386 lines
8.9 KiB
C
386 lines
8.9 KiB
C
/*
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* Intel Atom platform clocks driver for BayTrail and CherryTrail SoCs
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*
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* Copyright (C) 2016, Intel Corporation
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* Author: Irina Tirdea <irina.tirdea@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/clk-provider.h>
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#include <linux/clkdev.h>
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#include <linux/err.h>
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#include <linux/platform_data/x86/clk-pmc-atom.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#define PLT_CLK_NAME_BASE "pmc_plt_clk"
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#define PMC_CLK_CTL_OFFSET 0x60
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#define PMC_CLK_CTL_SIZE 4
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#define PMC_CLK_NUM 6
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#define PMC_CLK_CTL_GATED_ON_D3 0x0
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#define PMC_CLK_CTL_FORCE_ON 0x1
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#define PMC_CLK_CTL_FORCE_OFF 0x2
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#define PMC_CLK_CTL_RESERVED 0x3
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#define PMC_MASK_CLK_CTL GENMASK(1, 0)
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#define PMC_MASK_CLK_FREQ BIT(2)
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#define PMC_CLK_FREQ_XTAL (0 << 2) /* 25 MHz */
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#define PMC_CLK_FREQ_PLL (1 << 2) /* 19.2 MHz */
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struct clk_plt_fixed {
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struct clk_hw *clk;
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struct clk_lookup *lookup;
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};
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struct clk_plt {
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struct clk_hw hw;
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void __iomem *reg;
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struct clk_lookup *lookup;
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/* protect access to PMC registers */
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spinlock_t lock;
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};
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#define to_clk_plt(_hw) container_of(_hw, struct clk_plt, hw)
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struct clk_plt_data {
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struct clk_plt_fixed **parents;
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u8 nparents;
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struct clk_plt *clks[PMC_CLK_NUM];
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struct clk_lookup *mclk_lookup;
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};
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/* Return an index in parent table */
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static inline int plt_reg_to_parent(int reg)
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{
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switch (reg & PMC_MASK_CLK_FREQ) {
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default:
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case PMC_CLK_FREQ_XTAL:
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return 0;
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case PMC_CLK_FREQ_PLL:
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return 1;
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}
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}
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/* Return clk index of parent */
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static inline int plt_parent_to_reg(int index)
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{
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switch (index) {
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default:
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case 0:
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return PMC_CLK_FREQ_XTAL;
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case 1:
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return PMC_CLK_FREQ_PLL;
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}
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}
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/* Abstract status in simpler enabled/disabled value */
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static inline int plt_reg_to_enabled(int reg)
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{
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switch (reg & PMC_MASK_CLK_CTL) {
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case PMC_CLK_CTL_GATED_ON_D3:
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case PMC_CLK_CTL_FORCE_ON:
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return 1; /* enabled */
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case PMC_CLK_CTL_FORCE_OFF:
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case PMC_CLK_CTL_RESERVED:
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default:
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return 0; /* disabled */
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}
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}
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static void plt_clk_reg_update(struct clk_plt *clk, u32 mask, u32 val)
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{
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u32 tmp;
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unsigned long flags;
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spin_lock_irqsave(&clk->lock, flags);
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tmp = readl(clk->reg);
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tmp = (tmp & ~mask) | (val & mask);
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writel(tmp, clk->reg);
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spin_unlock_irqrestore(&clk->lock, flags);
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}
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static int plt_clk_set_parent(struct clk_hw *hw, u8 index)
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{
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struct clk_plt *clk = to_clk_plt(hw);
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plt_clk_reg_update(clk, PMC_MASK_CLK_FREQ, plt_parent_to_reg(index));
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return 0;
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}
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static u8 plt_clk_get_parent(struct clk_hw *hw)
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{
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struct clk_plt *clk = to_clk_plt(hw);
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u32 value;
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value = readl(clk->reg);
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return plt_reg_to_parent(value);
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}
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static int plt_clk_enable(struct clk_hw *hw)
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{
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struct clk_plt *clk = to_clk_plt(hw);
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plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_ON);
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return 0;
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}
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static void plt_clk_disable(struct clk_hw *hw)
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{
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struct clk_plt *clk = to_clk_plt(hw);
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plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_OFF);
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}
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static int plt_clk_is_enabled(struct clk_hw *hw)
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{
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struct clk_plt *clk = to_clk_plt(hw);
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u32 value;
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value = readl(clk->reg);
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return plt_reg_to_enabled(value);
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}
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static const struct clk_ops plt_clk_ops = {
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.enable = plt_clk_enable,
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.disable = plt_clk_disable,
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.is_enabled = plt_clk_is_enabled,
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.get_parent = plt_clk_get_parent,
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.set_parent = plt_clk_set_parent,
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.determine_rate = __clk_mux_determine_rate,
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};
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static struct clk_plt *plt_clk_register(struct platform_device *pdev, int id,
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void __iomem *base,
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const char **parent_names,
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int num_parents)
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{
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struct clk_plt *pclk;
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struct clk_init_data init;
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int ret;
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pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
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if (!pclk)
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return ERR_PTR(-ENOMEM);
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init.name = kasprintf(GFP_KERNEL, "%s_%d", PLT_CLK_NAME_BASE, id);
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init.ops = &plt_clk_ops;
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init.flags = 0;
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init.parent_names = parent_names;
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init.num_parents = num_parents;
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pclk->hw.init = &init;
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pclk->reg = base + PMC_CLK_CTL_OFFSET + id * PMC_CLK_CTL_SIZE;
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spin_lock_init(&pclk->lock);
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/*
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* If the clock was already enabled by the firmware mark it as critical
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* to avoid it being gated by the clock framework if no driver owns it.
