+++ /dev/null
-From patchwork Fri Dec 8 09:42:28 2017
-Content-Type: text/plain; charset="utf-8"
-MIME-Version: 1.0
-Content-Transfer-Encoding: 7bit
-Subject: [v4,10/12] clk: qcom: Add safe switch hook for krait mux clocks
-From: Sricharan R <sricharan@codeaurora.org>
-X-Patchwork-Id: 10102057
-Message-Id: <1512726150-7204-11-git-send-email-sricharan@codeaurora.org>
-To: mturquette@baylibre.com, sboyd@codeaurora.org,
- devicetree@vger.kernel.org, linux-pm@vger.kernel.org,
- linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
- viresh.kumar@linaro.org, linux-arm-kernel@lists.infradead.org
-Cc: sricharan@codeaurora.org
-Date: Fri, 8 Dec 2017 15:12:28 +0530
-
-When the Hfplls are reprogrammed during the rate change,
-the primary muxes which are sourced from the same hfpll
-for higher frequencies, needs to be switched to the 'safe
-secondary mux' as the parent for that small window. This
-is done by registering a clk notifier for the muxes and
-switching to the safe parent in the PRE_RATE_CHANGE notifier
-and back to the original parent in the POST_RATE_CHANGE notifier.
-
-Signed-off-by: Sricharan R <sricharan@codeaurora.org>
----
- drivers/clk/qcom/clk-krait.c | 2 ++
- drivers/clk/qcom/clk-krait.h | 3 +++
- drivers/clk/qcom/krait-cc.c | 56 ++++++++++++++++++++++++++++++++++++++++++++
- 3 files changed, 61 insertions(+)
-
---- a/drivers/clk/qcom/clk-krait.c
-+++ b/drivers/clk/qcom/clk-krait.c
-@@ -60,6 +60,8 @@ static int krait_mux_set_parent(struct c
- if (__clk_is_enabled(hw->clk))
- __krait_mux_set_sel(mux, sel);
-
-+ mux->reparent = true;
-+
- return 0;
- }
-
---- a/drivers/clk/qcom/clk-krait.h
-+++ b/drivers/clk/qcom/clk-krait.h
-@@ -23,6 +23,9 @@ struct krait_mux_clk {
- u32 shift;
- u32 en_mask;
- bool lpl;
-+ u8 safe_sel;
-+ u8 old_index;
-+ bool reparent;
-
- struct clk_hw hw;
- struct notifier_block clk_nb;
---- a/drivers/clk/qcom/krait-cc.c
-+++ b/drivers/clk/qcom/krait-cc.c
-@@ -35,6 +35,49 @@ static unsigned int pri_mux_map[] = {
- 0,
- };
-
-+/*
-+ * Notifier function for switching the muxes to safe parent
-+ * while the hfpll is getting reprogrammed.
-+ */
-+static int krait_notifier_cb(struct notifier_block *nb,
-+ unsigned long event,
-+ void *data)
-+{
-+ int ret = 0;
-+ struct krait_mux_clk *mux = container_of(nb, struct krait_mux_clk,
-+ clk_nb);
-+ /* Switch to safe parent */
-+ if (event == PRE_RATE_CHANGE) {
-+ mux->old_index = krait_mux_clk_ops.get_parent(&mux->hw);
-+ ret = krait_mux_clk_ops.set_parent(&mux->hw, mux->safe_sel);
-+ mux->reparent = false;
-+ /*
-+ * By the time POST_RATE_CHANGE notifier is called,
-+ * clk framework itself would have changed the parent for the new rate.
-+ * Only otherwise, put back to the old parent.
-+ */
-+ } else if (event == POST_RATE_CHANGE) {
-+ if (!mux->reparent)
-+ ret = krait_mux_clk_ops.set_parent(&mux->hw,
-+ mux->old_index);
-+ }
-+
-+ return notifier_from_errno(ret);
-+}
-+
-+static int krait_notifier_register(struct device *dev, struct clk *clk,
-+ struct krait_mux_clk *mux)
-+{
-+ int ret = 0;
-+
-+ mux->clk_nb.notifier_call = krait_notifier_cb;
-+ ret = clk_notifier_register(clk, &mux->clk_nb);
-+ if (ret)
-+ dev_err(dev, "failed to register clock notifier: %d\n", ret);
-+
-+ return ret;
-+}
-+
- static int
- krait_add_div(struct device *dev, int id, const char *s, unsigned int offset)
- {
-@@ -79,6 +122,7 @@ static int
- krait_add_sec_mux(struct device *dev, int id, const char *s,
- unsigned int offset, bool unique_aux)
- {
-+ int ret;
- struct krait_mux_clk *mux;
- static const char *sec_mux_list[] = {
- "acpu_aux",
-@@ -102,6 +146,7 @@ krait_add_sec_mux(struct device *dev, in
- mux->shift = 2;
- mux->parent_map = sec_mux_map;
- mux->hw.init = &init;
-+ mux->safe_sel = 0;
-
- init.name = kasprintf(GFP_KERNEL, "krait%s_sec_mux", s);
- if (!init.name)
-@@ -117,6 +162,11 @@ krait_add_sec_mux(struct device *dev, in
-
- clk = devm_clk_register(dev, &mux->hw);
-
-+ ret = krait_notifier_register(dev, clk, mux);
-+ if (ret)
-+ goto unique_aux;
-+
-+unique_aux:
- if (unique_aux)
- kfree(sec_mux_list[0]);
- err_aux:
-@@ -128,6 +178,7 @@ static struct clk *
- krait_add_pri_mux(struct device *dev, int id, const char *s,
- unsigned int offset)
- {
-+ int ret;
- struct krait_mux_clk *mux;
- const char *p_names[3];
- struct clk_init_data init = {
-@@ -148,6 +199,7 @@ krait_add_pri_mux(struct device *dev, in
- mux->lpl = id >= 0;
- mux->parent_map = pri_mux_map;
- mux->hw.init = &init;
-+ mux->safe_sel = 2;
-
- init.name = kasprintf(GFP_KERNEL, "krait%s_pri_mux", s);
- if (!init.name)
-@@ -173,6 +225,10 @@ krait_add_pri_mux(struct device *dev, in
-
- clk = devm_clk_register(dev, &mux->hw);
-
-+ ret = krait_notifier_register(dev, clk, mux);
-+ if (ret)
-+ goto err_p3;
-+err_p3:
- kfree(p_names[2]);
- err_p2:
- kfree(p_names[1]);
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