- 根目录:
- drivers
- clk
- clk-vt8500.c
/*
* Clock implementation for VIA/Wondermedia SoC's
* Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*
*/
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#define LEGACY_PMC_BASE 0xD8130000
/* All clocks share the same lock as none can be changed concurrently */
static DEFINE_SPINLOCK(_lock);
struct clk_device {
struct clk_hw hw;
void __iomem *div_reg;
unsigned int div_mask;
void __iomem *en_reg;
int en_bit;
spinlock_t *lock;
};
/*
* Add new PLL_TYPE_x definitions here as required. Use the first known model
* to support the new type as the name.
* Add case statements to vtwm_pll_recalc_rate(), vtwm_pll_round_round() and
* vtwm_pll_set_rate() to handle the new PLL_TYPE_x
*/
#define PLL_TYPE_VT8500 0
#define PLL_TYPE_WM8650 1
#define PLL_TYPE_WM8750 2
#define PLL_TYPE_WM8850 3
struct clk_pll {
struct clk_hw hw;
void __iomem *reg;
spinlock_t *lock;
int type;
};
static void __iomem *pmc_base;
static __init void vtwm_set_pmc_base(void)
{
struct device_node *np =
of_find_compatible_node(NULL, NULL, "via,vt8500-pmc");
if (np)
pmc_base = of_iomap(np, 0);
else
pmc_base = ioremap(LEGACY_PMC_BASE, 0x1000);
of_node_put(np);
if (!pmc_base)
pr_err("%s:of_iomap(pmc) failed\n", __func__);
}
#define to_clk_device(_hw) container_of(_hw, struct clk_device, hw)
#define VT8500_PMC_BUSY_MASK 0x18
static void vt8500_pmc_wait_busy(void)
{
while (readl(pmc_base) & VT8500_PMC_BUSY_MASK)
cpu_relax();
}
static int vt8500_dclk_enable(struct clk_hw *hw)
{
struct clk_device *cdev = to_clk_device(hw);
u32 en_val;
unsigned long flags = 0;
spin_lock_irqsave(cdev->lock, flags);
en_val = readl(cdev->en_reg);
en_val |= BIT(cdev->en_bit);
writel(en_val, cdev->en_reg);
spin_unlock_irqrestore(cdev->lock, flags);
return 0;
}
static void vt8500_dclk_disable(struct clk_hw *hw)
{
struct clk_device *cdev = to_clk_device(hw);
u32 en_val;
unsigned long flags = 0;
spin_lock_irqsave(cdev->lock, flags);
en_val = readl(cdev->en_reg);
en_val &= ~BIT(cdev->en_bit);
writel(en_val, cdev->en_reg);
spin_unlock_irqrestore(cdev->lock, flags);
}
static int vt8500_dclk_is_enabled(struct clk_hw *hw)
{
struct clk_device *cdev = to_clk_device(hw);
u32 en_val = (readl(cdev->en_reg) & BIT(cdev->en_bit));
return en_val ? 1 : 0;
}
static unsigned long vt8500_dclk_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_device *cdev = to_clk_device(hw);
u32 div = readl(cdev->div_reg) & cdev->div_mask;
/* Special case for SDMMC devices */
if ((cdev->div_mask == 0x3F) && (div & BIT(5)))
div = 64 * (div & 0x1f);
/* div == 0 is actually the highest divisor */
if (div == 0)
div = (cdev->div_mask + 1);
return parent_rate / div;
}
static long vt8500_dclk_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_device *cdev = to_clk_device(hw);
u32 divisor;
if (rate == 0)
return 0;
divisor = *prate / rate;
/* If prate / rate would be decimal, incr the divisor */
if (rate * divisor < *prate)
divisor++;
/*
* If this is a request for SDMMC we have to adjust the divisor
* when >31 to use the fixed predivisor
*/
if ((cdev->div_mask == 0x3F) && (divisor > 31)) {
divisor = 64 * ((divisor / 64) + 1);
}
return *prate / divisor;
}
static int vt8500_dclk_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_device *cdev = to_clk_device(hw);
u32 divisor;
unsigned long flags = 0;
if (rate == 0)
return 0;
divisor = parent_rate / rate;
if (divisor == cdev->div_mask + 1)
divisor = 0;
/* SDMMC mask may need to be corrected before testing if its valid */
if ((cdev->div_mask == 0x3F) && (divisor > 31)) {
/*
* Bit 5 is a fixed /64 predivisor. If the requested divisor
* is >31 then correct for the fixed divisor being required.
