clk: change clk_ops' ->determine_rate() prototype

Clock rates are stored in an unsigned long field, but ->determine_rate()
(which returns a rounded rate from a requested one) returns a long
value (errors are reported using negative error codes), which can lead
to long overflow if the clock rate exceed 2Ghz.

Change ->determine_rate() prototype to return 0 or an error code, and pass
a pointer to a clk_rate_request structure containing the expected target
rate and the rate constraints imposed by clk users.

The clk_rate_request structure might be extended in the future to contain
other kind of constraints like the rounding policy, the maximum clock
inaccuracy or other things that are not yet supported by the CCF
(power consumption constraints ?).

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
CC: Jonathan Corbet <corbet@lwn.net>
CC: Tony Lindgren <tony@atomide.com>
CC: Ralf Baechle <ralf@linux-mips.org>
CC: "Emilio López" <emilio@elopez.com.ar>
CC: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Tero Kristo <t-kristo@ti.com>
CC: Peter De Schrijver <pdeschrijver@nvidia.com>
CC: Prashant Gaikwad <pgaikwad@nvidia.com>
CC: Stephen Warren <swarren@wwwdotorg.org>
CC: Thierry Reding <thierry.reding@gmail.com>
CC: Alexandre Courbot <gnurou@gmail.com>
CC: linux-doc@vger.kernel.org
CC: linux-kernel@vger.kernel.org
CC: linux-arm-kernel@lists.infradead.org
CC: linux-omap@vger.kernel.org
CC: linux-mips@linux-mips.org
CC: linux-tegra@vger.kernel.org
[sboyd@codeaurora.org: Fix parent dereference problem in
__clk_determine_rate()]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Romain Perier <romain.perier@gmail.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
[sboyd@codeaurora.org: Folded in fix from Heiko for fixed-rate
clocks without parents or a rate determining op]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

2 files changed, 27 insertions, 26 deletions

diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
index 8c86c0f7..43dacad 100644
--- a/drivers/clk/at91/clk-programmable.c
+++ b/drivers/clk/at91/clk-programmable.c
@@ -54,12 +54,8 @@ static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
 	return parent_rate >> pres;
 }
 
-static long clk_programmable_determine_rate(struct clk_hw *hw,
-					    unsigned long rate,
-					    unsigned long min_rate,
-					    unsigned long max_rate,
-					    unsigned long *best_parent_rate,
-					    struct clk_hw **best_parent_hw)
+static int clk_programmable_determine_rate(struct clk_hw *hw,
+					   struct clk_rate_request *req)
 {
 	struct clk *parent = NULL;
 	long best_rate = -EINVAL;
@@ -76,24 +72,29 @@ static long clk_programmable_determine_rate(struct clk_hw *hw,
 		parent_rate = __clk_get_rate(parent);
 		for (shift = 0; shift < PROG_PRES_MASK; shift++) {
 			tmp_rate = parent_rate >> shift;
-			if (tmp_rate <= rate)
+			if (tmp_rate <= req->rate)
 				break;
 		}
 
-		if (tmp_rate > rate)
+		if (tmp_rate > req->rate)
 			continue;
 
-		if (best_rate < 0 || (rate - tmp_rate) < (rate - best_rate)) {
+		if (best_rate < 0 ||
+		    (req->rate - tmp_rate) < (req->rate - best_rate)) {
 			best_rate = tmp_rate;
-			*best_parent_rate = parent_rate;
-			*best_parent_hw = __clk_get_hw(parent);
+			req->best_parent_rate = parent_rate;
+			req->best_parent_hw = __clk_get_hw(parent);
 		}
 
 		if (!best_rate)
 			break;
 	}
 
-	return best_rate;
+	if (best_rate < 0)
+		return best_rate;
+
+	req->rate = best_rate;
+	return 0;
 }
 
 static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)
diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c
index b0cbd2b..24747df 100644
--- a/drivers/clk/at91/clk-usb.c
+++ b/drivers/clk/at91/clk-usb.c
@@ -56,12 +56,8 @@ static unsigned long at91sam9x5_clk_usb_recalc_rate(struct clk_hw *hw,
 	return DIV_ROUND_CLOSEST(parent_rate, (usbdiv + 1));
 }
 
-static long at91sam9x5_clk_usb_determine_rate(struct clk_hw *hw,
-					      unsigned long rate,
-					      unsigned long min_rate,
-					      unsigned long max_rate,
-					      unsigned long *best_parent_rate,
-					      struct clk_hw **best_parent_hw)
+static int at91sam9x5_clk_usb_determine_rate(struct clk_hw *hw,
+					     struct clk_rate_request *req)
 {
 	struct clk *parent = NULL;
 	long best_rate = -EINVAL;
@@ -80,23 +76,23 @@ static long at91sam9x5_clk_usb_determine_rate(struct clk_hw *hw,
 		for (div = 1; div < SAM9X5_USB_MAX_DIV + 2; div++) {
 			unsigned long tmp_parent_rate;
 
-			tmp_parent_rate = rate * div;
+			tmp_parent_rate = req->rate * div;
 			tmp_parent_rate = __clk_round_rate(parent,
 							   tmp_parent_rate);
 			tmp_rate = DIV_ROUND_CLOSEST(tmp_parent_rate, div);
-			if (tmp_rate < rate)
-				tmp_diff = rate - tmp_rate;
+			if (tmp_rate < req->rate)
+				tmp_diff = req->rate - tmp_rate;
 			else
-				tmp_diff = tmp_rate - rate;
+				tmp_diff = tmp_rate - req->rate;
 
 			if (best_diff < 0 || best_diff > tmp_diff) {
 				best_rate = tmp_rate;
 				best_diff = tmp_diff;
-				*best_parent_rate = tmp_parent_rate;
-				*best_parent_hw = __clk_get_hw(parent);
+				req->best_parent_rate = tmp_parent_rate;
+				req->best_parent_hw = __clk_get_hw(parent);
 			}
 
-			if (!best_diff || tmp_rate < rate)
+			if (!best_diff || tmp_rate < req->rate)
 				break;
 		}
 
@@ -104,7 +100,11 @@ static long at91sam9x5_clk_usb_determine_rate(struct clk_hw *hw,
 			break;
 	}
 
-	return best_rate;
+	if (best_rate < 0)
+		return best_rate;
+
+	req->rate = best_rate;
+	return 0;
 }
 
 static int at91sam9x5_clk_usb_set_parent(struct clk_hw *hw, u8 index)