+/*
+ * Custom GPIO-based I2C driver
+ *
+ * Copyright (C) 2007 Gabor Juhos <juhosg at openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * ---------------------------------------------------------------------------
+ *
+ * The behaviour of this driver can be altered by setting some parameters
+ * from the insmod command line.
+ *
+ * The following parameters are adjustable:
+ *
+ * bus0 These four arguments can be arrays of
+ * bus1 1-8 unsigned integers as follows:
+ * bus2
+ * bus3 <id>,<sda>,<scl>,<udelay>,<timeout>,<sda_od>,<scl_od>,<scl_oo>
+ *
+ * where:
+ *
+ * <id> ID to used as device_id for the corresponding bus (required)
+ * <sda> GPIO pin ID to used for SDA (required)
+ * <scl> GPIO pin ID to used for SCL (required)
+ * <udelay> signal toggle delay.
+ * <timeout> clock stretching timeout.
+ * <sda_od> SDA is configured as open drain.
+ * <scl_od> SCL is configured as open drain.
+ * <scl_oo> SCL output drivers cannot be turned off.
+ *
+ * See include/i2c-gpio.h for more information about the parameters.
+ *
+ * If this driver is built into the kernel, you can use the following kernel
+ * command line parameters, with the same values as the corresponding module
+ * parameters listed above:
+ *
+ * i2c-gpio-custom.bus0
+ * i2c-gpio-custom.bus1
+ * i2c-gpio-custom.bus2
+ * i2c-gpio-custom.bus3
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+
+#include <linux/i2c-gpio.h>
+
+#define DRV_NAME "i2c-gpio-custom"
+#define DRV_DESC "Custom GPIO-based I2C driver"
+#define DRV_VERSION "0.1.0"
+
+#define PFX DRV_NAME ": "
+
+#define BUS_PARAM_ID 0
+#define BUS_PARAM_SDA 1
+#define BUS_PARAM_SCL 2
+#define BUS_PARAM_UDELAY 3
+#define BUS_PARAM_TIMEOUT 4
+#define BUS_PARAM_SDA_OD 5
+#define BUS_PARAM_SCL_OD 6
+#define BUS_PARAM_SCL_OO 7
+
+#define BUS_PARAM_REQUIRED 3
+#define BUS_PARAM_COUNT 8
+#define BUS_COUNT_MAX 4
+
+static unsigned int bus0[BUS_PARAM_COUNT] __initdata;
+static unsigned int bus1[BUS_PARAM_COUNT] __initdata;
+static unsigned int bus2[BUS_PARAM_COUNT] __initdata;
+static unsigned int bus3[BUS_PARAM_COUNT] __initdata;
+
+static unsigned int bus_nump[BUS_COUNT_MAX] __initdata;
+
+#define BUS_PARM_DESC \
+ " config -> id,sda,scl[,udelay,timeout,sda_od,scl_od,scl_oo]"
+
+module_param_array(bus0, uint, &bus_nump[0], 0);
+MODULE_PARM_DESC(bus0, "bus0" BUS_PARM_DESC);
+module_param_array(bus1, uint, &bus_nump[1], 0);
+MODULE_PARM_DESC(bus1, "bus1" BUS_PARM_DESC);
+module_param_array(bus2, uint, &bus_nump[2], 0);
+MODULE_PARM_DESC(bus2, "bus2" BUS_PARM_DESC);
+module_param_array(bus3, uint, &bus_nump[3], 0);
+MODULE_PARM_DESC(bus3, "bus3" BUS_PARM_DESC);
+
+static struct platform_device *devices[BUS_COUNT_MAX];
+static unsigned int nr_devices;
+
+static void i2c_gpio_custom_cleanup(void)
+{
+ int i;
+
+ for (i = 0; i < nr_devices; i++)
+ if (devices[i])
+ platform_device_unregister(devices[i]);
+}
+
+static int __init i2c_gpio_custom_add_one(unsigned int id, unsigned int *params)
+{
+ struct platform_device *pdev;
+ struct i2c_gpio_platform_data pdata;
+ int err;
+
+ if (!bus_nump[id])
+ return 0;
+
+ if (bus_nump[id] < BUS_PARAM_REQUIRED) {
+ printk(KERN_ERR PFX "not enough parameters for bus%d\n", id);
+ err = -EINVAL;
+ goto err;
+ }
+
+ pdev = platform_device_alloc("i2c-gpio", params[BUS_PARAM_ID]);
+ if (!pdev) {
+ err = -ENOMEM;
+ goto err;
+ }
+
+ devices[nr_devices++] = pdev;
+
+ pdata.sda_pin = params[BUS_PARAM_SDA];
+ pdata.scl_pin = params[BUS_PARAM_SCL];
+ pdata.udelay = params[BUS_PARAM_UDELAY];
+ pdata.timeout = params[BUS_PARAM_TIMEOUT];
+ pdata.sda_is_open_drain = params[BUS_PARAM_SDA_OD] != 0;
+ pdata.scl_is_open_drain = params[BUS_PARAM_SCL_OD] != 0;
+ pdata.scl_is_output_only = params[BUS_PARAM_SCL_OO] != 0;
+
+ err = platform_device_add_data(pdev, &pdata, sizeof(pdata));
+ if (err)
+ goto err;
+
+ err = platform_device_register(pdev);
+ if (err)
+ goto err;
+
+ return 0;
+
+err:
+ return err;
+}
+
+static int __init i2c_gpio_custom_probe(void)
+{
+ int err;
+
+ printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
+
+ err = i2c_gpio_custom_add_one(0, bus0);
+ if (err) goto err;
+
+ err = i2c_gpio_custom_add_one(1, bus1);
+ if (err) goto err;
+
+ err = i2c_gpio_custom_add_one(2, bus2);
+ if (err) goto err;
+
+ err = i2c_gpio_custom_add_one(3, bus3);
+ if (err) goto err;
+
+ if (!nr_devices) {
+ printk(KERN_ERR PFX "no bus parameter(s) specified\n");
+ err = -ENODEV;
+ goto err;
+ }
+
+ return 0;
+
+err:
+ i2c_gpio_custom_cleanup();
+ return err;
+}
+
+#ifdef MODULE
+static int __init i2c_gpio_custom_init(void)
+{
+ return i2c_gpio_custom_probe();
+}
+module_init(i2c_gpio_custom_init);
+
+static void __exit i2c_gpio_custom_exit(void)
+{
+ i2c_gpio_custom_cleanup();
+}
+module_exit(i2c_gpio_custom_exit);
+#else
+subsys_initcall(i2c_gpio_custom_probe);
+#endif /* MODULE*/
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org >");
+MODULE_DESCRIPTION(DRV_DESC);
+MODULE_VERSION(DRV_VERSION);
projects / openwrt.git / commitdiff