From 62b7f5931c54e96fca56dd8761b0e466d355c881 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
Date: Thu, 18 Feb 2021 18:04:33 +0100
Subject: bcm27xx: import latest patches from the RPi foundation
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

bcm2708: boot tested on RPi B+ v1.2
bcm2709: boot tested on RPi 3B v1.2 and RPi 4B v1.1 4G
bcm2710: boot tested on RPi 3B v1.2
bcm2711: boot tested on RPi 4B v1.1 4G

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
(cherry-picked from commit f07e572f64)
---
 .../950-0986-gpio-Add-gpio-fsm-driver.patch        | 1182 ++++++++++++++++++++
 1 file changed, 1182 insertions(+)
 create mode 100644 target/linux/bcm27xx/patches-5.4/950-0986-gpio-Add-gpio-fsm-driver.patch

(limited to 'target/linux/bcm27xx/patches-5.4/950-0986-gpio-Add-gpio-fsm-driver.patch')

diff --git a/target/linux/bcm27xx/patches-5.4/950-0986-gpio-Add-gpio-fsm-driver.patch b/target/linux/bcm27xx/patches-5.4/950-0986-gpio-Add-gpio-fsm-driver.patch
new file mode 100644
index 0000000000..7076026e7c
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.4/950-0986-gpio-Add-gpio-fsm-driver.patch
@@ -0,0 +1,1182 @@
+From c31626a9e173f2b2e0adc4cb8bfbb86a958bafcd Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Wed, 30 Sep 2020 12:00:54 +0100
+Subject: [PATCH] gpio: Add gpio-fsm driver
+
+The gpio-fsm driver implements simple state machines that allow GPIOs
+to be controlled in response to inputs from other GPIOs - real and
+soft/virtual - and time delays. It can:
++ create dummy GPIOs for drivers that demand them,
++ drive multiple GPIOs from a single input, with optional delays,
++ add a debounce circuit to an input,
++ drive pattern sequences onto LEDs
+etc.
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.com>
+---
+ drivers/gpio/Kconfig                |    9 +
+ drivers/gpio/Makefile               |    1 +
+ drivers/gpio/gpio-fsm.c             | 1103 +++++++++++++++++++++++++++
+ include/dt-bindings/gpio/gpio-fsm.h |   21 +
+ 4 files changed, 1134 insertions(+)
+ create mode 100644 drivers/gpio/gpio-fsm.c
+ create mode 100644 include/dt-bindings/gpio/gpio-fsm.h
+
+--- a/drivers/gpio/Kconfig
++++ b/drivers/gpio/Kconfig
+@@ -1071,6 +1071,15 @@ config HTC_EGPIO
+ 	  several HTC phones.  It provides basic support for input
+ 	  pins, output pins, and irqs.
+ 
++config GPIO_FSM
++	tristate "GPIO FSM support"
++	help
++	  The GPIO FSM driver allows the creation of state machines for
++	  manipulating GPIOs (both real and virtual), with state transitions
++	  triggered by GPIO edges or delays.
++
++	  If unsure, say N.
++
+ config GPIO_JANZ_TTL
+ 	tristate "Janz VMOD-TTL Digital IO Module"
+ 	depends on MFD_JANZ_CMODIO
+--- a/drivers/gpio/Makefile
++++ b/drivers/gpio/Makefile
+@@ -55,6 +55,7 @@ obj-$(CONFIG_GPIO_EP93XX)		+= gpio-ep93x
+ obj-$(CONFIG_GPIO_EXAR)			+= gpio-exar.o
+ obj-$(CONFIG_GPIO_F7188X)		+= gpio-f7188x.o
+ obj-$(CONFIG_GPIO_FTGPIO010)		+= gpio-ftgpio010.o
++obj-$(CONFIG_GPIO_FSM)			+= gpio-fsm.o
+ obj-$(CONFIG_GPIO_GE_FPGA)		+= gpio-ge.o
+ obj-$(CONFIG_GPIO_GPIO_MM)		+= gpio-gpio-mm.o
+ obj-$(CONFIG_GPIO_GRGPIO)		+= gpio-grgpio.o
+--- /dev/null
++++ b/drivers/gpio/gpio-fsm.c
+@@ -0,0 +1,1103 @@
++// SPDX-License-Identifier: GPL-2.0+
++/*
++ *  GPIO FSM driver
++ *
++ *  This driver implements simple state machines that allow real GPIOs to be
++ *  controlled in response to inputs from other GPIOs - real and soft/virtual -
++ *  and time delays. It can:
++ *  + create dummy GPIOs for drivers that demand them
++ *  + drive multiple GPIOs from a single input,  with optional delays
++ *  + add a debounce circuit to an input
++ *  + drive pattern sequences onto LEDs
++ *  etc.
++ *
++ *  Copyright (C) 2020 Raspberry Pi (Trading) Ltd.
