From: Lucas Stach <l.stach@xxxxxxxxxxxxxx> 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 <l.stach@xxxxxxxxxxxxxx> Signed-off-by: Abel Vesa <abel.vesa@xxxxxxx> Reviewed-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> --- drivers/clk/imx/Makefile | 1 + drivers/clk/imx/clk-frac-pll.c | 221 +++++++++++++++++++++++++++++++++++++++++ drivers/clk/imx/clk.h | 3 + 3 files changed, 225 insertions(+) create mode 100644 drivers/clk/imx/clk-frac-pll.c diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile index 8c3baa7..4893c1f 100644 --- a/drivers/clk/imx/Makefile +++ b/drivers/clk/imx/Makefile @@ -6,6 +6,7 @@ obj-y += \ clk-cpu.o \ clk-fixup-div.o \ clk-fixup-mux.o \ + clk-frac-pll.o \ clk-gate-exclusive.o \ clk-gate2.o \ clk-pllv1.o \ diff --git a/drivers/clk/imx/clk-frac-pll.c b/drivers/clk/imx/clk-frac-pll.c new file mode 100644 index 0000000..a800093 --- /dev/null +++ b/drivers/clk/imx/clk-frac-pll.c @@ -0,0 +1,221 @@ +// 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 <linux/clk-provider.h> +#include <linux/err.h> +#include <linux/iopoll.h> +#include <linux/slab.h> +#include <linux/bitfield.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; + + val = readl_relaxed(pll->base + PLL_CFG0); + divq = ((val & PLL_OUTPUT_DIV_MASK) + 1) * 2; + val = readl_relaxed(pll->base + PLL_CFG1); + divff = FIELD_GET(PLL_FRAC_DIV_MASK, val); + divfi = val & PLL_INT_DIV_MASK; + + temp64 *= 8; + temp64 *= divff; + do_div(temp64, PLL_FRAC_DENOM); + temp64 /= divq; + + return parent_rate * 8 * (divfi + 1) / divq + (unsigned long)temp64; +} + +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; + divfi = rate / parent_rate; + 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); + + return (parent_rate * divfi + temp64) / 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_CAST(hw); + } + + return hw->clk; +} diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h index 5895e223..44a1f14 100644 --- a/drivers/clk/imx/clk.h +++ b/drivers/clk/imx/clk.h @@ -27,6 +27,9 @@ struct clk *imx_clk_pllv1(enum imx_pllv1_type type, const char *name, struct clk *imx_clk_pllv2(const char *name, const char *parent, void __iomem *base); +struct clk *imx_clk_frac_pll(const char *name, const char *parent_name, + void __iomem *base); + enum imx_pllv3_type { IMX_PLLV3_GENERIC, IMX_PLLV3_SYS, -- 2.7.4
