diff mbox series

[v7,2/5] clk: imx: add fractional PLL output clock

Message ID 1537438000-20313-3-git-send-email-abel.vesa@nxp.com (mailing list archive)
State Superseded, archived
Headers show
Series [v7,1/5] dt-bindings: add binding for i.MX8MQ CCM | expand

Commit Message

Abel Vesa Sept. 20, 2018, 10:06 a.m. UTC
From: Lucas Stach <l.stach@pengutronix.de>

This is a new clock type introduced on i.MX8.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
---
 drivers/clk/imx/Makefile       |   1 +
 drivers/clk/imx/clk-frac-pll.c | 230 +++++++++++++++++++++++++++++++++++++++++
 drivers/clk/imx/clk.h          |   3 +
 3 files changed, 234 insertions(+)
 create mode 100644 drivers/clk/imx/clk-frac-pll.c

Comments

Andrey Smirnov Sept. 20, 2018, 11:45 p.m. UTC | #1
On Thu, Sep 20, 2018 at 3:07 AM Abel Vesa <abel.vesa@nxp.com> wrote:
>
> From: Lucas Stach <l.stach@pengutronix.de>
>
> This is a new clock type introduced on i.MX8.
>
> Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
> Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
> ---
>  drivers/clk/imx/Makefile       |   1 +
>  drivers/clk/imx/clk-frac-pll.c | 230 +++++++++++++++++++++++++++++++++++++++++
>  drivers/clk/imx/clk.h          |   3 +
>  3 files changed, 234 insertions(+)
>  create mode 100644 drivers/clk/imx/clk-frac-pll.c
>
> diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
> index 8c3baa7..4893c1f 100644
> --- a/drivers/clk/imx/Makefile
> +++ b/drivers/clk/imx/Makefile
> @@ -6,6 +6,7 @@ obj-y += \
>         clk-cpu.o \
>         clk-fixup-div.o \
>         clk-fixup-mux.o \
> +       clk-frac-pll.o \
>         clk-gate-exclusive.o \
>         clk-gate2.o \
>         clk-pllv1.o \
> diff --git a/drivers/clk/imx/clk-frac-pll.c b/drivers/clk/imx/clk-frac-pll.c
> new file mode 100644
> index 0000000..c80c6ed
> --- /dev/null
> +++ b/drivers/clk/imx/clk-frac-pll.c
> @@ -0,0 +1,230 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2018 NXP.
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/jiffies.h>
> +#include <linux/slab.h>
> +
> +#include "clk.h"
> +
> +#define PLL_CFG0               0x0
> +#define PLL_CFG1               0x4
> +
> +#define PLL_LOCK_STATUS                BIT(31)
> +#define PLL_PD                 19
> +#define PLL_PD_MASK            BIT(PLL_PD)
> +#define PLL_BYPASS             14
> +#define PLL_BYPASS_MASK                BIT(PLL_BYPASS)
> +#define PLL_NEWDIV_VAL         BIT(12)
> +#define PLL_NEWDIV_ACK         BIT(11)
> +#define PLL_FRAC_DIV_MASK      0xffffff
> +#define PLL_INT_DIV_MASK       0x7f
> +#define PLL_OUTPUT_DIV_MASK    0x1f
> +#define PLL_FRAC_DENOM         0x1000000
> +
> +struct clk_frac_pll {
> +       struct clk_hw   hw;
> +       void __iomem    *base;
> +};
> +
> +#define to_clk_frac_pll(_hw) container_of(_hw, struct clk_frac_pll, hw)
> +
> +static int clk_wait_lock(struct clk_frac_pll *pll)
> +{
> +       unsigned long timeout = jiffies + msecs_to_jiffies(10);
> +       u32 val;
> +
> +       /* Wait for PLL to lock */
> +       do {
> +               if (readl_relaxed(pll->base) & PLL_LOCK_STATUS)
> +                       break;
> +               if (time_after(jiffies, timeout))
> +                       break;
> +       } while (1);
> +
> +       return readl_poll_timeout(pll->base, val,
> +                                       val & PLL_LOCK_STATUS, 0, 1000);

Is this code intentional? It seems to me those two are almost
identical wait loops, so it's a bit confusing to see without at least
a comment why it is done that way. If it is intentional, can the first
loop be replaced with readx_poll_timeout(readl_relaxed, ...) ?

