From 0f44af555e03079b9b8d8ed9833fa0fda67cd4a1 Mon Sep 17 00:00:00 2001 From: Icenowy Zheng Date: Wed, 17 Jun 2020 08:39:18 +0800 Subject: [PATCH 306/478] clk: sunxi-ng: add support for rate resetting notifier In some situaitons, we will want a clock rate be kept while its parent can change, for example, to make dual-head work on A64, TCON0 clock needs to be kept for LCD display and its parent (or grandparent) PLL-Video0 need to be changed for HDMI display. (There's a quirk on A64 that HDMI PHY can only use PLL-Video0, not PLL-Video1). Add a notifier helper to create such kind of rate keeping notifier by reset the rate after the parent changed. Signed-off-by: Icenowy Zheng --- drivers/clk/sunxi-ng/ccu_common.c | 22 ++++++++++++++++++++++ drivers/clk/sunxi-ng/ccu_common.h | 12 ++++++++++++ 2 files changed, 34 insertions(+) diff --git a/drivers/clk/sunxi-ng/ccu_common.c b/drivers/clk/sunxi-ng/ccu_common.c index 88cb569e5..5627b6a13 100644 --- a/drivers/clk/sunxi-ng/ccu_common.c +++ b/drivers/clk/sunxi-ng/ccu_common.c @@ -194,6 +194,28 @@ int devm_sunxi_ccu_probe(struct device *dev, void __iomem *reg, return 0; } +static int ccu_rate_reset_notifier_cb(struct notifier_block *nb, + unsigned long event, void *data) +{ + struct ccu_rate_reset_nb *rate_reset = to_ccu_rate_reset_nb(nb); + + if (event == PRE_RATE_CHANGE) { + rate_reset->saved_rate = clk_get_rate(rate_reset->target_clk); + } else if (event == POST_RATE_CHANGE) { + clk_set_rate(rate_reset->target_clk, rate_reset->saved_rate); + } + + return NOTIFY_DONE; +} + +int ccu_rate_reset_notifier_register(struct ccu_rate_reset_nb *rate_reset_nb) +{ + rate_reset_nb->clk_nb.notifier_call = ccu_rate_reset_notifier_cb; + + return clk_notifier_register(rate_reset_nb->common->hw.clk, + &rate_reset_nb->clk_nb); +} + void of_sunxi_ccu_probe(struct device_node *node, void __iomem *reg, const struct sunxi_ccu_desc *desc) { diff --git a/drivers/clk/sunxi-ng/ccu_common.h b/drivers/clk/sunxi-ng/ccu_common.h index 98a1834b5..4faee6619 100644 --- a/drivers/clk/sunxi-ng/ccu_common.h +++ b/drivers/clk/sunxi-ng/ccu_common.h @@ -63,6 +63,18 @@ struct ccu_pll_nb { int ccu_pll_notifier_register(struct ccu_pll_nb *pll_nb); +struct ccu_rate_reset_nb { + struct notifier_block clk_nb; + struct ccu_common *common; + + struct clk *target_clk; + unsigned long saved_rate; +}; + +#define to_ccu_rate_reset_nb(_nb) container_of(_nb, struct ccu_rate_reset_nb, clk_nb) + +int ccu_rate_reset_notifier_register(struct ccu_rate_reset_nb *rate_reset_nb); + int devm_sunxi_ccu_probe(struct device *dev, void __iomem *reg, const struct sunxi_ccu_desc *desc); void of_sunxi_ccu_probe(struct device_node *node, void __iomem *reg, -- 2.35.3