Merge tag 'clk-for-linus-3.18' of git://git.linaro.org/people/mike.turquette/linux

Pull clock tree updates from Mike Turquette:
 "The clk tree changes for 3.18 are dominated by clock drivers.  Mostly
  fixes and enhancements to existing drivers as well as new drivers.
  This tag contains a bit more arch code than I usually take due to some
  OMAP2+ changes.  Additionally it contains the restart notifier
  handlers which are merged as a dependency into several trees.

  The PXA changes are the only messy part.  Due to having a stable tree
  I had to revert one patch and follow up with one more fix near the tip
  of this tag.  Some dead code is introduced but it will soon become
  live code after 3.18-rc1 is released as the rest of the PXA family is
  converted over to the common clock framework.

  Another trend in this tag is that multiple vendors have started to
  push the complexity of changing their CPU frequency into the clock
  driver, whereas this used to be done in CPUfreq drivers.

  Changes to the clk core include a generic gpio-clock type and a
  clk_set_phase() function added to the top-level clk.h api.  Due to
  some confusion on the fbdev mailing list the kernel boot parameters
  documentation was updated to further explain the clk_ignore_unused
  parameter, which is often required by users of the simplefb driver.

  Finally some fixes to the locking around the clock debugfs stuff was
  done to prevent deadlocks when interacting with other subsystems."

* tag 'clk-for-linus-3.18' of git://git.linaro.org/people/mike.turquette/linux: (99 commits)
  clk: pxa clocks build system fix
  Revert "arm: pxa: Transition pxa27x to clk framework"
  clk: samsung: register restart handlers for s3c2412 and s3c2443
  clk: rockchip: add restart handler
  clk: rockchip: rk3288: i2s_frac adds flag to set parent's rate
  doc/kernel-parameters.txt: clarify clk_ignore_unused
  arm: pxa: Transition pxa27x to clk framework
  dts: add devicetree bindings for pxa27x clocks
  clk: add pxa27x clock drivers
  arm: pxa: add clock pll selection bits
  clk: dts: document pxa clock binding
  clk: add pxa clocks infrastructure
  clk: gpio-gate: Ensure gpiod_ APIs are prototyped
  clk: ti: dra7-atl-clock: Mark the device as pm_runtime_irq_safe
  clk: ti: LLVMLinux: Move __init outside of type definition
  clk: ti: consider the fact that of_clk_get() might return an error
  clk: ti: dra7-atl-clock: fix a memory leak
  clk: ti: change clock init to use generic of_clk_init
  clk: hix5hd2: add I2C clocks
  clk: hix5hd2: add watchdog0 clocks
  ...

2 files changed, 96 insertions, 84 deletions

diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c
index cf6ed023504c..6ec79dbc0840 100644
--- a/drivers/clk/at91/clk-pll.c
+++ b/drivers/clk/at91/clk-pll.c
@@ -15,6 +15,7 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/io.h>
+#include <linux/kernel.h>
 #include <linux/wait.h>
 #include <linux/sched.h>
 #include <linux/interrupt.h>
@@ -29,9 +30,12 @@
 #define PLL_DIV(reg)		((reg) & PLL_DIV_MASK)
 #define PLL_MUL(reg, layout)	(((reg) >> (layout)->mul_shift) & \
 				 (layout)->mul_mask)
+#define PLL_MUL_MIN		2
+#define PLL_MUL_MASK(layout)	((layout)->mul_mask)
+#define PLL_MUL_MAX(layout)	(PLL_MUL_MASK(layout) + 1)
 #define PLL_ICPR_SHIFT(id)	((id) * 16)
 #define PLL_ICPR_MASK(id)	(0xffff << PLL_ICPR_SHIFT(id))
-#define PLL_MAX_COUNT		0x3ff
+#define PLL_MAX_COUNT		0x3f
 #define PLL_COUNT_SHIFT		8
 #define PLL_OUT_SHIFT		14
 #define PLL_MAX_ID		1
@@ -147,115 +151,113 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
 					 unsigned long parent_rate)
 {
 	struct clk_pll *pll = to_clk_pll(hw);
-	const struct clk_pll_layout *layout = pll->layout;
-	struct at91_pmc *pmc = pll->pmc;
-	int offset = PLL_REG(pll->id);
-	u32 tmp = pmc_read(pmc, offset) & layout->pllr_mask;
-	u8 div = PLL_DIV(tmp);
-	u16 mul = PLL_MUL(tmp, layout);
-	if (!div || !mul)
+
+	if (!pll->div || !pll->mul)
 		return 0;
 
