trunk-47381HEADmaster

1 files changed, 365 insertions, 0 deletions

diff --git a/package/kernel/spi-gpio-custom/src/spi-gpio-custom.c b/package/kernel/spi-gpio-custom/src/spi-gpio-custom.c
new file mode 100644
index 0000000..a4f93c6
--- /dev/null
+++ b/package/kernel/spi-gpio-custom/src/spi-gpio-custom.c
@@ -0,0 +1,365 @@
+/*
+ *  Custom GPIO-based SPI driver
+ *
+ *  Copyright (C) 2013 Marco Burato <zmaster.adsl@gmail.com>
+ *
+ *  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.
+ *
+ *  Based on i2c-gpio-custom by:
+ *  Copyright (C) 2007-2008 Gabor Juhos <juhosg@openwrt.org>
+ * ---------------------------------------------------------------------------
+ *
+ *  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>,<sck>,<mosi>,<miso>,<mode1>,<maxfreq1>,<cs1>,...
+ *
+ *  where:
+ *
+ *  <id>	ID to used as device_id for the corresponding bus (required)
+ *  <sck>	GPIO pin ID to be used for bus SCK (required)
+ *  <mosi>	GPIO pin ID to be used for bus MOSI (required*)
+ *  <miso>	GPIO pin ID to be used for bus MISO (required*)
+ *  <modeX>	Mode configuration for slave X in the bus (required)
+ *		(see /include/linux/spi/spi.h)
+ *  <maxfreqX>	Maximum clock frequency in Hz for slave X in the bus (required)
+ *  <csX>	GPIO pin ID to be used for slave X CS (required**)
+ *
+ *	Notes:
+ *	*	If a signal is not used (for example there is no MISO) you need
+ *		to set the GPIO pin ID for that signal to an invalid value.
+ *	**	If you only have 1 slave in the bus with no CS, you can omit the
+ *		<cs1> param or set it to an invalid GPIO id to disable it. When
+ *		you have 2 or more slaves, they must all have a valid CS.
+ *
+ *  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:
+ *
+ *	spi-gpio-custom.bus0
+ *	spi-gpio-custom.bus1
+ *	spi-gpio-custom.bus2
+ *	spi-gpio-custom.bus3
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+
+#include <linux/gpio.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_gpio.h>
+
+#define DRV_NAME	"spi-gpio-custom"
+#define DRV_DESC	"Custom GPIO-based SPI driver"
+#define DRV_VERSION	"0.1"
+
+#define PFX		DRV_NAME ": "
+
+#define BUS_PARAM_ID		0
+#define BUS_PARAM_SCK		1
+#define BUS_PARAM_MOSI		2
+#define BUS_PARAM_MISO		3
+#define BUS_PARAM_MODE1		4
+#define BUS_PARAM_MAXFREQ1	5
+#define BUS_PARAM_CS1		6
+
+#define BUS_SLAVE_COUNT_MAX	8
+#define BUS_PARAM_REQUIRED	6
+#define BUS_PARAM_PER_SLAVE	3
+#define BUS_PARAM_COUNT		(4+BUS_PARAM_PER_SLAVE*BUS_SLAVE_COUNT_MAX)
+#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,sck,mosi,miso,mode1,maxfreq1[,cs1,mode2,maxfreq2,cs2,...]"
+
+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 spi_gpio_custom_cleanup(void)
+{
+	int i;
+
+	for (i = 0; i < nr_devices; i++)
+		if (devices[i])
+			platform_device_unregister(devices[i]);
+}
+
+static int spi_gpio_custom_get_slave_mode(unsigned int id,
+					  unsigned int *params,
+					  int slave_index)
+{
+	int param_index;
+
+	param_index = BUS_PARAM_MODE1+slave_index*BUS_PARAM_PER_SLAVE;
+	if (param_index >= bus_nump[id])
+		return -1;
+
+	return params[param_index];
+}
+static int spi_gpio_custom_get_slave_maxfreq(unsigned int id,
+					     unsigned int *params,
+					     int slave_index)
+{
+	int param_index;
+
+	param_index = BUS_PARAM_MAXFREQ1+slave_index*BUS_PARAM_PER_SLAVE;
+	if (param_index >= bus_nump[id])
+		return -1;
+
+	return params[param_index];
+}
+static int spi_gpio_custom_get_slave_cs(unsigned int id,
+					unsigned int *params,
+					int slave_index)
+{
+	int param_index;
+
+	param_index = BUS_PARAM_CS1+slave_index*BUS_PARAM_PER_SLAVE;
+	if (param_index >= bus_nump[id])
+		return -1;
+	if (!gpio_is_valid(params[param_index]))
+		return -1;
+
+	return params[param_index];
+}
+
+static int spi_gpio_custom_check_params(unsigned int id, unsigned int *params)
+{
+	int i;
+	struct spi_master *master;
+
+	if (bus_nump[id] < BUS_PARAM_REQUIRED) {
+		printk(KERN_ERR PFX "not enough values for parameter bus%d\n",
+		       id);
+		return -EINVAL;
+	}
+
+	if (bus_nump[id] > (1+BUS_PARAM_CS1)) {
+		/* more than 1 device: check CS GPIOs */
+		for (i = 0; i < BUS_SLAVE_COUNT_MAX; i++) {
+			/* no more slaves? */
+			if (spi_gpio_custom_get_slave_mode(id, params, i) < 0)
+				break;
+
+			if (spi_gpio_custom_get_slave_cs(id, params, i) < 0) {
