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Subject[RFC PATCH 3/4] GPT driver for in-kernel IR support.
Date
GPT is a GPIO pin that is cable able of measuring the lenght of pulses.
GPTs are common on embedded systems
---
drivers/input/ir/Kconfig | 6 +
drivers/input/ir/Makefile | 1
drivers/input/ir/ir-gpt.c | 214 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 221 insertions(+), 0 deletions(-)
create mode 100644 drivers/input/ir/ir-gpt.c
diff --git a/drivers/input/ir/Kconfig b/drivers/input/ir/Kconfig
index 8afd2d6..b80ab31 100644
--- a/drivers/input/ir/Kconfig
+++ b/drivers/input/ir/Kconfig
@@ -11,4 +11,10 @@ menuconfig INPUT_IR

if INPUT_IR

+config IR_GPT
+ tristate "GPT Based IR Receiver"
+ default m
+ help
+ Driver for GPT-based IR receiver found on Digispeaker
+
endif
diff --git a/drivers/input/ir/Makefile b/drivers/input/ir/Makefile
index 08e6954..7082f1d 100644
--- a/drivers/input/ir/Makefile
+++ b/drivers/input/ir/Makefile
@@ -3,3 +3,4 @@

# Each configuration option enables a list of files.

+obj-$(CONFIG_IR_GPT) += ir-gpt.o
diff --git a/drivers/input/ir/ir-gpt.c b/drivers/input/ir/ir-gpt.c
new file mode 100644
index 0000000..445ff27
--- /dev/null
+++ b/drivers/input/ir/ir-gpt.c
@@ -0,0 +1,214 @@
+/*
+ * GPT timer based IR device
+ *
+ * Copyright (C) 2008 Jon Smirl <jonsmirl@gmail.com>
+ */
+
+#define DEBUG
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/input.h>
+#include <asm/io.h>
+#include <asm/mpc52xx.h>
+
+#define MAX_SAMPLES 200
+
+struct ir_gpt {
+ int irq;
+ struct mpc52xx_gpt __iomem *regs;
+ spinlock_t lock;
+ struct work_struct queue;
+ int head, tail, previous;
+ unsigned int samples[MAX_SAMPLES];
+ struct input_dev *input;
+};
+
+static void ir_event(struct work_struct *work)
+{
+ unsigned long flags;
+ int delta, count;
+ unsigned int sample, wrap, bit;
+ struct ir_gpt *ir_gpt = container_of(work, struct ir_gpt, queue);
+
+ while (1) {
+ spin_lock_irqsave(ir_gpt->lock, flags);
+ if (ir_gpt->tail == ir_gpt->head) {
+ spin_unlock_irqrestore(ir_gpt->lock, flags);
+ break;
+ }
+ sample = ir_gpt->samples[ir_gpt->tail];
+
+ ir_gpt->tail++;
+ if (ir_gpt->tail >= MAX_SAMPLES)
+ ir_gpt->tail = 0;
+
+ spin_unlock_irqrestore(ir_gpt->lock, flags);
+
+ count = sample >> 16;
+ wrap = (sample >> 12) & 7;
+ bit = (sample >> 8) & 1;
+
+ delta = count - ir_gpt->previous;
+ delta += wrap * 0x10000;
+
+ ir_gpt->previous = count;
+
+ input_ir_decode(ir_gpt->input, delta, bit);
+ }
+}
+
+/*
+ * Interrupt handlers
+ */
+static irqreturn_t dpeak_ir_irq(int irq, void *_ir)
+{
+ unsigned long flags;
+ unsigned int sample, next;
+ struct ir_gpt *ir_gpt = _ir;
+
+ sample = in_be32(&ir_gpt->regs->status);
+ out_be32(&ir_gpt->regs->status, 0xF);
+
+ spin_lock_irqsave(ir_gpt->lock, flags);
+ ir_gpt->samples[ir_gpt->head] = sample;
+ next = ir_gpt->head + 1;
+ ir_gpt->head = (next >= MAX_SAMPLES ? 0 : next);
+ spin_unlock_irqrestore(ir_gpt->lock, flags);
+
+ schedule_work(&ir_gpt->queue);
+
+ return IRQ_HANDLED;
+}
+
+
+/* ---------------------------------------------------------------------
+ * OF platform bus binding code:
+ * - Probe/remove operations
