diff options
author | viresh kumar <viresh.kumar@st.com> | 2010-04-01 12:30:46 +0100 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-04-14 11:34:33 +0100 |
commit | 8c0236fc465c71d98203bcf5609db01b9cf5f70f (patch) | |
tree | be5754541381f3978a470455a0d0892f278ef689 /arch/arm/plat-spear/clock.c | |
parent | 986435e3596cbae662b86812e4563fbb6013b994 (diff) |
ARM: 6014/1: ST SPEAr: Added clock framework for SPEAr platform and machines
Clock framework for SPEAr is based upon clkdev framework for ARM
Reviewed-by: Linus Walleij <linux.walleij@stericsson.com>
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/plat-spear/clock.c')
-rw-r--r-- | arch/arm/plat-spear/clock.c | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/arch/arm/plat-spear/clock.c b/arch/arm/plat-spear/clock.c new file mode 100644 index 00000000000..ee4f90e534d --- /dev/null +++ b/arch/arm/plat-spear/clock.c @@ -0,0 +1,435 @@ +/* + * arch/arm/plat-spear/clock.c + * + * Clock framework for SPEAr platform + * + * Copyright (C) 2009 ST Microelectronics + * Viresh Kumar<viresh.kumar@st.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/bug.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/spinlock.h> +#include <mach/misc_regs.h> +#include <plat/clock.h> + +static DEFINE_SPINLOCK(clocks_lock); +static LIST_HEAD(root_clks); + +static void propagate_rate(struct list_head *); + +static int generic_clk_enable(struct clk *clk) +{ + unsigned int val; + + if (!clk->en_reg) + return -EFAULT; + + val = readl(clk->en_reg); + if (unlikely(clk->flags & RESET_TO_ENABLE)) + val &= ~(1 << clk->en_reg_bit); + else + val |= 1 << clk->en_reg_bit; + + writel(val, clk->en_reg); + + return 0; +} + +static void generic_clk_disable(struct clk *clk) +{ + unsigned int val; + + if (!clk->en_reg) + return; + + val = readl(clk->en_reg); + if (unlikely(clk->flags & RESET_TO_ENABLE)) + val |= 1 << clk->en_reg_bit; + else + val &= ~(1 << clk->en_reg_bit); + + writel(val, clk->en_reg); +} + +/* generic clk ops */ +static struct clkops generic_clkops = { + .enable = generic_clk_enable, + .disable = generic_clk_disable, +}; + +/* + * clk_enable - inform the system when the clock source should be running. + * @clk: clock source + * + * If the clock can not be enabled/disabled, this should return success. + * + * Returns success (0) or negative errno. + */ +int clk_enable(struct clk *clk) +{ + unsigned long flags; + int ret = 0; + + if (!clk || IS_ERR(clk)) + return -EFAULT; + + spin_lock_irqsave(&clocks_lock, flags); + if (clk->usage_count == 0) { + if (clk->ops && clk->ops->enable) + ret = clk->ops->enable(clk); + } + clk->usage_count++; + spin_unlock_irqrestore(&clocks_lock, flags); + + return ret; +} +EXPORT_SYMBOL(clk_enable); + +/* + * clk_disable - inform the system when the clock source is no longer required. + * @clk: clock source + * + * Inform the system that a clock source is no longer required by + * a driver and may be shut down. + * + * Implementation detail: if the clock source is shared between + * multiple drivers, clk_enable() calls must be balanced by the + * same number of clk_disable() calls for the clock source to be + * disabled. + */ +void clk_disable(struct clk *clk) +{ + unsigned long flags; + + if (!clk || IS_ERR(clk)) + return; + + WARN_ON(clk->usage_count == 0); + + spin_lock_irqsave(&clocks_lock, flags); + clk->usage_count--; + if (clk->usage_count == 0) { + if (clk->ops && clk->ops->disable) + clk->ops->disable(clk); + } + spin_unlock_irqrestore(&clocks_lock, flags); +} +EXPORT_SYMBOL(clk_disable); + +/** + * clk_get_rate - obtain the current clock rate (in Hz) for a clock source. + * This is only valid once the clock source has been enabled. + * @clk: clock source + */ +unsigned long clk_get_rate(struct clk *clk) +{ + unsigned long flags, rate; + + spin_lock_irqsave(&clocks_lock, flags); + rate = clk->rate; + spin_unlock_irqrestore(&clocks_lock, flags); + + return