ucmb: Experimental SPI-GPIO based communication channel

SVN-Revision: 14478

package/ucmb/Makefile

@@ -0,0 +1,39 @@
+#
+# Copyright (C) 2009 OpenWrt.org
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+
+include $(TOPDIR)/rules.mk
+include $(INCLUDE_DIR)/kernel.mk
+
+PKG_NAME:=ucmb
+PKG_RELEASE:=1
+
+include $(INCLUDE_DIR)/package.mk
+
+define KernelPackage/ucmb
+  SUBMENU:=Other modules
+  DEPENDS:=@LINUX_2_6 +kmod-spi-gpio
+  KCONFIG:=CONFIG_SPI=y \
+          CONFIG_SPI_MASTER=y
+  TITLE:=Microcontroller Message Bus (EXPERIMENTAL)
+  FILES:=$(PKG_BUILD_DIR)/ucmb.$(LINUX_KMOD_SUFFIX)
+  AUTOLOAD:=$(call AutoLoad,93,ucmb)
+endef
+
+define Build/Prepare
+	mkdir -p $(PKG_BUILD_DIR)
+	$(CP) ./src/* $(PKG_BUILD_DIR)/
+endef
+
+define Build/Compile
+	$(MAKE) -C "$(LINUX_DIR)" \
+		CROSS_COMPILE="$(TARGET_CROSS)" \
+		ARCH="$(LINUX_KARCH)" \
+		SUBDIRS="$(PKG_BUILD_DIR)" \
+		EXTRA_CFLAGS="$(BUILDFLAGS)" \
+		modules
+endef
+
+$(eval $(call KernelPackage,ucmb))