++ */
++
++#include <linux/err.h>
++#include <linux/gpio.h>
++#include <linux/gpio/driver.h>
++#include <linux/interrupt.h>
++#include <linux/module.h>
++#include <linux/platform_device.h>
++
++#include <dt-bindings/gpio/gpio-fsm.h>
++
++#define MODULE_NAME "gpio-fsm"
++
++#define GF_IO_TYPE(x) ((u32)(x) & 0xffff)
++#define GF_IO_INDEX(x) ((u32)(x) >> 16)
++
++enum {
++	SIGNAL_GPIO,
++	SIGNAL_SOFT
++};
++
++enum {
++	INPUT_GPIO,
++	INPUT_SOFT
++};
++
++enum {
++	SYM_UNDEFINED,
++	SYM_NAME,
++	SYM_SET,
++	SYM_START,
++	SYM_SHUTDOWN,
++
++	SYM_MAX
++};
++
++struct soft_gpio {
++	int dir;
++	int value;
++};
++
++struct input_gpio_state {
++	struct gpio_fsm *gf;
++	struct gpio_desc  *desc;
++	struct fsm_state *target;
++	int index;
++	int value;
++	int irq;
++	bool enabled;
++	bool active_low;
++};
++
++struct gpio_event {
++	int index;
++	int value;
++	struct fsm_state *target;
++};
++
++struct symtab_entry {
++	const char *name;
++	void *value;
++	struct symtab_entry *next;
++};
++
++struct output_signal {
++	u8 type;
++	u8 value;
++	u16 index;
++};
++
++struct fsm_state {
++	const char *name;
++	struct output_signal *signals;
++	struct gpio_event *gpio_events;
++	struct gpio_event *soft_events;
++	struct fsm_state *delay_target;
++	struct fsm_state *shutdown_target;
++	unsigned int num_signals;
++	unsigned int num_gpio_events;
++	unsigned int num_soft_events;
++	unsigned int delay_ms;
++	unsigned int shutdown_ms;
++};
++
++struct gpio_fsm {
++	struct gpio_chip gc;
++	struct device *dev;
++	spinlock_t spinlock;
++	struct work_struct work;
++	struct timer_list timer;
++	wait_queue_head_t shutdown_event;
++	struct fsm_state *states;
++	struct input_gpio_state *input_gpio_states;
++	struct gpio_descs *input_gpios;
++	struct gpio_descs *output_gpios;
++	struct soft_gpio *soft_gpios;
++	struct fsm_state *start_state;
++	struct fsm_state *shutdown_state;
++	unsigned int num_states;
++	unsigned int num_output_gpios;
++	unsigned int num_input_gpios;
++	unsigned int num_soft_gpios;
++	unsigned int shutdown_timeout_ms;
++	unsigned int shutdown_jiffies;
++
++	struct fsm_state *current_state;
++	struct fsm_state *next_state;
++	struct fsm_state *delay_target_state;
++	int delay_ms;
++	unsigned int debug;
++	bool shutting_down;
++	struct symtab_entry *symtab;
++};
++
++static struct symtab_entry *do_add_symbol(struct symtab_entry **symtab,
++					  const char *name, void *value)
++{
++	struct symtab_entry **p = symtab;
++
++	while (*p && strcmp((*p)->name, name))
++		p = &(*p)->next;
++
++	if (*p) {
++		/* This is an existing symbol */
++		if ((*p)->value) {
++			/* Already defined */
++			if (value) {
++				if ((uintptr_t)value < SYM_MAX)
++					return ERR_PTR(-EINVAL);
++				else
++					return ERR_PTR(-EEXIST);
++			}
++		} else {
++			/* Undefined */
++			(*p)->value = value;
++		}
++	} else {
++		/* This is a new symbol */
++		*p = kmalloc(sizeof(struct symtab_entry), GFP_KERNEL);
++		if (*p) {
++			(*p)->name = name;
++			(*p)->value = value;
++			(*p)->next = NULL;
++		}
++	}
++	return *p;
++}
++
++static int add_symbol(struct symtab_entry **symtab,
++		      const char *name, void *value)
++{
++	struct symtab_entry *sym = do_add_symbol(symtab, name, value);
++
++	return PTR_ERR_OR_ZERO(sym);
++}
++
++static struct symtab_entry *get_symbol(struct symtab_entry **symtab,
++				       const char *name)
++{
++	struct symtab_entry *sym = do_add_symbol(symtab, name, NULL);
++
++	if (IS_ERR(sym))
++		return NULL;
++	return sym;
++}
++
++static void free_symbols(struct symtab_entry **symtab)
++{
++	struct symtab_entry *sym = *symtab;
++	void *p;
++
++	*symtab = NULL;
++	while (sym) {
++		p = sym;
++		sym = sym->next;
++		kfree(p);
++	}
++}
++
++static int gpio_fsm_get_direction(struct gpio_chip *gc, unsigned int off)
++{
++	struct gpio_fsm *gf = gpiochip_get_data(gc);
++	struct soft_gpio *sg;
++
++	if (off >= gf->num_soft_gpios)
++		return -EINVAL;
++	sg = &gf->soft_gpios[off];
++
++	return sg->dir;
++}
++