*/
divisor = 0x20 + (divisor / 64);
}
if (divisor > cdev->div_mask) {
pr_err("%s: invalid divisor for clock\n", __func__);
return -EINVAL;
}
spin_lock_irqsave(cdev->lock, flags);
vt8500_pmc_wait_busy();
writel(divisor, cdev->div_reg);
vt8500_pmc_wait_busy();
spin_unlock_irqrestore(cdev->lock, flags);
return 0;
}
static const struct clk_ops vt8500_gated_clk_ops = {
.enable = vt8500_dclk_enable,
.disable = vt8500_dclk_disable,
.is_enabled = vt8500_dclk_is_enabled,
};
static const struct clk_ops vt8500_divisor_clk_ops = {
.round_rate = vt8500_dclk_round_rate,
.set_rate = vt8500_dclk_set_rate,
.recalc_rate = vt8500_dclk_recalc_rate,
};
static const struct clk_ops vt8500_gated_divisor_clk_ops = {
.enable = vt8500_dclk_enable,
.disable = vt8500_dclk_disable,
.is_enabled = vt8500_dclk_is_enabled,
.round_rate = vt8500_dclk_round_rate,
.set_rate = vt8500_dclk_set_rate,
.recalc_rate = vt8500_dclk_recalc_rate,
};
#define CLK_INIT_GATED BIT(0)
#define CLK_INIT_DIVISOR BIT(1)
#define CLK_INIT_GATED_DIVISOR (CLK_INIT_DIVISOR | CLK_INIT_GATED)
static __init void vtwm_device_clk_init(struct device_node *node)
{
u32 en_reg, div_reg;
struct clk *clk;
struct clk_device *dev_clk;
const char *clk_name = node->name;
const char *parent_name;
struct clk_init_data init;
int rc;
int clk_init_flags = 0;
if (!pmc_base)
vtwm_set_pmc_base();
dev_clk = kzalloc(sizeof(*dev_clk), GFP_KERNEL);
if (WARN_ON(!dev_clk))
return;
dev_clk->lock = &_lock;
rc = of_property_read_u32(node, "enable-reg", &en_reg);
if (!rc) {
dev_clk->en_reg = pmc_base + en_reg;
rc = of_property_read_u32(node, "enable-bit", &dev_clk->en_bit);
if (rc) {
pr_err("%s: enable-bit property required for gated clock\n",
__func__);
return;
}
clk_init_flags |= CLK_INIT_GATED;
}
rc = of_property_read_u32(node, "divisor-reg", &div_reg);
if (!rc) {
dev_clk->div_reg = pmc_base + div_reg;
/*
* use 0x1f as the default mask since it covers
* almost all the clocks and reduces dts properties
*/
dev_clk->div_mask = 0x1f;
of_property_read_u32(node, "divisor-mask", &dev_clk->div_mask);
clk_init_flags |= CLK_INIT_DIVISOR;
}
of_property_read_string(node, "clock-output-names", &clk_name);
switch (clk_init_flags) {
case CLK_INIT_GATED:
init.ops = &vt8500_gated_clk_ops;
break;
case CLK_INIT_DIVISOR:
init.ops = &vt8500_divisor_clk_ops;
break;
case CLK_INIT_GATED_DIVISOR:
init.ops = &vt8500_gated_divisor_clk_ops;
break;
default:
pr_err("%s: Invalid clock description in device tree\n",
__func__);
kfree(dev_clk);
return;
}
init.name = clk_name;
init.flags = 0;
parent_name = of_clk_get_parent_name(node, 0);
init.parent_names = &parent_name;
init.num_parents = 1;
dev_clk->hw.init = &init;
clk = clk_register(NULL, &dev_clk->hw);
if (WARN_ON(IS_ERR(clk))) {
kfree(dev_clk);
return;
}
rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
clk_register_clkdev(clk, clk_name, NULL);
}
CLK_OF_DECLARE(vt8500_device, "via,vt8500-device-clock", vtwm_device_clk_init);
/* PLL clock related functions */
#define to_clk_pll(_hw) container_of(_hw, struct clk_pll, hw)
/* Helper macros for PLL_VT8500 */
#define VT8500_PLL_MUL(x) ((x & 0x1F) << 1)
#define VT8500_PLL_DIV(x) ((x & 0x100) ? 1 : 2)
