66de922076
[ Upstream commit 30eaf02149ecc3c5815e45d27187bf09e925071d ] The function zynqmp_pll_round_rate is used to find a most appropriate PLL frequency which the hardware can generate according to the desired frequency. For example, if the desired frequency is 297MHz, considering the limited range from PS_PLL_VCO_MIN (1.5GHz) to PS_PLL_VCO_MAX (3.0GHz) of PLL, zynqmp_pll_round_rate should return 1.872GHz (297MHz * 5). There are two problems with the current code of zynqmp_pll_round_rate: 1) When the rate is below PS_PLL_VCO_MIN, it can't find a correct rate when the parameter "rate" is an integer multiple of *prate, in other words, if "f" is zero, zynqmp_pll_round_rate won't return a valid frequency which is from PS_PLL_VCO_MIN to PS_PLL_VCO_MAX. For example, *prate is 33MHz and the rate is 660MHz, zynqmp_pll_round_rate will not boost up rate and just return 660MHz, and this will cause clk_calc_new_rates failure since zynqmp_pll_round_rate returns an invalid rate out of its boundaries. 2) Even if the rate is higher than PS_PLL_VCO_MIN, there is still a risk that zynqmp_pll_round_rate returns an invalid rate because the function DIV_ROUND_CLOSEST makes some loss in the fractional part. If the parent clock *prate is 33333333Hz and we want to set the PLL rate to 1.5GHz, this function will return 1499999985Hz by using the formula below: value = *prate * DIV_ROUND_CLOSEST(rate, *prate)). This value is also invalid since it's slightly smaller than PS_PLL_VCO_MIN. because DIV_ROUND_CLOSEST makes some loss in the fractional part. Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com> Link: https://lore.kernel.org/r/20220826142030.213805-1-quanyang.wang@windriver.com Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com> Signed-off-by: Stephen Boyd <sboyd@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
335 lines
8.4 KiB
C
335 lines
8.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Zynq UltraScale+ MPSoC PLL driver
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*
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* Copyright (C) 2016-2018 Xilinx
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*/
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#include <linux/clk.h>
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#include <linux/clk-provider.h>
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#include <linux/slab.h>
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#include "clk-zynqmp.h"
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/**
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* struct zynqmp_pll - PLL clock
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* @hw: Handle between common and hardware-specific interfaces
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* @clk_id: PLL clock ID
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*/
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struct zynqmp_pll {
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struct clk_hw hw;
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u32 clk_id;
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};
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#define to_zynqmp_pll(_hw) container_of(_hw, struct zynqmp_pll, hw)
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#define PLL_FBDIV_MIN 25
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#define PLL_FBDIV_MAX 125
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#define PS_PLL_VCO_MIN 1500000000
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#define PS_PLL_VCO_MAX 3000000000UL
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enum pll_mode {
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PLL_MODE_INT,
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PLL_MODE_FRAC,
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};
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#define FRAC_OFFSET 0x8
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#define PLLFCFG_FRAC_EN BIT(31)
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#define FRAC_DIV BIT(16) /* 2^16 */
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/**
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* zynqmp_pll_get_mode() - Get mode of PLL
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* @hw: Handle between common and hardware-specific interfaces
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*
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* Return: Mode of PLL
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*/
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static inline enum pll_mode zynqmp_pll_get_mode(struct clk_hw *hw)
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{
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struct zynqmp_pll *clk = to_zynqmp_pll(hw);
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u32 clk_id = clk->clk_id;
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const char *clk_name = clk_hw_get_name(hw);
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u32 ret_payload[PAYLOAD_ARG_CNT];
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int ret;
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const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
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ret = eemi_ops->ioctl(0, IOCTL_GET_PLL_FRAC_MODE, clk_id, 0,
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ret_payload);
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if (ret)
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pr_warn_once("%s() PLL get frac mode failed for %s, ret = %d\n",
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__func__, clk_name, ret);
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return ret_payload[1];
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}
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/**
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* zynqmp_pll_set_mode() - Set the PLL mode
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* @hw: Handle between common and hardware-specific interfaces
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* @on: Flag to determine the mode
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*/
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static inline void zynqmp_pll_set_mode(struct clk_hw *hw, bool on)
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{
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struct zynqmp_pll *clk = to_zynqmp_pll(hw);