++static int gpio_fsm_get(struct gpio_chip *gc, unsigned int off)
++{
++	struct gpio_fsm *gf = gpiochip_get_data(gc);
++	struct soft_gpio *sg;
++
++	if (off >= gf->num_soft_gpios)
++		return -EINVAL;
++	sg = &gf->soft_gpios[off];
++
++	return sg->value;
++}
++
++static void gpio_fsm_go_to_state(struct gpio_fsm *gf,
++				   struct fsm_state *new_state)
++{
++	struct input_gpio_state *inp_state;
++	struct gpio_event *gp_ev;
++	struct fsm_state *state;
++	int i;
++
++	dev_dbg(gf->dev, "go_to_state(%s)\n",
++		  new_state ? new_state->name : "<unset>");
++
++	spin_lock(&gf->spinlock);
++
++	if (gf->next_state) {
++		/* Something else has already requested a transition */
++		spin_unlock(&gf->spinlock);
++		return;
++	}
++
++	gf->next_state = new_state;
++	state = gf->current_state;
++	gf->delay_target_state = NULL;
++
++	if (state) {
++		/* Disarm any GPIO IRQs */
++		for (i = 0; i < state->num_gpio_events; i++) {
++			gp_ev = &state->gpio_events[i];
++			inp_state = &gf->input_gpio_states[gp_ev->index];
++			inp_state->target = NULL;
++		}
++	}
++
++	spin_unlock(&gf->spinlock);
++
++	if (new_state)
++		schedule_work(&gf->work);
++}
++
++static void gpio_fsm_set_soft(struct gpio_fsm *gf,
++				unsigned int off, int val)
++{
++	struct soft_gpio *sg = &gf->soft_gpios[off];
++	struct gpio_event *gp_ev;
++	struct fsm_state *state;
++	int i;
++
++	dev_dbg(gf->dev, "set(%d,%d)\n", off, val);
++	state = gf->current_state;
++	sg->value = val;
++	for (i = 0; i < state->num_soft_events; i++) {
++		gp_ev = &state->soft_events[i];
++		if (gp_ev->index == off && gp_ev->value == val) {
++			if (gf->debug)
++				dev_info(gf->dev,
++					 "GF_SOFT %d->%d -> %s\n", gp_ev->index,
++					 gp_ev->value, gp_ev->target->name);
++			gpio_fsm_go_to_state(gf, gp_ev->target);
++			break;
++		}
++	}
++}
++
++static int gpio_fsm_direction_input(struct gpio_chip *gc, unsigned int off)
++{
++	struct gpio_fsm *gf = gpiochip_get_data(gc);
++	struct soft_gpio *sg;
++
++	if (off >= gf->num_soft_gpios)
++		return -EINVAL;
++	sg = &gf->soft_gpios[off];
++	sg->dir = GPIOF_DIR_IN;
++
++	return 0;
++}
++
++static int gpio_fsm_direction_output(struct gpio_chip *gc, unsigned int off,
++				       int value)
++{
++	struct gpio_fsm *gf = gpiochip_get_data(gc);
++	struct soft_gpio *sg;
++
++	if (off >= gf->num_soft_gpios)
++		return -EINVAL;
++	sg = &gf->soft_gpios[off];
++	sg->dir = GPIOF_DIR_OUT;
++	gpio_fsm_set_soft(gf, off, value);
++
++	return 0;
++}
++
++static void gpio_fsm_set(struct gpio_chip *gc, unsigned int off, int val)
++{
++	struct gpio_fsm *gf;
++
++	gf = gpiochip_get_data(gc);
++	if (off < gf->num_soft_gpios)
++		gpio_fsm_set_soft(gf, off, val);
++}
++
++static void gpio_fsm_enter_state(struct gpio_fsm *gf,
++				   struct fsm_state *state)
++{
++	struct input_gpio_state *inp_state;
++	struct output_signal *signal;
++	struct gpio_event *event;
++	struct gpio_desc *gpiod;
++	struct soft_gpio *soft;
++	int value;
++	int i;
++
++	dev_dbg(gf->dev, "enter_state(%s)\n", state->name);
++
++	gf->current_state = state;
++
++	// 1. Apply any listed signals
++	for (i = 0; i < state->num_signals; i++) {
++		signal = &state->signals[i];
++
++		if (gf->debug)
++			dev_info(gf->dev, "  set %s %d->%d\n",
++				 (signal->type == SIGNAL_GPIO) ? "GF_OUT" :
++				 "GF_SOFT",
++				 signal->index, signal->value);
++		switch (signal->type) {
++		case SIGNAL_GPIO:
++			gpiod = gf->output_gpios->desc[signal->index];
++			gpiod_set_value_cansleep(gpiod, signal->value);
++			break;
++		case SIGNAL_SOFT:
++			soft = &gf->soft_gpios[signal->index];
++			gpio_fsm_set_soft(gf, signal->index, signal->value);
++			break;
++		}
++	}
++
++	// 2. Exit if successfully reached shutdown state
++	if (gf->shutting_down && state == state->shutdown_target) {
++		wake_up(&gf->shutdown_event);
++		return;
++	}
++
++	// 3. Schedule a timer callback if shutting down
++	if (state->shutdown_target) {
++		// Remember the absolute shutdown time in case remove is called
++		// at a later time.
