* Copyright (c) 2003 Wasabi Systems, Inc.

/* $NetBSD: i2c.c,v 1.92 2025/01/27 17:01:53 riastradh Exp $ */

/*
* Copyright (c) 2003 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Jason R. Thorpe for Wasabi Systems, Inc.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed for the NetBSD Project by
* Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
* 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.
*/

#ifdef _KERNEL_OPT
#include "opt_i2c.h"

#include "opt_fdt.h"
#ifdef FDT
#define I2C_USE_FDT
#endif /* FDT */

#if defined(__aarch64__) || defined(__amd64__)
#include "acpica.h"
#if NACPICA > 0
#define I2C_USE_ACPI
#endif /* NACPICA > 0 */
#endif /* __aarch64__ || __amd64__ */

#endif /* _KERNEL_OPT */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: i2c.c,v 1.92 2025/01/27 17:01:53 riastradh Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/event.h>
#include <sys/conf.h>
#include <sys/malloc.h>
#include <sys/kmem.h>
#include <sys/kthread.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/fcntl.h>
#include <sys/module.h>
#include <sys/once.h>
#include <sys/mutex.h>

#ifdef I2C_USE_ACPI
#include <dev/acpi/acpivar.h>
#endif /* I2C_USE_ACPI */

#ifdef I2C_USE_FDT
#include <dev/fdt/fdtvar.h>
#endif /* I2C_USE_FDT */

#include <dev/i2c/i2cvar.h>

#include "ioconf.h"
#include "locators.h"

#ifndef I2C_MAX_ADDR
#define I2C_MAX_ADDR 0x3ff /* 10-bit address, max */
#endif

struct iic_softc {
device_t sc_dev;
i2c_tag_t sc_tag;
device_t sc_devices[I2C_MAX_ADDR + 1];
};

static dev_type_open(iic_open);
static dev_type_close(iic_close);
static dev_type_ioctl(iic_ioctl);

int iic_init(void);

kmutex_t iic_mtx;
int iic_refcnt;

ONCE_DECL(iic_once);

const struct cdevsw iic_cdevsw = {
.d_open = iic_open,
.d_close = iic_close,
.d_read = noread,
.d_write = nowrite,
.d_ioctl = iic_ioctl,
.d_stop = nostop,
.d_tty = notty,
.d_poll = nopoll,
.d_mmap = nommap,
.d_kqfilter = nokqfilter,
.d_discard = nodiscard,
.d_flag = D_OTHER
};

static void iic_fill_compat(struct i2c_attach_args*, const char*,
size_t, char **);

static int
iic_print_direct(void *aux, const char *pnp)
{
struct i2c_attach_args *ia = aux;

if (pnp != NULL)
aprint_normal("%s%s%s%s at %s addr 0x%02x",
ia->ia_name ? ia->ia_name : "(unknown)",
ia->ia_ncompat ? " (" : "",
ia->ia_ncompat ? ia->ia_compat[0] : "",
ia->ia_ncompat ? ")" : "",
pnp, ia->ia_addr);
else
aprint_normal(" addr 0x%02x", ia->ia_addr);

return UNCONF;
}

static int
iic_print(void *aux, const char *pnp)
{
struct i2c_attach_args *ia = aux;

if (ia->ia_addr != (i2c_addr_t)IICCF_ADDR_DEFAULT)
aprint_normal(" addr 0x%x", ia->ia_addr);

return UNCONF;
}

static bool
iic_is_special_address(i2c_addr_t addr)
{

/*
* See: https://www.i2c-bus.org/addressing/
*/

/* General Call (read) / Start Byte (write) */
if (addr == 0x00)
return (true);

/* CBUS Addresses */
if (addr == 0x01)
return (true);

/* Reserved for Different Bus Formats */
if (addr == 0x02)
return (true);

/* Reserved for future purposes */
if (addr == 0x03)
return (true);

/* High Speed Master Code */
if ((addr & 0x7c) == 0x04)
return (true);

/* 10-bit Slave Addressing prefix */
if ((addr & 0x7c) == 0x78)
return (true);

