diff mbox series

[8/8] clk: imx: pll14xx: Support dynamic rates

Message ID 20220223075601.3652543-9-s.hauer@pengutronix.de (mailing list archive)
State Superseded, archived
Headers show
Series clk: i.MX: PLL14xx: Support dynamic rates | expand

Commit Message

Sascha Hauer Feb. 23, 2022, 7:56 a.m. UTC 
The pll1443x PLL so far only supports rates from a rate table passed
during initialization. Calculating PLL settings dynamically helps audio
applications to get their desired rates, so support for this is added
in this patch.

The strategy to get to the PLL setting for a rate is:

- First try to only adjust kdiv which specifies the fractional part of the PLL.
  This setting can be changed without glitches on the output and is therefore
  preferred
- When that isn't possible then the rate table is searched for suitable rates,
  so for standard rates the same settings are used as without this patch
- As a last resort the best settings are calculated dynamically

The code in this patch is based on patches from Adrian Alonso <adrian.alonso@nxp.com>
and Mads Bligaard Nielsen <bli@bang-olufsen.dk>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/clk/imx/clk-pll14xx.c | 143 ++++++++++++++++++++++++++++++----
 1 file changed, 126 insertions(+), 17 deletions(-)

Comments

kernel test robot Feb. 23, 2022, 12:48 p.m. UTC | #1 
Hi Sascha,

I love your patch! Perhaps something to improve:

[auto build test WARNING on shawnguo/for-next]
[also build test WARNING on clk/clk-next v5.17-rc5 next-20220222]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Sascha-Hauer/clk-i-MX-PLL14xx-Support-dynamic-rates/20220223-155846
base:   https://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git for-next
config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20220223/202202232005.F6GoajML-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/c2601acc01166ae3f20b60817e44d3e94a023c6f
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sascha-Hauer/clk-i-MX-PLL14xx-Support-dynamic-rates/20220223-155846
        git checkout c2601acc01166ae3f20b60817e44d3e94a023c6f
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=alpha SHELL=/bin/bash drivers/clk/imx/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/clk/imx/clk-pll14xx.c: In function 'imx_pll14xx_calc_settings':
   drivers/clk/imx/clk-pll14xx.c:149:16: error: implicit declaration of function 'FIELD_GET'; did you mean 'FOLL_GET'? [-Werror=implicit-function-declaration]
     149 |         mdiv = FIELD_GET(MDIV_MASK, pll_div_ctl0);
         |                ^~~~~~~~~
         |                FOLL_GET
>> drivers/clk/imx/clk-pll14xx.c:6:21: warning: format '%ld' expects argument of type 'long int', but argument 6 has type 'int' [-Wformat=]
       6 | #define pr_fmt(fmt) "pll14xx: " fmt
         |                     ^~~~~~~~~~~
   include/linux/dynamic_debug.h:134:29: note: in expansion of macro 'pr_fmt'
     134 |                 func(&id, ##__VA_ARGS__);               \
         |                             ^~~~~~~~~~~
   include/linux/dynamic_debug.h:152:9: note: in expansion of macro '__dynamic_func_call'
     152 |         __dynamic_func_call(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
         |         ^~~~~~~~~~~~~~~~~~~
   include/linux/dynamic_debug.h:162:9: note: in expansion of macro '_dynamic_func_call'
     162 |         _dynamic_func_call(fmt, __dynamic_pr_debug,             \
         |         ^~~~~~~~~~~~~~~~~~
   include/linux/printk.h:570:9: note: in expansion of macro 'dynamic_pr_debug'
     570 |         dynamic_pr_debug(fmt, ##__VA_ARGS__)
         |         ^~~~~~~~~~~~~~~~
   drivers/clk/imx/clk-pll14xx.c:160:17: note: in expansion of macro 'pr_debug'
     160 |                 pr_debug("%s: in=%ld, want=%ld Only adjust kdiv %ld -> %d\n",
         |                 ^~~~~~~~
   In file included from include/asm-generic/bug.h:22,
                    from arch/alpha/include/asm/bug.h:23,
                    from include/linux/bug.h:5,
                    from include/linux/thread_info.h:13,
                    from include/asm-generic/current.h:5,
                    from ./arch/alpha/include/generated/asm/current.h:1,
                    from include/linux/mutex.h:14,
                    from include/linux/kernfs.h:11,
                    from include/linux/sysfs.h:16,
                    from include/linux/kobject.h:20,
                    from include/linux/of.h:17,
                    from include/linux/clk-provider.h:9,
                    from drivers/clk/imx/clk-pll14xx.c:9:
   drivers/clk/imx/clk-pll14xx.c: In function 'clk_pll1416x_set_rate':
   include/linux/kern_levels.h:5:25: warning: format '%lu' expects argument of type 'long unsigned int', but argument 2 has type 'const char *' [-Wformat=]
       5 | #define KERN_SOH        "\001"          /* ASCII Start Of Header */
         |                         ^~~~~~
   include/linux/printk.h:418:25: note: in definition of macro 'printk_index_wrap'
     418 |                 _p_func(_fmt, ##__VA_ARGS__);                           \
         |                         ^~~~
   include/linux/printk.h:489:9: note: in expansion of macro 'printk'
     489 |         printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
         |         ^~~~~~
   include/linux/kern_levels.h:11:25: note: in expansion of macro 'KERN_SOH'
      11 | #define KERN_ERR        KERN_SOH "3"    /* error conditions */
         |                         ^~~~~~~~
   include/linux/printk.h:489:16: note: in expansion of macro 'KERN_ERR'
     489 |         printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
         |                ^~~~~~~~
   drivers/clk/imx/clk-pll14xx.c:293:17: note: in expansion of macro 'pr_err'
     293 |                 pr_err("Invalid rate %lu for pll clk %s\n", __func__,
         |                 ^~~~~~
   include/linux/kern_levels.h:5:25: warning: format '%s' expects argument of type 'char *', but argument 3 has type 'long unsigned int' [-Wformat=]
       5 | #define KERN_SOH        "\001"          /* ASCII Start Of Header */
         |                         ^~~~~~
   include/linux/printk.h:418:25: note: in definition of macro 'printk_index_wrap'
     418 |                 _p_func(_fmt, ##__VA_ARGS__);                           \
         |                         ^~~~
   include/linux/printk.h:489:9: note: in expansion of macro 'printk'
     489 |         printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
         |         ^~~~~~
   include/linux/kern_levels.h:11:25: note: in expansion of macro 'KERN_SOH'
      11 | #define KERN_ERR        KERN_SOH "3"    /* error conditions */
         |                         ^~~~~~~~
   include/linux/printk.h:489:16: note: in expansion of macro 'KERN_ERR'
     489 |         printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
         |                ^~~~~~~~
   drivers/clk/imx/clk-pll14xx.c:293:17: note: in expansion of macro 'pr_err'
     293 |                 pr_err("Invalid rate %lu for pll clk %s\n", __func__,
         |                 ^~~~~~
   include/linux/kern_levels.h:5:25: warning: too many arguments for format [-Wformat-extra-args]
       5 | #define KERN_SOH        "\001"          /* ASCII Start Of Header */
         |                         ^~~~~~
   include/linux/printk.h:418:25: note: in definition of macro 'printk_index_wrap'
     418 |                 _p_func(_fmt, ##__VA_ARGS__);                           \
         |                         ^~~~
   include/linux/printk.h:489:9: note: in expansion of macro 'printk'
     489 |         printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
         |         ^~~~~~
   include/linux/kern_levels.h:11:25: note: in expansion of macro 'KERN_SOH'
      11 | #define KERN_ERR        KERN_SOH "3"    /* error conditions */
         |                         ^~~~~~~~
   include/linux/printk.h:489:16: note: in expansion of macro 'KERN_ERR'
     489 |         printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
         |                ^~~~~~~~
   drivers/clk/imx/clk-pll14xx.c:293:17: note: in expansion of macro 'pr_err'
     293 |                 pr_err("Invalid rate %lu for pll clk %s\n", __func__,
         |                 ^~~~~~
   drivers/clk/imx/clk-pll14xx.c:302:24: error: implicit declaration of function 'FIELD_PREP' [-Werror=implicit-function-declaration]
     302 |                 tmp |= FIELD_PREP(SDIV_MASK, rate->sdiv);
         |                        ^~~~~~~~~~
   cc1: some warnings being treated as errors