++		gf->shutdown_jiffies =
++			jiffies + msecs_to_jiffies(state->shutdown_ms);
++
++		if (gf->shutting_down) {
++			gf->delay_target_state = state->shutdown_target;
++			gf->delay_ms = state->shutdown_ms;
++			mod_timer(&gf->timer, gf->shutdown_jiffies);
++		}
++	}
++
++	// During shutdown, skip everything else
++	if (gf->shutting_down)
++		return;
++
++	// Otherwise record what the shutdown time would be
++	gf->shutdown_jiffies = jiffies + msecs_to_jiffies(state->shutdown_ms);
++
++	// 4. Check soft inputs for transitions to take
++	for (i = 0; i < state->num_soft_events; i++) {
++		event = &state->soft_events[i];
++		if (gf->soft_gpios[event->index].value == event->value) {
++			if (gf->debug)
++				dev_info(gf->dev,
++					 "GF_SOFT %d=%d -> %s\n", event->index,
++					 event->value, event->target->name);
++			gpio_fsm_go_to_state(gf, event->target);
++			return;
++		}
++	}
++
++	// 5. Check GPIOs for transitions to take, enabling the IRQs
++	for (i = 0; i < state->num_gpio_events; i++) {
++		event = &state->gpio_events[i];
++		inp_state = &gf->input_gpio_states[event->index];
++		inp_state->target = event->target;
++		inp_state->value = event->value;
++		inp_state->enabled = true;
++
++		value = gpiod_get_value(gf->input_gpios->desc[event->index]);
++
++		// Clear stale event state
++		disable_irq(inp_state->irq);
++
++		irq_set_irq_type(inp_state->irq,
++				 (inp_state->value ^ inp_state->active_low) ?
++				 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING);
++		enable_irq(inp_state->irq);
++
++		if (value == event->value && inp_state->target) {
++			if (gf->debug)
++				dev_info(gf->dev,
++					 "GF_IN %d=%d -> %s\n", event->index,
++					 event->value, event->target->name);
++			gpio_fsm_go_to_state(gf, event->target);
++			return;
++		}
++	}
++
++	// 6. Schedule a timer callback if delay_target
++	if (state->delay_target) {
++		gf->delay_target_state = state->delay_target;
++		gf->delay_ms = state->delay_ms;
++		mod_timer(&gf->timer,
++			  jiffies + msecs_to_jiffies(state->delay_ms));
++	}
++}
++
++static void gpio_fsm_work(struct work_struct *work)
++{
++	struct input_gpio_state *inp_state;
++	struct fsm_state *new_state;
++	struct fsm_state *state;
++	struct gpio_event *gp_ev;
++	struct gpio_fsm *gf;
++	int i;
++
++	gf = container_of(work, struct gpio_fsm, work);
++	spin_lock(&gf->spinlock);
++	state = gf->current_state;
++	new_state = gf->next_state;
++	if (!new_state)
++		new_state = gf->delay_target_state;
++	gf->next_state = NULL;
++	gf->delay_target_state = NULL;
++	spin_unlock(&gf->spinlock);
++
++	if (state) {
++		/* Disable any enabled GPIO IRQs */
++		for (i = 0; i < state->num_gpio_events; i++) {
++			gp_ev = &state->gpio_events[i];
++			inp_state = &gf->input_gpio_states[gp_ev->index];
++			if (inp_state->enabled) {
++				inp_state->enabled = false;
++				irq_set_irq_type(inp_state->irq,
++						 IRQF_TRIGGER_NONE);
++			}
++		}
++	}
++
++	if (new_state)
++		gpio_fsm_enter_state(gf, new_state);
++}
++
++static irqreturn_t gpio_fsm_gpio_irq_handler(int irq, void *dev_id)
++{
++	struct input_gpio_state *inp_state = dev_id;
++	struct gpio_fsm *gf = inp_state->gf;
++	struct fsm_state *target;
++
++	target = inp_state->target;
++	if (!target)
++		return IRQ_NONE;
++
++	/* If the IRQ has fired then the desired state _must_ have occurred */
++	inp_state->enabled = false;
++	irq_set_irq_type(inp_state->irq, IRQF_TRIGGER_NONE);
++	if (gf->debug)
++		dev_info(gf->dev, "GF_IN %d->%d -> %s\n",
++			 inp_state->index, inp_state->value, target->name);
++	gpio_fsm_go_to_state(gf, target);
++	return IRQ_HANDLED;
++}
++
++static void gpio_fsm_timer(struct timer_list *timer)
++{
++	struct gpio_fsm *gf = container_of(timer, struct gpio_fsm, timer);
++	struct fsm_state *target;
++
++	target = gf->delay_target_state;
++	if (!target)
++		return;
++
++	if (gf->debug)
++		dev_info(gf->dev, "GF_DELAY %d -> %s\n", gf->delay_ms,
++			 target->name);
++
++	gpio_fsm_go_to_state(gf, target);
++}
++
++int gpio_fsm_parse_signals(struct gpio_fsm *gf, struct fsm_state *state,
++			     struct property *prop)
++{
++	const __be32 *cells = prop->value;
