path: root/drivers/clk/sirf/clk-common.c

/*
 * common clks module for all SiRF SoCs
 *
 * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
 *
 * Licensed under GPLv2 or later.
 */

#define KHZ     1000
#define MHZ     (KHZ * KHZ)

static void *sirfsoc_clk_vbase;
static void *sirfsoc_rsc_vbase;
static struct clk_onecell_data clk_data;

/*
 * SiRFprimaII clock controller
 * - 2 oscillators: osc-26MHz, rtc-32.768KHz
 * - 3 standard configurable plls: pll1, pll2 & pll3
 * - 2 exclusive plls: usb phy pll and sata phy pll
 * - 8 clock domains: cpu/cpudiv, mem/memdiv, sys/io, dsp, graphic, multimedia,
 *     display and sdphy.
 *     Each clock domain can select its own clock source from five clock sources,
 *     X_XIN, X_XINW, PLL1, PLL2 and PLL3. The domain clock is used as the source
 *     clock of the group clock.
 *     - dsp domain: gps, mf
 *     - io domain: dmac, nand, audio, uart, i2c, spi, usp, pwm, pulse
 *     - sys domain: security
 */

struct clk_pll {
	struct clk_hw hw;
	unsigned short regofs;  /* register offset */
};

#define to_pllclk(_hw) container_of(_hw, struct clk_pll, hw)

struct clk_dmn {
	struct clk_hw hw;
	signed char enable_bit; /* enable bit: 0 ~ 63 */
	unsigned short regofs;  /* register offset */
};

#define to_dmnclk(_hw) container_of(_hw, struct clk_dmn, hw)

struct clk_std {
	struct clk_hw hw;
	signed char enable_bit; /* enable bit: 0 ~ 63 */
};

#define to_stdclk(_hw) container_of(_hw, struct clk_std, hw)

static int std_clk_is_enabled(struct clk_hw *hw);
static int std_clk_enable(struct clk_hw *hw);
static void std_clk_disable(struct clk_hw *hw);

static inline unsigned long clkc_readl(unsigned reg)
{
	return readl(sirfsoc_clk_vbase + reg);
}

static inline void clkc_writel(u32 val, unsigned reg)
{
	writel(val, sirfsoc_clk_vbase + reg);
}

/*
 * std pll
 */

static unsigned long pll_clk_recalc_rate(struct clk_hw *hw,
	unsigned long parent_rate)
{
	unsigned long fin = parent_rate;
	struct clk_pll *clk = to_pllclk(hw);
	u32 regcfg2 = clk->regofs + SIRFSOC_CLKC_PLL1_CFG2 -
		SIRFSOC_CLKC_PLL1_CFG0;

	if (clkc_readl(regcfg2) & BIT(2)) {
		/* pll bypass mode */
		return fin;
	} else {
		/* fout = fin * nf / nr / od */
		u32 cfg0 = clkc_readl(clk->regofs);
		u32 nf = (cfg0 & (BIT(13) - 1)) + 1;
		u32 nr = ((cfg0 >> 13) & (BIT(6) - 1)) + 1;
		u32 od = ((cfg0 >> 19) & (BIT(4) - 1)) + 1;
		WARN_ON(fin % MHZ);
		return fin / MHZ * nf / nr / od * MHZ;
	}
}

static long pll_clk_round_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long *parent_rate)
{
	unsigned long fin, nf, nr, od;
	u64 dividend;

	/*
	 * fout = fin * nf / (nr * od);
	 * set od = 1, nr = fin/MHz, so fout = nf * MHz
	 */
	rate = rate - rate % MHZ;

	nf = rate / MHZ;
	if (nf > BIT(13))
		nf = BIT(13);
	if (nf < 1)
		nf = 1;

	fin = *parent_rate;

	nr = fin / MHZ;
	if (nr > BIT(6))
		nr = BIT(6);
	od = 1;

	dividend = (u64)fin * nf;
	do_div(dividend, nr * od);

	return (long)dividend;
}

static int pll_clk_set_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long parent_rate)
{
	struct clk_pll *clk = to_pllclk(hw);
	unsigned long fin, nf, nr, od, reg;

	/*
	 * fout = fin * nf / (nr * od);
	 * set od = 1, nr = fin/MHz, so fout = nf * MHz
	 */

	nf = rate / MHZ;
	if (unlikely((rate % MHZ) || nf > BIT(13) || nf < 1))
		return -EINVAL;

	fin = parent_rate;
	BUG_ON(fin < MHZ);

	nr = fi