> +}
> +
> +static int clk_wait_ack(struct clk_frac_pll *pll)
> +{
> +       unsigned long timeout = jiffies + msecs_to_jiffies(50);
> +       u32 val;
> +
> +       /* return directly if the pll is in powerdown or in bypass */
> +       if (readl_relaxed(pll->base) & (PLL_PD_MASK | PLL_BYPASS_MASK))
> +               return 0;
> +
> +       /* Wait for the pll's divfi and divff to be reloaded */
> +       do {
> +               if (readl_relaxed(pll->base) & PLL_NEWDIV_ACK)
> +                       break;
> +               if (time_after(jiffies, timeout))
> +                       break;
> +       } while (1);
> +
> +       return readl_poll_timeout(pll->base, val,
> +                                       val & PLL_NEWDIV_ACK, 0, 1000);
> +}

Ditto.

> +
> +static int clk_pll_prepare(struct clk_hw *hw)
> +{
> +       struct clk_frac_pll *pll = to_clk_frac_pll(hw);
> +       u32 val;
> +
> +       val = readl_relaxed(pll->base + PLL_CFG0);
> +       val &= ~PLL_PD_MASK;
> +       writel_relaxed(val, pll->base + PLL_CFG0);
> +
> +       return clk_wait_lock(pll);
> +}
> +
> +static void clk_pll_unprepare(struct clk_hw *hw)
> +{
> +       struct clk_frac_pll *pll = to_clk_frac_pll(hw);
> +       u32 val;
> +
> +       val = readl_relaxed(pll->base + PLL_CFG0);
> +       val |= PLL_PD_MASK;
> +       writel_relaxed(val, pll->base + PLL_CFG0);
> +}
> +
> +static int clk_pll_is_prepared(struct clk_hw *hw)
> +{
> +       struct clk_frac_pll *pll = to_clk_frac_pll(hw);
> +       u32 val;
> +
> +       val = readl_relaxed(pll->base + PLL_CFG0);
> +       return (val & PLL_PD_MASK) ? 0 : 1;
> +}
> +
> +static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
> +                                        unsigned long parent_rate)
> +{
> +       struct clk_frac_pll *pll = to_clk_frac_pll(hw);
> +       u32 val, divff, divfi, divq;
> +       u64 temp64;
> +
> +       val = readl_relaxed(pll->base + PLL_CFG0);
> +       divq = ((val & PLL_OUTPUT_DIV_MASK) + 1) * 2;
> +       val = readl_relaxed(pll->base + PLL_CFG1);
> +       divff = (val >> 7) & PLL_FRAC_DIV_MASK;

Just as a suggestion you can do:

#define PLL_FRAC_DIV GENMASK(30, 7)

divff = FIELD_GET(PLL_FRAC_DIV, val)

it's a bit nicer (IMHO, of course) because it allows you to avoid
having to encode shit and mask separately and mask definition can be
easily verified against the datasheet.

