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 "clock.h"
25 #include "clock3517.h"
26 #include "cm3xxx.h"
27 #include "cm-regbits-34xx.h"
28
29 /*
30 * In AM35xx IPSS, the {ICK,FCK} enable bits for modules are exported
31 * in the same register at a bit offset of 0x8. The EN_ACK for ICK is
32 * at an offset of 4 from ICK enable bit.
33 */
34 #define AM35XX_IPSS_ICK_MASK 0xF
35 #define AM35XX_IPSS_ICK_EN_ACK_OFFSET 0x4
36 #define AM35XX_IPSS_ICK_FCK_OFFSET 0x8
37 #define AM35XX_IPSS_CLK_IDLEST_VAL 0
38
39 /**
40 * am35xx_clk_find_idlest - return clock ACK info for AM35XX IPSS
41 * @clk: struct clk * being enabled
42 * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
43 * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
44 * @idlest_val: pointer to a u8 to store the CM_IDLEST indicator
45 *
46 * The interface clocks on AM35xx IPSS reflects the clock idle status
47 * in the enable register itsel at a bit offset of 4 from the enable
48 * bit. A value of 1 indicates that clock is enabled.
49 */
am35xx_clk_find_idlest(struct clk_hw_omap * clk,void __iomem ** idlest_reg,u8 * idlest_bit,u8 * idlest_val)50 static void am35xx_clk_find_idlest(struct clk_hw_omap *clk,
51 void __iomem **idlest_reg,
52 u8 *idlest_bit,
53 u8 *idlest_val)
54 {
55 *idlest_reg = (__force void __iomem *)(clk->enable_reg);
56 *idlest_bit = clk->enable_bit + AM35XX_IPSS_ICK_EN_ACK_OFFSET;
57 *idlest_val = AM35XX_IPSS_CLK_IDLEST_VAL;
58 }
59
60 /**
61 * am35xx_clk_find_companion - find companion clock to @clk
62 * @clk: struct clk * to find the companion clock of
63 * @other_reg: void __iomem ** to return the companion clock CM_*CLKEN va in
64 * @other_bit: u8 ** to return the companion clock bit shift in
65 *
66 * Some clocks don't have companion clocks. For example, modules with
67 * only an interface clock (such as HECC) don't have a companion
68 * clock. Right now, this code relies on the hardware exporting a bit
69 * in the correct companion register that indicates that the
70 * nonexistent 'companion clock' is active. Future patches will
71 * associate this type of code with per-module data structures to
72 * avoid this issue, and remove the casts. No return value.
73 */
am35xx_clk_find_companion(struct clk_hw_omap * clk,void __iomem ** other_reg,u8 * other_bit)74 static void am35xx_clk_find_companion(struct clk_hw_omap *clk,
75 void __iomem **other_reg,
76 u8 *other_bit)
77 {
78 *other_reg = (__force void __iomem *)(clk->enable_reg);
79 if (clk->enable_bit & AM35XX_IPSS_ICK_MASK)
80 *other_bit = clk->enable_bit + AM35XX_IPSS_ICK_FCK_OFFSET;
81 else
82 *other_bit = clk->enable_bit - AM35XX_IPSS_ICK_FCK_OFFSET;
83 }
84 const struct clk_hw_omap_ops clkhwops_am35xx_ipss_module_wait = {
85 .find_idlest = am35xx_clk_find_idlest,
86 .find_companion = am35xx_clk_find_companion,
87 };
88
89 /**
90 * am35xx_clk_ipss_find_idlest - return CM_IDLEST info for IPSS
91 * @clk: struct clk * being enabled
92 * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
93 * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
94 * @idlest_val: pointer to a u8 to store the CM_IDLEST indicator
95 *
96 * The IPSS target CM_IDLEST bit is at a different shift from the
97 * CM_{I,F}CLKEN bit. Pass back the correct info via @idlest_reg
98 * and @idlest_bit. No return value.
99 */
am35xx_clk_ipss_find_idlest(struct clk_hw_omap * clk,void __iomem ** idlest_reg,u8 * idlest_bit,u8 * idlest_val)100 static void am35xx_clk_ipss_find_idlest(struct clk_hw_omap *clk,
101 void __iomem **idlest_reg,
102 u8 *idlest_bit,
103 u8 *idlest_val)
104 {
105 u32 r;
106
107 r = (((__force u32)clk->enable_reg & ~0xf0) | 0x20);
108 *idlest_reg = (__force void __iomem *)r;
109 *idlest_bit = AM35XX_ST_IPSS_SHIFT;
110 *idlest_val = OMAP34XX_CM_IDLEST_VAL;
111 }
112
113 const struct clk_hw_omap_ops clkhwops_am35xx_ipss_wait = {
114 .allow_idle = omap2_clkt_iclk_allow_idle,
115 .deny_idle = omap2_clkt_iclk_deny_idle,
116 .find_idlest = am35xx_clk_ipss_find_idlest,
117 .find_companion = omap2_clk_dflt_find_companion,
118 };
119