++	struct output_signal *signal;
++	u32 io;
++	u32 type;
++	u32 index;
++	u32 value;
++	int ret = 0;
++	int i;
++
++	if (prop->length % 8) {
++		dev_err(gf->dev, "malformed set in state %s\n",
++			state->name);
++		return -EINVAL;
++	}
++
++	state->num_signals = prop->length/8;
++	state->signals = devm_kcalloc(gf->dev, state->num_signals,
++				      sizeof(struct output_signal),
++				      GFP_KERNEL);
++	for (i = 0; i < state->num_signals; i++) {
++		signal = &state->signals[i];
++		io = be32_to_cpu(cells[0]);
++		type = GF_IO_TYPE(io);
++		index = GF_IO_INDEX(io);
++		value = be32_to_cpu(cells[1]);
++
++		if (type != GF_OUT && type != GF_SOFT) {
++			dev_err(gf->dev,
++				"invalid set type %d in state %s\n",
++				type, state->name);
++			ret = -EINVAL;
++			break;
++		}
++		if (type == GF_OUT && index >= gf->num_output_gpios) {
++			dev_err(gf->dev,
++				"invalid GF_OUT number %d in state %s\n",
++				index, state->name);
++			ret = -EINVAL;
++			break;
++		}
++		if (type == GF_SOFT && index >= gf->num_soft_gpios) {
++			dev_err(gf->dev,
++				"invalid GF_SOFT number %d in state %s\n",
++				index, state->name);
++			ret = -EINVAL;
++			break;
++		}
++		if (value != 0 && value != 1) {
++			dev_err(gf->dev,
++				"invalid set value %d in state %s\n",
++				value, state->name);
++			ret = -EINVAL;
++			break;
++		}
++		signal->type = (type == GF_OUT) ? SIGNAL_GPIO : SIGNAL_SOFT;
++		signal->index = index;
++		signal->value = value;
++		cells += 2;
++	}
++
++	return ret;
++}
++
++struct gpio_event *new_event(struct gpio_event **events, int *num_events)
++{
++	int num = ++(*num_events);
++	*events = krealloc(*events, num * sizeof(struct gpio_event),
++			   GFP_KERNEL);
++	return *events ? *events + (num - 1) : NULL;
++}
++
++int gpio_fsm_parse_events(struct gpio_fsm *gf, struct fsm_state *state,
++			    struct property *prop)
++{
++	const __be32 *cells = prop->value;
++	struct symtab_entry *sym;
++	int num_cells;
++	int ret = 0;
++	int i;
++
++	if (prop->length % 8) {
++		dev_err(gf->dev,
++			"malformed transitions from state %s to state %s\n",
++			state->name, prop->name);
++		return -EINVAL;
++	}
++
++	sym = get_symbol(&gf->symtab, prop->name);
++	num_cells = prop->length / 4;
++	i = 0;
++	while (i < num_cells) {
++		struct gpio_event *gp_ev;
++		u32 event, param;
++		u32 index;
++
++		event = be32_to_cpu(cells[i++]);
++		param = be32_to_cpu(cells[i++]);
++		index = GF_IO_INDEX(event);
++
++		switch (GF_IO_TYPE(event)) {
++		case GF_IN:
++			if (index >= gf->num_input_gpios) {
++				dev_err(gf->dev,
++					"invalid GF_IN %d in transitions from state %s to state %s\n",
++					index, state->name, prop->name);
++				return -EINVAL;
++			}
++			if (param > 1) {
++				dev_err(gf->dev,
++					"invalid GF_IN value %d in transitions from state %s to state %s\n",
++					param, state->name, prop->name);
++				return -EINVAL;
++			}
++			gp_ev = new_event(&state->gpio_events,
++					  &state->num_gpio_events);
++			if (!gp_ev)
++				return -ENOMEM;
++			gp_ev->index = index;
++			gp_ev->value = param;
++			gp_ev->target = (struct fsm_state *)sym;
++			break;
++
++		case GF_SOFT:
++			if (index >= gf->num_soft_gpios) {
++				dev_err(gf->dev,
++					"invalid GF_SOFT %d in transitions from state %s to state %s\n",
++					index, state->name, prop->name);
++				return -EINVAL;
++			}
++			if (param > 1) {
++				dev_err(gf->dev,
++					"invalid GF_SOFT value %d in transitions from state %s to state %s\n",
++					param, state->name, prop->name);
++				return -EINVAL;
++			}
++			gp_ev = new_event(&state->soft_events,
++					  &state->num_soft_events);
++			if (!gp_ev)
++				return -ENOMEM;
++			gp_ev->index = index;
++			gp_ev->value = param;
++			gp_ev->target = (struct fsm_state *)sym;
++			break;
++
++		case GF_DELAY:
++			if (state->delay_target) {
++				dev_err(gf->dev,
++					"state %s has multiple GF_DELAYs\n",
++					state->name);
++				return -EINVAL;
++			}
++			state->delay_target = (struct fsm_state *)sym;
++			state->delay_ms = param;
++			break;
++
++		case GF_SHUTDOWN:
++			if (state->shutdown_target == state) {
++				dev_err(gf->dev,
++					"shutdown state %s has GF_SHUTDOWN\n",
