79 lines
2.8 KiB
Diff
79 lines
2.8 KiB
Diff
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From f5046f071cd795a5a7d575d1077df108797b80ad Mon Sep 17 00:00:00 2001
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From: Icenowy Zheng <icenowy@aosc.io>
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Date: Wed, 17 Jun 2020 08:39:18 +0800
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Subject: [PATCH 202/469] clk: sunxi-ng: add support for rate resetting
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notifier
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In some situaitons, we will want a clock rate be kept while its parent
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can change, for example, to make dual-head work on A64, TCON0 clock
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needs to be kept for LCD display and its parent (or grandparent)
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PLL-Video0 need to be changed for HDMI display. (There's a quirk on A64
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that HDMI PHY can only use PLL-Video0, not PLL-Video1).
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Add a notifier helper to create such kind of rate keeping notifier by
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reset the rate after the parent changed.
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Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
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---
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drivers/clk/sunxi-ng/ccu_common.c | 22 ++++++++++++++++++++++
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drivers/clk/sunxi-ng/ccu_common.h | 12 ++++++++++++
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2 files changed, 34 insertions(+)
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diff --git a/drivers/clk/sunxi-ng/ccu_common.c b/drivers/clk/sunxi-ng/ccu_common.c
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index 8d28a7a079d0..434fa46ad460 100644
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--- a/drivers/clk/sunxi-ng/ccu_common.c
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+++ b/drivers/clk/sunxi-ng/ccu_common.c
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@@ -87,6 +87,28 @@ int ccu_pll_notifier_register(struct ccu_pll_nb *pll_nb)
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}
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EXPORT_SYMBOL_NS_GPL(ccu_pll_notifier_register, SUNXI_CCU);
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+static int ccu_rate_reset_notifier_cb(struct notifier_block *nb,
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+ unsigned long event, void *data)
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+{
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+ struct ccu_rate_reset_nb *rate_reset = to_ccu_rate_reset_nb(nb);
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+
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+ if (event == PRE_RATE_CHANGE) {
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+ rate_reset->saved_rate = clk_get_rate(rate_reset->target_clk);
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+ } else if (event == POST_RATE_CHANGE) {
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+ clk_set_rate(rate_reset->target_clk, rate_reset->saved_rate);
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+ }
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+
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+ return NOTIFY_DONE;
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+}
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+
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+int ccu_rate_reset_notifier_register(struct ccu_rate_reset_nb *rate_reset_nb)
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+{
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+ rate_reset_nb->clk_nb.notifier_call = ccu_rate_reset_notifier_cb;
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+
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+ return clk_notifier_register(rate_reset_nb->common->hw.clk,
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+ &rate_reset_nb->clk_nb);
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+}
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+
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static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
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struct device_node *node, void __iomem *reg,
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const struct sunxi_ccu_desc *desc)
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diff --git a/drivers/clk/sunxi-ng/ccu_common.h b/drivers/clk/sunxi-ng/ccu_common.h
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index fbf16c6b896d..6b0b05fae123 100644
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--- a/drivers/clk/sunxi-ng/ccu_common.h
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+++ b/drivers/clk/sunxi-ng/ccu_common.h
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@@ -69,4 +69,16 @@ int devm_sunxi_ccu_probe(struct device *dev, void __iomem *reg,
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void of_sunxi_ccu_probe(struct device_node *node, void __iomem *reg,
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const struct sunxi_ccu_desc *desc);
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+struct ccu_rate_reset_nb {
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+ struct notifier_block clk_nb;
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+ struct ccu_common *common;
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+
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+ struct clk *target_clk;
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+ unsigned long saved_rate;
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+};
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+
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+#define to_ccu_rate_reset_nb(_nb) container_of(_nb, struct ccu_rate_reset_nb, clk_nb)
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+
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+int ccu_rate_reset_notifier_register(struct ccu_rate_reset_nb *rate_reset_nb);
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+
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#endif /* _COMMON_H_ */
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--
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2.34.1
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