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145 lines
3.4 KiB
145 lines
3.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2016 Rafał Miłecki <[email protected]> |
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*/ |
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#include <linux/clk-provider.h> |
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#include <linux/err.h> |
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#include <linux/io.h> |
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#include <linux/mfd/syscon.h> |
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#include <linux/of.h> |
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#include <linux/of_address.h> |
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#include <linux/regmap.h> |
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#include <linux/slab.h> |
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#define PMU_XTAL_FREQ_RATIO 0x66c |
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#define XTAL_ALP_PER_4ILP 0x00001fff |
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#define XTAL_CTL_EN 0x80000000 |
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#define PMU_SLOW_CLK_PERIOD 0x6dc |
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struct bcm53573_ilp { |
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struct clk_hw hw; |
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struct regmap *regmap; |
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}; |
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static int bcm53573_ilp_enable(struct clk_hw *hw) |
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{ |
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struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw); |
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regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0x10199); |
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regmap_write(ilp->regmap, 0x674, 0x10000); |
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return 0; |
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} |
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static void bcm53573_ilp_disable(struct clk_hw *hw) |
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{ |
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struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw); |
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regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0); |
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regmap_write(ilp->regmap, 0x674, 0); |
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} |
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static unsigned long bcm53573_ilp_recalc_rate(struct clk_hw *hw, |
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unsigned long parent_rate) |
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{ |
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struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw); |
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struct regmap *regmap = ilp->regmap; |
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u32 last_val, cur_val; |
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int sum = 0, num = 0, loop_num = 0; |
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int avg; |
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/* Enable measurement */ |
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regmap_write(regmap, PMU_XTAL_FREQ_RATIO, XTAL_CTL_EN); |
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/* Read initial value */ |
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regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &last_val); |
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last_val &= XTAL_ALP_PER_4ILP; |
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/* |
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* At minimum we should loop for a bit to let hardware do the |
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* measurement. This isn't very accurate however, so for a better |
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* precision lets try getting 20 different values for and use average. |
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*/ |
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while (num < 20) { |
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regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &cur_val); |
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cur_val &= XTAL_ALP_PER_4ILP; |
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if (cur_val != last_val) { |
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/* Got different value, use it */ |
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sum += cur_val; |
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num++; |
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loop_num = 0; |
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last_val = cur_val; |
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} else if (++loop_num > 5000) { |
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/* Same value over and over, give up */ |
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sum += cur_val; |
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num++; |
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break; |
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} |
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cpu_relax(); |
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} |
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/* Disable measurement to save power */ |
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regmap_write(regmap, PMU_XTAL_FREQ_RATIO, 0x0); |
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avg = sum / num; |
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return parent_rate * 4 / avg; |
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} |
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static const struct clk_ops bcm53573_ilp_clk_ops = { |
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.enable = bcm53573_ilp_enable, |
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.disable = bcm53573_ilp_disable, |
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.recalc_rate = bcm53573_ilp_recalc_rate, |
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}; |
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static void bcm53573_ilp_init(struct device_node *np) |
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{ |
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struct bcm53573_ilp *ilp; |
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struct clk_init_data init = { }; |
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const char *parent_name; |
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int err; |
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ilp = kzalloc(sizeof(*ilp), GFP_KERNEL); |
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if (!ilp) |
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return; |
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parent_name = of_clk_get_parent_name(np, 0); |
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if (!parent_name) { |
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err = -ENOENT; |
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goto err_free_ilp; |
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} |
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ilp->regmap = syscon_node_to_regmap(of_get_parent(np)); |
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if (IS_ERR(ilp->regmap)) { |
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err = PTR_ERR(ilp->regmap); |
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goto err_free_ilp; |
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} |
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init.name = np->name; |
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init.ops = &bcm53573_ilp_clk_ops; |
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init.parent_names = &parent_name; |
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init.num_parents = 1; |
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ilp->hw.init = &init; |
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err = clk_hw_register(NULL, &ilp->hw); |
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if (err) |
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goto err_free_ilp; |
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err = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &ilp->hw); |
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if (err) |
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goto err_clk_hw_unregister; |
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return; |
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err_clk_hw_unregister: |
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clk_hw_unregister(&ilp->hw); |
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err_free_ilp: |
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kfree(ilp); |
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pr_err("Failed to init ILP clock: %d\n", err); |
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} |
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/* We need it very early for arch code, before device model gets ready */ |
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CLK_OF_DECLARE(bcm53573_ilp_clk, "brcm,bcm53573-ilp", bcm53573_ilp_init);
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