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*/
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if (plt_clk_is_enabled(&pclk->hw))
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init.flags |= CLK_IS_CRITICAL;
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ret = devm_clk_hw_register(&pdev->dev, &pclk->hw);
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if (ret) {
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pclk = ERR_PTR(ret);
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goto err_free_init;
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}
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pclk->lookup = clkdev_hw_create(&pclk->hw, init.name, NULL);
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if (!pclk->lookup) {
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pclk = ERR_PTR(-ENOMEM);
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goto err_free_init;
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}
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err_free_init:
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kfree(init.name);
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return pclk;
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}
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static void plt_clk_unregister(struct clk_plt *pclk)
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{
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clkdev_drop(pclk->lookup);
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}
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static struct clk_plt_fixed *plt_clk_register_fixed_rate(struct platform_device *pdev,
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const char *name,
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const char *parent_name,
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unsigned long fixed_rate)
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{
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struct clk_plt_fixed *pclk;
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pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
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if (!pclk)
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return ERR_PTR(-ENOMEM);
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pclk->clk = clk_hw_register_fixed_rate(&pdev->dev, name, parent_name,
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0, fixed_rate);
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if (IS_ERR(pclk->clk))
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return ERR_CAST(pclk->clk);
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pclk->lookup = clkdev_hw_create(pclk->clk, name, NULL);
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if (!pclk->lookup) {
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clk_hw_unregister_fixed_rate(pclk->clk);
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return ERR_PTR(-ENOMEM);
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}
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return pclk;
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}
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static void plt_clk_unregister_fixed_rate(struct clk_plt_fixed *pclk)
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{
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clkdev_drop(pclk->lookup);
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clk_hw_unregister_fixed_rate(pclk->clk);
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}
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static void plt_clk_unregister_fixed_rate_loop(struct clk_plt_data *data,
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unsigned int i)
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{
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while (i--)
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plt_clk_unregister_fixed_rate(data->parents[i]);
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}
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static void plt_clk_free_parent_names_loop(const char **parent_names,
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unsigned int i)
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{
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while (i--)
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kfree_const(parent_names[i]);
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kfree(parent_names);
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}
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static void plt_clk_unregister_loop(struct clk_plt_data *data,
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unsigned int i)
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{
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while (i--)
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plt_clk_unregister(data->clks[i]);
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}
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static const char **plt_clk_register_parents(struct platform_device *pdev,
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struct clk_plt_data *data,
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const struct pmc_clk *clks)
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{
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const char **parent_names;
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unsigned int i;
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int err;
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int nparents = 0;
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data->nparents = 0;
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while (clks[nparents].name)
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nparents++;
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data->parents = devm_kcalloc(&pdev->dev, nparents,
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sizeof(*data->parents), GFP_KERNEL);
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if (!data->parents)
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return ERR_PTR(-ENOMEM);
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parent_names = kcalloc(nparents, sizeof(*parent_names),
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GFP_KERNEL);
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if (!parent_names)
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return ERR_PTR(-ENOMEM);
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for (i = 0; i < nparents; i++) {
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data->parents[i] =
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plt_clk_register_fixed_rate(pdev, clks[i].name,
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clks[i].parent_name,
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clks[i].freq);
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if (IS_ERR(data->parents[i])) {
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err = PTR_ERR(data->parents[i]);
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goto err_unreg;
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}
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parent_names[i] = kstrdup_const(clks[i].name, GFP_KERNEL);
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}
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data->nparents = nparents;
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return parent_names;
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err_unreg:
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plt_clk_unregister_fixed_rate_loop(data, i);
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plt_clk_free_parent_names_loop(parent_names, i);
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return ERR_PTR(err);
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}
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static void plt_clk_unregister_parents(struct clk_plt_data *data)
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{
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plt_clk_unregister_fixed_rate_loop(data, data->nparents);
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}
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static int plt_clk_probe(struct platform_device *pdev)
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{
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const struct pmc_clk_data *pmc_data;
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const char **parent_names;
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struct clk_plt_data *data;
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unsigned int i;
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int err;
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pmc_data = dev_get_platdata(&pdev->dev);
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if (!pmc_data || !pmc_data->clks)
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return -EINVAL;
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data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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parent_names = plt_clk_register_parents(pdev, data, pmc_data->clks);
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if (IS_ERR(parent_names))
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return PTR_ERR(parent_names);
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for (i = 0; i < PMC_CLK_NUM; i++) {
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data->clks[i] = plt_clk_register(pdev, i, pmc_data->base,
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parent_names, data->nparents);
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if (IS_ERR(data->clks[i])) {
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err = PTR_ERR(data->clks[i]);
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goto err_unreg_clk_plt;
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}
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}
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data->mclk_lookup = clkdev_hw_create(&data->clks[3]->hw, "mclk", NULL);
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if (!data->mclk_lookup) {
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err = -ENOMEM;
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goto err_unreg_clk_plt;
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}
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plt_clk_free_parent_names_loop(parent_names, data->nparents);
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platform_set_drvdata(pdev, data);
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return 0;
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err_unreg_clk_plt:
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plt_clk_unregister_loop(data, i);
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plt_clk_unregister_parents(data);
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plt_clk_free_parent_names_loop(parent_names, data->nparents);
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return err;
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}
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static int plt_clk_remove(struct platform_device *pdev)
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{
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struct clk_plt_data *data;
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data = platform_get_drvdata(pdev);
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clkdev_drop(data->mclk_lookup);
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plt_clk_unregister_loop(data, PMC_CLK_NUM);
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plt_clk_unregister_parents(data);
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return 0;
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}
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static struct platform_driver plt_clk_driver = {
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.driver = {
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.name = "clk-pmc-atom",
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},
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.probe = plt_clk_probe,
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.remove = plt_clk_remove,
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};
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builtin_platform_driver(plt_clk_driver);
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