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u32 clk_id = clk->clk_id;
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const char *clk_name = clk_hw_get_name(hw);
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int ret;
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u32 mode;
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const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
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if (on)
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mode = PLL_MODE_FRAC;
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else
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mode = PLL_MODE_INT;
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ret = eemi_ops->ioctl(0, IOCTL_SET_PLL_FRAC_MODE, clk_id, mode, NULL);
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if (ret)
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pr_warn_once("%s() PLL set frac mode failed for %s, ret = %d\n",
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__func__, clk_name, ret);
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}
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/**
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* zynqmp_pll_round_rate() - Round a clock frequency
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* @hw: Handle between common and hardware-specific interfaces
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* @rate: Desired clock frequency
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* @prate: Clock frequency of parent clock
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*
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* Return: Frequency closest to @rate the hardware can generate
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*/
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static long zynqmp_pll_round_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long *prate)
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{
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u32 fbdiv;
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u32 mult, div;
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/* Let rate fall inside the range PS_PLL_VCO_MIN ~ PS_PLL_VCO_MAX */
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if (rate > PS_PLL_VCO_MAX) {
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div = DIV_ROUND_UP(rate, PS_PLL_VCO_MAX);
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rate = rate / div;
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}
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if (rate < PS_PLL_VCO_MIN) {
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mult = DIV_ROUND_UP(PS_PLL_VCO_MIN, rate);
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rate = rate * mult;
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}
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fbdiv = DIV_ROUND_CLOSEST(rate, *prate);
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if (fbdiv < PLL_FBDIV_MIN || fbdiv > PLL_FBDIV_MAX) {
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fbdiv = clamp_t(u32, fbdiv, PLL_FBDIV_MIN, PLL_FBDIV_MAX);
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rate = *prate * fbdiv;
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}
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return rate;
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}
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/**
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* zynqmp_pll_recalc_rate() - Recalculate clock frequency
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* @hw: Handle between common and hardware-specific interfaces
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* @parent_rate: Clock frequency of parent clock
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*
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* Return: Current clock frequency
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*/
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static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct zynqmp_pll *clk = to_zynqmp_pll(hw);
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u32 clk_id = clk->clk_id;
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const char *clk_name = clk_hw_get_name(hw);
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u32 fbdiv, data;
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unsigned long rate, frac;
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u32 ret_payload[PAYLOAD_ARG_CNT];
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int ret;
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const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
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ret = eemi_ops->clock_getdivider(clk_id, &fbdiv);
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if (ret)
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pr_warn_once("%s() get divider failed for %s, ret = %d\n",
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__func__, clk_name, ret);
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rate = parent_rate * fbdiv;
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if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {
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eemi_ops->ioctl(0, IOCTL_GET_PLL_FRAC_DATA, clk_id, 0,
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ret_payload);
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data = ret_payload[1];
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frac = (parent_rate * data) / FRAC_DIV;
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rate = rate + frac;
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}
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return rate;
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}
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/**
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* zynqmp_pll_set_rate() - Set rate of PLL
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* @hw: Handle between common and hardware-specific interfaces
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* @rate: Frequency of clock to be set
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* @parent_rate: Clock frequency of parent clock
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*
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* Set PLL divider to set desired rate.
