clk: at91: clk-generated: pass the id of changeable parent at registration

Pass the ID of changeable parent at registration. This will allow
the scalability of this clock driver with regards to the changeable
parent ID for versions of this IP where changeable parent is not the
last one in the parents list (e.g. SAMA7G5). With this the clock flags
are set to zero in case we have no changeable parent. Also in
clk_generated_best_diff() the *best_diff variable is check against
tmp_diff variable using ">=" operator instead of ">" so that in case
the requested frequency could be obtained using fix parents + gck
dividers but the clock also supports changeable parent to be able
to force the usage of the changeable parent.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1595403506-8209-11-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

1 files changed, 14 insertions, 12 deletions

diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
index 2448bdc63425..f9ca04c97128 100644
--- a/drivers/clk/at91/clk-generated.c
+++ b/drivers/clk/at91/clk-generated.c
@@ -18,8 +18,6 @@
 
 #define GENERATED_MAX_DIV	255
 
-#define GCK_INDEX_DT_AUDIO_PLL	5
-
 struct clk_generated {
 	struct clk_hw hw;
 	struct regmap *regmap;
@@ -29,7 +27,7 @@ struct clk_generated {
 	u32 gckdiv;
 	const struct clk_pcr_layout *layout;
 	u8 parent_id;
-	bool audio_pll_allowed;
+	int chg_pid;
 };
 
 #define to_clk_generated(hw) \
@@ -109,7 +107,7 @@ static void clk_generated_best_diff(struct clk_rate_request *req,
 		tmp_rate = parent_rate / div;
 	tmp_diff = abs(req->rate - tmp_rate);
 
-	if (*best_diff < 0 || *best_diff > tmp_diff) {
+	if (*best_diff < 0 || *best_diff >= tmp_diff) {
 		*best_rate = tmp_rate;
 		*best_diff = tmp_diff;
 		req->best_parent_rate = parent_rate;
@@ -129,7 +127,10 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
 	int i;
 	u32 div;
 
-	for (i = 0; i < clk_hw_get_num_parents(hw) - 1; i++) {
+	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
+		if (gck->chg_pid == i)
+			continue;
+
 		parent = clk_hw_get_parent_by_index(hw, i);
 		if (!parent)
 			continue;
@@ -161,10 +162,10 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
 	 * that the only clks able to modify gck rate are those of audio IPs.
 	 */
 
-	if (!gck->audio_pll_allowed)
+	if (gck->chg_pid < 0)
 		goto end;
 
-	parent = clk_hw_get_parent_by_index(hw, GCK_INDEX_DT_AUDIO_PLL);
+	parent = clk_hw_get_parent_by_index(hw, gck->chg_pid);
 	if (!parent)
 		goto end;
 
@@ -272,8 +273,8 @@ struct clk_hw * __init
 at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock,
 			    const struct clk_pcr_layout *layout,
 			    const char *name, const char **parent_names,
-			    u8 num_parents, u8 id, bool pll_audio,
-			    const struct clk_range *range)
+			    u8 num_parents, u8 id,
+			    const struct clk_range *range, int chg_pid)
 {
 	struct clk_generated *gck;
 	struct clk_init_data init;
@@ -288,15 +289,16 @@ at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock,
 	init.ops = &generated_ops;
 	init.parent_names = parent_names;
 	init.num_parents = num_parents;
-	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
-		CLK_SET_RATE_PARENT;
+	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
+	if (chg_pid >= 0)
+		init.flags |= CLK_SET_RATE_PARENT;
 
 	gck->id = id;
 	gck->hw.init = &init;
 	gck->regmap = regmap;
 	gck->lock = lock;
 	gck->range = *range;
-	gck->audio_pll_allowed = pll_audio;
+	gck->chg_pid = chg_pid;
 	gck->layout = layout;
 
 	clk_generated_startup(gck);