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clk: vt8500: Add support for clocks on the WM8850 SoCs

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The WM8850 has a different PLL clock to the previous versions. This
patch adds support for the WM8850-style PLL clocks.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
This commit is contained in:
Tony Prisk 2013-05-13 20:20:59 +12:00 committed by Mike Turquette
parent d41d580587
commit 518d4709f1
2 changed files with 73 additions and 0 deletions
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2
Documentation/devicetree/bindings/clock/vt8500.txt
View File

@ -8,6 +8,8 @@ Required properties:
- compatible : shall be one of the following:
"via,vt8500-pll-clock" - for a VT8500/WM8505 PLL clock
"wm,wm8650-pll-clock" - for a WM8650 PLL clock
"wm,wm8750-pll-clock" - for a WM8750 PLL clock
"wm,wm8850-pll-clock" - for a WM8850 PLL clock
"via,vt8500-device-clock" - for a VT/WM device clock
Required properties for PLL clocks:

71
drivers/clk/clk-vt8500.c
View File

@ -42,6 +42,7 @@ struct clk_device {
#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;
@ -327,6 +328,15 @@ CLK_OF_DECLARE(vt8500_device, "via,vt8500-device-clock", vtwm_device_clk_init);
#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)
@ -466,6 +476,49 @@ static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate,
*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)
{
@ -489,6 +542,10 @@ static int vtwm_pll_set_rate(struct clk_hw *hw, unsigned long rate,
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;
@ -525,6 +582,10 @@ static long vtwm_pll_round_rate(struct clk_hw *hw, unsigned long rate,
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;
}
@ -552,6 +613,10 @@ static unsigned long vtwm_pll_recalc_rate(struct clk_hw *hw,
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;
}
@ -628,6 +693,12 @@ static void __init wm8750_pll_init(struct device_node *node)
}
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);
void __init vtwm_clk_init(void __iomem *base)
{
if (!base)