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*
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* Returns: rate which is set on success else error code
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*/
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static int zynqmp_pll_set_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long parent_rate)
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{
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struct zynqmp_pll *clk = to_zynqmp_pll(hw);
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u32 clk_id = clk->clk_id;
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const char *clk_name = clk_hw_get_name(hw);
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u32 fbdiv;
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long rate_div, frac, m, f;
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int ret;
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const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
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rate_div = (rate * FRAC_DIV) / parent_rate;
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f = rate_div % FRAC_DIV;
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zynqmp_pll_set_mode(hw, !!f);
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if (f) {
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m = rate_div / FRAC_DIV;
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m = clamp_t(u32, m, (PLL_FBDIV_MIN), (PLL_FBDIV_MAX));
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rate = parent_rate * m;
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frac = (parent_rate * f) / FRAC_DIV;
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ret = eemi_ops->clock_setdivider(clk_id, m);
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if (ret)
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pr_warn_once("%s() set divider failed for %s, ret = %d\n",
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__func__, clk_name, ret);
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eemi_ops->ioctl(0, IOCTL_SET_PLL_FRAC_DATA, clk_id, f, NULL);
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return rate + frac;
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}
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fbdiv = DIV_ROUND_CLOSEST(rate, parent_rate);
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fbdiv = clamp_t(u32, fbdiv, PLL_FBDIV_MIN, PLL_FBDIV_MAX);
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ret = eemi_ops->clock_setdivider(clk_id, fbdiv);
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if (ret)
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pr_warn_once("%s() set divider failed for %s, ret = %d\n",
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__func__, clk_name, ret);
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return parent_rate * fbdiv;
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}
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/**
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* zynqmp_pll_is_enabled() - Check if a clock is enabled
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* @hw: Handle between common and hardware-specific interfaces
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*
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* Return: 1 if the clock is enabled, 0 otherwise
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*/
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static int zynqmp_pll_is_enabled(struct clk_hw *hw)
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{
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struct zynqmp_pll *clk = to_zynqmp_pll(hw);
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const char *clk_name = clk_hw_get_name(hw);
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u32 clk_id = clk->clk_id;
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unsigned int state;
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int ret;
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const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
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ret = eemi_ops->clock_getstate(clk_id, &state);
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if (ret) {
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pr_warn_once("%s() clock get state failed for %s, ret = %d\n",
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__func__, clk_name, ret);
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return -EIO;
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}
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return state ? 1 : 0;
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}
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/**
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* zynqmp_pll_enable() - Enable clock
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* @hw: Handle between common and hardware-specific interfaces
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*
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* Return: 0 on success else error code
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*/
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static int zynqmp_pll_enable(struct clk_hw *hw)
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{
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struct zynqmp_pll *clk = to_zynqmp_pll(hw);
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const char *clk_name = clk_hw_get_name(hw);
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u32 clk_id = clk->clk_id;
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int ret;
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const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
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if (zynqmp_pll_is_enabled(hw))
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return 0;
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ret = eemi_ops->clock_enable(clk_id);
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if (ret)
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pr_warn_once("%s() clock enable failed for %s, ret = %d\n",
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__func__, clk_name, ret);
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return ret;
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}
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/**
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* zynqmp_pll_disable() - Disable clock
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* @hw: Handle between common and hardware-specific interfaces
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*/
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static void zynqmp_pll_disable(struct clk_hw *hw)
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{
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struct zynqmp_pll *clk = to_zynqmp_pll(hw);
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const char *clk_name = clk_hw_get_name(hw);
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u32 clk_id = clk->clk_id;
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int ret;
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const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
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if (!zynqmp_pll_is_enabled(hw))
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return;
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ret = eemi_ops->clock_disable(clk_id);
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if (ret)
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pr_warn_once("%s() clock disable failed for %s, ret = %d\n",
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__func__, clk_name, ret);
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}
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static const struct clk_ops zynqmp_pll_ops = {
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.enable = zynqmp_pll_enable,
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.disable = zynqmp_pll_disable,
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.is_enabled = zynqmp_pll_is_enabled,
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.round_rate = zynqmp_pll_round_rate,
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.recalc_rate = zynqmp_pll_recalc_rate,
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.set_rate = zynqmp_pll_set_rate,
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};
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/**
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* zynqmp_clk_register_pll() - Register PLL with the clock framework
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* @name: PLL name
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* @clk_id: Clock ID
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* @parents: Name of this clock's parents
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* @num_parents: Number of parents
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* @nodes: Clock topology node
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*
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* Return: clock hardware to the registered clock
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*/
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struct clk_hw *zynqmp_clk_register_pll(const char *name, u32 clk_id,
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const char * const *parents,
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u8 num_parents,
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const struct clock_topology *nodes)
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{
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struct zynqmp_pll *pll;
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struct clk_hw *hw;
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struct clk_init_data init;
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int ret;
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init.name = name;
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init.ops = &zynqmp_pll_ops;
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init.flags = nodes->flag;
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init.parent_names = parents;
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init.num_parents = 1;
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pll = kzalloc(sizeof(*pll), GFP_KERNEL);
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if (!pll)
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return ERR_PTR(-ENOMEM);
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pll->hw.init = &init;
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pll->clk_id = clk_id;
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hw = &pll->hw;
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ret = clk_hw_register(NULL, hw);
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if (ret) {
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kfree(pll);
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return ERR_PTR(ret);
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}
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clk_hw_set_rate_range(hw, PS_PLL_VCO_MIN, PS_PLL_VCO_MAX);
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if (ret < 0)
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pr_err("%s:ERROR clk_set_rate_range failed %d\n", name, ret);
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return hw;
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}
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