diff options
author | Hans-Christian Egtvedt <hcegtvedt@atmel.com> | 2007-12-19 09:29:19 +0100 |
---|---|---|
committer | Haavard Skinnemoen <haavard.skinnemoen@atmel.com> | 2008-04-19 20:40:08 -0400 |
commit | 35bf50ccc80584a1404982f02fc4368e991ff55c (patch) | |
tree | bb9add62acc4151b36c88b6bc893dc2000f08029 /arch/avr32 | |
parent | e723ff666a5da8f7fda4e36ebfeafac2175a5c6e (diff) | |
download | linux-35bf50ccc80584a1404982f02fc4368e991ff55c.tar.bz2 |
avr32: Implement set_rate(), set_parent() and mode() for pll1
This patch is a take two of adding full functionality to PLL1 on
AT32AP7000. This allows board-specific code and drivers to configure
and enable PLL1. This is useful when precise control over the
frequency of e.g. a genclock is needed and requested by users for the
ABDAC device.
The patch is based upon previous patches from both Haavard Skinnemoen
and David Brownell.
Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Diffstat (limited to 'arch/avr32')
-rw-r--r-- | arch/avr32/mach-at32ap/at32ap700x.c | 153 |
1 files changed, 150 insertions, 3 deletions
diff --git a/arch/avr32/mach-at32ap/at32ap700x.c b/arch/avr32/mach-at32ap/at32ap700x.c index 22c302ad9b3f..0f24b4f85c17 100644 --- a/arch/avr32/mach-at32ap/at32ap700x.c +++ b/arch/avr32/mach-at32ap/at32ap700x.c @@ -6,6 +6,7 @@ * published by the Free Software Foundation. */ #include <linux/clk.h> +#include <linux/delay.h> #include <linux/fb.h> #include <linux/init.h> #include <linux/platform_device.h> @@ -99,6 +100,9 @@ unsigned long at32ap7000_osc_rates[3] = { [2] = 12000000, }; +static struct clk osc0; +static struct clk osc1; + static unsigned long osc_get_rate(struct clk *clk) { return at32ap7000_osc_rates[clk->index]; @@ -108,9 +112,6 @@ static unsigned long pll_get_rate(struct clk *clk, unsigned long control) { unsigned long div, mul, rate; - if (!(control & PM_BIT(PLLEN))) - return 0; - div = PM_BFEXT(PLLDIV, control) + 1; mul = PM_BFEXT(PLLMUL, control) + 1; @@ -121,6 +122,71 @@ static unsigned long pll_get_rate(struct clk *clk, unsigned long control) return rate; } +static long pll_set_rate(struct clk *clk, unsigned long rate, + u32 *pll_ctrl) +{ + unsigned long mul; + unsigned long mul_best_fit = 0; + unsigned long div; + unsigned long div_min; + unsigned long div_max; + unsigned long div_best_fit = 0; + unsigned long base; + unsigned long pll_in; + unsigned long actual = 0; + unsigned long rate_error; + unsigned long rate_error_prev = ~0UL; + u32 ctrl; + + /* Rate must be between 80 MHz and 200 Mhz. */ + if (rate < 80000000UL || rate > 200000000UL) + return -EINVAL; + + ctrl = PM_BF(PLLOPT, 4); + base = clk->parent->get_rate(clk->parent); + + /* PLL input frequency must be between 6 MHz and 32 MHz. */ + div_min = DIV_ROUND_UP(base, 32000000UL); + div_max = base / 6000000UL; + + if (div_max < div_min) + return -EINVAL; + + for (div = div_min; div <= div_max; div++) { + pll_in = (base + div / 2) / div; + mul = (rate + pll_in / 2) / pll_in; + + if (mul == 0) + continue; + + actual = pll_in * mul; + rate_error = abs(actual - rate); + + if (rate_error < rate_error_prev) { + mul_best_fit = mul; + div_best_fit = div; + rate_error_prev = rate_error; + } + + if (rate_error == 0) + break; + } + + if (div_best_fit == 0) + return -EINVAL; + + ctrl |= PM_BF(PLLMUL, mul_best_fit - 1); + ctrl |= PM_BF(PLLDIV, div_best_fit - 1); + ctrl |= PM_BF(PLLCOUNT, 16); + + if (clk->parent == &osc1) + ctrl |= PM_BIT(PLLOSC); + + *pll_ctrl = ctrl; + + return actual; +} + static unsigned long pll0_get_rate(struct clk *clk) { u32 control; @@ -130,6 +196,41 @@ static unsigned long pll0_get_rate(struct clk *clk) return pll_get_rate(clk, control); } +static void pll1_mode(struct clk *clk, int enabled) +{ + unsigned long timeout; + u32 status; + u32 ctrl; + + ctrl = pm_readl(PLL1); + + if (enabled) { + if (!PM_BFEXT(PLLMUL, ctrl) && !PM_BFEXT(PLLDIV, ctrl)) { + pr_debug("clk %s: failed to enable, rate not set\n", + clk->name); + return; + } + + ctrl |= PM_BIT(PLLEN); + pm_writel(PLL1, ctrl); + + /* Wait for PLL lock. */ + for (timeout = 10000; timeout; timeout--) { + status = pm_readl(ISR); + if (status & PM_BIT(LOCK1)) + break; + udelay(10); + } + + if (!(status & PM_BIT(LOCK1))) + printk(KERN_ERR "clk %s: timeout waiting for lock\n", + clk->name); + } else { + ctrl &= ~PM_BIT(PLLEN); + pm_writel(PLL1, ctrl); + } +} + static unsigned long pll1_get_rate(struct clk *clk) { u32 control; @@ -139,6 +240,49 @@ static unsigned long pll1_get_rate(struct clk *clk) return pll_get_rate(clk, control); } +static long pll1_set_rate(struct clk *clk, unsigned long rate, int apply) +{ + u32 ctrl = 0; + unsigned long actual_rate; + + actual_rate = pll_set_rate(clk, rate, &ctrl); + + if (apply) { + if (actual_rate != rate) + return -EINVAL; + if (clk->users > 0) + return -EBUSY; + pr_debug(KERN_INFO "clk %s: new rate %lu (actual rate %lu)\n", + clk->name, rate, actual_rate); + pm_writel(PLL1, ctrl); + } + + return actual_rate; +} + +static int pll1_set_parent(struct clk *clk, struct clk *parent) +{ + u32 ctrl; + + if (clk->users > 0) + return -EBUSY; + + ctrl = pm_readl(PLL1); + WARN_ON(ctrl & PM_BIT(PLLEN)); + + if (parent == &osc0) + ctrl &= ~PM_BIT(PLLOSC); + else if (parent == &osc1) + ctrl |= PM_BIT(PLLOSC); + else + return -EINVAL; + + pm_writel(PLL1, ctrl); + clk->parent = parent; + + return 0; +} + /* * The AT32AP7000 has five primary clock sources: One 32kHz * oscillator, two crystal oscillators and two PLLs. @@ -167,7 +311,10 @@ static struct clk pll0 = { }; static struct clk pll1 = { .name = "pll1", + .mode = pll1_mode, .get_rate = pll1_get_rate, + .set_rate = pll1_set_rate, + .set_parent = pll1_set_parent, .parent = &osc0, }; |