clk: sifive: Sync-up WRPLL library with upstream Linux
Now that SiFive clock driver is merged in upstream Linux, we
sync-up WRPLL library used by SiFive clock driver with upstream
Linux sources.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/clk/analogbits/wrpll-cln28hpc.c b/drivers/clk/analogbits/wrpll-cln28hpc.c
index 68eb114..776ead3 100644
--- a/drivers/clk/analogbits/wrpll-cln28hpc.c
+++ b/drivers/clk/analogbits/wrpll-cln28hpc.c
@@ -1,20 +1,9 @@
// SPDX-License-Identifier: GPL-2.0
/*
- * Copyright (c) 2019 Western Digital Corporation or its affiliates.
- *
- * Copyright (C) 2018 SiFive, Inc.
+ * Copyright (C) 2018-2019 SiFive, Inc.
* Wesley Terpstra
* Paul Walmsley
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
* This library supports configuration parsing and reprogramming of
* the CLN28HPC variant of the Analog Bits Wide Range PLL. The
* intention is for this library to be reusable for any device that
@@ -29,6 +18,7 @@
* References:
* - Analog Bits "Wide Range PLL Datasheet", version 2015.10.01
* - SiFive FU540-C000 Manual v1p0, Chapter 7 "Clocking and Reset"
+ * https://static.dev.sifive.com/FU540-C000-v1.0.pdf
*/
#include <linux/bug.h>
@@ -84,40 +74,38 @@
* range selection.
*
* Return: The RANGE value to be presented to the PLL configuration inputs,
- * or -1 upon error.
+ * or a negative return code upon error.
*/
static int __wrpll_calc_filter_range(unsigned long post_divr_freq)
{
- u8 range;
-
if (post_divr_freq < MIN_POST_DIVR_FREQ ||
post_divr_freq > MAX_POST_DIVR_FREQ) {
WARN(1, "%s: post-divider reference freq out of range: %lu",
__func__, post_divr_freq);
- return -1;
+ return -ERANGE;
}
- if (post_divr_freq < 11000000)
- range = 1;
- else if (post_divr_freq < 18000000)
- range = 2;
- else if (post_divr_freq < 30000000)
- range = 3;
- else if (post_divr_freq < 50000000)
- range = 4;
- else if (post_divr_freq < 80000000)
- range = 5;
- else if (post_divr_freq < 130000000)
- range = 6;
- else
- range = 7;
+ switch (post_divr_freq) {
+ case 0 ... 10999999:
+ return 1;
+ case 11000000 ... 17999999:
+ return 2;
+ case 18000000 ... 29999999:
+ return 3;
+ case 30000000 ... 49999999:
+ return 4;
+ case 50000000 ... 79999999:
+ return 5;
+ case 80000000 ... 129999999:
+ return 6;
+ }
- return range;
+ return 7;
}
/**
* __wrpll_calc_fbdiv() - return feedback fixed divide value
- * @c: ptr to a struct analogbits_wrpll_cfg record to read from
+ * @c: ptr to a struct wrpll_cfg record to read from
*
* The internal feedback path includes a fixed by-two divider; the
* external feedback path does not. Return the appropriate divider
@@ -132,7 +120,7 @@
* Return: 2 if internal feedback is enabled or 1 if external feedback
* is enabled.
*/
-static u8 __wrpll_calc_fbdiv(struct analogbits_wrpll_cfg *c)
+static u8 __wrpll_calc_fbdiv(const struct wrpll_cfg *c)
{
return (c->flags & WRPLL_FLAGS_INT_FEEDBACK_MASK) ? 2 : 1;
}
@@ -172,7 +160,7 @@
*vco_rate = MIN_VCO_FREQ;
} else {
divq = ilog2(s);
- *vco_rate = target_rate << divq;
+ *vco_rate = (u64)target_rate << divq;
}
wcd_out:
@@ -181,7 +169,7 @@
/**
* __wrpll_update_parent_rate() - update PLL data when parent rate changes
- * @c: ptr to a struct analogbits_wrpll_cfg record to write PLL data to
+ * @c: ptr to a struct wrpll_cfg record to write PLL data to
* @parent_rate: PLL input refclk rate (pre-R-divider)
*
* Pre-compute some data used by the PLL configuration algorithm when
@@ -189,46 +177,40 @@
* computation when the parent rate remains constant - expected to be
* the common case.
