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Diffstat (limited to 'drivers/pinctrl/aspeed/pinmux-aspeed.c')
-rw-r--r--drivers/pinctrl/aspeed/pinmux-aspeed.c101
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;
+}