From 6209624b9a5c1e417b142e9688f5fc96c1e0cd58 Mon Sep 17 00:00:00 2001 From: Lucas Stach Date: Sat, 1 Dec 2018 10:52:11 +0000 Subject: clk: imx: Add fractional PLL output clock This is a new fractional clock type introduced on i.MX8. The description of this fractional clock can be found here: https://www.nxp.com/docs/en/reference-manual/IMX8MDQLQRM.pdf#page=834 Signed-off-by: Lucas Stach Signed-off-by: Abel Vesa Reviewed-by: Sascha Hauer Signed-off-by: Stephen Boyd --- drivers/clk/imx/clk-frac-pll.c | 232 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 232 insertions(+) create mode 100644 drivers/clk/imx/clk-frac-pll.c (limited to 'drivers/clk/imx/clk-frac-pll.c') diff --git a/drivers/clk/imx/clk-frac-pll.c b/drivers/clk/imx/clk-frac-pll.c new file mode 100644 index 000000000000..0026c3969b1e --- /dev/null +++ b/drivers/clk/imx/clk-frac-pll.c @@ -0,0 +1,232 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2018 NXP. + * + * This driver supports the fractional plls found in the imx8m SOCs + * + * Documentation for this fractional pll can be found at: + * https://www.nxp.com/docs/en/reference-manual/IMX8MDQLQRM.pdf#page=834 + */ + +#include +#include +#include +#include +#include + +#include "clk.h" + +#define PLL_CFG0 0x0 +#define PLL_CFG1 0x4 + +#define PLL_LOCK_STATUS BIT(31) +#define PLL_PD_MASK BIT(19) +#define PLL_BYPASS_MASK BIT(14) +#define PLL_NEWDIV_VAL BIT(12) +#define PLL_NEWDIV_ACK BIT(11) +#define PLL_FRAC_DIV_MASK GENMASK(30, 7) +#define PLL_INT_DIV_MASK GENMASK(6, 0) +#define PLL_OUTPUT_DIV_MASK GENMASK(4, 0) +#define PLL_FRAC_DENOM 0x1000000 + +#define PLL_FRAC_LOCK_TIMEOUT 10000 +#define PLL_FRAC_ACK_TIMEOUT 500000 + +struct clk_frac_pll { + struct clk_hw hw; + void __iomem *base; +}; + +#define to_clk_frac_pll(_hw) container_of(_hw, struct clk_frac_pll, hw) + +static int clk_wait_lock(struct clk_frac_pll *pll) +{ + u32 val; + + return readl_poll_timeout(pll->base, val, val & PLL_LOCK_STATUS, 0, + PLL_FRAC_LOCK_TIMEOUT); +} + +static int clk_wait_ack(struct clk_frac_pll *pll) +{ + u32 val; + + /* return directly if the pll is in powerdown or in bypass */ + if (readl_relaxed(pll->base) & (PLL_PD_MASK | PLL_BYPASS_MASK)) + return 0; + + /* Wait for the pll's divfi and divff to be reloaded */ + return readl_poll_timeout(pll->base, val, val & PLL_NEWDIV_ACK, 0, + PLL_FRAC_ACK_TIMEOUT); +} + +static int clk_pll_prepare(struct clk_hw *hw) +{ + struct clk_frac_pll *pll = to_clk_frac_pll(hw); + u32 val; + + val = readl_relaxed(pll->base + PLL_CFG0); + val &= ~PLL_PD_MASK; + writel_relaxed(val, pll->base + PLL_CFG0); + + return clk_wait_lock(pll); +} + +static void clk_pll_unprepare(struct clk_hw *hw) +{ + struct clk_frac_pll *pll = to_clk_frac_pll(hw); + u32 val; + + val = readl_relaxed(pll->base + PLL_CFG0); + val |= PLL_PD_MASK; + writel_relaxed(val, pll->base + PLL_CFG0); +} + +static int clk_pll_is_prepared(struct clk_hw *hw) +{ + struct clk_frac_pll *pll = to_clk_frac_pll(hw); + u32 val; + + val = readl_relaxed(pll->base + PLL_CFG0); + return (val & PLL_PD_MASK) ? 