linux-kernel - [PATCH v5 21/21] clk: tegra: pll: Fix issues with rates for VCO PLLs

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Message-ID: <1431451444-23155-23-git-send-email-rklein@nvidia.com>
Date:	Tue, 12 May 2015 13:24:04 -0400
From:	Rhyland Klein <rklein@...dia.com>
To:	Peter De Schrijver <pdeschrijver@...dia.com>
CC:	Mike Turquette <mturquette@...aro.org>,
	Stephen Warren <swarren@...dotorg.org>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Alexandre Courbot <gnurou@...il.com>,
	Bill Huang <bilhuang@...dia.com>,
	Paul Walmsley <pwalmsley@...dia.com>,
	Jim Lin <jilin@...dia.com>, Benson Leung <bleung@...omium.org>,
	linux-clk@...r.kernel.org, linux-tegra@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Andrew Bresticker <abrestic@...omium.org>,
	Rhyland Klein <rklein@...dia.com>
Subject: [PATCH v5 21/21] clk: tegra: pll: Fix issues with rates for VCO PLLs

From: Andrew Bresticker <abrestic@...omium.org>

Without this change clk_get_rate would return the final output
rather than the VCO output as it would factor in the pdiv when
it shouldn't. This will cause problems for all dividers in the
subtree of the VCO PLL.

Signed-off-by: Andrew Bresticker <abrestic@...omium.org>
Signed-off-by: Rhyland Klein <rklein@...dia.com>
---
v5:
  - Switched to using flag for VCO_OUT

v3:
  - Added fix for this bug which was found during testing

 drivers/clk/tegra/clk-pll.c |   16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
index 43d7ee4fb603..11d97fd559d6 100644
--- a/drivers/clk/tegra/clk-pll.c
+++ b/drivers/clk/tegra/clk-pll.c
@@ -737,6 +737,8 @@ static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 		spin_lock_irqsave(pll->lock, flags);
 
 	_get_pll_mnp(pll, &old_cfg);
+	if (pll->params->flags & TEGRA_PLL_VCO_OUT)
+		cfg.p = old_cfg.p;
 
 	if (old_cfg.m != cfg.m || old_cfg.n != cfg.n || old_cfg.p != cfg.p ||
 		old_cfg.sdm_data != cfg.sdm_data)
@@ -796,11 +798,15 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
 
 	_get_pll_mnp(pll, &cfg);
 
-	pdiv = _hw_to_p_div(hw, cfg.p);
-	if (pdiv < 0) {
-		WARN(1, "Clock %s has invalid pdiv value : 0x%x\n",
-			__clk_get_name(hw->clk), cfg.p);
+	if (pll->params->flags & TEGRA_PLL_VCO_OUT) {
 		pdiv = 1;
+	} else {
+		pdiv = _hw_to_p_div(hw, cfg.p);
+		if (pdiv < 0) {
+			WARN(1, "Clock %s has invalid pdiv value : 0x%x\n",
+				__clk_get_name(hw->clk), cfg.p);
+			pdiv = 1;
+		}
 	}
 
 	if (pll->params->set_gain)
@@ -1087,6 +1093,8 @@ static int clk_pllxc_set_rate(struct clk_hw *hw, unsigned long rate,
 		spin_lock_irqsave(pll->lock, flags);
 
 	_get_pll_mnp(pll, &old_cfg);
+	if (pll->params->flags & TEGRA_PLL_VCO_OUT)
+		cfg.p = old_cfg.p;
 
 	if (old_cfg.m != cfg.m || old_cfg.n != cfg.n || old_cfg.p != cfg.p)
 		ret = _program_pll(hw, &cfg, rate);
-- 
1.7.9.5

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