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authorGeorgi Djakov <georgi.djakov@linaro.org>2017-12-05 17:46:59 +0200
committerStephen Boyd <sboyd@codeaurora.org>2018-01-02 10:00:24 -0800
commit081bfeed5f1b8394d993afa6b0ce20ed3e868960 (patch)
treec8b3e1123868a819f068c95bd7855a49a47a2d32 /drivers/clk
parent0c6ab1b8f8940d4ddbfff7ddff080cbfb5f32b02 (diff)
clk: qcom: Add regmap mux-div clocks support
Add support for hardware that can switch both parent clock and divider at the same time. This avoids generating intermediate frequencies from either the old parent clock and new divider or new parent clock and old divider combinations. Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> Tested-by: Amit Kucheria <amit.kucheria@linaro.org> [sboyd@codeaurora.org: Change a comment style, drop parent_map in favor of a u32 array instead, export symbols for clk_ops and mux function] Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Diffstat (limited to 'drivers/clk')
-rw-r--r--drivers/clk/qcom/Makefile1
-rw-r--r--drivers/clk/qcom/clk-regmap-mux-div.c231
-rw-r--r--drivers/clk/qcom/clk-regmap-mux-div.h44
3 files changed, 276 insertions, 0 deletions
diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index e767c60c24ec..7c51d877f967 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -10,6 +10,7 @@ clk-qcom-y += clk-rcg2.o
clk-qcom-y += clk-branch.o
clk-qcom-y += clk-regmap-divider.o
clk-qcom-y += clk-regmap-mux.o
+clk-qcom-y += clk-regmap-mux-div.o
clk-qcom-y += reset.o
clk-qcom-$(CONFIG_QCOM_GDSC) += gdsc.o
diff --git a/drivers/clk/qcom/clk-regmap-mux-div.c b/drivers/clk/qcom/clk-regmap-mux-div.c
new file mode 100644
index 000000000000..6044839da85a
--- /dev/null
+++ b/drivers/clk/qcom/clk-regmap-mux-div.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2017, Linaro Limited
+ * Author: Georgi Djakov <georgi.djakov@linaro.org>
+ */
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/regmap.h>
+
+#include "clk-regmap-mux-div.h"
+
+#define CMD_RCGR 0x0
+#define CMD_RCGR_UPDATE BIT(0)
+#define CMD_RCGR_DIRTY_CFG BIT(4)
+#define CMD_RCGR_ROOT_OFF BIT(31)
+#define CFG_RCGR 0x4
+
+#define to_clk_regmap_mux_div(_hw) \
+ container_of(to_clk_regmap(_hw), struct clk_regmap_mux_div, clkr)
+
+int mux_div_set_src_div(struct clk_regmap_mux_div *md, u32 src, u32 div)
+{
+ int ret, count;
+ u32 val, mask;
+ const char *name = clk_hw_get_name(&md->clkr.hw);
+
+ val = (div << md->hid_shift) | (src << md->src_shift);
+ mask = ((BIT(md->hid_width) - 1) << md->hid_shift) |
+ ((BIT(md->src_width) - 1) << md->src_shift);
+
+ ret = regmap_update_bits(md->clkr.regmap, CFG_RCGR + md->reg_offset,
+ mask, val);
+ if (ret)
+ return ret;
+
+ ret = regmap_update_bits(md->clkr.regmap, CMD_RCGR + md->reg_offset,
+ CMD_RCGR_UPDATE, CMD_RCGR_UPDATE);
+ if (ret)
+ return ret;
+
+ /* Wait for update to take effect */
+ for (count = 500; count > 0; count--) {
+ ret = regmap_read(md->clkr.regmap, CMD_RCGR + md->reg_offset,
+ &val);
+ if (ret)
+ return ret;
+ if (!(val & CMD_RCGR_UPDATE))
+ return 0;
+ udelay(1);
+ }
+
+ pr_err("%s: RCG did not update its configuration", name);
+ return -EBUSY;
+}
+EXPORT_SYMBOL_GPL(mux_div_set_src_div);
