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Diffstat (limited to '')
-rw-r--r-- | drivers/pinctrl/aspeed/pinmux-aspeed.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/drivers/pinctrl/aspeed/pinmux-aspeed.c b/drivers/pinctrl/aspeed/pinmux-aspeed.c new file mode 100644 index 000000000..4aa46383c --- /dev/null +++ b/drivers/pinctrl/aspeed/pinmux-aspeed.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Copyright (C) 2019 IBM Corp. */ + +/* Pieces to enable drivers to implement the .set callback */ + +#include "pinmux-aspeed.h" + +static const char *const aspeed_pinmux_ips[] = { + [ASPEED_IP_SCU] = "SCU", + [ASPEED_IP_GFX] = "GFX", + [ASPEED_IP_LPC] = "LPC", +}; + +static inline void aspeed_sig_desc_print_val( + const struct aspeed_sig_desc *desc, bool enable, u32 rv) +{ + pr_debug("Want %s%X[0x%08X]=0x%X, got 0x%X from 0x%08X\n", + aspeed_pinmux_ips[desc->ip], desc->reg, + desc->mask, enable ? desc->enable : desc->disable, + (rv & desc->mask) >> __ffs(desc->mask), rv); +} + +/** + * aspeed_sig_desc_eval() - Query the enabled or disabled state of a signal + * descriptor. + * + * @desc: The signal descriptor of interest + * @enabled: True to query the enabled state, false to query disabled state + * @map: The IP block's regmap instance + * + * Return: 1 if the descriptor's bitfield is configured to the state + * selected by @enabled, 0 if not, and less than zero if an unrecoverable + * failure occurred + * + * Evaluation of descriptor state is non-trivial in that it is not a binary + * outcome: The bitfields can be greater than one bit in size and thus can take + * a value that is neither the enabled nor disabled state recorded in the + * descriptor (typically this means a different function to the one of interest + * is enabled). Thus we must explicitly test for either condition as required. + */ +int aspeed_sig_desc_eval(const struct aspeed_sig_desc *desc, + bool enabled, struct regmap *map) +{ + int ret; + unsigned int raw; + u32 want; + + if (!map) + return -ENODEV; + + ret = regmap_read(map, desc->reg, &raw); + if (ret) + return ret; + + aspeed_sig_desc_print_val(desc, enabled, raw); + want = enabled ? desc->enable : desc->disable; + + return ((raw & desc->mask) >> __ffs(desc->mask)) == want; +} + +/** + * aspeed_sig_expr_eval - Query the enabled or disabled state for a + * mux function's signal on a pin + * + * @ctx: The driver context for the pinctrl IP + * @expr: An expression controlling the signal for a mux function on a pin + * @enabled: True to query the enabled state, false to query disabled state + * + * Return: 1 if the expression composed by @enabled evaluates true, 0 if not, + * and less than zero if an unrecoverable failure occurred. + * + * A mux function is enabled or disabled if the function's signal expression + * for each pin in the function's pin group evaluates true for the desired + * state. An signal expression evaluates true if all of its associated signal + * descriptors evaluate true for the desired state. + * + * If an expression's state is described by more than one bit, either through + * multi-bit bitfields in a single signal descriptor or through multiple signal + * descriptors of a single bit then it is possible for the expression to be in + * neither the enabled nor disabled state. Thus we must explicitly test for + * either condition as required. + */ +int aspeed_sig_expr_eval(struct aspeed_pinmux_data *ctx, + const struct aspeed_sig_expr *expr, bool enabled) +{ + int ret; + int i; + + if (ctx->ops->eval) + return ctx->ops->eval(ctx, expr, enabled); + + for (i = 0; i < expr->ndescs; i++) { + const struct aspeed_sig_desc *desc = &expr->descs[i]; + + ret = aspeed_sig_desc_eval(desc, enabled, ctx->maps[desc->ip]); + if (ret <= 0) + return ret; + } + + return 1; +} |