/* Reserved for future purposes */
if ((addr & 0x7c) == 0x7c)
return (true);

return (false);
}

static int
iic_probe_none(struct iic_softc *sc,
const struct i2c_attach_args *ia, int flags)
{

return (0);
}

static int
iic_probe_smbus_quick_write(struct iic_softc *sc,
const struct i2c_attach_args *ia, int flags)
{
int error;

if ((error = iic_acquire_bus(ia->ia_tag, flags)) == 0) {
error = iic_smbus_quick_write(ia->ia_tag, ia->ia_addr, flags);
}
(void) iic_release_bus(ia->ia_tag, flags);

return (error);
}

static int
iic_probe_smbus_receive_byte(struct iic_softc *sc,
const struct i2c_attach_args *ia, int flags)
{
int error;

if ((error = iic_acquire_bus(ia->ia_tag, flags)) == 0) {
uint8_t dummy;

error = iic_smbus_receive_byte(ia->ia_tag, ia->ia_addr,
&dummy, flags);
}
(void) iic_release_bus(ia->ia_tag, flags);

return (error);
}

static bool
iic_indirect_driver_is_permitted(struct iic_softc *sc, cfdata_t cf)
{
prop_object_iterator_t iter;
prop_array_t permitlist;
prop_string_t pstr;
prop_type_t ptype;
bool rv = false;

permitlist = prop_dictionary_get(device_properties(sc->sc_dev),
I2C_PROP_INDIRECT_DEVICE_PERMITLIST);
if (permitlist == NULL) {
/* No permitlist -> everything allowed */
return (true);
}

if ((ptype = prop_object_type(permitlist)) != PROP_TYPE_ARRAY) {
aprint_error_dev(sc->sc_dev,
"invalid property type (%d) for '%s'; must be array (%d)\n",
ptype, I2C_PROP_INDIRECT_DEVICE_PERMITLIST,
PROP_TYPE_ARRAY);
return (false);
}

iter = prop_array_iterator(permitlist);
while ((pstr = prop_object_iterator_next(iter)) != NULL) {
if (prop_string_equals_string(pstr, cf->cf_name)) {
rv = true;
break;
}
}
prop_object_iterator_release(iter);

return (rv);
}

static int
iic_search(device_t parent, cfdata_t cf, const int *ldesc, void *aux)
{
struct iic_softc *sc = device_private(parent);
struct i2c_attach_args ia;
int (*probe_func)(struct iic_softc *,
const struct i2c_attach_args *, int);
prop_string_t pstr;
i2c_addr_t first_addr, last_addr;

/*
* Before we do any more work, consult the allowed-driver
* permit-list for this bus (if any).
*/
if (iic_indirect_driver_is_permitted(sc, cf) == false)
return (0);

/* default to "quick write". */
probe_func = iic_probe_smbus_quick_write;

pstr = prop_dictionary_get(device_properties(sc->sc_dev),
I2C_PROP_INDIRECT_PROBE_STRATEGY);
if (pstr == NULL) {
/* Use the default. */
} else if (prop_string_equals_string(pstr,
I2C_PROBE_STRATEGY_QUICK_WRITE)) {
probe_func = iic_probe_smbus_quick_write;
} else if (prop_string_equals_string(pstr,
I2C_PROBE_STRATEGY_RECEIVE_BYTE)) {
probe_func = iic_probe_smbus_receive_byte;
} else if (prop_string_equals_string(pstr,
I2C_PROBE_STRATEGY_NONE)) {
probe_func = iic_probe_none;
} else {
aprint_error_dev(sc->sc_dev,
"unknown probe strategy '%s'; defaulting to '%s'\n",
prop_string_value(pstr),
I2C_PROBE_STRATEGY_QUICK_WRITE);

/* Use the default. */
}

ia.ia_tag = sc->sc_tag;

ia.ia_name = NULL;
ia.ia_ncompat = 0;
ia.ia_compat = NULL;
ia.ia_prop = NULL;

if (cf->cf_loc[IICCF_ADDR] == IICCF_ADDR_DEFAULT) {
/*
* This particular config directive has
* wildcarded the address, so we will
* scan the entire bus for it.
*/
first_addr = 0;
last_addr = I2C_MAX_ADDR;
} else {
/*
* This config directive hard-wires the i2c
* bus address for the device, so there is
* no need to go poking around at any other
* addresses.
*/
if (cf->cf_loc[IICCF_ADDR] < 0 ||
cf->cf_loc[IICCF_ADDR] > I2C_MAX_ADDR) {
/* Invalid config directive! */
return (0);
}
first_addr = last_addr = cf->cf_loc[IICCF_ADDR];
}

for (ia.ia_addr = first_addr; ia.ia_addr <= last_addr; ia.ia_addr++) {
int error, match_result;

/*
* Skip I2C addresses that are reserved for
* special purposes.
*/
if (iic_is_special_address(ia.ia_addr))
continue;