-	return (parent_rate * (mul + 1)) / div;
+	return (parent_rate / pll->div) * (pll->mul + 1);
 }
 
 static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
 				     unsigned long parent_rate,
 				     u32 *div, u32 *mul,
 				     u32 *index) {
-	unsigned long maxrate;
-	unsigned long minrate;
-	unsigned long divrate;
-	unsigned long bestdiv = 1;
-	unsigned long bestmul;
-	unsigned long tmpdiv;
-	unsigned long roundup;
-	unsigned long rounddown;
-	unsigned long remainder;
-	unsigned long bestremainder;
-	unsigned long maxmul;
-	unsigned long maxdiv;
-	unsigned long mindiv;
-	int i = 0;
 	const struct clk_pll_layout *layout = pll->layout;
 	const struct clk_pll_characteristics *characteristics =
 							pll->characteristics;
+	unsigned long bestremainder = ULONG_MAX;
+	unsigned long maxdiv, mindiv, tmpdiv;
+	long bestrate = -ERANGE;
+	unsigned long bestdiv;
+	unsigned long bestmul;
+	int i = 0;
 
-	/* Minimum divider = 1 */
-	/* Maximum multiplier = max_mul */
-	maxmul = layout->mul_mask + 1;
-	maxrate = (parent_rate * maxmul) / 1;
-
-	/* Maximum divider = max_div */
-	/* Minimum multiplier = 2 */
-	maxdiv = PLL_DIV_MAX;
-	minrate = (parent_rate * 2) / maxdiv;
-
+	/* Check if parent_rate is a valid input rate */
 	if (parent_rate < characteristics->input.min ||
-	    parent_rate < characteristics->input.max)
-		return -ERANGE;
-
-	if (parent_rate < minrate || parent_rate > maxrate)
+	    parent_rate > characteristics->input.max)
 		return -ERANGE;
 
-	for (i = 0; i < characteristics->num_output; i++) {
-		if (parent_rate >= characteristics->output[i].min &&
-		    parent_rate <= characteristics->output[i].max)
-			break;
-	}
-
-	if (i >= characteristics->num_output)
-		return -ERANGE;
-
-	bestmul = rate / parent_rate;
-	rounddown = parent_rate % rate;
-	roundup = rate - rounddown;
-	bestremainder = roundup < rounddown ? roundup : rounddown;
-
-	if (!bestremainder) {
-		if (div)
-			*div = bestdiv;
-		if (mul)
-			*mul = bestmul;
-		if (index)
-			*index = i;
-		return rate;
-	}
-
-	maxdiv = 255 / (bestmul + 1);
-	if (parent_rate / maxdiv < characteristics->input.min)
-		maxdiv = parent_rate / characteristics->input.min;
-	mindiv = parent_rate / characteristics->input.max;
-	if (parent_rate % characteristics->input.max)
-		mindiv++;
-
-	for (tmpdiv = mindiv; tmpdiv < maxdiv; tmpdiv++) {
-		divrate = parent_rate / tmpdiv;
-
-		rounddown = rate % divrate;
-		roundup = divrate - rounddown;
-		remainder = roundup < rounddown ? roundup : rounddown;
-
+	/*
+	 * Calculate minimum divider based on the minimum multiplier, the
+	 * parent_rate and the requested rate.
+	 * Should always be 2 according to the input and output characteristics
+	 * of the PLL blocks.
+	 */
+	mindiv = (parent_rate * PLL_MUL_MIN) / rate;
+	if (!mindiv)
+		mindiv = 1;
+
+	/*
+	 * Calculate the maximum divider which is limited by PLL register
+	 * layout (limited by the MUL or DIV field size).
+	 */
+	maxdiv = DIV_ROUND_UP(parent_rate * PLL_MUL_MAX(layout), rate);
+	if (maxdiv > PLL_DIV_MAX)
+		maxdiv = PLL_DIV_MAX;
+
+	/*
+	 * Iterate over the acceptable divider values to find the best
+	 * divider/multiplier pair (the one that generates the closest
+	 * rate to the requested one).
+	 */
+	for (tmpdiv = mindiv; tmpdiv <= maxdiv; tmpdiv++) {
+		unsigned long remainder;
+		unsigned long tmprate;
+		unsigned long tmpmul;
+
+		/*
+		 * Calculate the multiplier associated with the current
+		 * divider that provide the closest rate to the requested one.
+		 */
+		tmpmul = DIV_ROUND_CLOSEST(rate, parent_rate / tmpdiv);
+		tmprate = (parent_rate / tmpdiv) * tmpmul;
+		if (tmprate > rate)
+			remainder = tmprate - rate;
+		else
+			remainder = rate - tmprate;
+
+		/*
+		 * Compare the remainder with the best remainder found until
+		 * now and elect a new best multiplier/divider pair if the
+		 * current remainder is smaller than the best one.
+		 */
 		if (remainder < bestremainder) {
 			bestremainder = remainder;
-			bestmul = rate / divrate;
 			bestdiv = tmpdiv;
+			bestmul = tmpmul;
+			bestrate = tmprate;
 		}
 