+
+static void mux_div_get_src_div(struct clk_regmap_mux_div *md, u32 *src,
+ u32 *div)
+{
+ u32 val, d, s;
+ const char *name = clk_hw_get_name(&md->clkr.hw);
+
+ regmap_read(md->clkr.regmap, CMD_RCGR + md->reg_offset, &val);
+
+ if (val & CMD_RCGR_DIRTY_CFG) {
+ pr_err("%s: RCG configuration is pending\n", name);
+ return;
+ }
+
+ regmap_read(md->clkr.regmap, CFG_RCGR + md->reg_offset, &val);
+ s = (val >> md->src_shift);
+ s &= BIT(md->src_width) - 1;
+ *src = s;
+
+ d = (val >> md->hid_shift);
+ d &= BIT(md->hid_width) - 1;
+ *div = d;
+}
+
+static inline bool is_better_rate(unsigned long req, unsigned long best,
+ unsigned long new)
+{
+ return (req <= new && new < best) || (best < req && best < new);
+}
+
+static int mux_div_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
+ unsigned int i, div, max_div;
+ unsigned long actual_rate, best_rate = 0;
+ unsigned long req_rate = req->rate;
+
+ for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
+ struct clk_hw *parent = clk_hw_get_parent_by_index(hw, i);
+ unsigned long parent_rate = clk_hw_get_rate(parent);
+
+ max_div = BIT(md->hid_width) - 1;
+ for (div = 1; div < max_div; div++) {
+ parent_rate = mult_frac(req_rate, div, 2);
+ parent_rate = clk_hw_round_rate(parent, parent_rate);
+ actual_rate = mult_frac(parent_rate, 2, div);
+
+ if (is_better_rate(req_rate, best_rate, actual_rate)) {
+ best_rate = actual_rate;
+ req->rate = best_rate;
+ req->best_parent_rate = parent_rate;
+ req->best_parent_hw = parent;
+ }
+
+ if (actual_rate < req_rate || best_rate <= req_rate)
+ break;
+ }
+ }
+
+ if (!best_rate)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int __mux_div_set_rate_and_parent(struct clk_hw *hw, unsigned long rate,
+ unsigned long prate, u32 src)
+{
+ struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
+ int ret;
+ u32 div, max_div, best_src = 0, best_div = 0;
+ unsigned int i;
+ unsigned long actual_rate, best_rate = 0;
+
+ for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
+ struct clk_hw *parent = clk_hw_get_parent_by_index(hw, i);
+ unsigned long parent_rate = clk_hw_get_rate(parent);
+
+ max_div = BIT(md->hid_width) - 1;
+ for (div = 1; div < max_div; div++) {
+ parent_rate = mult_frac(rate, div, 2);
+ parent_rate = clk_hw_round_rate(parent, parent_rate);
+ actual_rate = mult_frac(parent_rate, 2, div);
+
+ if (is_better_rate(rate, best_rate, actual_rate)) {
+ best_rate = actual_rate;
+ best_src = md->parent_map[i];
+ best_div = div - 1;
+ }
+
+ if (actual_rate < rate || best_rate <= rate)
+ break;
+ }
+ }
+
+ ret = mux_div_set_src_div(md, best_src, best_div);
+ if (!ret) {
+ md->div = best_div;
+ md->src = best_src;
+ }
+
+ return ret;
+}
+
+static u8 mux_div_get_parent(struct clk_hw *hw)
+{
+ struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
+ const char *name = clk_hw_get_name(hw);
+ u32 i, div, src = 0;
+
+ mux_div_get_src_div(md, &src, &div);
+
+ for (i = 0; i < clk_hw_get_num_parents(hw); i++)
+ if (src == md->parent_map[i])
+ return i;
+
+ pr_err("%s: Can't find parent with src %d\n", name, src);
+ return 0;
+}
+
+static int mux_div_set_parent(struct clk_hw *hw, u8 index)
