/* * 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) 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) 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_hw_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_hw_get_rate(dd->clk_bypass) == req->rate && (dd->modes & (1 << DPLL_LOW_POWER_BYPASS))) { req->best_parent_hw = dd->clk_bypass; } else { req->rate = omap4_dpll_regm4xen_round_rate(hw, req->rate, &req->best_parent_rate); req->best_parent_hw = dd->clk_ref; } req->best_parent_rate = req->rate; return 0; }