-/*
- * 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 __init 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 __init 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 __init 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 __init 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);
projects / openwrt / staging / stintel.git / commitdiff