diff options
Diffstat (limited to 'drivers/clk/ti/dpll44xx.c')
| -rw-r--r-- | drivers/clk/ti/dpll44xx.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/drivers/clk/ti/dpll44xx.c b/drivers/clk/ti/dpll44xx.c new file mode 100644 index 000000000000..73af77a90586 --- /dev/null +++ b/drivers/clk/ti/dpll44xx.c @@ -0,0 +1,227 @@ +/* + * OMAP4-specific DPLL control functions + * + * Copyright (C) 2011 Texas Instruments, Inc. + * Rajendra Nayak + * + * 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. + */ + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/bitops.h> +#include <linux/clk/ti.h> + +#include "clock.h" + +/* + * Maximum DPLL input frequency (FINT) and output frequency (FOUT) that + * can supported when using the DPLL low-power mode. Frequencies are + * defined in OMAP4430/60 Public TRM section 3.6.3.3.2 "Enable Control, + * Status, and Low-Power Operation Mode". + */ +#define OMAP4_DPLL_LP_FINT_MAX 1000000 +#define OMAP4_DPLL_LP_FOUT_MAX 100000000 + +/* + * Bitfield declarations + */ +#define OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK BIT(8) +#define OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK BIT(10) +#define OMAP4430_DPLL_REGM4XEN_MASK BIT(11) + +/* Static rate multiplier for OMAP4 REGM4XEN clocks */ +#define OMAP4430_REGM4XEN_MULT 4 + +static void omap4_dpllmx_allow_gatectrl(struct clk_hw_omap *clk) +{ + u32 v; + u32 mask; + + if (!clk || !clk->clksel_reg) + return; + + mask = clk->flags & CLOCK_CLKOUTX2 ? + OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK : + OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK; + + v = ti_clk_ll_ops->clk_readl(clk->clksel_reg); + /* Clear the bit to allow gatectrl */ + v &= ~mask; + ti_clk_ll_ops->clk_writel(v, clk->clksel_reg); +} + +static void omap4_dpllmx_deny_gatectrl(struct clk_hw_omap *clk) +{ + u32 v; + u32 mask; + + if (!clk || !clk->clksel_reg) + return; + + mask = clk->flags & CLOCK_CLKOUTX2 ? + OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK : + OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK; + + v = ti_clk_ll_ops->clk_readl(clk->clksel_reg); + /* Set the bit to deny gatectrl */ + v |= mask; + ti_clk_ll_ops->clk_writel(v, clk->clksel_reg); +} + +const struct clk_hw_omap_ops clkhwops_omap4_dpllmx = { + .allow_idle = omap4_dpllmx_allow_gatectrl, + .deny_idle = omap4_dpllmx_deny_gatectrl, +}; + +/** + * omap4_dpll_lpmode_recalc - compute DPLL low-power setting + * @dd: pointer to the dpll data structure + * + * Calculates if low-power mode can be enabled based upon the last + * multiplier and divider values calculated. If low-power mode can be + * enabled, then the bit to enable low-power mode is stored in the + * last_rounded_lpmode variable. This implementation is based upon the + * criteria for enabling low-power mode as described in the OMAP4430/60 + * Public TRM section 3.6.3.3.2 "Enable Control, Status, and Low-Power + * Operation Mode". + */ +static void omap4_dpll_lpmode_recalc(struct dpll_data *dd) +{ + long fint, fout; + + fint = __clk_get_rate(dd->clk_ref) / (dd->last_rounded_n + 1); + fout = fint * dd->last_rounded_m; + + if ((fint < OMAP4_DPLL_LP_FINT_MAX) && (fout < OMAP4_DPLL_LP_FOUT_MAX)) + dd->last_rounded_lpmode = 1; + else + dd->last_rounded_lpmode = 0; +} + +/** + * omap4_dpll_regm4xen_recalc - compute DPLL rate, considering REGM4XEN bit + * @clk: struct clk * of the DPLL to compute