+				printk(KERN_ERR PFX "invalid/missing CS gpio for slave %d on bus %d\n",
+				       i, params[BUS_PARAM_ID]);
+				return -EINVAL;
+			}
+		}
+	}
+
+	if (!gpio_is_valid(params[BUS_PARAM_SCK])) {
+		printk(KERN_ERR PFX "invalid SCK gpio for bus %d\n",
+		       params[BUS_PARAM_ID]);
+		return -EINVAL;
+	}
+
+	master = spi_busnum_to_master(params[BUS_PARAM_ID]);
+	if (master) {
+		spi_master_put(master);
+		printk(KERN_ERR PFX "bus %d already exists\n",
+		       params[BUS_PARAM_ID]);
+		return -EEXIST;
+	}
+
+	return 0;
+}
+
+static int __init spi_gpio_custom_add_one(unsigned int id, unsigned int *params)
+{
+	struct platform_device *pdev;
+	struct spi_gpio_platform_data pdata;
+	int i;
+	int num_cs;
+	int err;
+	struct spi_master *master;
+	struct spi_device *slave;
+	struct spi_board_info slave_info;
+	int mode, maxfreq, cs;
+
+
+	if (!bus_nump[id])
+		return 0;
+
+	err = spi_gpio_custom_check_params(id, params);
+	if (err)
+		goto err;
+
+	/* Create BUS device node */
+
+	pdev = platform_device_alloc("spi_gpio", params[BUS_PARAM_ID]);
+	if (!pdev) {
+		err = -ENOMEM;
+		goto err;
+	}
+
+	num_cs = 0;
+	for (i = 0; i < BUS_SLAVE_COUNT_MAX; i++) {
+		/* no more slaves? */
+		if (spi_gpio_custom_get_slave_mode(id, params, i) < 0)
+			break;
+
+		if (spi_gpio_custom_get_slave_cs(id, params, i) >= 0)
+			num_cs++;
+	}
+	if (num_cs == 0) {
+		/*
+		 * Even if no CS is used, spi modules expect
+		 * at least 1 (unused)
+		 */
+		num_cs = 1;
+	}
+
+	pdata.sck = params[BUS_PARAM_SCK];
+	pdata.mosi = gpio_is_valid(params[BUS_PARAM_MOSI])
+		? params[BUS_PARAM_MOSI]
+		: SPI_GPIO_NO_MOSI;
+	pdata.miso = gpio_is_valid(params[BUS_PARAM_MISO])
+		? params[BUS_PARAM_MISO]
+		: SPI_GPIO_NO_MISO;
+	pdata.num_chipselect = num_cs;
+
+	err = platform_device_add_data(pdev, &pdata, sizeof(pdata));
+	if (err) {
+		platform_device_put(pdev);
+		goto err;
+	}
+
+	err = platform_device_add(pdev);
+	if (err) {
+		printk(KERN_ERR PFX "platform_device_add failed with return code %d\n",
+		       err);
+		platform_device_put(pdev);
+		goto err;
+	}
+
+	/* Register SLAVE devices */
+
+	for (i = 0; i < BUS_SLAVE_COUNT_MAX; i++) {
+		mode = spi_gpio_custom_get_slave_mode(id, params, i);
+		maxfreq = spi_gpio_custom_get_slave_maxfreq(id, params, i);
+		cs = spi_gpio_custom_get_slave_cs(id, params, i);
+
+		/* no more slaves? */
+		if (mode < 0)
+			break;
+
+		memset(&slave_info, 0, sizeof(slave_info));
+		strcpy(slave_info.modalias, "spidev");
+		slave_info.controller_data = (void *)((cs >= 0)
+			? cs
+			: SPI_GPIO_NO_CHIPSELECT);
+		slave_info.max_speed_hz = maxfreq;
+		slave_info.bus_num = params[BUS_PARAM_ID];
+		slave_info.chip_select = i;
+		slave_info.mode = mode;
+
+		master = spi_busnum_to_master(params[BUS_PARAM_ID]);
+		if (!master) {
+			printk(KERN_ERR PFX "unable to get master for bus %d\n",
+			       params[BUS_PARAM_ID]);
+			err = -EINVAL;
+			goto err_unregister;
+		}
+		slave = spi_new_device(master, &slave_info);
+		spi_master_put(master);
+		if (!slave) {
+			printk(KERN_ERR PFX "unable to create slave %d for bus %d\n",
+			       i, params[BUS_PARAM_ID]);
+			/* Will most likely fail due to unsupported mode bits */
+			err = -EINVAL;
+			goto err_unregister;
+		}
+	}
+
+	devices[nr_devices++] = pdev;
+
+	return 0;
+
+err_unregister:
+	platform_device_unregister(pdev);
+err:
+	return err;
+}
+
+static int __init spi_gpio_custom_probe(void)
+{
+	int err;
+
+	printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
+
+	err = spi_gpio_custom_add_one(0, bus0);
+	if (err)
+		goto err;
+
+	err = spi_gpio_custom_add_one(1, bus1);
+	if (err)
+		goto err;
+
+	err = spi_gpio_custom_add_one(2, bus2);
+	if (err)
+		goto err;
+
+	err = spi_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:
+	spi_gpio_custom_cleanup();
+	return err;
+}
+
+#ifdef MODULE
+static int __init spi_gpio_custom_init(void)
+{
+	return spi_gpio_custom_probe();
+}
+module_init(spi_gpio_custom_init);
+
+static void __exit spi_gpio_custom_exit(void)
+{
+	spi_gpio_custom_cleanup();
+}
+module_exit(spi_gpio_custom_exit);
+#else
+subsys_initcall(spi_gpio_custom_probe);
+#endif /* MODULE*/
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Marco Burato <zmaster.adsl@gmail.com>");
+MODULE_DESCRIPTION(DRV_DESC);
+MODULE_VERSION(DRV_VERSION);