vim +6 drivers/clk/imx/clk-pll14xx.c

0c0c0d808f682f Sascha Hauer 2022-02-23 @6  #define pr_fmt(fmt) "pll14xx: " fmt
0c0c0d808f682f Sascha Hauer 2022-02-23  7  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/drivers/clk/imx/clk-pll14xx.c b/drivers/clk/imx/clk-pll14xx.c
index 28c75963a80bd..d2e2c742ce8f2 100644
--- a/drivers/clk/imx/clk-pll14xx.c
+++ b/drivers/clk/imx/clk-pll14xx.c
@@ -28,6 +28,8 @@ 
 #define PDIV_MASK	GENMASK(9, 4)
 #define SDIV_MASK	GENMASK(2, 0)
 #define KDIV_MASK	GENMASK(15, 0)
+#define KDIV_MIN	SHRT_MIN
+#define KDIV_MAX	SHRT_MAX
 
 #define LOCK_TIMEOUT_US		10000
 
@@ -112,7 +114,106 @@  static long pll14xx_calc_rate(struct clk_pll14xx *pll, int mdiv, int pdiv,
 	return fvco;
 }
 
-static long clk_pll14xx_round_rate(struct clk_hw *hw, unsigned long rate,
+static long pll1443x_calc_kdiv(int mdiv, int pdiv, int sdiv,
+		unsigned long rate, unsigned long prate)
+{
+	long kdiv;
+
+	/* calc kdiv = round(rate * pdiv * 65536 * 2^sdiv / prate) - (mdiv * 65536) */
+	kdiv = ((rate * ((pdiv * 65536) << sdiv) + prate / 2) / prate) - (mdiv * 65536);
+
+	return clamp_t(short, kdiv, KDIV_MIN, KDIV_MAX);
+}
+
+static void imx_pll14xx_calc_settings(struct clk_pll14xx *pll, unsigned long rate,
+				      unsigned long prate, struct imx_pll14xx_rate_table *t)
+{
+	u32 pll_div_ctl0, pll_div_ctl1;
+	int mdiv, pdiv, sdiv, kdiv;
+	long fvco, rate_min, rate_max, dist, best = LONG_MAX;
+	const struct imx_pll14xx_rate_table *tt;
+
+	/*
+	 * Fractional PLL constrains:
+	 *
+	 * a) 6MHz <= prate <= 25MHz
+	 * b) 1 <= p <= 63 (1 <= p <= 4 prate = 24MHz)
+	 * c) 64 <= m <= 1023
+	 * d) 0 <= s <= 6
+	 * e) -32768 <= k <= 32767
+	 *
+	 * fvco = (m * 65536 + k) * prate / (p * 65536)
+	 */
+
+	pll_div_ctl0 = readl_relaxed(pll->base + DIV_CTL0);
+	mdiv = FIELD_GET(MDIV_MASK, pll_div_ctl0);
+	pdiv = FIELD_GET(PDIV_MASK, pll_div_ctl0);
+	sdiv = FIELD_GET(SDIV_MASK, pll_div_ctl0);
+	pll_div_ctl1 = readl_relaxed(pll->base + DIV_CTL1);
+
+	/* First see if we can get the desired rate by only adjusting kdiv (glitch free) */
+	rate_min = pll14xx_calc_rate(pll, mdiv, pdiv, sdiv, KDIV_MIN, prate);
+	rate_max = pll14xx_calc_rate(pll, mdiv, pdiv, sdiv, KDIV_MAX, prate);
+
+	if (rate >= rate_min && rate <= rate_max) {
+		kdiv = pll1443x_calc_kdiv(mdiv, pdiv, sdiv, rate, prate);
+		pr_debug("%s: in=%ld, want=%ld Only adjust kdiv %ld -> %d\n",
+			 clk_hw_get_name(&pll->hw), prate, rate,