+		/*
+		 * We've found a perfect match!
+		 * Stop searching now and use this multiplier/divider pair.
+		 */
 		if (!remainder)
 			break;
 	}
 
-	rate = (parent_rate / bestdiv) * bestmul;
+	/* We haven't found any multiplier/divider pair => return -ERANGE */
+	if (bestrate < 0)
+		return bestrate;
+
+	/* Check if bestrate is a valid output rate  */
+	for (i = 0; i < characteristics->num_output; i++) {
+		if (bestrate >= characteristics->output[i].min &&
+		    bestrate <= characteristics->output[i].max)
+			break;
+	}
+
+	if (i >= characteristics->num_output)
+		return -ERANGE;
 
 	if (div)
 		*div = bestdiv;
 	if (mul)
-		*mul = bestmul;
+		*mul = bestmul - 1;
 	if (index)
 		*index = i;
 
-	return rate;
+	return bestrate;
 }
 
 static long clk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c
index 7d1d26a4bd04..24b5b020753a 100644
--- a/drivers/clk/at91/clk-usb.c
+++ b/drivers/clk/at91/clk-usb.c
@@ -238,16 +238,22 @@ static long at91rm9200_clk_usb_round_rate(struct clk_hw *hw, unsigned long rate,
 					  unsigned long *parent_rate)
 {
 	struct at91rm9200_clk_usb *usb = to_at91rm9200_clk_usb(hw);
+	struct clk *parent = __clk_get_parent(hw->clk);
 	unsigned long bestrate = 0;
 	int bestdiff = -1;
 	unsigned long tmprate;
 	int tmpdiff;
 	int i = 0;
 
-	for (i = 0; i < 4; i++) {
+	for (i = 0; i < RM9200_USB_DIV_TAB_SIZE; i++) {
+		unsigned long tmp_parent_rate;
+
 		if (!usb->divisors[i])
 			continue;
-		tmprate = *parent_rate / usb->divisors[i];
+
+		tmp_parent_rate = rate * usb->divisors[i];
+		tmp_parent_rate = __clk_round_rate(parent, tmp_parent_rate);
+		tmprate = tmp_parent_rate / usb->divisors[i];
 		if (tmprate < rate)
 			tmpdiff = rate - tmprate;
 		else
@@ -256,6 +262,7 @@ static long at91rm9200_clk_usb_round_rate(struct clk_hw *hw, unsigned long rate,
 		if (bestdiff < 0 || bestdiff > tmpdiff) {
 			bestrate = tmprate;
 			bestdiff = tmpdiff;
+			*parent_rate = tmp_parent_rate;
 		}
 
 		if (!bestdiff)
@@ -272,10 +279,13 @@ static int at91rm9200_clk_usb_set_rate(struct clk_hw *hw, unsigned long rate,
 	int i;
 	struct at91rm9200_clk_usb *usb = to_at91rm9200_clk_usb(hw);
 	struct at91_pmc *pmc = usb->pmc;
-	unsigned long div = parent_rate / rate;
+	unsigned long div;
 
-	if (parent_rate % rate)
+	if (!rate || parent_rate % rate)
 		return -EINVAL;
+
+	div = parent_rate / rate;
+
 	for (i = 0; i < RM9200_USB_DIV_TAB_SIZE; i++) {
 		if (usb->divisors[i] == div) {
 			tmp = pmc_read(pmc, AT91_CKGR_PLLBR) &
@@ -311,7 +321,7 @@ at91rm9200_clk_register_usb(struct at91_pmc *pmc, const char *name,
 	init.ops = &at91rm9200_usb_ops;
 	init.parent_names = &parent_name;
 	init.num_parents = 1;
-	init.flags = 0;
+	init.flags = CLK_SET_RATE_PARENT;
 
 	usb->hw.init = &init;
 	usb->pmc = pmc;