1 /*
2  * OMAP3517/3505-specific clock framework functions
3  *
4  * Copyright (C) 2010 Texas Instruments, Inc.
5  * Copyright (C) 2011 Nokia Corporation
6  *
7  * Ranjith Lohithakshan
8  * Paul Walmsley
9  *
10  * Parts of this code are based on code written by
11  * Richard Woodruff, Tony Lindgren, Tuukka Tikkanen, Karthik Dasu,
12  * Russell King
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License version 2 as
16  * published by the Free Software Foundation.
17  */
18 #undef DEBUG
19 
20 #include <linux/kernel.h>
21 #include <linux/clk.h>
22 #include <linux/io.h>
23 
24 #include <plat/clock.h>
25 
26 #include "clock.h"
27 #include "clock3517.h"
28 #include "cm2xxx_3xxx.h"
29 #include "cm-regbits-34xx.h"
30 
31 /*
32  * In AM35xx IPSS, the {ICK,FCK} enable bits for modules are exported
33  * in the same register at a bit offset of 0x8. The EN_ACK for ICK is
34  * at an offset of 4 from ICK enable bit.
35  */
36 #define AM35XX_IPSS_ICK_MASK			0xF
37 #define AM35XX_IPSS_ICK_EN_ACK_OFFSET 		0x4
38 #define AM35XX_IPSS_ICK_FCK_OFFSET		0x8
39 #define AM35XX_IPSS_CLK_IDLEST_VAL		0
40 
41 /**
42  * am35xx_clk_find_idlest - return clock ACK info for AM35XX IPSS
43  * @clk: struct clk * being enabled
44  * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
45  * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
46  * @idlest_val: pointer to a u8 to store the CM_IDLEST indicator
47  *
48  * The interface clocks on AM35xx IPSS reflects the clock idle status
49  * in the enable register itsel at a bit offset of 4 from the enable
50  * bit. A value of 1 indicates that clock is enabled.
51  */
am35xx_clk_find_idlest(struct clk * clk,void __iomem ** idlest_reg,u8 * idlest_bit,u8 * idlest_val)52 static void am35xx_clk_find_idlest(struct clk *clk,
53 					    void __iomem **idlest_reg,
54 					    u8 *idlest_bit,
55 					    u8 *idlest_val)
56 {
57 	*idlest_reg = (__force void __iomem *)(clk->enable_reg);
58 	*idlest_bit = clk->enable_bit + AM35XX_IPSS_ICK_EN_ACK_OFFSET;
59 	*idlest_val = AM35XX_IPSS_CLK_IDLEST_VAL;
60 }
61 
62 /**
63  * am35xx_clk_find_companion - find companion clock to @clk
64  * @clk: struct clk * to find the companion clock of
65  * @other_reg: void __iomem ** to return the companion clock CM_*CLKEN va in
66  * @other_bit: u8 ** to return the companion clock bit shift in
67  *
68  * Some clocks don't have companion clocks.  For example, modules with
69  * only an interface clock (such as HECC) don't have a companion
70  * clock.  Right now, this code relies on the hardware exporting a bit
71  * in the correct companion register that indicates that the
72  * nonexistent 'companion clock' is active.  Future patches will
73  * associate this type of code with per-module data structures to
74  * avoid this issue, and remove the casts.  No return value.
75  */
am35xx_clk_find_companion(struct clk * clk,void __iomem ** other_reg,u8 * other_bit)76 static void am35xx_clk_find_companion(struct clk *clk, void __iomem **other_reg,
77 					    u8 *other_bit)
78 {
79 	*other_reg = (__force void __iomem *)(clk->enable_reg);
80 	if (clk->enable_bit & AM35XX_IPSS_ICK_MASK)
81 		*other_bit = clk->enable_bit + AM35XX_IPSS_ICK_FCK_OFFSET;
82 	else
83 		*other_bit = clk->enable_bit - AM35XX_IPSS_ICK_FCK_OFFSET;
84 }
85 
86 const struct clkops clkops_am35xx_ipss_module_wait = {
87 	.enable		= omap2_dflt_clk_enable,
88 	.disable	= omap2_dflt_clk_disable,
89 	.find_idlest	= am35xx_clk_find_idlest,
90 	.find_companion	= am35xx_clk_find_companion,
91 };
92 
93 /**
94  * am35xx_clk_ipss_find_idlest - return CM_IDLEST info for IPSS
95  * @clk: struct clk * being enabled
96  * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
97  * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
98  * @idlest_val: pointer to a u8 to store the CM_IDLEST indicator
99  *
100  * The IPSS target CM_IDLEST bit is at a different shift from the
101  * CM_{I,F}CLKEN bit.  Pass back the correct info via @idlest_reg
102  * and @idlest_bit.  No return value.
103  */
am35xx_clk_ipss_find_idlest(struct clk * clk,void __iomem ** idlest_reg,u8 * idlest_bit,u8 * idlest_val)104 static void am35xx_clk_ipss_find_idlest(struct clk *clk,
105 					    void __iomem **idlest_reg,
106 					    u8 *idlest_bit,
107 					    u8 *idlest_val)
108 {
109 	u32 r;
110 
111 	r = (((__force u32)clk->enable_reg & ~0xf0) | 0x20);
112 	*idlest_reg = (__force void __iomem *)r;
113 	*idlest_bit = AM35XX_ST_IPSS_SHIFT;
114 	*idlest_val = OMAP34XX_CM_IDLEST_VAL;
115 }
116 
117 const struct clkops clkops_am35xx_ipss_wait = {
118 	.enable		= omap2_dflt_clk_enable,
119 	.disable	= omap2_dflt_clk_disable,
120 	.find_idlest	= am35xx_clk_ipss_find_idlest,
121 	.find_companion	= omap2_clk_dflt_find_companion,
122 	.allow_idle	= omap2_clkt_iclk_allow_idle,
123 	.deny_idle	= omap2_clkt_iclk_deny_idle,
124 };
125 
126 
127