+			 FIELD_GET(KDIV_MASK, pll_div_ctl1), kdiv);
+		fvco = pll14xx_calc_rate(pll, mdiv, pdiv, sdiv, kdiv, prate);
+		t->rate = (unsigned int)fvco;
+		t->mdiv = mdiv;
+		t->pdiv = pdiv;
+		t->sdiv = sdiv;
+		t->kdiv = kdiv;
+		return;
+	}
+
+	/* Then try if we can get the desired rate from one of the static entries */
+	tt = imx_get_pll_settings(pll, rate);
+	if (tt) {
+		pr_debug("%s: in=%ld, want=%ld, Using PLL setting from table\n",
+			 clk_hw_get_name(&pll->hw), prate, rate);
+		t->rate = tt->rate;
+		t->mdiv = tt->mdiv;
+		t->pdiv = tt->pdiv;
+		t->sdiv = tt->sdiv;
+		t->kdiv = tt->kdiv;
+		return;
+	}
+
+	/* Finally calculate best values */
+	for (pdiv = 1; pdiv <= 7; pdiv++) {
+		for (sdiv = 0; sdiv <= 6; sdiv++) {
+			/* calc mdiv = round(rate * pdiv * 2^sdiv) / prate) */
+			mdiv = DIV_ROUND_CLOSEST(rate * (pdiv << sdiv), prate);
+			mdiv = clamp(mdiv, 64, 1023);
+
+			kdiv = pll1443x_calc_kdiv(mdiv, pdiv, sdiv, rate, prate);
+			fvco = pll14xx_calc_rate(pll, mdiv, pdiv, sdiv, kdiv, prate);
+
+			/* best match */
+			dist = abs((long)rate - (long)fvco);
+			if (dist < best) {
+				best = dist;
+				t->rate = (unsigned int)fvco;
+				t->mdiv = mdiv;
+				t->pdiv = pdiv;
+				t->sdiv = sdiv;
+				t->kdiv = kdiv;
+
+				if (!dist)
+					goto found;
+			}
+		}
+	}
+found:
+	pr_debug("%s: in=%ld, want=%ld got=%d (pdiv=%d sdiv=%d mdiv=%d kdiv=%d)\n",
+		 clk_hw_get_name(&pll->hw), prate, rate, t->rate, t->pdiv, t->sdiv,
+		 t->mdiv, t->kdiv);
+}
+
+static long clk_pll1416x_round_rate(struct clk_hw *hw, unsigned long rate,
 			unsigned long *prate)
 {
 	struct clk_pll14xx *pll = to_clk_pll14xx(hw);
@@ -128,6 +229,17 @@  static long clk_pll14xx_round_rate(struct clk_hw *hw, unsigned long rate,
 	return rate_table[pll->rate_count - 1].rate;
 }
 
+static long clk_pll1443x_round_rate(struct clk_hw *hw, unsigned long rate,
+			unsigned long *prate)
+{
+	struct clk_pll14xx *pll = to_clk_pll14xx(hw);
+	struct imx_pll14xx_rate_table t;
+
+	imx_pll14xx_calc_settings(pll, rate, *prate, &t);
+
+	return t.rate;
+}
+
 static unsigned long clk_pll14xx_recalc_rate(struct clk_hw *hw,
 						  unsigned long parent_rate)
 {
@@ -238,25 +350,21 @@  static int clk_pll1443x_set_rate(struct clk_hw *hw, unsigned long drate,
 				 unsigned long prate)
 {
 	struct clk_pll14xx *pll = to_clk_pll14xx(hw);
-	const struct imx_pll14xx_rate_table *rate;
+	struct imx_pll14xx_rate_table rate;
 	u32 gnrl_ctl, div_ctl0;
 	int ret;
 
