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