2 * Custom GPIO-based I2C driver
4 * Copyright (C) 2007-2008 Gabor Juhos <juhosg@openwrt.org>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * ---------------------------------------------------------------------------
12 * The behaviour of this driver can be altered by setting some parameters
13 * from the insmod command line.
15 * The following parameters are adjustable:
17 * bus0 These four arguments can be arrays of
18 * bus1 1-8 unsigned integers as follows:
20 * bus3 <id>,<sda>,<scl>,<udelay>,<timeout>,<sda_od>,<scl_od>,<scl_oo>
24 * <id> ID to used as device_id for the corresponding bus (required)
25 * <sda> GPIO pin ID to used for SDA (required)
26 * <scl> GPIO pin ID to used for SCL (required)
27 * <udelay> signal toggle delay.
28 * <timeout> clock stretching timeout.
29 * <sda_od> SDA is configured as open drain.
30 * <scl_od> SCL is configured as open drain.
31 * <scl_oo> SCL output drivers cannot be turned off.
33 * See include/i2c-gpio.h for more information about the parameters.
35 * If this driver is built into the kernel, you can use the following kernel
36 * command line parameters, with the same values as the corresponding module
37 * parameters listed above:
39 * i2c-gpio-custom.bus0
40 * i2c-gpio-custom.bus1
41 * i2c-gpio-custom.bus2
42 * i2c-gpio-custom.bus3
45 #include <linux/kernel.h>
46 #include <linux/module.h>
47 #include <linux/init.h>
48 #include <linux/platform_device.h>
50 #include <linux/version.h>
51 #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 18, 0)
52 #include <linux/i2c-gpio.h>
54 #include <linux/platform_data/i2c-gpio.h>
57 #define DRV_NAME "i2c-gpio-custom"
58 #define DRV_DESC "Custom GPIO-based I2C driver"
59 #define DRV_VERSION "0.1.2"
61 #define PFX DRV_NAME ": "
63 #define BUS_PARAM_ID 0
64 #define BUS_PARAM_SDA 1
65 #define BUS_PARAM_SCL 2
66 #define BUS_PARAM_UDELAY 3
67 #define BUS_PARAM_TIMEOUT 4
68 #define BUS_PARAM_SDA_OD 5
69 #define BUS_PARAM_SCL_OD 6
70 #define BUS_PARAM_SCL_OO 7
72 #define BUS_PARAM_REQUIRED 3
73 #define BUS_PARAM_COUNT 8
74 #define BUS_COUNT_MAX 4
76 static unsigned int bus0
[BUS_PARAM_COUNT
] __initdata
;
77 static unsigned int bus1
[BUS_PARAM_COUNT
] __initdata
;
78 static unsigned int bus2
[BUS_PARAM_COUNT
] __initdata
;
79 static unsigned int bus3
[BUS_PARAM_COUNT
] __initdata
;
81 static unsigned int bus_nump
[BUS_COUNT_MAX
] __initdata
;
83 #define BUS_PARM_DESC \
84 " config -> id,sda,scl[,udelay,timeout,sda_od,scl_od,scl_oo]"
86 module_param_array(bus0
, uint
, &bus_nump
[0], 0);
87 MODULE_PARM_DESC(bus0
, "bus0" BUS_PARM_DESC
);
88 module_param_array(bus1
, uint
, &bus_nump
[1], 0);
89 MODULE_PARM_DESC(bus1
, "bus1" BUS_PARM_DESC
);
90 module_param_array(bus2
, uint
, &bus_nump
[2], 0);
91 MODULE_PARM_DESC(bus2
, "bus2" BUS_PARM_DESC
);
92 module_param_array(bus3
, uint
, &bus_nump
[3], 0);
93 MODULE_PARM_DESC(bus3
, "bus3" BUS_PARM_DESC
);
95 static struct platform_device
*devices
[BUS_COUNT_MAX
];
96 static unsigned int nr_devices
;
98 static void i2c_gpio_custom_cleanup(void)
102 for (i
= 0; i
< nr_devices
; i
++)
104 platform_device_unregister(devices
[i
]);
107 static int __init
i2c_gpio_custom_add_one(unsigned int id
, unsigned int *params
)
109 struct platform_device
*pdev
;
110 struct i2c_gpio_platform_data pdata
;
116 if (bus_nump
[id
] < BUS_PARAM_REQUIRED
) {
117 printk(KERN_ERR PFX
"not enough parameters for bus%d\n", id
);
122 pdev
= platform_device_alloc("i2c-gpio", params
[BUS_PARAM_ID
]);
128 pdata
.sda_pin
= params
[BUS_PARAM_SDA
];
129 pdata
.scl_pin
= params
[BUS_PARAM_SCL
];
130 pdata
.udelay
= params
[BUS_PARAM_UDELAY
];
131 pdata
.timeout
= params
[BUS_PARAM_TIMEOUT
];
132 pdata
.sda_is_open_drain
= params
[BUS_PARAM_SDA_OD
] != 0;
133 pdata
.scl_is_open_drain
= params
[BUS_PARAM_SCL_OD
] != 0;
134 pdata
.scl_is_output_only
= params
[BUS_PARAM_SCL_OO
] != 0;
136 err
= platform_device_add_data(pdev
, &pdata
, sizeof(pdata
));
140 err
= platform_device_add(pdev
);
144 devices
[nr_devices
++] = pdev
;
148 platform_device_put(pdev
);
153 static int __init
i2c_gpio_custom_probe(void)
157 printk(KERN_INFO DRV_DESC
" version " DRV_VERSION
"\n");
159 err
= i2c_gpio_custom_add_one(0, bus0
);
163 err
= i2c_gpio_custom_add_one(1, bus1
);
167 err
= i2c_gpio_custom_add_one(2, bus2
);
171 err
= i2c_gpio_custom_add_one(3, bus3
);
176 printk(KERN_ERR PFX
"no bus parameter(s) specified\n");
184 i2c_gpio_custom_cleanup();
189 static int __init
i2c_gpio_custom_init(void)
191 return i2c_gpio_custom_probe();
193 module_init(i2c_gpio_custom_init
);
195 static void __exit
i2c_gpio_custom_exit(void)
197 i2c_gpio_custom_cleanup();
199 module_exit(i2c_gpio_custom_exit
);
201 subsys_initcall(i2c_gpio_custom_probe
);
204 MODULE_LICENSE("GPL v2");
205 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org >");
206 MODULE_DESCRIPTION(DRV_DESC
);
207 MODULE_VERSION(DRV_VERSION
);