*
- * Returns: 0 upon success or -1 if the reference clock rate is out of range.
+ * Returns: 0 upon success or -ERANGE if the reference clock rate is
+ * out of range.
*/
-static int __wrpll_update_parent_rate(struct analogbits_wrpll_cfg *c,
+static int __wrpll_update_parent_rate(struct wrpll_cfg *c,
unsigned long parent_rate)
{
u8 max_r_for_parent;
if (parent_rate > MAX_INPUT_FREQ || parent_rate < MIN_POST_DIVR_FREQ)
- return -1;
+ return -ERANGE;
- c->_parent_rate = parent_rate;
+ c->parent_rate = parent_rate;
max_r_for_parent = div_u64(parent_rate, MIN_POST_DIVR_FREQ);
- c->_max_r = min_t(u8, MAX_DIVR_DIVISOR, max_r_for_parent);
+ c->max_r = min_t(u8, MAX_DIVR_DIVISOR, max_r_for_parent);
- /* Round up */
- c->_init_r = div_u64(parent_rate + MAX_POST_DIVR_FREQ - 1,
- MAX_POST_DIVR_FREQ);
+ c->init_r = DIV_ROUND_UP_ULL(parent_rate, MAX_POST_DIVR_FREQ);
return 0;
}
-/*
- * Public functions
- */
-
/**
- * analogbits_wrpll_configure() - compute PLL configuration for a target rate
- * @c: ptr to a struct analogbits_wrpll_cfg record to write into
+ * wrpll_configure() - compute PLL configuration for a target rate
+ * @c: ptr to a struct wrpll_cfg record to write into
* @target_rate: target PLL output clock rate (post-Q-divider)
* @parent_rate: PLL input refclk rate (pre-R-divider)
*
- * Given a pointer to a PLL context @c, a desired PLL target output
- * rate @target_rate, and a reference clock input rate @parent_rate,
- * compute the appropriate PLL signal configuration values. PLL
- * reprogramming is not glitchless, so the caller should switch any
- * downstream logic to a different clock source or clock-gate it
- * before presenting these values to the PLL configuration signals.
+ * Compute the appropriate PLL signal configuration values and store
+ * in PLL context @c. PLL reprogramming is not glitchless, so the
+ * caller should switch any downstream logic to a different clock
+ * source or clock-gate it before presenting these values to the PLL
+ * configuration signals.
*
* The caller must pass this function a pre-initialized struct
- * analogbits_wrpll_cfg record: either initialized to zero (with the
+ * wrpll_cfg record: either initialized to zero (with the
* exception of the .name and .flags fields) or read from the PLL.
*
* Context: Any context. Caller must protect the memory pointed to by @c
@@ -236,41 +218,26 @@
*
* Return: 0 upon success; anything else upon failure.
*/
-int analogbits_wrpll_configure_for_rate(struct analogbits_wrpll_cfg *c,
- u32 target_rate,
- unsigned long parent_rate)
+int wrpll_configure_for_rate(struct wrpll_cfg *c, u32 target_rate,
+ unsigned long parent_rate)
{
unsigned long ratio;
u64 target_vco_rate, delta, best_delta, f_pre_div, vco, vco_pre;
- u32 best_f, f, post_divr_freq, fbcfg;
+ u32 best_f, f, post_divr_freq;
u8 fbdiv, divq, best_r, r;
-
- if (!c)
- return -1;
+ int range;
if (c->flags == 0) {
WARN(1, "%s called with uninitialized PLL config", __func__);
- return -1;
- }
-
- fbcfg = WRPLL_FLAGS_INT_FEEDBACK_MASK | WRPLL_FLAGS_EXT_FEEDBACK_MASK;
- if ((c->flags & fbcfg) == fbcfg) {
- WARN(1, "%s called with invalid PLL config", __func__);
- return -1;
- }
-
- if (c->flags == WRPLL_FLAGS_EXT_FEEDBACK_MASK) {
- WARN(1, "%s: external feedback mode not currently supported",
- __func__);
- return -1;
+ return -EINVAL;
}
/* Initialize rounding data if it hasn't been initialized already */