Thanks,
Andrey Smirnov
diff mbox series

Patch

diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
index 8c3baa7..4893c1f 100644
--- a/drivers/clk/imx/Makefile
+++ b/drivers/clk/imx/Makefile
@@ -6,6 +6,7 @@  obj-y += \
 	clk-cpu.o \
 	clk-fixup-div.o \
 	clk-fixup-mux.o \
+	clk-frac-pll.o \
 	clk-gate-exclusive.o \
 	clk-gate2.o \
 	clk-pllv1.o \
diff --git a/drivers/clk/imx/clk-frac-pll.c b/drivers/clk/imx/clk-frac-pll.c
new file mode 100644
index 0000000..c80c6ed
--- /dev/null
+++ b/drivers/clk/imx/clk-frac-pll.c
@@ -0,0 +1,230 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018 NXP.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/jiffies.h>
+#include <linux/slab.h>
+
+#include "clk.h"
+
+#define PLL_CFG0		0x0
+#define PLL_CFG1		0x4
+
+#define PLL_LOCK_STATUS		BIT(31)
+#define PLL_PD			19
+#define PLL_PD_MASK		BIT(PLL_PD)
+#define PLL_BYPASS		14
+#define PLL_BYPASS_MASK		BIT(PLL_BYPASS)
+#define PLL_NEWDIV_VAL		BIT(12)
+#define PLL_NEWDIV_ACK		BIT(11)
+#define PLL_FRAC_DIV_MASK	0xffffff
+#define PLL_INT_DIV_MASK	0x7f
+#define PLL_OUTPUT_DIV_MASK	0x1f
+#define PLL_FRAC_DENOM		0x1000000
+
+struct clk_frac_pll {
+	struct clk_hw	hw;
+	void __iomem	*base;
+};
+
+#define to_clk_frac_pll(_hw) container_of(_hw, struct clk_frac_pll, hw)
+
+static int clk_wait_lock(struct clk_frac_pll *pll)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(10);
+	u32 val;
+
+	/* Wait for PLL to lock */
+	do {
+		if (readl_relaxed(pll->base) & PLL_LOCK_STATUS)
+			break;
+		if (time_after(jiffies, timeout))
+			break;
+	} while (1);
+
+	return readl_poll_timeout(pll->base, val,
+					val & PLL_LOCK_STATUS, 0, 1000);
+}
+
+static int clk_wait_ack(struct clk_frac_pll *pll)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(50);
+	u32 val;
+
+	/* return directly if the pll is in powerdown or in bypass */
+	if (readl_relaxed(pll->base) & (PLL_PD_MASK | PLL_BYPASS_MASK))
+		return 0;
+
+	/* Wait for the pll's divfi and divff to be reloaded */
+	do {
+		if (readl_relaxed(pll->base) & PLL_NEWDIV_ACK)
+			break;
+		if (time_after(jiffies, timeout))
+			break;
+	} while (1);
+
+	return readl_poll_timeout(pll->base, val,
+					val & PLL_NEWDIV_ACK, 0, 1000);
+}
+
+static int clk_pll_prepare(struct clk_hw *hw)
+{
+	struct clk_frac_pll *pll = to_clk_frac_pll(hw);
+	u32 val;
+
+	val = readl_relaxed(pll->base + PLL_CFG0);
+	val &= ~PLL_PD_MASK;
+	writel_relaxed(val, pll->base + PLL_CFG0);
+
+	return clk_wait_lock(pll);
+}
+
+static void clk_pll_unprepare(struct clk_hw *hw)
+{
+	struct clk_frac_pll *pll = to_clk_frac_pll(hw);
+	u32 val;
+
+	val = readl_relaxed(pll->base + PLL_CFG0);
+	val |= PLL_PD_MASK;
+	writel_relaxed(val, pll->base + PLL_CFG0);
+}
+
+static int clk_pll_is_prepared(struct clk_hw *hw)
+{
+	struct clk_frac_pll *pll = to_clk_frac_pll(hw);
+	u32 val;
+
+	val = readl_relaxed(pll->base + PLL_CFG0);
+	return (val & PLL_PD_MASK) ? 0 : 1;
+}
+
+static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
+					 unsigned long parent_rate)
+{
+	struct clk_frac_pll *pll = to_clk_frac_pll(hw);
+	u32 val, divff, divfi, divq;
+	u64 temp64;
+
+	val = readl_relaxed(pll->base + PLL_CFG0);
+	divq = ((val & PLL_OUTPUT_DIV_MASK) + 1) * 2;
+	val = readl_relaxed(pll->base + PLL_CFG1);
+	divff = (val >> 7) & PLL_FRAC_DIV_MASK;
+	divfi = (val & PLL_INT_DIV_MASK);
