summaryrefslogtreecommitdiffstats
path: root/drivers/clk/meson/clk-pll.c
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
commit76cb841cb886eef6b3bee341a2266c76578724ad (patch)
treef5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /drivers/clk/meson/clk-pll.c
parentInitial commit. (diff)
downloadlinux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz
linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/clk/meson/clk-pll.c')
-rw-r--r--drivers/clk/meson/clk-pll.c251
1 files changed, 251 insertions, 0 deletions
diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c
new file mode 100644
index 000000000..6fdad22a5
--- /dev/null
+++ b/drivers/clk/meson/clk-pll.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2015 Endless Mobile, Inc.
+ * Author: Carlo Caione <carlo@endlessm.com>
+ *
+ * Copyright (c) 2018 Baylibre, SAS.
+ * Author: Jerome Brunet <jbrunet@baylibre.com>
+ */
+
+/*
+ * In the most basic form, a Meson PLL is composed as follows:
+ *
+ * PLL
+ * +------------------------------+
+ * | |
+ * in -----[ /N ]---[ *M ]---[ >>OD ]----->> out
+ * | ^ ^ |
+ * +------------------------------+
+ * | |
+ * FREF VCO
+ *
+ * out = in * (m + frac / frac_max) / (n << sum(ods))
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#include "clkc.h"
+
+static inline struct meson_clk_pll_data *
+meson_clk_pll_data(struct clk_regmap *clk)
+{
+ return (struct meson_clk_pll_data *)clk->data;
+}
+
+static unsigned long __pll_params_to_rate(unsigned long parent_rate,
+ const struct pll_rate_table *pllt,
+ u16 frac,
+ struct meson_clk_pll_data *pll)
+{
+ u64 rate = (u64)parent_rate * pllt->m;
+ unsigned int od = pllt->od + pllt->od2 + pllt->od3;
+
+ if (frac && MESON_PARM_APPLICABLE(&pll->frac)) {
+ u64 frac_rate = (u64)parent_rate * frac;
+
+ rate += DIV_ROUND_UP_ULL(frac_rate,
+ (1 << pll->frac.width));
+ }
+
+ return DIV_ROUND_UP_ULL(rate, pllt->n << od);
+}
+
+static unsigned long meson_clk_pll_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+ struct pll_rate_table pllt;
+ u16 frac;
+
+ pllt.n = meson_parm_read(clk->map, &pll->n);
+ pllt.m = meson_parm_read(clk->map, &pll->m);
+ pllt.od = meson_parm_read(clk->map, &pll->od);
+
+ pllt.od2 = MESON_PARM_APPLICABLE(&pll->od2) ?
+ meson_parm_read(clk->map, &pll->od2) :
+ 0;
+
+ pllt.od3 = MESON_PARM_APPLICABLE(&pll->od3) ?
+ meson_parm_read(clk->map, &pll->od3) :
+ 0;
+
+ frac = MESON_PARM_APPLICABLE(&pll->frac) ?
+ meson_parm_read(clk->map, &pll->frac) :
+ 0;
+
+ return __pll_params_to_rate(parent_rate, &pllt, frac, pll);
+}
+
+static u16 __pll_params_with_frac(unsigned long rate,
+ unsigned long parent_rate,
+ const struct pll_rate_table *pllt,
+ struct meson_clk_pll_data *pll)
+{
+ u16 frac_max = (1 << pll->frac.width);
+ u64 val = (u64)rate * pllt->n;
+
+ val <<= pllt->od + pllt->od2 + pllt->od3;
+
+ if (pll->flags & CLK_MESON_PLL_ROUND_CLOSEST)
+ val = DIV_ROUND_CLOSEST_ULL(val * frac_max, parent_rate);
+ else
+ val = div_u64(val * frac_max, parent_rate);
+
+ val -= pllt->m * frac_max;
+
+ return min((u16)val, (u16)(frac_max - 1));
+}
+
+static const struct pll_rate_table *
+meson_clk_get_pll_settings(unsigned long rate,
+ struct meson_clk_pll_data *pll)
+{
+ const struct pll_rate_table *table = pll->table;
+ unsigned int i = 0;
+
+ if (!table)
+ return NULL;