/*
* Skip addresses where a device is already attached.
*/
if (sc->sc_devices[ia.ia_addr] != NULL)
continue;

/*
* Call the "match" routine for the device. If that
* returns success, then call the probe strategy
* function.
*
* We do it in this order because i2c devices tend
* to be found at a small number of possible addresses
* (e.g. read-time clocks that are only ever found at
* 0x68). This gives the driver a chance to skip any
* address that are not valid for the device, saving
* us from having to poke at the bus to see if anything
* is there.
*/
match_result = config_probe(parent, cf, &ia);/*XXX*/
if (match_result <= 0)
continue;

/*
* If the quality of the match by the driver was low
* (i.e. matched on being a valid address only, didn't
* perform any hardware probe), invoke our probe routine
* to see if it looks like something is really there.
*/
if (match_result == I2C_MATCH_ADDRESS_ONLY &&
(error = (*probe_func)(sc, &ia, 0)) != 0)
continue;

sc->sc_devices[ia.ia_addr] =
config_attach(parent, cf, &ia, iic_print, CFARGS_NONE);
}

return 0;
}

static void
iic_child_detach(device_t parent, device_t child)
{
struct iic_softc *sc = device_private(parent);
int i;

for (i = 0; i <= I2C_MAX_ADDR; i++)
if (sc->sc_devices[i] == child) {
sc->sc_devices[i] = NULL;
break;
}
}

static int
iic_rescan(device_t self, const char *ifattr, const int *locators)
{
config_search(self, NULL,
CFARGS(.search = iic_search,
.locators = locators));
return 0;
}

static int
iic_match(device_t parent, cfdata_t cf, void *aux)
{

return 1;
}

static void
iic_attach(device_t parent, device_t self, void *aux)
{
struct iic_softc *sc = device_private(self);
struct i2cbus_attach_args *iba = aux;
prop_array_t child_devices;
prop_dictionary_t props;
char *buf;
i2c_tag_t ic;
bool no_indirect_config = false;

aprint_naive("\n");
aprint_normal(": I2C bus\n");

sc->sc_dev = self;
sc->sc_tag = iba->iba_tag;
ic = sc->sc_tag;

if (!pmf_device_register(self, NULL, NULL))
aprint_error_dev(self, "couldn't establish power handler\n");

if (iba->iba_child_devices) {
child_devices = iba->iba_child_devices;
no_indirect_config = true;
} else {
props = device_properties(parent);
prop_dictionary_get_bool(props, "i2c-no-indirect-config",
&no_indirect_config);
child_devices = prop_dictionary_get(props, "i2c-child-devices");
}

if (child_devices) {
unsigned int i, count;
prop_dictionary_t dev;
prop_data_t cdata;
uint32_t addr;
uint64_t cookie;
uint32_t cookietype;
const char *name;
struct i2c_attach_args ia;
devhandle_t devhandle;
int loc[IICCF_NLOCS];

memset(loc, 0, sizeof loc);
count = prop_array_count(child_devices);
for (i = 0; i < count; i++) {
dev = prop_array_get(child_devices, i);
if (!dev) continue;
if (!prop_dictionary_get_string(
dev, "name", &name)) {
/* "name" property is optional. */
name = NULL;
}
if (!prop_dictionary_get_uint32(dev, "addr", &addr))
continue;
if (!prop_dictionary_get_uint64(dev, "cookie", &cookie))
cookie = 0;
if (!prop_dictionary_get_uint32(dev, "cookietype",
&cookietype))
cookietype = I2C_COOKIE_NONE;
loc[IICCF_ADDR] = addr;

memset(&ia, 0, sizeof ia);
ia.ia_addr = addr;
ia.ia_tag = ic;
ia.ia_name = name;
ia.ia_cookie = cookie;
ia.ia_cookietype = cookietype;
ia.ia_prop = dev;

devhandle = devhandle_invalid();
#ifdef I2C_USE_FDT
if (cookietype == I2C_COOKIE_OF) {
devhandle = devhandle_from_of(devhandle,
(int)cookie);
}
#endif /* I2C_USE_FDT */
#ifdef I2C_USE_ACPI
if (cookietype == I2C_COOKIE_ACPI) {
devhandle =
devhandle_from_acpi(devhandle,
(ACPI_HANDLE)cookie);
}
#endif /* I2C_USE_ACPI */

buf = NULL;
cdata = prop_dictionary_get(dev, "compatible");
if (cdata)
iic_fill_compat(&ia,
prop_data_value(cdata),
prop_data_size(cdata), &buf);