#define VT8500_BITS_TO_FREQ(r, m, d) \
((r / d) * m)
#define VT8500_BITS_TO_VAL(m, d) \
((d == 2 ? 0 : 0x100) | ((m >> 1) & 0x1F))
/* Helper macros for PLL_WM8650 */
#define WM8650_PLL_MUL(x) (x & 0x3FF)
#define WM8650_PLL_DIV(x) (((x >> 10) & 7) * (1 << ((x >> 13) & 3)))
#define WM8650_BITS_TO_FREQ(r, m, d1, d2) \
(r * m / (d1 * (1 << d2)))
#define WM8650_BITS_TO_VAL(m, d1, d2) \
((d2 << 13) | (d1 << 10) | (m & 0x3FF))
/* Helper macros for PLL_WM8750 */
#define WM8750_PLL_MUL(x) (((x >> 16) & 0xFF) + 1)
#define WM8750_PLL_DIV(x) ((((x >> 8) & 1) + 1) * (1 << (x & 7)))
#define WM8750_BITS_TO_FREQ(r, m, d1, d2) \
(r * (m+1) / ((d1+1) * (1 << d2)))
#define WM8750_BITS_TO_VAL(f, m, d1, d2) \
((f << 24) | ((m - 1) << 16) | ((d1 - 1) << 8) | d2)
/* Helper macros for PLL_WM8850 */
#define WM8850_PLL_MUL(x) ((((x >> 16) & 0x7F) + 1) * 2)
#define WM8850_PLL_DIV(x) ((((x >> 8) & 1) + 1) * (1 << (x & 3)))
#define WM8850_BITS_TO_FREQ(r, m, d1, d2) \
(r * ((m + 1) * 2) / ((d1+1) * (1 << d2)))
#define WM8850_BITS_TO_VAL(m, d1, d2) \
((((m / 2) - 1) << 16) | ((d1 - 1) << 8) | d2)
static void vt8500_find_pll_bits(unsigned long rate, unsigned long parent_rate,
u32 *multiplier, u32 *prediv)
{
unsigned long tclk;
/* sanity check */
if ((rate < parent_rate * 4) || (rate > parent_rate * 62)) {
pr_err("%s: requested rate out of range\n", __func__);
*multiplier = 0;
*prediv = 1;
return;
}
if (rate <= parent_rate * 31)
/* use the prediv to double the resolution */
*prediv = 2;
else
*prediv = 1;
*multiplier = rate / (parent_rate / *prediv);
tclk = (parent_rate / *prediv) * *multiplier;
if (tclk != rate)
pr_warn("%s: requested rate %lu, found rate %lu\n", __func__,
rate, tclk);
}
static void wm8650_find_pll_bits(unsigned long rate, unsigned long parent_rate,
u32 *multiplier, u32 *divisor1, u32 *divisor2)
{
u32 mul, div1, div2;
u32 best_mul, best_div1, best_div2;
unsigned long tclk, rate_err, best_err;
best_err = (unsigned long)-1;
/* Find the closest match (lower or equal to requested) */
for (div1 = 5; div1 >= 3; div1--)
for (div2 = 3; div2 >= 0; div2--)
for (mul = 3; mul <= 1023; mul++) {
tclk = parent_rate * mul / (div1 * (1 << div2));
if (tclk > rate)
continue;
/* error will always be +ve */
rate_err = rate - tclk;
if (rate_err == 0) {
*multiplier = mul;
*divisor1 = div1;
*divisor2 = div2;
return;
}
if (rate_err < best_err) {
best_err = rate_err;
best_mul = mul;
best_div1 = div1;
best_div2 = div2;
}
}
/* if we got here, it wasn't an exact match */
pr_warn("%s: requested rate %lu, found rate %lu\n", __func__, rate,
rate - best_err);
*multiplier = best_mul;
*divisor1 = best_div1;
*divisor2 = best_div2;
}
static u32 wm8750_get_filter(u32 parent_rate, u32 divisor1)
{
/* calculate frequency (MHz) after pre-divisor */
u32 freq = (parent_rate / 1000000) / (divisor1 + 1);
if ((freq < 10) || (freq > 200))
pr_warn("%s: PLL recommended input frequency 10..200Mhz (requested %d Mhz)\n",
__func__, freq);
if (freq >= 166)
return 7;
else if (freq >= 104)
return 6;
else if (freq >= 65)
return 5;
else if (freq >= 42)
return 4;
else if (freq >= 26)
return 3;
else if (freq >= 16)
return 2;
else if (freq >= 10)
return 1;
return 0;
}