+{
+ struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
+
+ return mux_div_set_src_div(md, md->parent_map[index], md->div);
+}
+
+static int mux_div_set_rate(struct clk_hw *hw,
+ unsigned long rate, unsigned long prate)
+{
+ struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
+
+ return __mux_div_set_rate_and_parent(hw, rate, prate, md->src);
+}
+
+static int mux_div_set_rate_and_parent(struct clk_hw *hw, unsigned long rate,
+ unsigned long prate, u8 index)
+{
+ struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
+
+ return __mux_div_set_rate_and_parent(hw, rate, prate,
+ md->parent_map[index]);
+}
+
+static unsigned long mux_div_recalc_rate(struct clk_hw *hw, unsigned long prate)
+{
+ struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
+ u32 div, src;
+ int i, num_parents = clk_hw_get_num_parents(hw);
+ const char *name = clk_hw_get_name(hw);
+
+ mux_div_get_src_div(md, &src, &div);
+ for (i = 0; i < num_parents; i++)
+ if (src == md->parent_map[i]) {
+ struct clk_hw *p = clk_hw_get_parent_by_index(hw, i);
+ unsigned long parent_rate = clk_hw_get_rate(p);
+
+ return mult_frac(parent_rate, 2, div + 1);
+ }
+
+ pr_err("%s: Can't find parent %d\n", name, src);
+ return 0;
+}
+
+const struct clk_ops clk_regmap_mux_div_ops = {
+ .get_parent = mux_div_get_parent,
+ .set_parent = mux_div_set_parent,
+ .set_rate = mux_div_set_rate,
+ .set_rate_and_parent = mux_div_set_rate_and_parent,
+ .determine_rate = mux_div_determine_rate,
+ .recalc_rate = mux_div_recalc_rate,
+};
+EXPORT_SYMBOL_GPL(clk_regmap_mux_div_ops);
diff --git a/drivers/clk/qcom/clk-regmap-mux-div.h b/drivers/clk/qcom/clk-regmap-mux-div.h
new file mode 100644
index 000000000000..6cd6261be7ac
--- /dev/null
+++ b/drivers/clk/qcom/clk-regmap-mux-div.h
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2017, Linaro Limited
+ * Author: Georgi Djakov <georgi.djakov@linaro.org>
+ */
+
+#ifndef __QCOM_CLK_REGMAP_MUX_DIV_H__
+#define __QCOM_CLK_REGMAP_MUX_DIV_H__
+
+#include <linux/clk-provider.h>
+#include "clk-regmap.h"
+
+/**
+ * struct mux_div_clk - combined mux/divider clock
+ * @reg_offset: offset of the mux/divider register
+ * @hid_width: number of bits in half integer divider
+ * @hid_shift: lowest bit of hid value field
+ * @src_width: number of bits in source select
+ * @src_shift: lowest bit of source select field
+ * @div: the divider raw configuration value
+ * @src: the mux index which will be used if the clock is enabled
+ * @parent_map: map from parent_names index to src_sel field
+ * @clkr: handle between common and hardware-specific interfaces
+ * @pclk: the input PLL clock
+ * @clk_nb: clock notifier for rate changes of the input PLL
+ */
+struct clk_regmap_mux_div {
+ u32 reg_offset;
+ u32 hid_width;
+ u32 hid_shift;
+ u32 src_width;
+ u32 src_shift;
+ u32 div;
+ u32 src;
+ const u32 *parent_map;
+ struct clk_regmap clkr;
+ struct clk *pclk;
+ struct notifier_block clk_nb;
+};
+
+extern const struct clk_ops clk_regmap_mux_div_ops;
+extern int mux_div_set_src_div(struct clk_regmap_mux_div *md, u32 src, u32 div);
+
+#endif

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