if (name == NULL && cdata == NULL) {
aprint_error_dev(self,
"WARNING: ignoring bad child device entry "
"for address 0x%02x\n", addr);
} else {
if (addr > I2C_MAX_ADDR) {
aprint_error_dev(self,
"WARNING: ignoring bad device "
"address @ 0x%02x\n", addr);
} else if (sc->sc_devices[addr] == NULL) {
sc->sc_devices[addr] =
config_found(self, &ia,
iic_print_direct,
CFARGS(.locators = loc,
.devhandle = devhandle));
}
}

if (ia.ia_compat)
free(ia.ia_compat, M_TEMP);
if (buf)
free(buf, M_TEMP);
}
} else if (!no_indirect_config) {
/*
* Attach all i2c devices described in the kernel
* configuration file.
*/
iic_rescan(self, "iic", NULL);
}
}

static int
iic_detach(device_t self, int flags)
{
int error;

error = config_detach_children(self, flags);
if (error)
return error;

pmf_device_deregister(self);

return 0;
}

static void
iic_fill_compat(struct i2c_attach_args *ia, const char *compat, size_t len,
char **buffer)
{
int count, i;
const char *c, *start, **ptr;

*buffer = NULL;
for (i = count = 0, c = compat; i < len; i++, c++)
if (*c == 0)
count++;
count += 2;
ptr = malloc(sizeof(char*)*count, M_TEMP, M_WAITOK);
if (!ptr) return;

for (i = count = 0, start = c = compat; i < len; i++, c++) {
if (*c == 0) {
ptr[count++] = start;
start = c+1;
}
}
if (start < compat+len) {
/* last string not 0 terminated */
size_t l = c-start;
*buffer = malloc(l+1, M_TEMP, M_WAITOK);
memcpy(*buffer, start, l);
(*buffer)[l] = 0;
ptr[count++] = *buffer;
}
ptr[count] = NULL;

ia->ia_compat = ptr;
ia->ia_ncompat = count;
}

/*
* iic_compatible_match --
* Match a device's "compatible" property against the list
* of compatible strings provided by the driver.
*/
int
iic_compatible_match(const struct i2c_attach_args *ia,
const struct device_compatible_entry *compats)
{
int match_result;

match_result = device_compatible_match(ia->ia_compat, ia->ia_ncompat,
compats);
if (match_result) {
match_result =
MIN(I2C_MATCH_DIRECT_COMPATIBLE + match_result - 1,
I2C_MATCH_DIRECT_COMPATIBLE_MAX);
}

return match_result;
}

/*
* iic_compatible_lookup --
* Look the compatible entry that matches one of the driver's
* "compatible" strings. The first match is returned.
*/
const struct device_compatible_entry *
iic_compatible_lookup(const struct i2c_attach_args *ia,
const struct device_compatible_entry *compats)
{
return device_compatible_lookup(ia->ia_compat, ia->ia_ncompat,
compats);
}

/*
* iic_use_direct_match --
* Helper for direct-config of i2c. Returns true if this is
* a direct-config situation, along with match result.
* Returns false if the driver should use indirect-config
* matching logic.
*/
bool
iic_use_direct_match(const struct i2c_attach_args *ia, const cfdata_t cf,
const struct device_compatible_entry *compats,
int *match_resultp)
{
KASSERT(match_resultp != NULL);

if (ia->ia_name != NULL &&
strcmp(ia->ia_name, cf->cf_name) == 0) {
*match_resultp = I2C_MATCH_DIRECT_SPECIFIC;
return true;
}

if (ia->ia_ncompat > 0 && ia->ia_compat != NULL) {
*match_resultp = iic_compatible_match(ia, compats);
return true;
}

return false;
}

static int
iic_open(dev_t dev, int flag, int fmt, lwp_t *l)
{
struct iic_softc *sc = device_lookup_private(&iic_cd, minor(dev));

mutex_enter(&iic_mtx);
if (sc == NULL) {
mutex_exit(&iic_mtx);
return ENXIO;
}
iic_refcnt++;
mutex_exit(&iic_mtx);

return 0;
}

static int
iic_close(dev_t dev, int flag, int fmt, lwp_t *l)
{

mutex_enter(&iic_mtx);
iic_refcnt--;
mutex_exit(&iic_mtx);

return 0;
}

static int
iic_ioctl_exec(struct iic_softc *sc, i2c_ioctl_exec_t *iie, int flag)
{
i2c_tag_t ic = sc->sc_tag;
uint8_t *buf = NULL;
void *cmd = NULL;
int error = 0;

