[PATCH 5/7] clk: at91: add sam9x60 PLL driver

Alexandre Belloni
2019-02-20T11:48:26Z

The PLLs on the sam9x60 (PLLA and USB PLL) use a different register set and
programming model than the previous SoCs.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
drivers/clk/at91/Makefile | 1 +
drivers/clk/at91/clk-sam9x60-pll.c | 329 +++++++++++++++++++++++++++++
drivers/clk/at91/pmc.h | 6 +
3 files changed, 336 insertions(+)
create mode 100644 drivers/clk/at91/clk-sam9x60-pll.c

diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index c75df1cad60e..0a30fc8dfcb0 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_HAVE_AT91_SMD) += clk-smd.o
obj-$(CONFIG_HAVE_AT91_H32MX) += clk-h32mx.o
obj-$(CONFIG_HAVE_AT91_GENERATED_CLK) += clk-generated.o
obj-$(CONFIG_HAVE_AT91_I2S_MUX_CLK) += clk-i2s-mux.o
+obj-$(CONFIG_HAVE_AT91_SAM9X60_PLL) += clk-sam9x60-pll.o
obj-$(CONFIG_SOC_AT91SAM9) += at91sam9260.o at91sam9rl.o at91sam9x5.o
obj-$(CONFIG_SOC_SAMA5D4) += sama5d4.o
obj-$(CONFIG_SOC_SAMA5D2) += sama5d2.o
diff --git a/drivers/clk/at91/clk-sam9x60-pll.c b/drivers/clk/at91/clk-sam9x60-pll.c
new file mode 100644
index 000000000000..a3d5c729e8b6
--- /dev/null
+++ b/drivers/clk/at91/clk-sam9x60-pll.c
@@ -0,0 +1,329 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Microchip Technology Inc.
+ *
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/at91_pmc.h>
+#include <linux/of.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+#include "pmc.h"
+
+#define PMC_PLL_CTRL0 0xc
+#define PMC_PLL_CTRL0_DIV_MSK GENMASK(7, 0)
+#define PMC_PLL_CTRL0_ENPLL BIT(28)
+#define PMC_PLL_CTRL0_ENPLLCK BIT(29)
+#define PMC_PLL_CTRL0_ENLOCK BIT(31)
+
+#define PMC_PLL_CTRL1 0x10
+#define PMC_PLL_CTRL1_FRACR_MSK GENMASK(21, 0)
+#define PMC_PLL_CTRL1_MUL_MSK GENMASK(30, 24)
+
+#define PMC_PLL_ACR 0x18
+#define PMC_PLL_ACR_UTMIVR BIT(12)
+#define PMC_PLL_ACR_UTMIBG BIT(13)
+#define PMC_PLL_ACR_LOOP_FILTER_MSK GENMASK(31, 24)
+
+#define PMC_PLL_UPDT 0x1c
+#define PMC_PLL_UPDT_UPDATE BIT(8)
+
+#define PMC_PLL_ISR0 0xec
+
+#define PLL_DIV_MAX (FIELD_GET(PMC_PLL_CTRL0_DIV_MSK, UINT_MAX) + 1)
+#define UPLL_DIV 2
+#define PLL_MUL_MAX (FIELD_GET(PMC_PLL_CTRL1_MUL_MSK, UINT_MAX) + 1)
+
+#define PLL_MAX_ID 1
+
+struct sam9x60_pll {
+ struct clk_hw hw;
+ struct regmap *regmap;
+ spinlock_t *lock;
+ const struct clk_pll_characteristics *characteristics;
+ u32 frac;
+ u8 id;
+ u8 div;
+ u16 mul;
+};
+
+#define to_sam9x60_pll(hw) container_of(hw, struct sam9x60_pll, hw)
+
+static inline bool sam9x60_pll_ready(struct regmap *regmap, int id)
+{
+ unsigned int status;
+
+ regmap_read(regmap, PMC_PLL_ISR0, &status);
+
+ return !!(status & BIT(id));
+}
+
+static int sam9x60_pll_prepare(struct clk_hw *hw)
+{
+ struct sam9x60_pll *pll = to_sam9x60_pll(hw);
+ struct regmap *regmap = pll->regmap;
+ unsigned long flags;
+ u8 div;
+ u16 mul;
+ u32 val;
+
+ spin_lock_irqsave(pll->lock, flags);
+ regmap_write(regmap, PMC_PLL_UPDT, pll->id);
+
+ regmap_read(regmap, PMC_PLL_CTRL0, &val);
+ div = FIELD_GET(PMC_PLL_CTRL0_DIV_MSK, val);
+
+ regmap_read(regmap, PMC_PLL_CTRL1, &val);
+ mul = FIELD_GET(PMC_PLL_CTRL1_MUL_MSK, val);
+
+ if (sam9x60_pll_ready(regmap, pll->id) &&
+ (div == pll->div && mul == pll->mul)) {
+ spin_unlock_irqrestore(pll->lock, flags);
+ return 0;
+ }