package/ucmb/src/Makefile

@@ -0,0 +1 @@
+obj-m := ucmb.o

package/ucmb/src/ucmb.c

@@ -0,0 +1,328 @@
+/*
+ * Microcontroller Message Bus
+ *
+ * Copyright (c) 2009 Michael Buesch <[email protected]>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include "ucmb.h"
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/miscdevice.h>
+#include <linux/fs.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_gpio.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/gfp.h>
+
+
+#define PFX	"ucmb: "
+
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Microcontroller Message Bus");
+MODULE_AUTHOR("Michael Buesch");
+
+
+struct ucmb {
+	/* Misc character device driver */
+	struct miscdevice mdev;
+	struct file_operations mdev_fops;
+
+	/* SPI driver */
+	struct spi_device *sdev;
+
+	/* SPI-GPIO driver */
+	struct spi_gpio_platform_data spi_gpio_pdata;
+	struct platform_device spi_gpio_pdev;
+};
+
+static int ucmb_spi_busnum_count = 1337;
+
+
+static struct ucmb_platform_data ucmb_list[] = {
+	{ //FIXME don't define it here.
+		.name		= "ucmb",
+		.gpio_sck	= 0,
+		.gpio_miso	= 1,
+		.gpio_mosi	= 2,
+	},
+};
+
+
+static int __devinit ucmb_spi_probe(struct spi_device *sdev)
+{
+	return 0;
+}
+
+static int __devexit ucmb_spi_remove(struct spi_device *sdev)
+{
+	return 0;
+}
+
+static struct spi_driver ucmb_spi_driver = {
+	.driver		= {
+		.name	= "ucmb",
+		.bus	= &spi_bus_type,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= ucmb_spi_probe,
+	.remove		= __devexit_p(ucmb_spi_remove),
+};
+
+static inline struct ucmb * filp_to_ucmb(struct file *filp)
+{
+	return container_of(filp->f_op, struct ucmb, mdev_fops);
+}
+
+/* FIXME offp */
+static ssize_t ucmb_read(struct file *filp, char __user *user_buf,
+			 size_t size, loff_t *offp)
+{
+	struct ucmb *ucmb = filp_to_ucmb(filp);
+	u8 *buf;
+	int err;
+
+	err = -E2BIG;
+	if (size > PAGE_SIZE)
+		goto out;
+
+	err = -ENOMEM;
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	err = spi_read(ucmb->sdev, buf, size);
+	if (err)
+		goto out_free;
+
+	err = -EFAULT;
+	if (copy_to_user(user_buf, buf, size))
+		goto out_free;
+
+	err = 0;
+
+out_free:
+	__free_page((unsigned long)buf);
+out:
+	return err ? err : size;
+}
+
+/* FIXME offp */
+static ssize_t ucmb_write(struct file *filp, const char __user *user_buf,
+			  size_t size, loff_t *offp)
+{
+	struct ucmb *ucmb = filp_to_ucmb(filp);
+	u8 *buf;
+	int err;
+
+	err = -ENOMEM;
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	size = min(PAGE_SIZE, size);
+	err = -EFAULT;
+	if (copy_from_user(buf, user_buf, size))
+		goto out_free;
+
+	err = spi_write(ucmb->sdev, buf, size);
+
+out_free:
+	__free_page((unsigned long)buf);
+out:
+	return err ? err : size;
+}
+
+static int __devinit ucmb_probe(struct platform_device *pdev)
+{
+	struct ucmb_platform_data *pdata;
+	struct ucmb *ucmb;
+	int err;
+	const int bus_num = ucmb_spi_busnum_count++;
+	struct spi_bitbang *bb;
+
+	pdata = pdev->dev.platform_data;
+	if (!pdata)
+		return -ENXIO;
+
+	ucmb = kzalloc(sizeof(struct ucmb), GFP_KERNEL);
+	if (!ucmb)
+		return -ENOMEM;
+
+	/* Create the SPI GPIO bus master. */
+
+#ifdef CONFIG_SPI_GPIO_MODULE
+	err = request_module("spi_gpio");
+	if (err)
+		printk(KERN_WARNING PFX "Failed to request spi_gpio module\n");
+#endif /* CONFIG_SPI_GPIO_MODULE */
+
+	ucmb->spi_gpio_pdata.sck = pdata->gpio_sck;
+	ucmb->spi_gpio_pdata.mosi = pdata->gpio_mosi;
+	ucmb->spi_gpio_pdata.miso = pdata->gpio_miso;
+	ucmb->spi_gpio_pdata.num_chipselect = 1;
+
+	ucmb->spi_gpio_pdev.name = "spi_gpio";
+	ucmb->spi_gpio_pdev.id = bus_num;
+	ucmb->spi_gpio_pdev.dev.platform_data = &ucmb->spi_gpio_pdata;
+
+	err = platform_device_register(&ucmb->spi_gpio_pdev);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to register SPI-GPIO platform device\n");
+		goto err_free_ucmb;
+	}
+	bb = platform_get_drvdata(&ucmb->spi_gpio_pdev);
+	if (!bb || !bb->master) {
+		printk(KERN_ERR PFX "No bitbanged master device found.\n");
+		goto err_unreg_spi_gpio_pdev;
