108 lines
2.2 KiB
C
108 lines
2.2 KiB
C
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/*
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* Copyright (C) 2014 Free Electrons
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*
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* License Terms: GNU General Public License v2
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* Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
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*
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* Allwinner A31 AR100 clock driver
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*
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*/
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#include <linux/bitops.h>
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#include <linux/clk-provider.h>
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#include <linux/init.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/spinlock.h>
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#include "clk-factors.h"
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/**
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* sun6i_get_ar100_factors - Calculates factors p, m for AR100
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*
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* AR100 rate is calculated as follows
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* rate = (parent_rate >> p) / (m + 1);
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*/
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static void sun6i_get_ar100_factors(struct factors_request *req)
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{
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unsigned long div;
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int shift;
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/* clock only divides */
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if (req->rate > req->parent_rate)
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req->rate = req->parent_rate;
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div = DIV_ROUND_UP(req->parent_rate, req->rate);
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if (div < 32)
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shift = 0;
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else if (div >> 1 < 32)
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shift = 1;
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else if (div >> 2 < 32)
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shift = 2;
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else
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shift = 3;
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div >>= shift;
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if (div > 32)
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div = 32;
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req->rate = (req->parent_rate >> shift) / div;
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req->m = div - 1;
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req->p = shift;
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}
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static const struct clk_factors_config sun6i_ar100_config = {
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.mwidth = 5,
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.mshift = 8,
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.pwidth = 2,
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.pshift = 4,
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};
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static const struct factors_data sun6i_ar100_data = {
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.mux = 16,
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.muxmask = GENMASK(1, 0),
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.table = &sun6i_ar100_config,
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.getter = sun6i_get_ar100_factors,
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};
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static DEFINE_SPINLOCK(sun6i_ar100_lock);
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static int sun6i_a31_ar100_clk_probe(struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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struct resource *r;
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void __iomem *reg;
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struct clk *clk;
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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reg = devm_ioremap_resource(&pdev->dev, r);
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if (IS_ERR(reg))
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return PTR_ERR(reg);
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clk = sunxi_factors_register(np, &sun6i_ar100_data, &sun6i_ar100_lock,
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reg);
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if (!clk)
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return -ENOMEM;
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platform_set_drvdata(pdev, clk);
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return 0;
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}
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static const struct of_device_id sun6i_a31_ar100_clk_dt_ids[] = {
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{ .compatible = "allwinner,sun6i-a31-ar100-clk" },
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{ /* sentinel */ }
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};
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static struct platform_driver sun6i_a31_ar100_clk_driver = {
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.driver = {
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.name = "sun6i-a31-ar100-clk",
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.of_match_table = sun6i_a31_ar100_clk_dt_ids,
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.suppress_bind_attrs = true,
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},
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.probe = sun6i_a31_ar100_clk_probe,
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};
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builtin_platform_driver(sun6i_a31_ar100_clk_driver);
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