++					state->name);
++				return -EINVAL;
++			} else if (state->shutdown_target) {
++				dev_err(gf->dev,
++					"state %s has multiple GF_SHUTDOWNs\n",
++					state->name);
++				return -EINVAL;
++			}
++			state->shutdown_target =
++				(struct fsm_state *)sym;
++			state->shutdown_ms = param;
++			break;
++
++		default:
++			dev_err(gf->dev,
++				"invalid event %08x in transitions from state %s to state %s\n",
++				event, state->name, prop->name);
++			return -EINVAL;
++		}
++	}
++	if (i != num_cells) {
++		dev_err(gf->dev,
++			"malformed transitions from state %s to state %s\n",
++			state->name, prop->name);
++		return -EINVAL;
++	}
++
++	return ret;
++}
++
++int gpio_fsm_parse_state(struct gpio_fsm *gf,
++			   struct fsm_state *state,
++			   struct device_node *np)
++{
++	struct symtab_entry *sym;
++	struct property *prop;
++	int ret;
++
++	state->name = np->name;
++	ret = add_symbol(&gf->symtab, np->name, state);
++	if (ret) {
++		switch (ret) {
++		case -EINVAL:
++			dev_err(gf->dev, "'%s' is not a valid state name\n",
++				np->name);
++			break;
++		case -EEXIST:
++			dev_err(gf->dev, "state %s already defined\n",
++				np->name);
++			break;
++		default:
++			dev_err(gf->dev, "error %d adding state %s symbol\n",
++				ret, np->name);
++			break;
++		}
++		return ret;
++	}
++
++	for_each_property_of_node(np, prop) {
++		sym = get_symbol(&gf->symtab, prop->name);
++		if (!sym) {
++			ret = -ENOMEM;
++			break;
++		}
++
++		switch ((uintptr_t)sym->value) {
++		case SYM_SET:
++			ret = gpio_fsm_parse_signals(gf, state, prop);
++			break;
++		case SYM_START:
++			if (gf->start_state) {
++				dev_err(gf->dev, "multiple start states\n");
++				ret = -EINVAL;
++			} else {
++				gf->start_state = state;
++			}
++			break;
++		case SYM_SHUTDOWN:
++			state->shutdown_target = state;
++			gf->shutdown_state = state;
++			break;
++		case SYM_NAME:
++			/* Ignore */
++			break;
++		default:
++			/* A set of transition events to this state */
++			ret = gpio_fsm_parse_events(gf, state, prop);
++			break;
++		}
++	}
++
++	return ret;
++}
++
++static void dump_all(struct gpio_fsm *gf)
++{
++	int i, j;
++
++	dev_info(gf->dev, "Input GPIOs:\n");
++	for (i = 0; i < gf->num_input_gpios; i++)
++		dev_info(gf->dev, "  %d: %p\n", i,
++			 gf->input_gpios->desc[i]);
++
++	dev_info(gf->dev, "Output GPIOs:\n");
++	for (i = 0; i < gf->num_output_gpios; i++)
++		dev_info(gf->dev, "  %d: %p\n", i,
++			 gf->output_gpios->desc[i]);
++
++	dev_info(gf->dev, "Soft GPIOs:\n");
++	for (i = 0; i < gf->num_soft_gpios; i++)
++		dev_info(gf->dev, "  %d: %s %d\n", i,
++			 (gf->soft_gpios[i].dir == GPIOF_DIR_IN) ? "IN" : "OUT",
++			 gf->soft_gpios[i].value);
++
++	dev_info(gf->dev, "Start state: %s\n",
++		 gf->start_state ? gf->start_state->name : "-");
++
++	dev_info(gf->dev, "Shutdown timeout: %d ms\n",
++		 gf->shutdown_timeout_ms);
++
++	for (i = 0; i < gf->num_states; i++) {
++		struct fsm_state *state = &gf->states[i];
++
++		dev_info(gf->dev, "State %s:\n", state->name);
++
++		if (state->shutdown_target == state)
++			dev_info(gf->dev, "  Shutdown state\n");
++
++		dev_info(gf->dev, "  Signals:\n");
++		for (j = 0; j < state->num_signals; j++) {
++			struct output_signal *signal = &state->signals[j];
++
++			dev_info(gf->dev, "    %d: %s %d=%d\n", j,
++				 (signal->type == SIGNAL_GPIO) ? "GPIO" :
++								 "SOFT",
++				 signal->index, signal->value);
++		}
++
++		dev_info(gf->dev, "  GPIO events:\n");
++		for (j = 0; j < state->num_gpio_events; j++) {
++			struct gpio_event *event = &state->gpio_events[j];
++
++			dev_info(gf->dev, "    %d: %d=%d -> %s\n", j,
++				 event->index, event->value,
++				 event->target->name);
++		}
++
++		dev_info(gf->dev, "  Soft events:\n");
++		for (j = 0; j < state->num_soft_events; j++) {
++			struct gpio_event *event = &state->soft_events[j];
++
++			dev_info(gf->dev, "    %d: %d=%d -> %s\n", j,
++				 event->index, event->value,
++				 event->target->name);
++		}
++
++		if (state->delay_target)
++			dev_info(gf->dev, "  Delay: %d ms -> %s\n",
++				 state->delay_ms, state->delay_target->name);
++