rate; +} +EXPORT_SYMBOL(clk_get_rate); + +/** + * clk_set_parent - set the parent clock source for this clock + * @clk: clock source + * @parent: parent clock source + * + * Returns success (0) or negative errno. + */ +int clk_set_parent(struct clk *clk, struct clk *parent) +{ + int i, found = 0, val = 0; + unsigned long flags; + + if (!clk || IS_ERR(clk) || !parent || IS_ERR(parent)) + return -EFAULT; + if (clk->usage_count) + return -EBUSY; + if (!clk->pclk_sel) + return -EPERM; + if (clk->pclk == parent) + return 0; + + for (i = 0; i < clk->pclk_sel->pclk_count; i++) { + if (clk->pclk_sel->pclk_info[i].pclk == parent) { + found = 1; + break; + } + } + + if (!found) + return -EINVAL; + + spin_lock_irqsave(&clocks_lock, flags); + /* reflect parent change in hardware */ + val = readl(clk->pclk_sel->pclk_sel_reg); + val &= ~(clk->pclk_sel->pclk_sel_mask << clk->pclk_sel_shift); + val |= clk->pclk_sel->pclk_info[i].pclk_mask << clk->pclk_sel_shift; + writel(val, clk->pclk_sel->pclk_sel_reg); + spin_unlock_irqrestore(&clocks_lock, flags); + + /* reflect parent change in software */ + clk->recalc(clk); + propagate_rate(&clk->children); + return 0; +} +EXPORT_SYMBOL(clk_set_parent); + +/* registers clock in platform clock framework */ +void clk_register(struct clk_lookup *cl) +{ + struct clk *clk = cl->clk; + unsigned long flags; + + if (!clk || IS_ERR(clk)) + return; + + spin_lock_irqsave(&clocks_lock, flags); + + INIT_LIST_HEAD(&clk->children); + if (clk->flags & ALWAYS_ENABLED) + clk->ops = NULL; + else if (!clk->ops) + clk->ops = &generic_clkops; + + /* root clock don't have any parents */ + if (!clk->pclk && !clk->pclk_sel) { + list_add(&clk->sibling, &root_clks); + /* add clocks with only one parent to parent's children list */ + } else if (clk->pclk && !clk->pclk_sel) { + list_add(&clk->sibling, &clk->pclk->children); + } else { + /* add clocks with > 1 parent to 1st parent's children list */ + list_add(&clk->sibling, + &clk->pclk_sel->pclk_info[0].pclk->children); + } + spin_unlock_irqrestore(&clocks_lock, flags); + + /* add clock to arm clockdev framework */ + clkdev_add(cl); +} + +/** + * propagate_rate - recalculate and propagate all clocks in list head + * + * Recalculates all root clocks in list head, which if the clock's .recalc is + * set correctly, should also propagate their rates. + */ +static void propagate_rate(struct list_head *lhead) +{ + struct clk *clkp, *_temp; + + list_for_each_entry_safe(clkp, _temp, lhead, sibling) { + if (clkp->recalc) + clkp->recalc(clkp); + propagate_rate(&clkp->children); + } +} + +/* returns current programmed clocks clock info structure */ +static struct pclk_info *pclk_info_get(struct clk *clk) +{ + unsigned int mask, i; + unsigned long flags; + struct pclk_info *info = NULL; + + spin_lock_irqsave(&clocks_lock, flags); + mask = (readl(clk->pclk_sel->pclk_sel_reg) >> clk->pclk_sel_shift) + & clk->pclk_sel->pclk_sel_mask; + + for (i = 0; i < clk->pclk_sel->pclk_count; i++) { + if (clk->pclk_sel->pclk_info[i].pclk_mask == mask) + info = &clk->pclk_sel->pclk_info[i]; + } + spin_unlock_irqrestore(&clocks_lock, flags); + + return info; +} + +/* + * Set pclk as cclk's parent and add clock sibling node to current parents + * children list + */ +static void change_parent(struct clk *cclk, struct clk *pclk) +{ + unsigned long flags; + + spin_lock_irqsave(&clocks_lock, flags); + list_del(&cclk->sibling); + list_add(&cclk->sibling, &pclk->children); + + cclk->pclk = pclk; + spin_unlock_irqrestore(&clocks_lock, flags); +} + +/* + * calculates current programmed rate of pll1 + * + * In normal mode + * rate = (2 * M[15:8] * Fin)/(N * 2^P) + * + * In Dithered mode + * rate = (2 * M[15:0] * Fin)/(256 * N * 2^P) + */ +void pll1_clk_recalc(struct clk *clk) +{ + struct pll_clk_config *config = clk->private_data; + unsigned int num = 2, den = 0, val, mode = 0; + unsigned