0 : 1; +} + +static unsigned long clk_pll_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_frac_pll *pll = to_clk_frac_pll(hw); + u32 val, divff, divfi, divq; + u64 temp64 = parent_rate; + u64 rate; + + val = readl_relaxed(pll->base + PLL_CFG0); + divq = (FIELD_GET(PLL_OUTPUT_DIV_MASK, val) + 1) * 2; + val = readl_relaxed(pll->base + PLL_CFG1); + divff = FIELD_GET(PLL_FRAC_DIV_MASK, val); + divfi = FIELD_GET(PLL_INT_DIV_MASK, val); + + temp64 *= 8; + temp64 *= divff; + do_div(temp64, PLL_FRAC_DENOM); + do_div(temp64, divq); + + rate = parent_rate * 8 * (divfi + 1); + do_div(rate, divq); + rate += temp64; + + return rate; +} + +static long clk_pll_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + u64 parent_rate = *prate; + u32 divff, divfi; + u64 temp64; + + parent_rate *= 8; + rate *= 2; + temp64 = rate; + do_div(temp64, parent_rate); + divfi = temp64; + temp64 = rate - divfi * parent_rate; + temp64 *= PLL_FRAC_DENOM; + do_div(temp64, parent_rate); + divff = temp64; + + temp64 = parent_rate; + temp64 *= divff; + do_div(temp64, PLL_FRAC_DENOM); + + rate = parent_rate * divfi + temp64; + + return rate / 2; +} + +/* + * To simplify the clock calculation, we can keep the 'PLL_OUTPUT_VAL' at zero + * (means the PLL output will be divided by 2). So the PLL output can use + * the below formula: + * pllout = parent_rate * 8 / 2 * DIVF_VAL; + * where DIVF_VAL = 1 + DIVFI + DIVFF / 2^24. + */ +static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_frac_pll *pll = to_clk_frac_pll(hw); + u32 val, divfi, divff; + u64 temp64 = parent_rate; + int ret; + + parent_rate *= 8; + rate *= 2; + divfi = rate / parent_rate; + temp64 *= rate - divfi; + temp64 *= PLL_FRAC_DENOM; + do_div(temp64, parent_rate); + divff = temp64; + + val = readl_relaxed(pll->base + PLL_CFG1); + val &= ~(PLL_FRAC_DIV_MASK | PLL_INT_DIV_MASK); + val |= (divff << 7) | (divfi - 1); + writel_relaxed(val, pll->base + PLL_CFG1); + + val = readl_relaxed(pll->base + PLL_CFG0); + val &= ~0x1f; + writel_relaxed(val, pll->base + PLL_CFG0); + + /* Set the NEV_DIV_VAL to reload the DIVFI and DIVFF */ + val = readl_relaxed(pll->base + PLL_CFG0); + val |= PLL_NEWDIV_VAL; + writel_relaxed(val, pll->base + PLL_CFG0); + + ret = clk_wait_ack(pll); + + /* clear the NEV_DIV_VAL */ + val = readl_relaxed(pll->base + PLL_CFG0); + val &= ~PLL_NEWDIV_VAL; + writel_relaxed(val, pll->base + PLL_CFG0); + + return ret; +} + +static const struct clk_ops clk_frac_pll_ops = { + .prepare = clk_pll_prepare, + .unprepare = clk_pll_unprepare, + .is_prepared = clk_pll_is_prepared, + .recalc_rate = clk_pll_recalc_rate, + .round_rate = clk_pll_round_rate, + .set_rate = clk_pll_set_rate, +}; + +struct clk *imx_clk_frac_pll(const char *name, const char *parent_name, + void __iomem *base) +{ + struct clk_init_data init; + struct clk_frac_pll *pll; + struct clk_hw *hw; + int ret; + + pll = kzalloc(sizeof(*pll), GFP_KERNEL); + if (!pll) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &clk_frac_pll_ops; + init.flags = 0; + init.parent_names = &parent_name; + init.num_parents = 1; + + pll->base = base; + pll->hw.init = &init; + + hw = &pll->hw; + + ret = clk_hw_register(NULL, hw); + if (ret) { + kfree(pll); + return ERR_PTR(ret); + } + + return hw->clk; +} -- cgit