_acquire_bus(sc->sc_tag, I2C_F_POLL);
error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr,
&cmd, sizeof cmd, &val, sizeof val, I2C_F_POLL);
iic_release_bus(sc->sc_tag, I2C_F_POLL);
if (error) {
printf("%s: can't write register 0x%02x\n",
sc->sc_dev.dv_xname, reg);
}
}
int
mcprtc_clock_read(struct mcprtc_softc *sc, struct clock_ymdhms *dt)
{
uint8_t regs[MCP794XX_NRTC_REGS];
uint8_t cmd = MCP794XX_SC;
int error;
/* Don't trust the RTC if the oscillator is not running. */
if (!(mcprtc_reg_read(sc, MCP794XX_DW) & MCP794XX_DW_OSCRUN))
return EIO;
iic_acquire_bus(sc->sc_tag, I2C_F_POLL);
error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
&cmd, sizeof(cmd), regs, MCP794XX_NRTC_REGS, I2C_F_POLL);
iic_release_bus(sc->sc_tag, I2C_F_POLL);
if (error) {
printf("%s: can't read RTC\n", sc->sc_dev.dv_xname);
return error;
}
/*
* Convert the MCP794XX's register values into something useable.
*/
dt->dt_sec = FROMBCD(regs[0] & 0x7f);
dt->dt_min = FROMBCD(regs[1] & 0x7f);
dt->dt_hour = FROMBCD(regs[2] & 0x1f);
if ((regs[2] & MCP794XX_HR_12H) && (regs[2] & MCP794XX_HR_PM))
dt->dt_hour += 12;
dt->dt_wday = FROMBCD(regs[3] & 0x7);
dt->dt_day = FROMBCD(regs[4] & 0x3f);
dt->dt_mon = FROMBCD(regs[5] & 0x1f);
dt->dt_year = FROMBCD(regs[6]) + 2000;
return 0;
}
int
mcprtc_clock_write(struct mcprtc_softc *sc, struct clock_ymdhms *dt)
{
uint8_t regs[MCP794XX_NRTC_REGS];
uint8_t cmd = MCP794XX_SC;
uint8_t oscoff, oscbit;
uint8_t reg;
int error, i;
/*
* Convert our time representation into something the MCP794XX
* can understand.
*/
regs[0] = TOBCD(dt->dt_sec);
regs[1] = TOBCD(dt->dt_min);
regs[2] = TOBCD(dt->dt_hour);
regs[3] = TOBCD(dt->dt_wday) | MCP794XX_DW_VBATEN;
regs[4] = TOBCD(dt->dt_day);
regs[5] = TOBCD(dt->dt_mon);
regs[6] = TOBCD(dt->dt_year - 2000);
/* Stop RTC. */
if (sc->sc_extosc) {
oscoff = MCP794XX_CR;
oscbit = MCP794XX_CR_EXTOSC;
} else {
oscoff = MCP794XX_SC;
oscbit = MCP794XX_SC_ST;
}
/* Stop RTC such that we can write to it. */
reg = mcprtc_reg_read(sc, oscoff);
reg &= ~oscbit;
mcprtc_reg_write(sc, oscoff, reg);
for (i = 0; i < 10; i++) {
reg = mcprtc_reg_read(sc, MCP794XX_DW);
if ((reg & MCP794XX_DW_OSCRUN) == 0)
break;
delay(10);
}
if (i == 10) {
error = EIO;
goto fail;
}
iic_acquire_bus(sc->sc_tag, I2C_F_POLL);
error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr,
&cmd, sizeof(cmd), regs, MCP794XX_NRTC_REGS, I2C_F_POLL);
iic_release_bus(sc->sc_tag, I2C_F_POLL);
/* Restart RTC. */
reg = mcprtc_reg_read(sc, oscoff);
reg |= oscbit;
mcprtc_reg_write(sc, oscoff, reg);
fail:
if (error) {
printf("%s: can't write RTC\n", sc->sc_dev.dv_xname);
return error;
}
return 0;
}
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