1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * IP block integration code for the HDQ1W/1-wire IP block |
4 | * |
5 | * Copyright (C) 2012 Texas Instruments, Inc. |
6 | * Paul Walmsley |
7 | * |
8 | * Based on the I2C reset code in arch/arm/mach-omap2/i2c.c by |
9 | * Avinash.H.M <avinashhm@ti.com> |
10 | */ |
11 | |
12 | #include <linux/kernel.h> |
13 | #include <linux/init.h> |
14 | #include <linux/err.h> |
15 | #include <linux/platform_device.h> |
16 | |
17 | #include "soc.h" |
18 | #include "omap_hwmod.h" |
19 | #include "omap_device.h" |
20 | #include "hdq1w.h" |
21 | |
22 | #include "prm.h" |
23 | #include "common.h" |
24 | |
25 | /** |
26 | * omap_hdq1w_reset - reset the OMAP HDQ1W module |
27 | * @oh: struct omap_hwmod * |
28 | * |
29 | * OCP soft reset the HDQ1W IP block. Section 20.6.1.4 "HDQ1W/1-Wire |
30 | * Software Reset" of the OMAP34xx Technical Reference Manual Revision |
31 | * ZR (SWPU223R) does not include the rather important fact that, for |
32 | * the reset to succeed, the HDQ1W module's internal clock gate must be |
33 | * programmed to allow the clock to propagate to the rest of the |
34 | * module. In this sense, it's rather similar to the I2C custom reset |
35 | * function. Returns 0. |
36 | */ |
37 | int omap_hdq1w_reset(struct omap_hwmod *oh) |
38 | { |
39 | u32 v; |
40 | int c = 0; |
41 | |
42 | /* Write to the SOFTRESET bit */ |
43 | omap_hwmod_softreset(oh); |
44 | |
45 | /* Enable the module's internal clocks */ |
46 | v = omap_hwmod_read(oh, HDQ_CTRL_STATUS_OFFSET); |
47 | v |= 1 << HDQ_CTRL_STATUS_CLOCKENABLE_SHIFT; |
48 | omap_hwmod_write(v, oh, HDQ_CTRL_STATUS_OFFSET); |
49 | |
50 | /* Poll on RESETDONE bit */ |
51 | omap_test_timeout((omap_hwmod_read(oh, |
52 | oh->class->sysc->syss_offs) |
53 | & SYSS_RESETDONE_MASK), |
54 | MAX_MODULE_SOFTRESET_WAIT, c); |
55 | |
56 | if (c == MAX_MODULE_SOFTRESET_WAIT) |
57 | pr_warn("%s: %s: softreset failed (waited %d usec)\n" , |
58 | __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT); |
59 | else |
60 | pr_debug("%s: %s: softreset in %d usec\n" , __func__, |
61 | oh->name, c); |
62 | |
63 | return 0; |
64 | } |
65 | |