+	}
+
+	/* Create the SPI device. */
+
+	ucmb->sdev = spi_alloc_device(bb->master);
+	if (!ucmb->sdev) {
+		printk(KERN_ERR PFX "Failed to allocate SPI device\n");
+		goto err_unreg_spi_gpio_pdev;
+	}
+	ucmb->sdev->max_speed_hz = 5000000;
+	ucmb->sdev->chip_select = 0;
+	ucmb->sdev->mode = SPI_MODE_0;
+	strlcpy(ucmb->sdev->modalias, "ucmb", /* We are the SPI driver. */
+		sizeof(ucmb->sdev->modalias));
+	ucmb->sdev->controller_data = (void *)SPI_GPIO_NO_CHIPSELECT;
+	err = spi_add_device(ucmb->sdev);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to add SPI device\n");
+		goto err_free_spi_device;
+	}
+
+	/* Create the Misc char device. */
+
+	ucmb->mdev.minor = MISC_DYNAMIC_MINOR;
+	ucmb->mdev.name = pdata->name;
+	ucmb->mdev.parent = &pdev->dev;
+	ucmb->mdev_fops.read = ucmb_read;
+	ucmb->mdev_fops.write = ucmb_write;
+	ucmb->mdev.fops = &ucmb->mdev_fops;
+
+	err = misc_register(&ucmb->mdev);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to register miscdev %s\n",
+		       ucmb->mdev.name);
+		goto err_unreg_spi_device;
+	}
+
+	platform_set_drvdata(pdev, ucmb);
+
+	printk(KERN_INFO PFX "Registered message bus \"%s\"\n", pdata->name);
+
+	return 0;
+
+err_unreg_spi_device:
+	spi_unregister_device(ucmb->sdev);
+err_free_spi_device:
+	spi_dev_put(ucmb->sdev);
+err_unreg_spi_gpio_pdev:
+	platform_device_unregister(&ucmb->spi_gpio_pdev);
+err_free_ucmb:
+	kfree(ucmb);
+
+	return err;
+}
+
+static int __devexit ucmb_remove(struct platform_device *pdev)
+{
+	struct ucmb *ucmb = platform_get_drvdata(pdev);
+	int err;
+
+	err = misc_deregister(&ucmb->mdev);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to unregister miscdev %s\n",
+		       ucmb->mdev.name);
+	}
+	spi_unregister_device(ucmb->sdev);
+	spi_dev_put(ucmb->sdev);
+	platform_device_unregister(&ucmb->spi_gpio_pdev);
+
+	kfree(ucmb);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static struct platform_driver ucmb_driver = {
+	.driver		= {
+		.name	= "ucmb",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= ucmb_probe,
+	.remove		= __devexit_p(ucmb_probe),
+};
+
+static int ucmb_modinit(void)
+{
+	struct ucmb_platform_data *pdata;
+	struct platform_device *pdev;
+	int err, i;
+
+	printk(KERN_INFO "Microcontroller message bus driver\n");
+
+	err = platform_driver_register(&ucmb_driver);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to register platform driver\n");
+		return err;
+	}
+	err = spi_register_driver(&ucmb_spi_driver);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to register SPI driver\n");
+		platform_driver_unregister(&ucmb_driver);
+		return err;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(ucmb_list); i++) {
+		pdata = &ucmb_list[i];
+
+		pdev = platform_device_alloc("ucmb", i);
+		if (!pdev) {
+			printk(KERN_ERR PFX "Failed to allocate platform device.\n");
+			break;
+		}
+		err = platform_device_add_data(pdev, pdata, sizeof(*pdata));
+		if (err) {
+			printk(KERN_ERR PFX "Failed to add platform data.\n");
+			platform_device_put(pdev);
+			break;
+		}
+		err = platform_device_add(pdev);
+		if (err) {
+			printk(KERN_ERR PFX "Failed to register platform device.\n");
+			platform_device_put(pdev);
+			break;
+		}
+		pdata->pdev = pdev;
+	}
+
+	return 0;
+}
+module_init(ucmb_modinit);
+
+static void ucmb_modexit(void)
+{
+	struct ucmb_platform_data *pdata;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ucmb_list); i++) {
+		pdata = &ucmb_list[i];
+
+		if (pdata->pdev) {
+			platform_device_unregister(pdata->pdev);
+			platform_device_put(pdata->pdev);
+		}
+	}
+	spi_unregister_driver(&ucmb_spi_driver);
+	platform_driver_unregister(&ucmb_driver);
+}
+module_exit(ucmb_modexit);

package/ucmb/src/ucmb.h

@@ -0,0 +1,13 @@
+#ifndef LINUX_UCMB_H_
+#define LINUX_UCMB_H_
+
+struct ucmb_platform_data {
+	const char *name;
+	unsigned int gpio_sck;
+	unsigned int gpio_miso;
+	unsigned int gpio_mosi;
+
+	struct platform_device *pdev; /* internal */
+};
+
+#endif /* LINUX_UCMB_H_ */