1 files changed, 361 insertions, 0 deletions
diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
new file mode 100644
index 000000000..943ea67bf
--- /dev/null
+++ b/drivers/clk/at91/clk-generated.c
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2015 Atmel Corporation,
+ *                     Nicolas Ferre <nicolas.ferre@atmel.com>
+ *
+ * Based on clk-programmable & clk-peripheral drivers by Boris BREZILLON.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/at91_pmc.h>
+#include <linux/of.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+#include "pmc.h"
+
+#define GENERATED_MAX_DIV	255
+
+struct clk_generated {
+	struct clk_hw hw;
+	struct regmap *regmap;
+	struct clk_range range;
+	spinlock_t *lock;
+	u32 *mux_table;
+	u32 id;
+	u32 gckdiv;
+	const struct clk_pcr_layout *layout;
+	struct at91_clk_pms pms;
+	u8 parent_id;
+	int chg_pid;
+};
+
+#define to_clk_generated(hw) \
+	container_of(hw, struct clk_generated, hw)
+
+static int clk_generated_set(struct clk_generated *gck, int status)
+{
+	unsigned long flags;
+	unsigned int enable = status ? AT91_PMC_PCR_GCKEN : 0;
+
+	spin_lock_irqsave(gck->lock, flags);
+	regmap_write(gck->regmap, gck->layout->offset,
+		     (gck->id & gck->layout->pid_mask));
+	regmap_update_bits(gck->regmap, gck->layout->offset,
+			   AT91_PMC_PCR_GCKDIV_MASK | gck->layout->gckcss_mask |
+			   gck->layout->cmd | enable,
+			   field_prep(gck->layout->gckcss_mask, gck->parent_id) |
+			   gck->layout->cmd |
+			   FIELD_PREP(AT91_PMC_PCR_GCKDIV_MASK, gck->gckdiv) |
+			   enable);
+	spin_unlock_irqrestore(gck->lock, flags);
+
+	return 0;
+}
+
+static int clk_generated_enable(struct clk_hw *hw)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+
+	pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n",
+		 __func__, gck->gckdiv, gck->parent_id);
+
+	clk_generated_set(gck, 1);
+
+	return 0;
+}
+
+static void clk_generated_disable(struct clk_hw *hw)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+	unsigned long flags;
+
+	spin_lock_irqsave(gck->lock, flags);
+	regmap_write(gck->regmap, gck->layout->offset,
+		     (gck->id & gck->layout->pid_mask));
+	regmap_update_bits(gck->regmap, gck->layout->offset,
+			   gck->layout->cmd | AT91_PMC_PCR_GCKEN,
+			   gck->layout->cmd);
+	spin_unlock_irqrestore(gck->lock, flags);
+}
+
+static int clk_generated_is_enabled(struct clk_hw *hw)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+	unsigned long flags;
+	unsigned int status;
+
+	spin_lock_irqsave(gck->lock, flags);
+	regmap_write(gck->regmap, gck->layout->offset,
+		     (gck->id & gck->layout->pid_mask));
+	regmap_read(gck->regmap, gck->layout->offset, &status);
+	spin_unlock_irqrestore(gck->lock, flags);
+
+	return !!(status & AT91_PMC_PCR_GCKEN);
+}
+
+static unsigned long
+clk_generated_recalc_rate(struct clk_hw *hw,
+			  unsigned long parent_rate)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+
+	return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1);
+}
+
+static void clk_generated_best_diff(struct clk_rate_request *req,
+				    struct clk_hw *parent,
+				    unsigned long parent_rate, u32 div,
+				    int *best_diff, long *best_rate)
+{
+	unsigned long tmp_rate;
+	int tmp_diff;
+
+	if (!div)
+		tmp_rate = parent_rate;
+	else
+		tmp_rate = parent_rate / div;
+
+	if (tmp_rate < req->min_rate || tmp_rate > req->max_rate)
+		return;
+
+	tmp_diff = abs(req->rate - tmp_rate);
+
+	if (*best_diff < 0 || *best_diff >= tmp_diff) {
+		*best_rate = tmp_rate;
+		*best_diff = tmp_diff;
+		req->best_parent_rate = parent_rate;
+		req->best_parent_hw = parent;
+	}
+}
+
+static int clk_generated_determine_rate(struct clk_hw *hw,
+					struct clk_rate_request *req)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+	struct clk_hw *parent = NULL;
+	long best_rate = -EINVAL;
+	unsigned long min_rate, parent_rate;
+	int best_diff = -1;
+	int i;
+	u32 div;
+
+	/* do not look for a rate that is outside of our range */
+	if (gck->range.max && req->rate > gck->range.max)
+		req->rate = gck->range.max;
+	if (gck->range.min && req->rate < gck->range.min)
+		req->rate = gck->range.min;
+
+	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
+		if (gck->chg_pid == i)
+			continue;
+
+		parent = clk_hw_get_parent_by_index(hw, i);
+		if (!parent)
+			continue;
+
+		parent_rate = clk_hw_get_rate(parent);
+		min_rate = DIV_ROUND_CLOSEST(parent_rate, GENERATED_MAX_DIV + 1);
+		if (!parent_rate ||
+		    (gck->range.max && min_rate > gck->range.max))
+			continue;
+
+		div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
+		if (div > GENERATED_MAX_DIV + 1)
+			div = GENERATED_MAX_DIV + 1;
+
+		clk_generated_best_diff(req, parent, parent_rate, div,
+					&best_diff, &best_rate);
+
+		if (!best_diff)
+			break;
+	}
+
+	/*
+	 * The audio_pll rate can be modified, unlike the five others clocks
+	 * that should never be altered.
