openwrt/target/linux/brcm2708/patches-4.4/0521-clk-bcm2835-Clamp-the-PLL-s-requested-rate-to-the-ha.patch

From 4d372013a839ae71582004fbc1aa1905c73d1497 Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Wed, 28 Sep 2016 17:58:52 -0700
Subject: [PATCH] clk: bcm2835: Clamp the PLL's requested rate to the hardware
 limits.

Fixes setting low-resolution video modes on HDMI.  Now the PLLH_PIX
divider adjusts itself until the PLLH is within bounds.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/clk/bcm/clk-bcm2835.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -523,8 +523,12 @@ static long bcm2835_pll_rate_from_diviso
 static long bcm2835_pll_round_rate(struct clk_hw *hw, unsigned long rate,
 				   unsigned long *parent_rate)
 {
+	struct bcm2835_pll *pll = container_of(hw, struct bcm2835_pll, hw);
+	const struct bcm2835_pll_data *data = pll->data;
 	u32 ndiv, fdiv;
 
+	rate = clamp(rate, data->min_rate, data->max_rate);
+
 	bcm2835_pll_choose_ndiv_and_fdiv(rate, *parent_rate, &ndiv, &fdiv);
 
 	return bcm2835_pll_rate_from_divisors(*parent_rate, ndiv, fdiv, 1);
@@ -629,13 +633,6 @@ static int bcm2835_pll_set_rate(struct c
 	u32 ana[4];
 	int i;
 
-	if (rate < data->min_rate || rate > data->max_rate) {
-		dev_err(cprman->dev, "%s: rate out of spec: %lu vs (%lu, %lu)\n",
-			clk_hw_get_name(hw), rate,
-			data->min_rate, data->max_rate);
-		return -EINVAL;
-	}
-
 	if (rate > data->max_fb_rate) {
 		use_fb_prediv = true;
 		rate /= 2;