-	rate = imx_get_pll_settings(pll, drate);
-	if (!rate) {
-		pr_err("%s: Invalid rate : %lu for pll clk %s\n", __func__,
-			drate, clk_hw_get_name(hw));
-		return -EINVAL;
-	}
+	imx_pll14xx_calc_settings(pll, drate, prate, &rate);
 
 	div_ctl0 = readl_relaxed(pll->base + DIV_CTL0);
 
-	if (!clk_pll14xx_mp_change(rate, div_ctl0)) {
+	if (!clk_pll14xx_mp_change(&rate, div_ctl0)) {
+		/* only sdiv and/or kdiv changed - no need to RESET PLL */
 		div_ctl0 &= ~SDIV_MASK;
-		div_ctl0 |= FIELD_PREP(SDIV_MASK, rate->sdiv);
+		div_ctl0 |= FIELD_PREP(SDIV_MASK, rate.sdiv);
 		writel_relaxed(div_ctl0, pll->base + DIV_CTL0);
 
-		writel_relaxed(FIELD_PREP(KDIV_MASK, rate->kdiv),
+		writel_relaxed(FIELD_PREP(KDIV_MASK, rate.kdiv),
 			       pll->base + DIV_CTL1);
 
 		return 0;
@@ -271,11 +379,12 @@  static int clk_pll1443x_set_rate(struct clk_hw *hw, unsigned long drate,
 	gnrl_ctl |= BYPASS_MASK;
 	writel_relaxed(gnrl_ctl, pll->base + GNRL_CTL);
 
-	div_ctl0 = FIELD_PREP(MDIV_MASK, rate->mdiv) |
-		   FIELD_PREP(PDIV_MASK, rate->pdiv) |
-		   FIELD_PREP(SDIV_MASK, rate->sdiv);
+	div_ctl0 = FIELD_PREP(MDIV_MASK, rate.mdiv) |
+		   FIELD_PREP(PDIV_MASK, rate.pdiv) |
+		   FIELD_PREP(SDIV_MASK, rate.sdiv);
 	writel_relaxed(div_ctl0, pll->base + DIV_CTL0);
-	writel_relaxed(FIELD_PREP(KDIV_MASK, rate->kdiv), pll->base + DIV_CTL1);
+
+	writel_relaxed(FIELD_PREP(KDIV_MASK, rate.kdiv), pll->base + DIV_CTL1);
 
 	/*
 	 * According to SPEC, t3 - t2 need to be greater than
@@ -358,7 +467,7 @@  static const struct clk_ops clk_pll1416x_ops = {
 	.unprepare	= clk_pll14xx_unprepare,
 	.is_prepared	= clk_pll14xx_is_prepared,
 	.recalc_rate	= clk_pll14xx_recalc_rate,
-	.round_rate	= clk_pll14xx_round_rate,
+	.round_rate	= clk_pll1416x_round_rate,
 	.set_rate	= clk_pll1416x_set_rate,
 };
 
@@ -371,7 +480,7 @@  static const struct clk_ops clk_pll1443x_ops = {
 	.unprepare	= clk_pll14xx_unprepare,
 	.is_prepared	= clk_pll14xx_is_prepared,
 	.recalc_rate	= clk_pll14xx_recalc_rate,
-	.round_rate	= clk_pll14xx_round_rate,
+	.round_rate	= clk_pll1443x_round_rate,
 	.set_rate	= clk_pll1443x_set_rate,
 };