static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate,
u32 *filter, u32 *multiplier, u32 *divisor1, u32 *divisor2)
{
u32 mul, div1, div2;
u32 best_mul, best_div1, best_div2;
unsigned long tclk, rate_err, best_err;
best_err = (unsigned long)-1;
/* Find the closest match (lower or equal to requested) */
for (div1 = 1; div1 >= 0; div1--)
for (div2 = 7; div2 >= 0; div2--)
for (mul = 0; mul <= 255; mul++) {
tclk = parent_rate * (mul + 1) / ((div1 + 1) * (1 << div2));
if (tclk > rate)
continue;
/* error will always be +ve */
rate_err = rate - tclk;
if (rate_err == 0) {
*filter = wm8750_get_filter(parent_rate, div1);
*multiplier = mul;
*divisor1 = div1;
*divisor2 = div2;
return;
}
if (rate_err < best_err) {
best_err = rate_err;
best_mul = mul;
best_div1 = div1;
best_div2 = div2;
}
}
/* if we got here, it wasn't an exact match */
pr_warn("%s: requested rate %lu, found rate %lu\n", __func__, rate,
rate - best_err);
*filter = wm8750_get_filter(parent_rate, best_div1);
*multiplier = best_mul;
*divisor1 = best_div1;
*divisor2 = best_div2;
}
static void wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate,
u32 *multiplier, u32 *divisor1, u32 *divisor2)
{
u32 mul, div1, div2;
u32 best_mul, best_div1, best_div2;
unsigned long tclk, rate_err, best_err;
best_err = (unsigned long)-1;
/* Find the closest match (lower or equal to requested) */
for (div1 = 1; div1 >= 0; div1--)
for (div2 = 3; div2 >= 0; div2--)
for (mul = 0; mul <= 127; mul++) {
tclk = parent_rate * ((mul + 1) * 2) /
((div1 + 1) * (1 << div2));
if (tclk > rate)
continue;
/* error will always be +ve */
rate_err = rate - tclk;
if (rate_err == 0) {
*multiplier = mul;
*divisor1 = div1;
*divisor2 = div2;
return;
}
if (rate_err < best_err) {
best_err = rate_err;
best_mul = mul;
best_div1 = div1;
best_div2 = div2;
}
}
/* if we got here, it wasn't an exact match */
pr_warn("%s: requested rate %lu, found rate %lu\n", __func__, rate,
rate - best_err);
*multiplier = best_mul;
*divisor1 = best_div1;
*divisor2 = best_div2;
}
static int vtwm_pll_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_pll *pll = to_clk_pll(hw);
u32 filter, mul, div1, div2;
u32 pll_val;
unsigned long flags = 0;
/* sanity check */
switch (pll->type) {
case PLL_TYPE_VT8500:
vt8500_find_pll_bits(rate, parent_rate, &mul, &div1);
pll_val = VT8500_BITS_TO_VAL(mul, div1);
break;
case PLL_TYPE_WM8650:
wm8650_find_pll_bits(rate, parent_rate, &mul, &div1, &div2);
pll_val = WM8650_BITS_TO_VAL(mul, div1, div2);
break;
case PLL_TYPE_WM8750:
wm8750_find_pll_bits(rate, parent_rate, &filter, &mul, &div1, &div2);
pll_val = WM8750_BITS_TO_VAL(filter, mul, div1, div2);
break;
case PLL_TYPE_WM8850:
wm8850_find_pll_bits(rate, parent_rate, &mul, &div1, &div2);
pll_val = WM8850_BITS_TO_VAL(mul, div1, div2);
break;
default:
pr_err("%s: invalid pll type\n", __func__);
return 0;
}
spin_lock_irqsave(pll->lock, flags);
vt8500_pmc_wait_busy();
writel(pll_val, pll->reg);
vt8500_pmc_wait_busy();
spin_unlock_irqrestore(pll->lock, flags);
return 0;
}
static long vtwm_pll_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_pll *pll = to_clk_pll(hw);
u32 filter, mul, div1, div2;
long round_rate;
switch (pll->type) {
