6.6-stable review patch. If anyone has any objections, please let me know.
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From: Xingyu Wu xingyu.wu@starfivetech.com
commit 538d5477b25289ac5d46ca37b9e5b4d685cbe019 upstream.
Add notifier function for PLL0 clock. In the function, the cpu_root clock should be operated by saving its current parent and setting a new safe parent (osc clock) before setting the PLL0 clock rate. After setting PLL0 rate, it should be switched back to the original parent clock.
Fixes: e2c510d6d630 ("riscv: dts: starfive: Add cpu scaling for JH7110 SoC") Cc: stable@vger.kernel.org Reviewed-by: Emil Renner Berthing emil.renner.berthing@canonical.com Signed-off-by: Xingyu Wu xingyu.wu@starfivetech.com Link: https://lore.kernel.org/r/20240826080430.179788-2-xingyu.wu@starfivetech.com Reviewed-by: Hal Feng hal.feng@starfivetech.com Tested-by: Michael Jeanson mjeanson@efficios.com Signed-off-by: Stephen Boyd sboyd@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- .../clk/starfive/clk-starfive-jh7110-sys.c | 31 ++++++++++++++++++- drivers/clk/starfive/clk-starfive-jh71x0.h | 2 ++ 2 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/starfive/clk-starfive-jh7110-sys.c b/drivers/clk/starfive/clk-starfive-jh7110-sys.c index 8f5e5abfa178..17325f17696f 100644 --- a/drivers/clk/starfive/clk-starfive-jh7110-sys.c +++ b/drivers/clk/starfive/clk-starfive-jh7110-sys.c @@ -385,6 +385,32 @@ int jh7110_reset_controller_register(struct jh71x0_clk_priv *priv, } EXPORT_SYMBOL_GPL(jh7110_reset_controller_register);
+/* + * This clock notifier is called when the rate of PLL0 clock is to be changed. + * The cpu_root clock should save the curent parent clock and switch its parent + * clock to osc before PLL0 rate will be changed. Then switch its parent clock + * back after the PLL0 rate is completed. + */ +static int jh7110_pll0_clk_notifier_cb(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct jh71x0_clk_priv *priv = container_of(nb, struct jh71x0_clk_priv, pll_clk_nb); + struct clk *cpu_root = priv->reg[JH7110_SYSCLK_CPU_ROOT].hw.clk; + int ret = 0; + + if (action == PRE_RATE_CHANGE) { + struct clk *osc = clk_get(priv->dev, "osc"); + + priv->original_clk = clk_get_parent(cpu_root); + ret = clk_set_parent(cpu_root, osc); + clk_put(osc); + } else if (action == POST_RATE_CHANGE) { + ret = clk_set_parent(cpu_root, priv->original_clk); + } + + return notifier_from_errno(ret); +} + static int __init jh7110_syscrg_probe(struct platform_device *pdev) { struct jh71x0_clk_priv *priv; @@ -413,7 +439,10 @@ static int __init jh7110_syscrg_probe(struct platform_device *pdev) if (IS_ERR(priv->pll[0])) return PTR_ERR(priv->pll[0]); } else { - clk_put(pllclk); + priv->pll_clk_nb.notifier_call = jh7110_pll0_clk_notifier_cb; + ret = clk_notifier_register(pllclk, &priv->pll_clk_nb); + if (ret) + return ret; priv->pll[0] = NULL; }
diff --git a/drivers/clk/starfive/clk-starfive-jh71x0.h b/drivers/clk/starfive/clk-starfive-jh71x0.h index 23e052fc1549..e3f441393e48 100644 --- a/drivers/clk/starfive/clk-starfive-jh71x0.h +++ b/drivers/clk/starfive/clk-starfive-jh71x0.h @@ -114,6 +114,8 @@ struct jh71x0_clk_priv { spinlock_t rmw_lock; struct device *dev; void __iomem *base; + struct clk *original_clk; + struct notifier_block pll_clk_nb; struct clk_hw *pll[3]; struct jh71x0_clk reg[]; };