xref: /openbmc/linux/arch/arm/mach-omap1/i2c.c (revision 7fc96d71)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Helper module for board specific I2C bus registration
4  *
5  * Copyright (C) 2009 Nokia Corporation.
6  */
7 
8 #include <linux/i2c.h>
9 #include <linux/platform_data/i2c-omap.h>
10 
11 #include "mux.h"
12 #include "soc.h"
13 #include "i2c.h"
14 
15 #define OMAP_I2C_SIZE		0x3f
16 #define OMAP1_I2C_BASE		0xfffb3800
17 
18 static const char name[] = "omap_i2c";
19 
20 static struct resource i2c_resources[2] = {
21 };
22 
23 static struct platform_device omap_i2c_devices[1] = {
24 };
25 
26 static void __init omap1_i2c_mux_pins(int bus_id)
27 {
28 	if (cpu_is_omap7xx()) {
29 		omap_cfg_reg(I2C_7XX_SDA);
30 		omap_cfg_reg(I2C_7XX_SCL);
31 	} else {
32 		omap_cfg_reg(I2C_SDA);
33 		omap_cfg_reg(I2C_SCL);
34 	}
35 }
36 
37 int __init omap_i2c_add_bus(struct omap_i2c_bus_platform_data *pdata,
38 				int bus_id)
39 {
40 	struct platform_device *pdev;
41 	struct resource *res;
42 
43 	if (bus_id > 1)
44 		return -EINVAL;
45 
46 	omap1_i2c_mux_pins(bus_id);
47 
48 	pdev = &omap_i2c_devices[bus_id - 1];
49 	pdev->id = bus_id;
50 	pdev->name = name;
51 	pdev->num_resources = ARRAY_SIZE(i2c_resources);
52 	res = i2c_resources;
53 	res[0].start = OMAP1_I2C_BASE;
54 	res[0].end = res[0].start + OMAP_I2C_SIZE;
55 	res[0].flags = IORESOURCE_MEM;
56 	res[1].start = INT_I2C;
57 	res[1].flags = IORESOURCE_IRQ;
58 	pdev->resource = res;
59 
60 	/* all OMAP1 have IP version 1 register set */
61 	pdata->rev = OMAP_I2C_IP_VERSION_1;
62 
63 	/* all OMAP1 I2C are implemented like this */
64 	pdata->flags = OMAP_I2C_FLAG_NO_FIFO |
65 		       OMAP_I2C_FLAG_SIMPLE_CLOCK |
66 		       OMAP_I2C_FLAG_16BIT_DATA_REG |
67 		       OMAP_I2C_FLAG_ALWAYS_ARMXOR_CLK;
68 
69 	/* how the cpu bus is wired up differs for 7xx only */
70 
71 	if (cpu_is_omap7xx())
72 		pdata->flags |= OMAP_I2C_FLAG_BUS_SHIFT_1;
73 	else
74 		pdata->flags |= OMAP_I2C_FLAG_BUS_SHIFT_2;
75 
76 	pdev->dev.platform_data = pdata;
77 
78 	return platform_device_register(pdev);
79 }
80 
81 #define OMAP_I2C_MAX_CONTROLLERS 4
82 static struct omap_i2c_bus_platform_data i2c_pdata[OMAP_I2C_MAX_CONTROLLERS];
83 
84 #define OMAP_I2C_CMDLINE_SETUP	(BIT(31))
85 
86 /**
87  * omap_i2c_bus_setup - Process command line options for the I2C bus speed
88  * @str: String of options
89  *
90  * This function allow to override the default I2C bus speed for given I2C
91  * bus with a command line option.
92  *
93  * Format: i2c_bus=bus_id,clkrate (in kHz)
94  *
95  * Returns 1 on success, 0 otherwise.
96  */
97 static int __init omap_i2c_bus_setup(char *str)
98 {
99 	int ints[3];
100 
101 	get_options(str, 3, ints);
102 	if (ints[0] < 2 || ints[1] < 1 ||
103 			ints[1] > OMAP_I2C_MAX_CONTROLLERS)
104 		return 0;
105 	i2c_pdata[ints[1] - 1].clkrate = ints[2];
106 	i2c_pdata[ints[1] - 1].clkrate |= OMAP_I2C_CMDLINE_SETUP;
107 
108 	return 1;
109 }
110 __setup("i2c_bus=", omap_i2c_bus_setup);
111 
112 /*
113  * Register busses defined in command line but that are not registered with
114  * omap_register_i2c_bus from board initialization code.
115  */
116 int __init omap_register_i2c_bus_cmdline(void)
117 {
118 	int i, err = 0;
119 
120 	for (i = 0; i < ARRAY_SIZE(i2c_pdata); i++)
121 		if (i2c_pdata[i].clkrate & OMAP_I2C_CMDLINE_SETUP) {
122 			i2c_pdata[i].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
123 			err = omap_i2c_add_bus(&i2c_pdata[i], i + 1);
124 			if (err)
125 				goto out;
126 		}
127 
128 out:
129 	return err;
130 }
131 
132 /**
133  * omap_register_i2c_bus - register I2C bus with device descriptors
134  * @bus_id: bus id counting from number 1
135  * @clkrate: clock rate of the bus in kHz
136  * @info: pointer into I2C device descriptor table or NULL
137  * @len: number of descriptors in the table
138  *
139  * Returns 0 on success or an error code.
140  */
141 int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
142 			  struct i2c_board_info const *info,
143 			  unsigned len)
144 {
145 	int err;
146 
147 	BUG_ON(bus_id < 1 || bus_id > OMAP_I2C_MAX_CONTROLLERS);
148 
149 	if (info) {
150 		err = i2c_register_board_info(bus_id, info, len);
151 		if (err)
152 			return err;
153 	}
154 
155 	if (!i2c_pdata[bus_id - 1].clkrate)
156 		i2c_pdata[bus_id - 1].clkrate = clkrate;
157 
158 	i2c_pdata[bus_id - 1].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
159 
160 	return omap_i2c_add_bus(&i2c_pdata[bus_id - 1], bus_id);
161 }
162 
163 static  int __init omap_i2c_cmdline(void)
164 {
165 	return omap_register_i2c_bus_cmdline();
166 }
167 subsys_initcall(omap_i2c_cmdline);
168