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9e1b7498 PW |
1 | /* |
2 | * IP block integration code for the HDQ1W/1-wire IP block | |
3 | * | |
4 | * Copyright (C) 2012 Texas Instruments, Inc. | |
5 | * Paul Walmsley | |
6 | * | |
7 | * Based on the I2C reset code in arch/arm/mach-omap2/i2c.c by | |
8 | * Avinash.H.M <avinashhm@ti.com> | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public License | |
12 | * version 2 as published by the Free Software Foundation. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, but | |
15 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA | |
22 | * 02110-1301 USA | |
23 | */ | |
24 | ||
96b1b29d PW |
25 | #include <linux/kernel.h> |
26 | #include <linux/init.h> | |
27 | #include <linux/err.h> | |
28 | #include <linux/platform_device.h> | |
29 | ||
9e1b7498 | 30 | #include <plat/omap_hwmod.h> |
96b1b29d | 31 | #include <plat/omap_device.h> |
9e1b7498 PW |
32 | #include <plat/hdq1w.h> |
33 | ||
34 | #include "common.h" | |
35 | ||
36 | /* Maximum microseconds to wait for OMAP module to softreset */ | |
37 | #define MAX_MODULE_SOFTRESET_WAIT 10000 | |
38 | ||
39 | /** | |
40 | * omap_hdq1w_reset - reset the OMAP HDQ1W module | |
41 | * @oh: struct omap_hwmod * | |
42 | * | |
43 | * OCP soft reset the HDQ1W IP block. Section 20.6.1.4 "HDQ1W/1-Wire | |
44 | * Software Reset" of the OMAP34xx Technical Reference Manual Revision | |
45 | * ZR (SWPU223R) does not include the rather important fact that, for | |
46 | * the reset to succeed, the HDQ1W module's internal clock gate must be | |
47 | * programmed to allow the clock to propagate to the rest of the | |
48 | * module. In this sense, it's rather similar to the I2C custom reset | |
49 | * function. Returns 0. | |
50 | */ | |
51 | int omap_hdq1w_reset(struct omap_hwmod *oh) | |
52 | { | |
53 | u32 v; | |
54 | int c = 0; | |
55 | ||
56 | /* Write to the SOFTRESET bit */ | |
57 | omap_hwmod_softreset(oh); | |
58 | ||
59 | /* Enable the module's internal clocks */ | |
60 | v = omap_hwmod_read(oh, HDQ_CTRL_STATUS_OFFSET); | |
61 | v |= 1 << HDQ_CTRL_STATUS_CLOCKENABLE_SHIFT; | |
62 | omap_hwmod_write(v, oh, HDQ_CTRL_STATUS_OFFSET); | |
63 | ||
64 | /* Poll on RESETDONE bit */ | |
65 | omap_test_timeout((omap_hwmod_read(oh, | |
66 | oh->class->sysc->syss_offs) | |
67 | & SYSS_RESETDONE_MASK), | |
68 | MAX_MODULE_SOFTRESET_WAIT, c); | |
69 | ||
70 | if (c == MAX_MODULE_SOFTRESET_WAIT) | |
71 | pr_warning("%s: %s: softreset failed (waited %d usec)\n", | |
72 | __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT); | |
73 | else | |
74 | pr_debug("%s: %s: softreset in %d usec\n", __func__, | |
75 | oh->name, c); | |
76 | ||
77 | return 0; | |
78 | } | |
96b1b29d PW |
79 | |
80 | static int __init omap_init_hdq(void) | |
81 | { | |
82 | int id = -1; | |
83 | struct platform_device *pdev; | |
84 | struct omap_hwmod *oh; | |
85 | char *oh_name = "hdq1w"; | |
86 | char *devname = "omap_hdq"; | |
87 | ||
88 | oh = omap_hwmod_lookup(oh_name); | |
89 | if (!oh) | |
90 | return 0; | |
91 | ||
92 | pdev = omap_device_build(devname, id, oh, NULL, 0, NULL, 0, 0); | |
93 | WARN(IS_ERR(pdev), "Can't build omap_device for %s:%s.\n", | |
94 | devname, oh->name); | |
95 | ||
96 | return 0; | |
97 | } | |
98 | arch_initcall(omap_init_hdq); |