1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Copyright (C) 2019 IBM Corp. */
3 
4 /* Pieces to enable drivers to implement the .set callback */
5 
6 #include "pinmux-aspeed.h"
7 
8 static const char *const aspeed_pinmux_ips[] = {
9 	[ASPEED_IP_SCU] = "SCU",
10 	[ASPEED_IP_GFX] = "GFX",
11 	[ASPEED_IP_LPC] = "LPC",
12 };
13 
14 static inline void aspeed_sig_desc_print_val(
15 		const struct aspeed_sig_desc *desc, bool enable, u32 rv)
16 {
17 	pr_debug("Want %s%X[0x%08X]=0x%X, got 0x%X from 0x%08X\n",
18 			aspeed_pinmux_ips[desc->ip], desc->reg,
19 			desc->mask, enable ? desc->enable : desc->disable,
20 			(rv & desc->mask) >> __ffs(desc->mask), rv);
21 }
22 
23 /**
24  * aspeed_sig_desc_eval() - Query the enabled or disabled state of a signal
25  * descriptor.
26  *
27  * @desc: The signal descriptor of interest
28  * @enabled: True to query the enabled state, false to query disabled state
29  * @map: The IP block's regmap instance
30  *
31  * Return: 1 if the descriptor's bitfield is configured to the state
32  * selected by @enabled, 0 if not, and less than zero if an unrecoverable
33  * failure occurred
34  *
35  * Evaluation of descriptor state is non-trivial in that it is not a binary
36  * outcome: The bitfields can be greater than one bit in size and thus can take
37  * a value that is neither the enabled nor disabled state recorded in the
38  * descriptor (typically this means a different function to the one of interest
39  * is enabled). Thus we must explicitly test for either condition as required.
40  */
41 int aspeed_sig_desc_eval(const struct aspeed_sig_desc *desc,
42 			 bool enabled, struct regmap *map)
43 {
44 	int ret;
45 	unsigned int raw;
46 	u32 want;
47 
48 	if (!map)
49 		return -ENODEV;
50 
51 	ret = regmap_read(map, desc->reg, &raw);
52 	if (ret)
53 		return ret;
54 
55 	aspeed_sig_desc_print_val(desc, enabled, raw);
56 	want = enabled ? desc->enable : desc->disable;
57 
58 	return ((raw & desc->mask) >> __ffs(desc->mask)) == want;
59 }
60 
61 /**
62  * Query the enabled or disabled state for a mux function's signal on a pin
63  *
64  * @ctx: The driver context for the pinctrl IP
65  * @expr: An expression controlling the signal for a mux function on a pin
66  * @enabled: True to query the enabled state, false to query disabled state
67  *
68  * Return: 1 if the expression composed by @enabled evaluates true, 0 if not,
69  * and less than zero if an unrecoverable failure occurred.
70  *
71  * A mux function is enabled or disabled if the function's signal expression
72  * for each pin in the function's pin group evaluates true for the desired
73  * state. An signal expression evaluates true if all of its associated signal
74  * descriptors evaluate true for the desired state.
75  *
76  * If an expression's state is described by more than one bit, either through
77  * multi-bit bitfields in a single signal descriptor or through multiple signal
78  * descriptors of a single bit then it is possible for the expression to be in
79  * neither the enabled nor disabled state. Thus we must explicitly test for
80  * either condition as required.
81  */
82 int aspeed_sig_expr_eval(struct aspeed_pinmux_data *ctx,
83 			 const struct aspeed_sig_expr *expr, bool enabled)
84 {
85 	int ret;
86 	int i;
87 
88 	if (ctx->ops->eval)
89 		return ctx->ops->eval(ctx, expr, enabled);
90 
91 	for (i = 0; i < expr->ndescs; i++) {
92 		const struct aspeed_sig_desc *desc = &expr->descs[i];
93 
94 		ret = aspeed_sig_desc_eval(desc, enabled, ctx->maps[desc->ip]);
95 		if (ret <= 0)
96 			return ret;
97 	}
98 
99 	return 1;
100 }
101