long flags; + + spin_lock_irqsave(&clocks_lock, flags); + mode = (readl(config->mode_reg) >> PLL_MODE_SHIFT) & + PLL_MODE_MASK; + + val = readl(config->cfg_reg); + /* calculate denominator */ + den = (val >> PLL_DIV_P_SHIFT) & PLL_DIV_P_MASK; + den = 1 << den; + den *= (val >> PLL_DIV_N_SHIFT) & PLL_DIV_N_MASK; + + /* calculate numerator & denominator */ + if (!mode) { + /* Normal mode */ + num *= (val >> PLL_NORM_FDBK_M_SHIFT) & PLL_NORM_FDBK_M_MASK; + } else { + /* Dithered mode */ + num *= (val >> PLL_DITH_FDBK_M_SHIFT) & PLL_DITH_FDBK_M_MASK; + den *= 256; + } + + clk->rate = (((clk->pclk->rate/10000) * num) / den) * 10000; + spin_unlock_irqrestore(&clocks_lock, flags); +} + +/* calculates current programmed rate of ahb or apb bus */ +void bus_clk_recalc(struct clk *clk) +{ + struct bus_clk_config *config = clk->private_data; + unsigned int div; + unsigned long flags; + + spin_lock_irqsave(&clocks_lock, flags); + div = ((readl(config->reg) >> config->shift) & config->mask) + 1; + clk->rate = (unsigned long)clk->pclk->rate / div; + spin_unlock_irqrestore(&clocks_lock, flags); +} + +/* + * calculates current programmed rate of auxiliary synthesizers + * used by: UART, FIRDA + * + * Fout from synthesizer can be given from two equations: + * Fout1 = (Fin * X/Y)/2 + * Fout2 = Fin * X/Y + * + * Selection of eqn 1 or 2 is programmed in register + */ +void aux_clk_recalc(struct clk *clk) +{ + struct aux_clk_config *config = clk->private_data; + struct pclk_info *pclk_info = NULL; + unsigned int num = 1, den = 1, val, eqn; + unsigned long flags; + + /* get current programmed parent */ + pclk_info = pclk_info_get(clk); + if (!pclk_info) { + spin_lock_irqsave(&clocks_lock, flags); + clk->pclk = NULL; + clk->rate = 0; + spin_unlock_irqrestore(&clocks_lock, flags); + return; + } + + change_parent(clk, pclk_info->pclk); + + spin_lock_irqsave(&clocks_lock, flags); + if (pclk_info->scalable) { + val = readl(config->synth_reg); + + eqn = (val >> AUX_EQ_SEL_SHIFT) & AUX_EQ_SEL_MASK; + if (eqn == AUX_EQ1_SEL) + den *= 2; + + /* calculate numerator */ + num = (val >> AUX_XSCALE_SHIFT) & AUX_XSCALE_MASK; + + /* calculate denominator */ + den *= (val >> AUX_YSCALE_SHIFT) & AUX_YSCALE_MASK; + val = (((clk->pclk->rate/10000) * num) / den) * 10000; + } else + val = clk->pclk->rate; + + clk->rate = val; + spin_unlock_irqrestore(&clocks_lock, flags); +} + +/* + * calculates current programmed rate of gpt synthesizers + * Fout from synthesizer can be given from below equations: + * Fout= Fin/((2 ^ (N+1)) * (M+1)) + */ +void gpt_clk_recalc(struct clk *clk) +{ + struct aux_clk_config *config = clk->private_data; + struct pclk_info *pclk_info = NULL; + unsigned int div = 1, val; + unsigned long flags; + + pclk_info = pclk_info_get(clk); + if (!pclk_info) { + spin_lock_irqsave(&clocks_lock, flags); + clk->pclk = NULL; + clk->rate = 0; + spin_unlock_irqrestore(&clocks_lock, flags); + return; + } + + change_parent(clk, pclk_info->pclk); + + spin_lock_irqsave(&clocks_lock, flags); + if (pclk_info->scalable) { + val = readl(config->synth_reg); + div += (val >> GPT_MSCALE_SHIFT) & GPT_MSCALE_MASK; + div *= 1 << (((val >> GPT_NSCALE_SHIFT) & GPT_NSCALE_MASK) + 1); + } + + clk->rate = (unsigned long)clk->pclk->rate / div; + spin_unlock_irqrestore(&clocks_lock, flags); +} + +/* + * Used for clocks that always have same value as the parent clock divided by a + * fixed divisor + */ +void follow_parent(struct clk *clk) +{ + unsigned long flags; + + spin_lock_irqsave(&clocks_lock, flags); + clk->rate = clk->pclk->rate; + spin_unlock_irqrestore(&clocks_lock, flags); +} + +/** + * recalc_root_clocks - recalculate and propagate all root clocks + * + * Recalculates all root clocks (clocks with no parent), which if the + * clock's .recalc is set correctly, should also propagate their rates. + */ +void recalc_root_clocks(void) +{ + propagate_rate(&root_clks); +} |