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path: root/drivers/clk/at91/clk-generated.c
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-rw-r--r--drivers/clk/at91/clk-generated.c332
1 files changed, 332 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..fe772baeb
--- /dev/null
+++ b/drivers/clk/at91/clk-generated.c
@@ -0,0 +1,332 @@
+// 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;
+ u8 parent_id;
+ int chg_pid;
+};
+
+#define to_clk_generated(hw) \
+ container_of(hw, struct clk_generated, hw)
+
+static int clk_generated_enable(struct clk_hw *hw)
+{
+ struct clk_generated *gck = to_clk_generated(hw);
+ unsigned long flags;
+
+ pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n",
+ __func__, gck->gckdiv, gck->parent_id);
+
+ 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 | AT91_PMC_PCR_GCKEN,
+ field_prep(gck->layout->gckcss_mask, gck->parent_id) |
+ gck->layout->cmd |
+ FIELD_PREP(AT91_PMC_PCR_GCKDIV_MASK, gck->gckdiv) |
+ AT91_PMC_PCR_GCKEN);
+ spin_unlock_irqrestore(gck->lock, flags);
+ 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;
+ struct clk_rate_request req_parent = *req;
+ 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++) {
+ req_parent.rate = 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 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,
+};
+
+/**
+ * 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);
+ } else {
+ pmc_register_id(id);
+ }
+
+ return hw;
+}