+
+ /* Recommended value for PMC_PLL_ACR.LOOP_FILTER is 0x9 */
+ regmap_update_bits(regmap, PMC_PLL_ACR,
+ PMC_PLL_ACR_LOOP_FILTER_MSK, 0x9);
+
+ regmap_write(regmap, PMC_PLL_CTRL1,
+ FIELD_PREP(PMC_PLL_CTRL1_MUL_MSK, pll->mul));
+
+ if (pll->characteristics->upll) {
+ /* Enable the UTMI internal bandgap */
+ regmap_update_bits(regmap, PMC_PLL_ACR,
+ PMC_PLL_ACR_UTMIBG, PMC_PLL_ACR_UTMIBG);
+
+ udelay(10);
+
+ /* Enable the UTMI internal regulator */
+ regmap_update_bits(regmap, PMC_PLL_ACR,
+ PMC_PLL_ACR_UTMIVR, PMC_PLL_ACR_UTMIVR);
+
+ udelay(10);
+ }
+
+ regmap_update_bits(regmap, PMC_PLL_UPDT,
+ PMC_PLL_UPDT_UPDATE, PMC_PLL_UPDT_UPDATE);
+
+ regmap_write(regmap, PMC_PLL_CTRL0,
+ PMC_PLL_CTRL0_ENLOCK | PMC_PLL_CTRL0_ENPLL |
+ PMC_PLL_CTRL0_ENPLLCK | pll->div);
+
+ regmap_update_bits(regmap, PMC_PLL_UPDT,
+ PMC_PLL_UPDT_UPDATE, PMC_PLL_UPDT_UPDATE);
+
+ while (!sam9x60_pll_ready(regmap, pll->id))
+ cpu_relax();
+
+ spin_unlock_irqrestore(pll->lock, flags);
+
+ return 0;
+}
+
+static int sam9x60_pll_is_prepared(struct clk_hw *hw)
+{
+ struct sam9x60_pll *pll = to_sam9x60_pll(hw);
+
+ return sam9x60_pll_ready(pll->regmap, pll->id);
+}
+
+static void sam9x60_pll_unprepare(struct clk_hw *hw)
+{
+ struct sam9x60_pll *pll = to_sam9x60_pll(hw);
+ unsigned long flags;
+
+ spin_lock_irqsave(pll->lock, flags);
+
+ regmap_write(pll->regmap, PMC_PLL_UPDT, pll->id);
+
+ regmap_update_bits(pll->regmap, PMC_PLL_CTRL0,
+ PMC_PLL_CTRL0_ENPLLCK, 0);
+
+ regmap_update_bits(pll->regmap, PMC_PLL_UPDT,
+ PMC_PLL_UPDT_UPDATE, PMC_PLL_UPDT_UPDATE);
+
+ regmap_update_bits(pll->regmap, PMC_PLL_CTRL0, PMC_PLL_CTRL0_ENPLL, 0);
+
+ if (pll->characteristics->upll)
+ regmap_update_bits(pll->regmap, PMC_PLL_ACR,
+ PMC_PLL_ACR_UTMIBG | PMC_PLL_ACR_UTMIVR, 0);
+
+ regmap_update_bits(pll->regmap, PMC_PLL_UPDT,
+ PMC_PLL_UPDT_UPDATE, PMC_PLL_UPDT_UPDATE);
+
+ spin_unlock_irqrestore(pll->lock, flags);
+}
+
+static unsigned long sam9x60_pll_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct sam9x60_pll *pll = to_sam9x60_pll(hw);
+
+ return (parent_rate * (pll->mul + 1)) / (pll->div + 1);
+}
+
+static long sam9x60_pll_get_best_div_mul(struct sam9x60_pll *pll,
+ unsigned long rate,
+ unsigned long parent_rate,
+ bool update)
+{
+ const struct clk_pll_characteristics *characteristics =
+ pll->characteristics;
+ unsigned long bestremainder = ULONG_MAX;
+ unsigned long maxdiv, mindiv, tmpdiv;
+ long bestrate = -ERANGE;
+ unsigned long bestdiv = 0;
+ unsigned long bestmul = 0;
+ unsigned long bestfrac = 0;
+
+ if (rate < characteristics->output[0].min ||
+ rate > characteristics->output[0].max)
+ return -ERANGE;
+
+ if (!pll->characteristics->upll) {
+ mindiv = parent_rate / rate;
+ if (mindiv < 2)
+ mindiv = 2;
+
+ maxdiv = DIV_ROUND_UP(parent_rate * PLL_MUL_MAX, rate);
+ if (maxdiv > PLL_DIV_MAX)
+ maxdiv = PLL_DIV_MAX;
+ } else {
+ mindiv = maxdiv = UPLL_DIV;
+ }
+
+ for (tmpdiv = mindiv; tmpdiv <= maxdiv; tmpdiv++) {
+ unsigned long remainder;
+ unsigned long tmprate;
+ unsigned long tmpmul;
+ unsigned long tmpfrac = 0;
+
+ /*
+ * Calculate the multiplier associated with the current
+ * divider that provide the closest rate to the requested one.
+ */
+ tmpmul = mult_frac(rate, tmpdiv, parent_rate);
+ tmprate = mult_frac(parent_rate, tmpmul, tmpdiv);