+ * - OF device match table
+ */
+static int __devinit ir_gpt_of_probe(struct of_device *op,
+ const struct of_device_id *match)
+{
+ struct ir_gpt *ir_gpt;
+ struct resource res;
+ int ret, rc;
+
+ dev_dbg(&op->dev, "ir_gpt_of_probe\n");
+
+ /* Allocate and initialize the driver private data */
+ ir_gpt = kzalloc(sizeof *ir_gpt, GFP_KERNEL);
+ if (!ir_gpt)
+ return -ENOMEM;
+
+ ir_gpt->input = input_allocate_device();
+ if (!ir_gpt->input) {
+ ret = -ENOMEM;
+ goto free_mem;
+ }
+ ret = input_ir_create(ir_gpt->input, ir_gpt, NULL);
+ if (ret)
+ goto free_input;
+
+ ir_gpt->input->name = "GPT IR Receiver";
+ ret = input_register_device(ir_gpt->input);
+ if (ret)
+ goto free_input;
+
+ spin_lock_init(&ir_gpt->lock);
+ INIT_WORK (&ir_gpt->queue, ir_event);
+
+ /* Fetch the registers and IRQ of the GPT */
+ if (of_address_to_resource(op->node, 0, &res)) {
+ dev_err(&op->dev, "Missing reg property\n");
+ ret = -ENODEV;
+ goto free_input;
+ }
+ ir_gpt->regs = ioremap(res.start, 1 + res.end - res.start);
+ if (!ir_gpt->regs) {
+ dev_err(&op->dev, "Could not map registers\n");
+ ret = -ENODEV;
+ goto free_input;
+ }
+ ir_gpt->irq = irq_of_parse_and_map(op->node, 0);
+ if (ir_gpt->irq == NO_IRQ) {
+ ret = -ENODEV;
+ goto free_input;
+ }
+ dev_dbg(&op->dev, "ir_gpt_of_probe irq=%d\n", ir_gpt->irq);
+
+ rc = request_irq(ir_gpt->irq, &dpeak_ir_irq, IRQF_SHARED,
+ "gpt-ir", ir_gpt);
+ dev_dbg(&op->dev, "ir_gpt_of_probe request irq rc=%d\n", rc);
+
+ /* set prescale to ? */
+ out_be32(&ir_gpt->regs->count, 0x00870000);
+
+ /* Select input capture, enable the counter, and interrupt */
+ out_be32(&ir_gpt->regs->mode, 0x0);
+ out_be32(&ir_gpt->regs->mode, 0x00000501);
+
+ /* Save what we've done so it can be found again later */
+ dev_set_drvdata(&op->dev, ir_gpt);
+
+ printk("GPT IR Receiver driver\n");
+
+ return 0;
+
+free_input:
+ input_ir_destroy(ir_gpt->input);
+ input_free_device(ir_gpt->input);
+free_mem:
+ kfree(ir_gpt);
+ return ret;
+}
+
+static int __devexit ir_gpt_of_remove(struct of_device *op)
+{
+ struct ir_gpt *ir_gpt = dev_get_drvdata(&op->dev);
+
+ dev_dbg(&op->dev, "ir_gpt_remove()\n");
+
+ input_ir_destroy(ir_gpt->input);
+ input_free_device(ir_gpt->input);
+ kfree(ir_gpt);
+ dev_set_drvdata(&op->dev, NULL);
+
+ return 0;
+}
+
+/* Match table for of_platform binding */
+static struct of_device_id ir_gpt_match[] __devinitdata = {
+ { .compatible = "gpt-ir", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, ir_gpt_match);
+
+static struct of_platform_driver ir_gpt_driver = {
+ .match_table = ir_gpt_match,
+ .probe = ir_gpt_of_probe,
+ .remove = __devexit_p(ir_gpt_of_remove),
+ .driver = {
+ .name = "ir-gpt",
+ .owner = THIS_MODULE,
+ },
+};
+
+/* ---------------------------------------------------------------------
+ * Module setup and teardown; simply register the of_platform driver
+ */
+static int __init ir_gpt_init(void)
+{
+ return of_register_platform_driver(&ir_gpt_driver);
+}
+module_init(ir_gpt_init);
+
+static void __exit ir_gpt_exit(void)
+{
+ of_unregister_platform_driver(&ir_gpt_driver);
+}
+module_exit(ir_gpt_exit);


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