linux-kernel - [PATCH AUTOSEL 5.3 78/87] clk: imx: clk-pll14xx: unbypass PLL by default

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Date:   Tue, 24 Sep 2019 12:41:34 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Peng Fan <peng.fan@....com>,
        Leonard Crestez <leonard.crestez@....com>,
        Stephen Boyd <sboyd@...nel.org>,
        Sasha Levin <sashal@...nel.org>, linux-clk@...r.kernel.org
Subject: [PATCH AUTOSEL 5.3 78/87] clk: imx: clk-pll14xx: unbypass PLL by default

From: Peng Fan <peng.fan@....com>

[ Upstream commit a9aa8306074d9519dd6e5fdf07240b01bac72e04 ]

When registering the PLL, unbypass the PLL.
The PLL has two bypass control bit, BYPASS and EXT_BYPASS.
we will expose EXT_BYPASS to clk driver for mux usage, and keep
BYPASS inside pll14xx usage. The PLL has a restriction that
when M/P change, need to RESET/BYPASS pll to avoid glitch, so
we could not expose BYPASS.

To make it easy for clk driver usage, unbypass PLL which does
not hurt current function.

Fixes: 8646d4dcc7fb ("clk: imx: Add PLLs driver for imx8mm soc")
Reviewed-by: Leonard Crestez <leonard.crestez@....com>
Signed-off-by: Peng Fan <peng.fan@....com>
Link: https://lkml.kernel.org/r/1568043491-20680-3-git-send-email-peng.fan@nxp.com
Signed-off-by: Stephen Boyd <sboyd@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/clk/imx/clk-pll14xx.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/clk/imx/clk-pll14xx.c b/drivers/clk/imx/clk-pll14xx.c
index 656f48b002dd3..7a815ec76aa5c 100644
--- a/drivers/clk/imx/clk-pll14xx.c
+++ b/drivers/clk/imx/clk-pll14xx.c
@@ -368,6 +368,7 @@ struct clk *imx_clk_pll14xx(const char *name, const char *parent_name,
 	struct clk_pll14xx *pll;
 	struct clk *clk;
 	struct clk_init_data init;
+	u32 val;
 
 	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
 	if (!pll)
@@ -399,6 +400,10 @@ struct clk *imx_clk_pll14xx(const char *name, const char *parent_name,
 	pll->rate_table = pll_clk->rate_table;
 	pll->rate_count = pll_clk->rate_count;
 
+	val = readl_relaxed(pll->base + GNRL_CTL);
+	val &= ~BYPASS_MASK;
+	writel_relaxed(val, pll->base + GNRL_CTL);
+
 	clk = clk_register(NULL, &pll->hw);
 	if (IS_ERR(clk)) {
 		pr_err("%s: failed to register pll %s %lu\n",
-- 
2.20.1