case PLL_TYPE_VT8500:
vt8500_find_pll_bits(rate, *prate, &mul, &div1);
round_rate = VT8500_BITS_TO_FREQ(*prate, mul, div1);
break;
case PLL_TYPE_WM8650:
wm8650_find_pll_bits(rate, *prate, &mul, &div1, &div2);
round_rate = WM8650_BITS_TO_FREQ(*prate, mul, div1, div2);
break;
case PLL_TYPE_WM8750:
wm8750_find_pll_bits(rate, *prate, &filter, &mul, &div1, &div2);
round_rate = WM8750_BITS_TO_FREQ(*prate, mul, div1, div2);
break;
case PLL_TYPE_WM8850:
wm8850_find_pll_bits(rate, *prate, &mul, &div1, &div2);
round_rate = WM8850_BITS_TO_FREQ(*prate, mul, div1, div2);
break;
default:
round_rate = 0;
}
return round_rate;
}
static unsigned long vtwm_pll_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_pll *pll = to_clk_pll(hw);
u32 pll_val = readl(pll->reg);
unsigned long pll_freq;
switch (pll->type) {
case PLL_TYPE_VT8500:
pll_freq = parent_rate * VT8500_PLL_MUL(pll_val);
pll_freq /= VT8500_PLL_DIV(pll_val);
break;
case PLL_TYPE_WM8650:
pll_freq = parent_rate * WM8650_PLL_MUL(pll_val);
pll_freq /= WM8650_PLL_DIV(pll_val);
break;
case PLL_TYPE_WM8750:
pll_freq = parent_rate * WM8750_PLL_MUL(pll_val);
pll_freq /= WM8750_PLL_DIV(pll_val);
break;
case PLL_TYPE_WM8850:
pll_freq = parent_rate * WM8850_PLL_MUL(pll_val);
pll_freq /= WM8850_PLL_DIV(pll_val);
break;
default:
pll_freq = 0;
}
return pll_freq;
}
static const struct clk_ops vtwm_pll_ops = {
.round_rate = vtwm_pll_round_rate,
.set_rate = vtwm_pll_set_rate,
.recalc_rate = vtwm_pll_recalc_rate,
};
static __init void vtwm_pll_clk_init(struct device_node *node, int pll_type)
{
u32 reg;
struct clk *clk;
struct clk_pll *pll_clk;
const char *clk_name = node->name;
const char *parent_name;
struct clk_init_data init;
int rc;
if (!pmc_base)
vtwm_set_pmc_base();
rc = of_property_read_u32(node, "reg", ®);
if (WARN_ON(rc))
return;
pll_clk = kzalloc(sizeof(*pll_clk), GFP_KERNEL);
if (WARN_ON(!pll_clk))
return;
pll_clk->reg = pmc_base + reg;
pll_clk->lock = &_lock;
pll_clk->type = pll_type;
of_property_read_string(node, "clock-output-names", &clk_name);
init.name = clk_name;
init.ops = &vtwm_pll_ops;
init.flags = 0;
parent_name = of_clk_get_parent_name(node, 0);
init.parent_names = &parent_name;
init.num_parents = 1;
pll_clk->hw.init = &init;
clk = clk_register(NULL, &pll_clk->hw);
if (WARN_ON(IS_ERR(clk))) {
kfree(pll_clk);
return;
}
rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
clk_register_clkdev(clk, clk_name, NULL);
}
/* Wrappers for initialization functions */
static void __init vt8500_pll_init(struct device_node *node)
{
vtwm_pll_clk_init(node, PLL_TYPE_VT8500);
}
CLK_OF_DECLARE(vt8500_pll, "via,vt8500-pll-clock", vt8500_pll_init);
static void __init wm8650_pll_init(struct device_node *node)
{
vtwm_pll_clk_init(node, PLL_TYPE_WM8650);
}
CLK_OF_DECLARE(wm8650_pll, "wm,wm8650-pll-clock", wm8650_pll_init);
static void __init wm8750_pll_init(struct device_node *node)
{
vtwm_pll_clk_init(node, PLL_TYPE_WM8750);
}
CLK_OF_DECLARE(wm8750_pll, "wm,wm8750-pll-clock", wm8750_pll_init);
static void __init wm8850_pll_init(struct device_node *node)
{
vtwm_pll_clk_init(node, PLL_TYPE_WM8850);
}
CLK_OF_DECLARE(wm8850_pll, "wm,wm8850-pll-clock", wm8850_pll_init);