- if (parent_rate != c->_parent_rate) {
+ if (parent_rate != c->parent_rate) {
if (__wrpll_update_parent_rate(c, parent_rate)) {
pr_err("%s: PLL input rate is out of range\n",
__func__);
- return -1;
+ return -ERANGE;
}
}
@@ -281,11 +248,12 @@
c->flags |= WRPLL_FLAGS_BYPASS_MASK;
return 0;
}
+
c->flags &= ~WRPLL_FLAGS_BYPASS_MASK;
/* Calculate the Q shift and target VCO rate */
divq = __wrpll_calc_divq(target_rate, &target_vco_rate);
- if (divq == 0)
+ if (!divq)
return -1;
c->divq = divq;
@@ -301,8 +269,7 @@
* Consider all values for R which land within
* [MIN_POST_DIVR_FREQ, MAX_POST_DIVR_FREQ]; prefer smaller R
*/
- for (r = c->_init_r; r <= c->_max_r; ++r) {
- /* What is the best F we can pick in this case? */
+ for (r = c->init_r; r <= c->max_r; ++r) {
f_pre_div = ratio * r;
f = (f_pre_div + (1 << ROUND_SHIFT)) >> ROUND_SHIFT;
f >>= (fbdiv - 1);
@@ -334,46 +301,54 @@
post_divr_freq = div_u64(parent_rate, best_r);
/* Pick the best PLL jitter filter */
- c->range = __wrpll_calc_filter_range(post_divr_freq);
+ range = __wrpll_calc_filter_range(post_divr_freq);
+ if (range < 0)
+ return range;
+ c->range = range;
return 0;
}
/**
- * analogbits_wrpll_calc_output_rate() - calculate the PLL's target output rate
- * @c: ptr to a struct analogbits_wrpll_cfg record to read from
+ * wrpll_calc_output_rate() - calculate the PLL's target output rate
+ * @c: ptr to a struct wrpll_cfg record to read from
* @parent_rate: PLL refclk rate
*
* Given a pointer to the PLL's current input configuration @c and the
* PLL's input reference clock rate @parent_rate (before the R
* pre-divider), calculate the PLL's output clock rate (after the Q
- * post-divider)
+ * post-divider).
*
* Context: Any context. Caller must protect the memory pointed to by @c
* from simultaneous modification.
*
- * Return: the PLL's output clock rate, in Hz.
+ * Return: the PLL's output clock rate, in Hz. The return value from
+ * this function is intended to be convenient to pass directly
+ * to the Linux clock framework; thus there is no explicit
+ * error return value.
*/
-unsigned long analogbits_wrpll_calc_output_rate(struct analogbits_wrpll_cfg *c,
- unsigned long parent_rate)
+unsigned long wrpll_calc_output_rate(const struct wrpll_cfg *c,
+ unsigned long parent_rate)
{
u8 fbdiv;
u64 n;
- WARN(c->flags & WRPLL_FLAGS_EXT_FEEDBACK_MASK,
- "external feedback mode not yet supported");
+ if (c->flags & WRPLL_FLAGS_EXT_FEEDBACK_MASK) {
+ WARN(1, "external feedback mode not yet supported");
+ return ULONG_MAX;
+ }
fbdiv = __wrpll_calc_fbdiv(c);
n = parent_rate * fbdiv * (c->divf + 1);
- n = div_u64(n, (c->divr + 1));
+ n = div_u64(n, c->divr + 1);
n >>= c->divq;
return n;
}
/**
- * analogbits_wrpll_calc_max_lock_us() - return the time for the PLL to lock
- * @c: ptr to a struct analogbits_wrpll_cfg record to read from
+ * wrpll_calc_max_lock_us() - return the time for the PLL to lock
+ * @c: ptr to a struct wrpll_cfg record to read from
*
* Return the minimum amount of time (in microseconds) that the caller
* must wait after reprogramming the PLL to ensure that it is locked
@@ -383,7 +358,7 @@
* Return: the minimum amount of time the caller must wait for the PLL
* to lock (in microseconds)
*/
-unsigned int analogbits_wrpll_calc_max_lock_us(struct analogbits_wrpll_cfg *c)
+unsigned int wrpll_calc_max_lock_us(const struct wrpll_cfg *c)
{
return MAX_LOCK_US;
}