+
+ /* Find the first table element exceeding rate */
+ while (table[i].rate && table[i].rate <= rate)
+ i++;
+
+ if (i != 0) {
+ if (MESON_PARM_APPLICABLE(&pll->frac) ||
+ !(pll->flags & CLK_MESON_PLL_ROUND_CLOSEST) ||
+ (abs(rate - table[i - 1].rate) <
+ abs(rate - table[i].rate)))
+ i--;
+ }
+
+ return (struct pll_rate_table *)&table[i];
+}
+
+static long meson_clk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+ const struct pll_rate_table *pllt =
+ meson_clk_get_pll_settings(rate, pll);
+ u16 frac;
+
+ if (!pllt)
+ return meson_clk_pll_recalc_rate(hw, *parent_rate);
+
+ if (!MESON_PARM_APPLICABLE(&pll->frac)
+ || rate == pllt->rate)
+ return pllt->rate;
+
+ /*
+ * The rate provided by the setting is not an exact match, let's
+ * try to improve the result using the fractional parameter
+ */
+ frac = __pll_params_with_frac(rate, *parent_rate, pllt, pll);
+
+ return __pll_params_to_rate(*parent_rate, pllt, frac, pll);
+}
+
+static int meson_clk_pll_wait_lock(struct clk_hw *hw)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+ int delay = 24000000;
+
+ do {
+ /* Is the clock locked now ? */
+ if (meson_parm_read(clk->map, &pll->l))
+ return 0;
+
+ delay--;
+ } while (delay > 0);
+
+ return -ETIMEDOUT;
+}
+
+static void meson_clk_pll_init(struct clk_hw *hw)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+
+ if (pll->init_count) {
+ meson_parm_write(clk->map, &pll->rst, 1);
+ regmap_multi_reg_write(clk->map, pll->init_regs,
+ pll->init_count);
+ meson_parm_write(clk->map, &pll->rst, 0);
+ }
+}
+
+static int meson_clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+ const struct pll_rate_table *pllt;
+ unsigned long old_rate;
+ u16 frac = 0;
+
+ if (parent_rate == 0 || rate == 0)
+ return -EINVAL;
+
+ old_rate = clk_hw_get_rate(hw);
+
+ pllt = meson_clk_get_pll_settings(rate, pll);
+ if (!pllt)
+ return -EINVAL;
+
+ /* Put the pll in reset to write the params */
+ meson_parm_write(clk->map, &pll->rst, 1);
+
+ meson_parm_write(clk->map, &pll->n, pllt->n);
+ meson_parm_write(clk->map, &pll->m, pllt->m);
+ meson_parm_write(clk->map, &pll->od, pllt->od);
+
+ if (MESON_PARM_APPLICABLE(&pll->od2))
+ meson_parm_write(clk->map, &pll->od2, pllt->od2);
+
+ if (MESON_PARM_APPLICABLE(&pll->od3))
+ meson_parm_write(clk->map, &pll->od3, pllt->od3);
+
+ if (MESON_PARM_APPLICABLE(&pll->frac)) {
+ frac = __pll_params_with_frac(rate, parent_rate, pllt, pll);
+ meson_parm_write(clk->map, &pll->frac, frac);
+ }
+
+ /* make sure the reset is cleared at this point */
+ meson_parm_write(clk->map, &pll->rst, 0);
+
+ if (meson_clk_pll_wait_lock(hw)) {
+ pr_warn("%s: pll did not lock, trying to restore old rate %lu\n",
+ __func__, old_rate);
+ /*
+ * FIXME: Do we really need/want this HACK ?
+ * It looks unsafe. what happens if the clock gets into a
+ * broken state and we can't lock back on the old_rate ? Looks
+ * like an infinite recursion is possible
+ */
+ meson_clk_pll_set_rate(hw, old_rate, parent_rate);
+ }
+
+ return 0;
+}
+
+const struct clk_ops meson_clk_pll_ops = {
+ .init = meson_clk_pll_init,
+ .recalc_rate = meson_clk_pll_recalc_rate,
+ .round_rate = meson_clk_pll_round_rate,
+ .set_rate = meson_clk_pll_set_rate,
+};
+
+const struct clk_ops meson_clk_pll_ro_ops = {
+ .recalc_rate = meson_clk_pll_recalc_rate,
+};