++		if (state->shutdown_target && state->shutdown_target != state)
++			dev_info(gf->dev, "  Shutdown: %d ms -> %s\n",
++				 state->shutdown_ms,
++				 state->shutdown_target->name);
++	}
++	dev_info(gf->dev, "\n");
++}
++
++static int resolve_sym_to_state(struct gpio_fsm *gf, struct fsm_state **pstate)
++{
++	struct symtab_entry *sym = (struct symtab_entry *)*pstate;
++
++	if (!sym)
++		return -ENOMEM;
++
++	*pstate = sym->value;
++
++	if (!*pstate) {
++		dev_err(gf->dev, "state %s not defined\n",
++			sym->name);
++		return -EINVAL;
++	}
++
++	return 0;
++}
++
++static int gpio_fsm_probe(struct platform_device *pdev)
++{
++	struct input_gpio_state *inp_state;
++	struct device *dev = &pdev->dev;
++	struct device_node *np = dev->of_node;
++	struct device_node *cp;
++	struct gpio_fsm *gf;
++	u32 debug = 0;
++	int num_states;
++	u32 num_soft_gpios;
++	int ret;
++	int i;
++	static const char *const reserved_symbols[] = {
++		[SYM_NAME] = "name",
++		[SYM_SET] = "set",
++		[SYM_START] = "start_state",
++		[SYM_SHUTDOWN] = "shutdown_state",
++	};
++
++	if (of_property_read_u32(np, "num-soft-gpios", &num_soft_gpios)) {
++		dev_err(dev, "missing 'num-soft-gpios' property\n");
++		return -EINVAL;
++	}
++
++	of_property_read_u32(np, "debug", &debug);
++
++	gf = devm_kzalloc(dev, sizeof(*gf), GFP_KERNEL);
++	if (!gf)
++		return -ENOMEM;
++
++	gf->dev = dev;
++	gf->debug = debug;
++
++	if (of_property_read_u32(np, "shutdown-timeout-ms",
++				 &gf->shutdown_timeout_ms))
++		gf->shutdown_timeout_ms = 5000;
++
++	gf->num_soft_gpios = num_soft_gpios;
++	gf->soft_gpios = devm_kcalloc(dev, num_soft_gpios,
++				      sizeof(struct soft_gpio), GFP_KERNEL);
++	if (!gf->soft_gpios)
++		return -ENOMEM;
++	for (i = 0; i < num_soft_gpios; i++) {
++		struct soft_gpio *sg = &gf->soft_gpios[i];
++
++		sg->dir = GPIOF_DIR_IN;
++		sg->value = 0;
++	}
++
++	gf->input_gpios = devm_gpiod_get_array_optional(dev, "input", GPIOD_IN);
++	if (IS_ERR(gf->input_gpios)) {
++		ret = PTR_ERR(gf->input_gpios);
++		dev_err(dev, "failed to get input gpios from DT - %d\n", ret);
++		return ret;
++	}
++	gf->num_input_gpios = (gf->input_gpios ? gf->input_gpios->ndescs : 0);
++
++	gf->input_gpio_states = devm_kcalloc(dev, gf->num_input_gpios,
++					     sizeof(struct input_gpio_state),
++					     GFP_KERNEL);
++	if (!gf->input_gpio_states)
++		return -ENOMEM;
++	for (i = 0; i < gf->num_input_gpios; i++) {
++		inp_state = &gf->input_gpio_states[i];
++		inp_state->desc = gf->input_gpios->desc[i];
++		inp_state->gf = gf;
++		inp_state->index = i;
++		inp_state->irq = gpiod_to_irq(inp_state->desc);
++		inp_state->active_low = gpiod_is_active_low(inp_state->desc);
++		if (inp_state->irq >= 0)
++			ret = devm_request_irq(gf->dev, inp_state->irq,
++					       gpio_fsm_gpio_irq_handler,
++					       IRQF_TRIGGER_NONE,
++					       dev_name(dev),
++					       inp_state);
++		else
++			ret = inp_state->irq;
++
++		if (ret) {
++			dev_err(dev,
++				"failed to get IRQ for input gpio - %d\n",
++				ret);
++			return ret;
++		}
++	}
++
++	gf->output_gpios = devm_gpiod_get_array_optional(dev, "output",
++							 GPIOD_OUT_LOW);
++	if (IS_ERR(gf->output_gpios)) {
++		ret = PTR_ERR(gf->output_gpios);
++		dev_err(dev, "failed to get output gpios from DT - %d\n", ret);
++		return ret;
++	}
++	gf->num_output_gpios = (gf->output_gpios ? gf->output_gpios->ndescs :
++				0);
++
++	num_states = of_get_child_count(np);
++	if (!num_states) {
++		dev_err(dev, "no states declared\n");
++		return -EINVAL;
++	}
++	gf->states = devm_kcalloc(dev, num_states,
++				  sizeof(struct fsm_state), GFP_KERNEL);
++	if (!gf->states)
++		return -ENOMEM;
++
++	// add reserved words to the symbol table
++	for (i = 0; i < ARRAY_SIZE(reserved_symbols); i++) {
++		if (reserved_symbols[i])
++			add_symbol(&gf->symtab, reserved_symbols[i], (void *)i);
++	}
++
++	// parse the state
++	for_each_child_of_node(np, cp) {
++		struct fsm_state *state = &gf->states[gf->num_states];
++
++		ret = gpio_fsm_parse_state(gf, state, cp);
++		if (ret)
++			return ret;
++		gf->num_states++;
++	}
++
++	if (!gf->start_state) {
++		dev_err(gf->dev, "no start state defined\n");
++		return -EINVAL;
++	}