/* Validate parameters */
if (iie->iie_addr > I2C_MAX_ADDR)
return EINVAL;
if (iie->iie_cmdlen > I2C_EXEC_MAX_CMDLEN ||
iie->iie_buflen > I2C_EXEC_MAX_BUFLEN)
return EINVAL;
if (iie->iie_cmd != NULL && iie->iie_cmdlen == 0)
return EINVAL;
if (iie->iie_buf != NULL && iie->iie_buflen == 0)
return EINVAL;
if (I2C_OP_WRITE_P(iie->iie_op) && (flag & FWRITE) == 0)
return EBADF;

#if 0
/* Disallow userspace access to devices that have drivers attached. */
if (sc->sc_devices[iie->iie_addr] != NULL)
return EBUSY;
#endif

if (iie->iie_cmd != NULL) {
cmd = kmem_alloc(iie->iie_cmdlen, KM_SLEEP);
error = copyin(iie->iie_cmd, cmd, iie->iie_cmdlen);
if (error)
goto out;
}

if (iie->iie_buf != NULL) {
buf = kmem_alloc(iie->iie_buflen, KM_SLEEP);
if (I2C_OP_WRITE_P(iie->iie_op)) {
error = copyin(iie->iie_buf, buf, iie->iie_buflen);
if (error)
goto out;
}
}

iic_acquire_bus(ic, 0);
error = iic_exec(ic, iie->iie_op, iie->iie_addr, cmd, iie->iie_cmdlen,
buf, iie->iie_buflen, 0);
iic_release_bus(ic, 0);

/*
* Some drivers return error codes on failure, and others return -1.
*/
if (error < 0)
error = EIO;

out:
if (!error && iie->iie_buf != NULL && I2C_OP_READ_P(iie->iie_op))
error = copyout(buf, iie->iie_buf, iie->iie_buflen);

if (buf)
kmem_free(buf, iie->iie_buflen);

if (cmd)
kmem_free(cmd, iie->iie_cmdlen);

return error;
}

static int
iic_ioctl(dev_t dev, u_long cmd, void *data, int flag, lwp_t *l)
{
struct iic_softc *sc = device_lookup_private(&iic_cd, minor(dev));

if (sc == NULL)
return ENXIO;

switch (cmd) {
case I2C_IOCTL_EXEC:
return iic_ioctl_exec(sc, (i2c_ioctl_exec_t *)data, flag);
default:
return ENODEV;
}
}

CFATTACH_DECL3_NEW(iic, sizeof(struct iic_softc),
iic_match, iic_attach, iic_detach, NULL, iic_rescan, iic_child_detach,
DVF_DETACH_SHUTDOWN);

MODULE(MODULE_CLASS_DRIVER, iic, "i2cexec,i2c_bitbang,i2c_subr");

#ifdef _MODULE
#include "ioconf.c"
#endif

int
iic_init(void)
{

mutex_init(&iic_mtx, MUTEX_DEFAULT, IPL_NONE);
iic_refcnt = 0;
return 0;
}

static int
iic_modcmd(modcmd_t cmd, void *opaque)
{
#ifdef _MODULE
int bmajor, cmajor;
#endif
int error;

error = 0;
switch (cmd) {
case MODULE_CMD_INIT:
RUN_ONCE(&iic_once, iic_init);

#ifdef _MODULE
mutex_enter(&iic_mtx);
bmajor = cmajor = -1;
error = devsw_attach("iic", NULL, &bmajor,
&iic_cdevsw, &cmajor);
if (error != 0) {
mutex_exit(&iic_mtx);
break;
}
error = config_init_component(cfdriver_ioconf_iic,
cfattach_ioconf_iic, cfdata_ioconf_iic);
if (error) {
aprint_error("%s: unable to init component\n",
iic_cd.cd_name);
devsw_detach(NULL, &iic_cdevsw);
}
mutex_exit(&iic_mtx);
#endif
break;
case MODULE_CMD_FINI:
mutex_enter(&iic_mtx);
if (iic_refcnt != 0) {
mutex_exit(&iic_mtx);
return EBUSY;
}
#ifdef _MODULE
error = config_fini_component(cfdriver_ioconf_iic,
cfattach_ioconf_iic, cfdata_ioconf_iic);
if (error != 0) {
mutex_exit(&iic_mtx);
break;
}
devsw_detach(NULL, &iic_cdevsw);
#endif
mutex_exit(&iic_mtx);
break;
default:
error = ENOTTY;
}
return error;
}