+ remainder = rate - tmprate;
+
+ if (remainder) {
+ tmpfrac = DIV_ROUND_CLOSEST_ULL((u64)remainder * tmpdiv * (1 << 22),
+ parent_rate);
+
+ tmprate += DIV_ROUND_CLOSEST_ULL((u64)tmpfrac * parent_rate,
+ tmpdiv * (1 << 22));
+
+ 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;
+ bestdiv = tmpdiv;
+ bestmul = tmpmul;
+ bestrate = tmprate;
+ bestfrac = tmpfrac;
+ }
+
+ /* We've found a perfect match! */
+ if (!remainder)
+ break;
+ }
+
+ /* Check if bestrate is a valid output rate */
+ if (bestrate < characteristics->output[0].min &&
+ bestrate > characteristics->output[0].max)
+ return -ERANGE;
+
+ if (update) {
+ pll->div = bestdiv - 1;
+ pll->mul = bestmul - 1;
+ pll->frac = bestfrac;
+ }
+
+ return bestrate;
+}
+
+static long sam9x60_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct sam9x60_pll *pll = to_sam9x60_pll(hw);
+
+ return sam9x60_pll_get_best_div_mul(pll, rate, *parent_rate, false);
+}
+
+static int sam9x60_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct sam9x60_pll *pll = to_sam9x60_pll(hw);
+
+ return sam9x60_pll_get_best_div_mul(pll, rate, parent_rate, true);
+}
+
+static const struct clk_ops pll_ops = {
+ .prepare = sam9x60_pll_prepare,
+ .unprepare = sam9x60_pll_unprepare,
+ .is_prepared = sam9x60_pll_is_prepared,
+ .recalc_rate = sam9x60_pll_recalc_rate,
+ .round_rate = sam9x60_pll_round_rate,
+ .set_rate = sam9x60_pll_set_rate,
+};
+
+struct clk_hw * __init
+sam9x60_clk_register_pll(struct regmap *regmap, spinlock_t *lock,
+ const char *name, const char *parent_name, u8 id,
+ const struct clk_pll_characteristics *characteristics)
+{
+ struct sam9x60_pll *pll;
+ struct clk_hw *hw;
+ struct clk_init_data init;
+ unsigned int pllr;
+ int ret;
+
+ if (id > PLL_MAX_ID)
+ return ERR_PTR(-EINVAL);
+
+ pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+ if (!pll)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &pll_ops;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+ init.flags = CLK_SET_RATE_GATE;
+
+ pll->id = id;
+ pll->hw.init = &init;
+ pll->characteristics = characteristics;
+ pll->regmap = regmap;
+ pll->lock = lock;
+
+ regmap_write(regmap, PMC_PLL_UPDT, id);
+ regmap_read(regmap, PMC_PLL_CTRL0, &pllr);
+ pll->div = FIELD_GET(PMC_PLL_CTRL0_DIV_MSK, pllr);
+ regmap_read(regmap, PMC_PLL_CTRL1, &pllr);
+ pll->mul = FIELD_GET(PMC_PLL_CTRL1_MUL_MSK, pllr);
+
+ hw = &pll->hw;
+ ret = clk_hw_register(NULL, hw);
+ if (ret) {
+ kfree(pll);
+ hw = ERR_PTR(ret);
+ }
+
+ return hw;
+}
+
diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index 4a30c20f17f1..fb9e9c4cdc8d 100644
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -69,6 +69,7 @@ struct clk_pll_characteristics {
struct clk_range *output;
u16 *icpll;
u8 *out;
+ u8 upll : 1;
};

struct clk_programmable_layout {
@@ -169,6 +170,11 @@ struct clk_hw * __init
at91_clk_register_plldiv(struct regmap *regmap, const char *name,
const char *parent_name);

+struct clk_hw * __init
+sam9x60_clk_register_pll(struct regmap *regmap, spinlock_t *lock,
+ const char *name, const char *parent_name, u8 id,
+ const struct clk_pll_characteristics *characteristics);
+
struct clk_hw * __init
at91_clk_register_programmable(struct regmap *regmap, const char *name,
const char **parent_names, u8 num_parents, u8 id,
--
2.20.1