++
++	// resolve symbol pointers into state pointers
++	for (i = 0; !ret && i < gf->num_states; i++) {
++		struct fsm_state *state = &gf->states[i];
++		int j;
++
++		for (j = 0; !ret && j < state->num_gpio_events; j++) {
++			struct gpio_event *ev = &state->gpio_events[j];
++
++			ret = resolve_sym_to_state(gf, &ev->target);
++		}
++
++		for (j = 0; !ret && j < state->num_soft_events; j++) {
++			struct gpio_event *ev = &state->soft_events[j];
++
++			ret = resolve_sym_to_state(gf, &ev->target);
++		}
++
++		if (!ret) {
++			resolve_sym_to_state(gf, &state->delay_target);
++			if (state->shutdown_target != state)
++				resolve_sym_to_state(gf,
++						     &state->shutdown_target);
++		}
++	}
++
++	if (!ret && gf->debug > 1)
++		dump_all(gf);
++
++	free_symbols(&gf->symtab);
++
++	if (ret)
++		return ret;
++
++	gf->gc.parent = dev;
++	gf->gc.label = np->name;
++	gf->gc.owner = THIS_MODULE;
++	gf->gc.of_node = np;
++	gf->gc.base = -1;
++	gf->gc.ngpio = num_soft_gpios;
++
++	gf->gc.get_direction = gpio_fsm_get_direction;
++	gf->gc.direction_input = gpio_fsm_direction_input;
++	gf->gc.direction_output = gpio_fsm_direction_output;
++	gf->gc.get = gpio_fsm_get;
++	gf->gc.set = gpio_fsm_set;
++	gf->gc.can_sleep = true;
++	spin_lock_init(&gf->spinlock);
++	INIT_WORK(&gf->work, gpio_fsm_work);
++	timer_setup(&gf->timer, gpio_fsm_timer, 0);
++	init_waitqueue_head(&gf->shutdown_event);
++
++	platform_set_drvdata(pdev, gf);
++
++	if (gf->debug)
++		dev_info(gf->dev, "Start -> %s\n", gf->start_state->name);
++
++	gpio_fsm_go_to_state(gf, gf->start_state);
++
++	return devm_gpiochip_add_data(dev, &gf->gc, gf);
++}
++
++static int gpio_fsm_remove(struct platform_device *pdev)
++{
++	struct gpio_fsm *gf = platform_get_drvdata(pdev);
++	int i;
++
++	if (gf->shutdown_state) {
++		if (gf->debug)
++			dev_info(gf->dev, "Shutting down...\n");
++
++		spin_lock(&gf->spinlock);
++		gf->shutting_down = true;
++		if (gf->current_state->shutdown_target &&
++		    gf->current_state->shutdown_target != gf->current_state) {
++			gf->delay_target_state =
++				gf->current_state->shutdown_target;
++			mod_timer(&gf->timer, gf->shutdown_jiffies);
++		}
++		spin_unlock(&gf->spinlock);
++
++		wait_event_timeout(gf->shutdown_event,
++				   gf->current_state->shutdown_target ==
++				   gf->current_state,
++				   msecs_to_jiffies(gf->shutdown_timeout_ms));
++		if (gf->current_state->shutdown_target == gf->current_state)
++			gpio_fsm_enter_state(gf, gf->shutdown_state);
++	}
++	cancel_work_sync(&gf->work);
++	del_timer_sync(&gf->timer);
++
++	/* Events aren't allocated from managed storage */
++	for (i = 0; i < gf->num_states; i++) {
++		kfree(gf->states[i].gpio_events);
++		kfree(gf->states[i].soft_events);
++	}
++	if (gf->debug)
++		dev_info(gf->dev, "Exiting\n");
++
++	return 0;
++}
++
++static void gpio_fsm_shutdown(struct platform_device *pdev)
++{
++	gpio_fsm_remove(pdev);
++}
++
++static const struct of_device_id gpio_fsm_ids[] = {
++	{ .compatible = "rpi,gpio-fsm" },
++	{ }
++};
++MODULE_DEVICE_TABLE(of, gpio_fsm_ids);
++
++static struct platform_driver gpio_fsm_driver = {
++	.driver	= {
++		.name		= MODULE_NAME,
++		.of_match_table	= of_match_ptr(gpio_fsm_ids),
++	},
++	.probe = gpio_fsm_probe,
++	.remove = gpio_fsm_remove,
++	.shutdown = gpio_fsm_shutdown,
++};
++module_platform_driver(gpio_fsm_driver);
++
++MODULE_LICENSE("GPL");
++MODULE_AUTHOR("Phil Elwell <phil@raspberrypi.com>");
++MODULE_DESCRIPTION("GPIO FSM driver");
++MODULE_ALIAS("platform:gpio-fsm");
+--- /dev/null
++++ b/include/dt-bindings/gpio/gpio-fsm.h
+@@ -0,0 +1,21 @@
++/* SPDX-License-Identifier: GPL-2.0+ */
++/*
++ * This header provides constants for binding rpi,gpio-fsm.
++ */
++
++#ifndef _DT_BINDINGS_GPIO_FSM_H
++#define _DT_BINDINGS_GPIO_FSM_H
++
++#define GF_IN       0
++#define GF_OUT      1
++#define GF_SOFT     2
++#define GF_DELAY    3
++#define GF_SHUTDOWN 4
++
++#define GF_IO(t, v) (((v) << 16) | ((t) & 0xffff))
++
++#define GF_IP(x)    GF_IO(GF_IN, (x))
++#define GF_OP(x)    GF_IO(GF_OUT, (x))
++#define GF_SW(x)    GF_IO(GF_SOFT, (x))
++
++#endif
-- 
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