/* $NetBSD: fdt_pinctrl.c,v 1.10 2019/10/01 23:32:52 jmcneill Exp $ */

/* $NetBSD: fdt_pinctrl.c,v 1.10 2019/10/01 23:32:52 jmcneill Exp $ */

/*-
* Copyright (c) 2019 Jason R. Thorpe
* Copyright (c) 2017 Jared McNeill <[email protected]>
* Copyright (c) 2015 Martin Fouts
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: fdt_pinctrl.c,v 1.10 2019/10/01 23:32:52 jmcneill Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/gpio.h>
#include <sys/kmem.h>
#include <sys/queue.h>

#include <libfdt.h>
#include <dev/fdt/fdtvar.h>

struct fdtbus_pinctrl_controller {
device_t pc_dev;
int pc_phandle;
const struct fdtbus_pinctrl_controller_func *pc_funcs;

LIST_ENTRY(fdtbus_pinctrl_controller) pc_next;
};

static LIST_HEAD(, fdtbus_pinctrl_controller) fdtbus_pinctrl_controllers =
LIST_HEAD_INITIALIZER(fdtbus_pinctrl_controllers);

int
fdtbus_register_pinctrl_config(device_t dev, int phandle,
const struct fdtbus_pinctrl_controller_func *funcs)
{
struct fdtbus_pinctrl_controller *pc;

pc = kmem_alloc(sizeof(*pc), KM_SLEEP);
pc->pc_dev = dev;
pc->pc_phandle = phandle;
pc->pc_funcs = funcs;

LIST_INSERT_HEAD(&fdtbus_pinctrl_controllers, pc, pc_next);

return 0;
}

static struct fdtbus_pinctrl_controller *
fdtbus_pinctrl_lookup(int phandle)
{
struct fdtbus_pinctrl_controller *pc;

LIST_FOREACH(pc, &fdtbus_pinctrl_controllers, pc_next) {
if (pc->pc_phandle == phandle)
return pc;
}

return NULL;
}

int
fdtbus_pinctrl_set_config_index(int phandle, u_int index)
{
struct fdtbus_pinctrl_controller *pc;
const u_int *pinctrl_data;
char buf[16];
u_int xref, pinctrl_cells;
int len, error;

snprintf(buf, sizeof(buf), "pinctrl-%u", index);

pinctrl_data = fdtbus_get_prop(phandle, buf, &len);
if (pinctrl_data == NULL)
return ENOENT;

while (len > 0) {
xref = fdtbus_get_phandle_from_native(be32toh(pinctrl_data[0]));
pc = fdtbus_pinctrl_lookup(xref);
if (pc == NULL)
return ENXIO;

if (of_getprop_uint32(OF_parent(xref), "#pinctrl-cells", &pinctrl_cells) != 0)
pinctrl_cells = 1;

error = pc->pc_funcs->set_config(pc->pc_dev, pinctrl_data, pinctrl_cells * 4);
if (error != 0)
return error;

pinctrl_data += pinctrl_cells;
len -= (pinctrl_cells * 4);
}

return 0;
}

int
fdtbus_pinctrl_set_config(int phandle, const char *cfgname)
{
u_int index;
int err;

err = fdtbus_get_index(phandle, "pinctrl-names", cfgname, &index);
if (err != 0)
return ENOENT;

return fdtbus_pinctrl_set_config_index(phandle, index);
}

bool
fdtbus_pinctrl_has_config(int phandle, const char *cfgname)
{
u_int index;

return fdtbus_get_index(phandle, "pinctrl-names", cfgname, &index) == 0;
}

/*
* Helper routines for parsing put properties related to pinctrl bindings.
*/

/*
* Pin mux settings apply to sets of pins specified by one of 3
* sets of properties:
*
* - "pins" + "function"
* - "groups" + "function"
* - "pinmux"
*
* Eactly one of those 3 combinations must be specified.
*/

const char *
fdtbus_pinctrl_parse_function(int phandle)
{
return fdtbus_get_string(phandle, "function");
}

const void *
fdtbus_pinctrl_parse_pins(int phandle, int *pins_len)
{
int len;