the rate for + * + * Compute the output rate for the OMAP4 DPLL represented by @clk. + * Takes the REGM4XEN bit into consideration, which is needed for the + * OMAP4 ABE DPLL. Returns the DPLL's output rate (before M-dividers) + * upon success, or 0 upon error. + */ +unsigned long omap4_dpll_regm4xen_recalc(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_hw_omap *clk = to_clk_hw_omap(hw); + u32 v; + unsigned long rate; + struct dpll_data *dd; + + if (!clk || !clk->dpll_data) + return 0; + + dd = clk->dpll_data; + + rate = omap2_get_dpll_rate(clk); + + /* regm4xen adds a multiplier of 4 to DPLL calculations */ + v = ti_clk_ll_ops->clk_readl(dd->control_reg); + if (v & OMAP4430_DPLL_REGM4XEN_MASK) + rate *= OMAP4430_REGM4XEN_MULT; + + return rate; +} + +/** + * omap4_dpll_regm4xen_round_rate - round DPLL rate, considering REGM4XEN bit + * @clk: struct clk * of the DPLL to round a rate for + * @target_rate: the desired rate of the DPLL + * + * Compute the rate that would be programmed into the DPLL hardware + * for @clk if set_rate() were to be provided with the rate + * @target_rate. Takes the REGM4XEN bit into consideration, which is + * needed for the OMAP4 ABE DPLL. Returns the rounded rate (before + * M-dividers) upon success, -EINVAL if @clk is null or not a DPLL, or + * ~0 if an error occurred in omap2_dpll_round_rate(). + */ +long omap4_dpll_regm4xen_round_rate(struct clk_hw *hw, + unsigned long target_rate, + unsigned long *parent_rate) +{ + struct clk_hw_omap *clk = to_clk_hw_omap(hw); + struct dpll_data *dd; + long r; + + if (!clk || !clk->dpll_data) + return -EINVAL; + + dd = clk->dpll_data; + + dd->last_rounded_m4xen = 0; + + /* + * First try to compute the DPLL configuration for + * target rate without using the 4X multiplier. + */ + r = omap2_dpll_round_rate(hw, target_rate, NULL); + if (r != ~0) + goto out; + + /* + * If we did not find a valid DPLL configuration, try again, but + * this time see if using the 4X multiplier can help. Enabling the + * 4X multiplier is equivalent to dividing the target rate by 4. + */ + r = omap2_dpll_round_rate(hw, target_rate / OMAP4430_REGM4XEN_MULT, + NULL); + if (r == ~0) + return r; + + dd->last_rounded_rate *= OMAP4430_REGM4XEN_MULT; + dd->last_rounded_m4xen = 1; + +out: + omap4_dpll_lpmode_recalc(dd); + + return dd->last_rounded_rate; +} + +/** + * omap4_dpll_regm4xen_determine_rate - determine rate for a DPLL + * @hw: pointer to the clock to determine rate for + * @req: target rate request + * + * Determines which DPLL mode to use for reaching a desired rate. + * Checks whether the DPLL shall be in bypass or locked mode, and if + * locked, calculates the M,N values for the DPLL via round-rate. + * Returns 0 on success and a negative error value otherwise. + */ +int omap4_dpll_regm4xen_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + struct clk_hw_omap *clk = to_clk_hw_omap(hw); + struct dpll_data *dd; + + if (!req->rate) + return -EINVAL; + + dd = clk->dpll_data; + if (!dd) + return -EINVAL; + + if (__clk_get_rate(dd->clk_bypass) == req->rate && + (dd->modes & (1 << DPLL_LOW_POWER_BYPASS))) { + req->best_parent_hw = __clk_get_hw(dd->clk_bypass); + } else { + req->rate = omap4_dpll_regm4xen_round_rate(hw, req->rate, + &req->best_parent_rate); + req->best_parent_hw = __clk_get_hw(dd->clk_ref); + } + + req->best_parent_rate = req->rate; + + return 0; +} |