+	 * The audio_pll can technically be used by multiple consumers. However,
+	 * with the rate locking, the first consumer to enable to clock will be
+	 * the one definitely setting the rate of the clock.
+	 * Since audio IPs are most likely to request the same rate, we enforce
+	 * that the only clks able to modify gck rate are those of audio IPs.
+	 */
+
+	if (gck->chg_pid < 0)
+		goto end;
+
+	parent = clk_hw_get_parent_by_index(hw, gck->chg_pid);
+	if (!parent)
+		goto end;
+
+	for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {
+		struct clk_rate_request req_parent;
+
+		clk_hw_forward_rate_request(hw, req, parent, &req_parent, req->rate * div);
+		if (__clk_determine_rate(parent, &req_parent))
+			continue;
+		clk_generated_best_diff(req, parent, req_parent.rate, div,
+					&best_diff, &best_rate);
+
+		if (!best_diff)
+			break;
+	}
+
+end:
+	pr_debug("GCLK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
+		 __func__, best_rate,
+		 __clk_get_name((req->best_parent_hw)->clk),
+		 req->best_parent_rate);
+
+	if (best_rate < 0 || (gck->range.max && best_rate > gck->range.max))
+		return -EINVAL;
+
+	req->rate = best_rate;
+	return 0;
+}
+
+/* No modification of hardware as we have the flag CLK_SET_PARENT_GATE set */
+static int clk_generated_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+
+	if (index >= clk_hw_get_num_parents(hw))
+		return -EINVAL;
+
+	if (gck->mux_table)
+		gck->parent_id = clk_mux_index_to_val(gck->mux_table, 0, index);
+	else
+		gck->parent_id = index;
+
+	return 0;
+}
+
+static u8 clk_generated_get_parent(struct clk_hw *hw)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+
+	return gck->parent_id;
+}
+
+/* No modification of hardware as we have the flag CLK_SET_RATE_GATE set */
+static int clk_generated_set_rate(struct clk_hw *hw,
+				  unsigned long rate,
+				  unsigned long parent_rate)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+	u32 div;
+
+	if (!rate)
+		return -EINVAL;
+
+	if (gck->range.max && rate > gck->range.max)
+		return -EINVAL;
+
+	div = DIV_ROUND_CLOSEST(parent_rate, rate);
+	if (div > GENERATED_MAX_DIV + 1 || !div)
+		return -EINVAL;
+
+	gck->gckdiv = div - 1;
+	return 0;
+}
+
+static int clk_generated_save_context(struct clk_hw *hw)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+
+	gck->pms.status = clk_generated_is_enabled(&gck->hw);
+
+	return 0;
+}
+
+static void clk_generated_restore_context(struct clk_hw *hw)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+
+	if (gck->pms.status)
+		clk_generated_set(gck, gck->pms.status);
+}
+
+static const struct clk_ops generated_ops = {
+	.enable = clk_generated_enable,
+	.disable = clk_generated_disable,
+	.is_enabled = clk_generated_is_enabled,
+	.recalc_rate = clk_generated_recalc_rate,
+	.determine_rate = clk_generated_determine_rate,
+	.get_parent = clk_generated_get_parent,
+	.set_parent = clk_generated_set_parent,
+	.set_rate = clk_generated_set_rate,
+	.save_context = clk_generated_save_context,
+	.restore_context = clk_generated_restore_context,
+};
+
+/**
+ * clk_generated_startup - Initialize a given clock to its default parent and
+ * divisor parameter.
+ *
+ * @gck:	Generated clock to set the startup parameters for.
+ *
+ * Take parameters from the hardware and update local clock configuration
+ * accordingly.
+ */
+static void clk_generated_startup(struct clk_generated *gck)
+{
+	u32 tmp;
+	unsigned long flags;
+
+	spin_lock_irqsave(gck->lock, flags);
+	regmap_write(gck->regmap, gck->layout->offset,
+		     (gck->id & gck->layout->pid_mask));
+	regmap_read(gck->regmap, gck->layout->offset, &tmp);
+	spin_unlock_irqrestore(gck->lock, flags);
+
+	gck->parent_id = field_get(gck->layout->gckcss_mask, tmp);
+	gck->gckdiv = FIELD_GET(AT91_PMC_PCR_GCKDIV_MASK, tmp);
+}
+
+struct clk_hw * __init
+at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock,
+			    const struct clk_pcr_layout *layout,
+			    const char *name, const char **parent_names,
+			    u32 *mux_table, u8 num_parents, u8 id,
+			    const struct clk_range *range,
+			    int chg_pid)
+{
+	struct clk_generated *gck;
+	struct clk_init_data init;
+	struct clk_hw *hw;
+	int ret;
+
+	gck = kzalloc(sizeof(*gck), GFP_KERNEL);
+	if (!gck)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &generated_ops;
+	init.parent_names = parent_names;
+	init.num_parents = num_parents;
+	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
+	if (chg_pid >= 0)
+		init.flags |= CLK_SET_RATE_PARENT;
+
+	gck->id = id;
+	gck->hw.init = &init;
+	gck->regmap = regmap;
+	gck->lock = lock;
+	gck->range = *range;
+	gck->chg_pid = chg_pid;
+	gck->layout = layout;
+	gck->mux_table = mux_table;
+
+	clk_generated_startup(gck);
+	hw = &gck->hw;
+	ret = clk_hw_register(NULL, &gck->hw);
+	if (ret) {
+		kfree(gck);
+		hw = ERR_PTR(ret);
+	}
+
+	return hw;
+}