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Message-Id: <1442507969-18062-3-git-send-email-georgi.djakov@linaro.org>
Date: Thu, 17 Sep 2015 19:39:27 +0300
From: Georgi Djakov <georgi.djakov@...aro.org>
To: sboyd@...eaurora.org
Cc: mturquette@...libre.com, linux-clk@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
georgi.djakov@...aro.org
Subject: [PATCH v5 2/4] clk: qcom: Add support for RCGs with shared branches
Some root clock generators may have child branches that are controlled
by different CPUs. These RCGs require some special operations:
- some enable bits have to be toggled when we set the rate;
- if RCG is disabled we only cache the rate and set it later when enabled;
- when the RCG is disabled, the mux is set to the safe source;
Signed-off-by: Georgi Djakov <georgi.djakov@...aro.org>
---
drivers/clk/qcom/clk-rcg.h | 4 +-
drivers/clk/qcom/clk-rcg2.c | 91 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 94 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/qcom/clk-rcg.h b/drivers/clk/qcom/clk-rcg.h
index 31f92d70e8e0..5012e5b90cfb 100644
--- a/drivers/clk/qcom/clk-rcg.h
+++ b/drivers/clk/qcom/clk-rcg.h
@@ -153,8 +153,8 @@ extern const struct clk_ops clk_dyn_rcg_ops;
* @hid_width: number of bits in half integer divider
* @parent_map: map from software's parent index to hardware's src_sel field
* @freq_tbl: frequency table
+ * @current_freq: last cached frequency when using branches with shared RCGs
* @clkr: regmap clock handle
- * @lock: register lock
*
*/
struct clk_rcg2 {
@@ -163,12 +163,14 @@ struct clk_rcg2 {
u8 hid_width;
const struct parent_map *parent_map;
const struct freq_tbl *freq_tbl;
+ unsigned long current_freq;
struct clk_regmap clkr;
};
#define to_clk_rcg2(_hw) container_of(to_clk_regmap(_hw), struct clk_rcg2, clkr)
extern const struct clk_ops clk_rcg2_ops;
+extern const struct clk_ops clk_rcg2_shared_ops;
extern const struct clk_ops clk_edp_pixel_ops;
extern const struct clk_ops clk_byte_ops;
extern const struct clk_ops clk_byte2_ops;
diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index d941dea6f7c7..c7b9b32742e5 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -300,6 +300,97 @@ const struct clk_ops clk_rcg2_ops = {
};
EXPORT_SYMBOL_GPL(clk_rcg2_ops);
+static int clk_rcg2_shared_force_enable(struct clk_hw *hw, unsigned long rate)
+{
+ struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+ const char *name = clk_hw_get_name(hw);
+ int ret, count;
+
+ /* force enable RCG */
+ ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CMD_REG,
+ CMD_ROOT_EN, CMD_ROOT_EN);
+ if (ret)
+ return ret;
+
+ /* wait for RCG to turn ON */
+ for (count = 500; count > 0; count--) {
+ ret = clk_rcg2_is_enabled(hw);
+ if (ret)
+ break;
+ udelay(1);
+ }
+ if (!count)
+ pr_err("%s: RCG did not turn on\n", name);
+
+ /* set clock rate */
+ ret = __clk_rcg2_set_rate(hw, rate);
+ if (ret)
+ return ret;
+
+ /* clear force enable RCG */
+ return regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CMD_REG,
+ CMD_ROOT_EN, 0);
+}
+
+static int clk_rcg2_shared_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+
+ /* cache the rate */
+ rcg->current_freq = rate;
+
+ if (!__clk_is_enabled(hw->clk))
+ return 0;
+
+ return clk_rcg2_shared_force_enable(hw, rcg->current_freq);
+}
+
+static unsigned long
+clk_rcg2_shared_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+ struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+ unsigned long rate;
+ u32 cfg, hid_div, mask;
+
+ regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG, &cfg);
+
+ mask = BIT(rcg->hid_width) - 1;
+ hid_div = cfg >> CFG_SRC_DIV_SHIFT;
+ hid_div &= mask;
+
+ rate = (parent_rate * 2) / (hid_div + 1);
+
+ rcg->current_freq = rate;
+
+ return rate;
+}
+
+static int clk_rcg2_shared_enable(struct clk_hw *hw)
+{
+ struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+
+ return clk_rcg2_shared_force_enable(hw, rcg->current_freq);
+}
+
+static void clk_rcg2_shared_disable(struct clk_hw *hw)
+{
+ struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+
+ /* switch to XO, which is the lowest entry in the freq table */
+ clk_rcg2_shared_set_rate(hw, rcg->freq_tbl[0].freq, 0);
+}
+
+const struct clk_ops clk_rcg2_shared_ops = {
+ .enable = clk_rcg2_shared_enable,
+ .disable = clk_rcg2_shared_disable,
+ .get_parent = clk_rcg2_get_parent,
+ .recalc_rate = clk_rcg2_shared_recalc_rate,
+ .determine_rate = clk_rcg2_determine_rate,
+ .set_rate = clk_rcg2_shared_set_rate,
+};
+EXPORT_SYMBOL_GPL(clk_rcg2_shared_ops);
+
struct frac_entry {
int num;
int den;
--
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