/*
* The pinctrl bindings specify that entries in "pins"
* may be integers or strings; this is determined by
* the hardware-specific binding.
*/

len = OF_getproplen(phandle, "pins");
if (len > 0) {
return fdtbus_get_prop(phandle, "pins", pins_len);
}

return NULL;
}

const char *
fdtbus_pinctrl_parse_groups(int phandle, int *groups_len)
{
int len;

len = OF_getproplen(phandle, "groups");
if (len > 0) {
*groups_len = len;
return fdtbus_get_string(phandle, "groups");
}

return NULL;
}

const u_int *
fdtbus_pinctrl_parse_pinmux(int phandle, int *pinmux_len)
{
int len;

len = OF_getproplen(phandle, "pinmux");
if (len > 0) {
return fdtbus_get_prop(phandle, "pinmux", pinmux_len);
}

return NULL;
}

int
fdtbus_pinctrl_parse_bias(int phandle, int *pull_strength)
{
const char *bias_prop = NULL;
int bias = -1;

/*
* bias-pull-{up,down,pin-default} properties have an optional
* argument: the pull strength in Ohms. (In practice, this is
* sometimes a hardware-specific constant.)
*
* XXXJRT How to represent bias-pull-pin-default?
*/

if (of_hasprop(phandle, "bias-disable")) {
bias = 0;
} else if (of_hasprop(phandle, "bias-pull-up")) {
bias_prop = "bias-pull-up";
bias = GPIO_PIN_PULLUP;
} else if (of_hasprop(phandle, "bias-pull-down")) {
bias_prop = "bias-pull-down";
bias = GPIO_PIN_PULLDOWN;
}

if (pull_strength) {
*pull_strength = -1;
if (bias_prop) {
uint32_t val;
if (of_getprop_uint32(phandle, bias_prop, &val) == 0) {
*pull_strength = (int)val;
}
}
}

return bias;
}

int
fdtbus_pinctrl_parse_drive(int phandle)
{
int drive = -1;

if (of_hasprop(phandle, "drive-push-pull"))
drive = GPIO_PIN_PUSHPULL;
else if (of_hasprop(phandle, "drive-open-drain"))
drive = GPIO_PIN_OPENDRAIN;
else if (of_hasprop(phandle, "drive-open-source"))
drive = 0;

return drive;
}

int
fdtbus_pinctrl_parse_drive_strength(int phandle)
{
int val;

/*
* drive-strength has as an argument the target strength
* in mA.
*/

if (of_getprop_uint32(phandle, "drive-strength", &val) == 0)
return val;

return -1;
}
int fdtbus_pinctrl_parse_input_output(int phandle, int *output_value)
{
int direction = -1;
int pinval = -1;

if (of_hasprop(phandle, "input-enable")) {
direction = GPIO_PIN_INPUT;
} else if (of_hasprop(phandle, "input-disable")) {
/*
* XXXJRT How to represent this? This is more than
* just "don't set the direction" - it's an active
* command that might involve disabling an input
* buffer on the pin.
*/
}

if (of_hasprop(phandle, "output-enable")) {
if (direction == -1)
direction = 0;
direction |= GPIO_PIN_OUTPUT;
} else if (of_hasprop(phandle, "output-disable")) {
if (direction == -1)
direction = 0;
direction |= GPIO_PIN_TRISTATE;
}

if (of_hasprop(phandle, "output-low")) {
if (direction == -1)
direction = 0;
direction |= GPIO_PIN_OUTPUT;
pinval = GPIO_PIN_LOW;
} else if (of_hasprop(phandle, "output-high")) {
if (direction == -1)
direction = 0;
direction |= GPIO_PIN_OUTPUT;
pinval = GPIO_PIN_HIGH;
}

if (output_value)
*output_value = pinval;

/*
* XXX input-schmitt-enable
* XXX input-schmitt-disable
*/

if (direction != -1
&& (direction & (GPIO_PIN_INPUT | GPIO_PIN_OUTPUT))
== (GPIO_PIN_INPUT | GPIO_PIN_OUTPUT)) {
direction |= GPIO_PIN_INOUT;
}

return direction;
}