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path: root/target/linux/bcm27xx/patches-5.4/950-0986-gpio-Add-gpio-fsm-driver.patch
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-rw-r--r--target/linux/bcm27xx/patches-5.4/950-0986-gpio-Add-gpio-fsm-driver.patch1182
1 files changed, 1182 insertions, 0 deletions
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
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-08 16:56:55 +0000