+
+	temp64 = (u64)parent_rate * 8;
+	temp64 *= divff;
+	do_div(temp64, PLL_FRAC_DENOM);
+	temp64 /= divq;
+
+	return parent_rate * 8 * (divfi + 1) / divq + (unsigned long)temp64;
+}
+
+static long clk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+			       unsigned long *prate)
+{
+	unsigned long parent_rate = *prate;
+	u32 divff, divfi;
+	u64 temp64;
+
+	parent_rate *= 8;
+	rate *= 2;
+	divfi = rate / parent_rate;
+	temp64 = (u64)(rate - divfi * parent_rate);
+	temp64 *= PLL_FRAC_DENOM;
+	do_div(temp64, parent_rate);
+	divff = temp64;
+
+	temp64 = (u64)parent_rate;
+	temp64 *= divff;
+	do_div(temp64, PLL_FRAC_DENOM);
+
+	return (parent_rate * divfi + (unsigned long)temp64) / 2;
+}
+
+/*
+ * To simplify the clock calculation, we can keep the 'PLL_OUTPUT_VAL' at zero
+ * (means the PLL output will be divided by 2). So the PLL output can use
+ * the below formula:
+ * pllout = parent_rate * 8 / 2 * DIVF_VAL;
+ * where DIVF_VAL = 1 + DIVFI + DIVFF / 2^24.
+ */
+static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+			    unsigned long parent_rate)
+{
+	struct clk_frac_pll *pll = to_clk_frac_pll(hw);
+	u32 val, divfi, divff;
+	u64 temp64;
+	int ret;
+
+	parent_rate *= 8;
+	rate *= 2;
+	divfi = rate / parent_rate;
+	temp64 = (u64) (rate - divfi * parent_rate);
+	temp64 *= PLL_FRAC_DENOM;
+	do_div(temp64, parent_rate);
+	divff = temp64;
+
+	val = readl_relaxed(pll->base + PLL_CFG1);
+	val &= ~((PLL_FRAC_DIV_MASK << 7) | (PLL_INT_DIV_MASK));
+	val |= ((divff << 7) | (divfi - 1));
+	writel_relaxed(val, pll->base + PLL_CFG1);
+
+	val = readl_relaxed(pll->base + PLL_CFG0);
+	val &= ~0x1f;
+	writel_relaxed(val, pll->base + PLL_CFG0);
+
+	/* Set the NEV_DIV_VAL to reload the DIVFI and DIVFF */
+	val = readl_relaxed(pll->base + PLL_CFG0);
+	val |= PLL_NEWDIV_VAL;
+	writel_relaxed(val, pll->base + PLL_CFG0);
+
+	ret = clk_wait_ack(pll);
+
+	/* clear the NEV_DIV_VAL */
+	val = readl_relaxed(pll->base + PLL_CFG0);
+	val &= ~PLL_NEWDIV_VAL;
+	writel_relaxed(val, pll->base + PLL_CFG0);
+
+	return ret;
+}
+
+static const struct clk_ops clk_frac_pll_ops = {
+	.prepare	= clk_pll_prepare,
+	.unprepare	= clk_pll_unprepare,
+	.is_prepared	= clk_pll_is_prepared,
+	.recalc_rate	= clk_pll_recalc_rate,
+	.round_rate	= clk_pll_round_rate,
+	.set_rate	= clk_pll_set_rate,
+};
+
+struct clk *imx_clk_frac_pll(const char *name, const char *parent_name,
+			     void __iomem *base)
+{
+	struct clk_init_data init;
+	struct clk_frac_pll *pll;
+	struct clk *clk;
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	pll->base = base;
+	init.name = name;
+	init.ops = &clk_frac_pll_ops;
+	init.flags = 0;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	pll->hw.init = &init;
+
+	clk = clk_register(NULL, &pll->hw);
+	if (IS_ERR(clk))
+		kfree(pll);
+
+	return clk;
+}
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index 8076ec0..13daf1c 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -27,6 +27,9 @@  struct clk *imx_clk_pllv1(enum imx_pllv1_type type, const char *name,
 struct clk *imx_clk_pllv2(const char *name, const char *parent,
 		void __iomem *base);
 
+struct clk *imx_clk_frac_pll(const char *name, const char *parent_name,
+			     void __iomem *base);
+
 enum imx_pllv3_type {
 	IMX_PLLV3_GENERIC,
 	IMX_PLLV3_SYS,