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 "soc.h"
9 #include "omap_hwmod.h"
10 #include "omap_device.h"
11
12 #include "prm.h"
13 #include "common.h"
14 #include "i2c.h"
15
16 /* In register I2C_CON, Bit 15 is the I2C enable bit */
17 #define I2C_EN BIT(15)
18 #define OMAP2_I2C_CON_OFFSET 0x24
19 #define OMAP4_I2C_CON_OFFSET 0xA4
20
21 #define MAX_OMAP_I2C_HWMOD_NAME_LEN 16
22
23 /**
24 * omap_i2c_reset - reset the omap i2c module.
25 * @oh: struct omap_hwmod *
26 *
27 * The i2c moudle in omap2, omap3 had a special sequence to reset. The
28 * sequence is:
29 * - Disable the I2C.
30 * - Write to SOFTRESET bit.
31 * - Enable the I2C.
32 * - Poll on the RESETDONE bit.
33 * The sequence is implemented in below function. This is called for 2420,
34 * 2430 and omap3.
35 */
36 int omap_i2c_reset(struct omap_hwmod *oh)
37 {
38 u32 v;
39 u16 i2c_con;
40 int c = 0;
41
42 if (soc_is_omap24xx() || soc_is_omap34xx() || soc_is_am35xx())
43 i2c_con = OMAP2_I2C_CON_OFFSET;
44 else
45 i2c_con = OMAP4_I2C_CON_OFFSET;
46
47 /* Disable I2C */
48 v = omap_hwmod_read(oh, i2c_con);
49 v &= ~I2C_EN;
50 omap_hwmod_write(v, oh, i2c_con);
51
52 /* Write to the SOFTRESET bit */
53 omap_hwmod_softreset(oh);
54
55 /* Enable I2C */
56 v = omap_hwmod_read(oh, i2c_con);
57 v |= I2C_EN;
58 omap_hwmod_write(v, oh, i2c_con);
59
60 /* Poll on RESETDONE bit */
61 omap_test_timeout((omap_hwmod_read(oh,
62 oh->class->sysc->syss_offs)
63 & SYSS_RESETDONE_MASK),
64 MAX_MODULE_SOFTRESET_WAIT, c);
65
66 if (c == MAX_MODULE_SOFTRESET_WAIT)
67 pr_warn("%s: %s: softreset failed (waited %d usec)\n",
68 __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
69 else
70 pr_debug("%s: %s: softreset in %d usec\n", __func__,
71 oh->name, c);
72
73 return 0;
74 }
75
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