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161 lines
3.9 KiB
161 lines
3.9 KiB
/* |
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* Clock Driver for Allo DAC |
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* |
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* Author: Baswaraj K <[email protected]> |
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* Copyright 2016 |
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* based on code by Stuart MacLean |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms 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 that it will be useful, but |
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* WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* General Public License for 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/kernel.h> |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/slab.h> |
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#include <linux/platform_device.h> |
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/* Clock rate of CLK44EN attached to GPIO6 pin */ |
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#define CLK_44EN_RATE 45158400UL |
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/* Clock rate of CLK48EN attached to GPIO3 pin */ |
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#define CLK_48EN_RATE 49152000UL |
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/** |
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* struct allo_dac_clk - Common struct to the Allo DAC |
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* @hw: clk_hw for the common clk framework |
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* @mode: 0 => CLK44EN, 1 => CLK48EN |
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*/ |
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struct clk_allo_hw { |
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struct clk_hw hw; |
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uint8_t mode; |
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}; |
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#define to_allo_clk(_hw) container_of(_hw, struct clk_allo_hw, hw) |
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static const struct of_device_id clk_allo_dac_dt_ids[] = { |
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{ .compatible = "allo,dac-clk",}, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, clk_allo_dac_dt_ids); |
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static unsigned long clk_allo_dac_recalc_rate(struct clk_hw *hw, |
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unsigned long parent_rate) |
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{ |
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return (to_allo_clk(hw)->mode == 0) ? CLK_44EN_RATE : |
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CLK_48EN_RATE; |
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} |
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static long clk_allo_dac_round_rate(struct clk_hw *hw, |
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unsigned long rate, unsigned long *parent_rate) |
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{ |
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long actual_rate; |
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if (rate <= CLK_44EN_RATE) { |
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actual_rate = (long)CLK_44EN_RATE; |
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} else if (rate >= CLK_48EN_RATE) { |
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actual_rate = (long)CLK_48EN_RATE; |
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} else { |
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long diff44Rate = (long)(rate - CLK_44EN_RATE); |
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long diff48Rate = (long)(CLK_48EN_RATE - rate); |
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if (diff44Rate < diff48Rate) |
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actual_rate = (long)CLK_44EN_RATE; |
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else |
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actual_rate = (long)CLK_48EN_RATE; |
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} |
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return actual_rate; |
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} |
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static int clk_allo_dac_set_rate(struct clk_hw *hw, |
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unsigned long rate, unsigned long parent_rate) |
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{ |
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unsigned long actual_rate; |
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struct clk_allo_hw *clk = to_allo_clk(hw); |
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actual_rate = (unsigned long)clk_allo_dac_round_rate(hw, rate, |
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&parent_rate); |
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clk->mode = (actual_rate == CLK_44EN_RATE) ? 0 : 1; |
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return 0; |
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} |
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const struct clk_ops clk_allo_dac_rate_ops = { |
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.recalc_rate = clk_allo_dac_recalc_rate, |
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.round_rate = clk_allo_dac_round_rate, |
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.set_rate = clk_allo_dac_set_rate, |
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}; |
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static int clk_allo_dac_probe(struct platform_device *pdev) |
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{ |
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int ret; |
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struct clk_allo_hw *proclk; |
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struct clk *clk; |
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struct device *dev; |
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struct clk_init_data init; |
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dev = &pdev->dev; |
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proclk = kzalloc(sizeof(struct clk_allo_hw), GFP_KERNEL); |
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if (!proclk) |
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return -ENOMEM; |
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init.name = "clk-allo-dac"; |
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init.ops = &clk_allo_dac_rate_ops; |
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init.flags = 0; |
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init.parent_names = NULL; |
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init.num_parents = 0; |
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proclk->mode = 0; |
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proclk->hw.init = &init; |
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clk = devm_clk_register(dev, &proclk->hw); |
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if (!IS_ERR(clk)) { |
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ret = of_clk_add_provider(dev->of_node, of_clk_src_simple_get, |
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clk); |
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} else { |
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dev_err(dev, "Fail to register clock driver\n"); |
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kfree(proclk); |
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ret = PTR_ERR(clk); |
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} |
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return ret; |
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} |
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static int clk_allo_dac_remove(struct platform_device *pdev) |
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{ |
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of_clk_del_provider(pdev->dev.of_node); |
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return 0; |
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} |
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static struct platform_driver clk_allo_dac_driver = { |
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.probe = clk_allo_dac_probe, |
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.remove = clk_allo_dac_remove, |
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.driver = { |
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.name = "clk-allo-dac", |
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.of_match_table = clk_allo_dac_dt_ids, |
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}, |
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}; |
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static int __init clk_allo_dac_init(void) |
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{ |
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return platform_driver_register(&clk_allo_dac_driver); |
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} |
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core_initcall(clk_allo_dac_init); |
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static void __exit clk_allo_dac_exit(void) |
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{ |
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platform_driver_unregister(&clk_allo_dac_driver); |
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} |
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module_exit(clk_allo_dac_exit); |
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MODULE_DESCRIPTION("Allo DAC clock driver"); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_ALIAS("platform:clk-allo-dac");
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