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314 lines
7.4 KiB
314 lines
7.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* System Control and Power Interface (SCPI) Protocol based clock driver |
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* |
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* Copyright (C) 2015 ARM Ltd. |
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*/ |
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#include <linux/clk-provider.h> |
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#include <linux/device.h> |
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#include <linux/err.h> |
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#include <linux/of.h> |
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#include <linux/module.h> |
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#include <linux/of_platform.h> |
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#include <linux/platform_device.h> |
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#include <linux/scpi_protocol.h> |
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struct scpi_clk { |
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u32 id; |
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struct clk_hw hw; |
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struct scpi_dvfs_info *info; |
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struct scpi_ops *scpi_ops; |
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}; |
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#define to_scpi_clk(clk) container_of(clk, struct scpi_clk, hw) |
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static struct platform_device *cpufreq_dev; |
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static unsigned long scpi_clk_recalc_rate(struct clk_hw *hw, |
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unsigned long parent_rate) |
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{ |
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struct scpi_clk *clk = to_scpi_clk(hw); |
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return clk->scpi_ops->clk_get_val(clk->id); |
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} |
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static long scpi_clk_round_rate(struct clk_hw *hw, unsigned long rate, |
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unsigned long *parent_rate) |
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{ |
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/* |
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* We can't figure out what rate it will be, so just return the |
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* rate back to the caller. scpi_clk_recalc_rate() will be called |
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* after the rate is set and we'll know what rate the clock is |
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* running at then. |
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*/ |
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return rate; |
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} |
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static int scpi_clk_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 scpi_clk *clk = to_scpi_clk(hw); |
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return clk->scpi_ops->clk_set_val(clk->id, rate); |
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} |
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static const struct clk_ops scpi_clk_ops = { |
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.recalc_rate = scpi_clk_recalc_rate, |
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.round_rate = scpi_clk_round_rate, |
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.set_rate = scpi_clk_set_rate, |
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}; |
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/* find closest match to given frequency in OPP table */ |
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static long __scpi_dvfs_round_rate(struct scpi_clk *clk, unsigned long rate) |
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{ |
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int idx; |
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unsigned long fmin = 0, fmax = ~0, ftmp; |
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const struct scpi_opp *opp = clk->info->opps; |
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for (idx = 0; idx < clk->info->count; idx++, opp++) { |
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ftmp = opp->freq; |
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if (ftmp >= rate) { |
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if (ftmp <= fmax) |
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fmax = ftmp; |
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break; |
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} else if (ftmp >= fmin) { |
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fmin = ftmp; |
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} |
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} |
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return fmax != ~0 ? fmax : fmin; |
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} |
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static unsigned long scpi_dvfs_recalc_rate(struct clk_hw *hw, |
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unsigned long parent_rate) |
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{ |
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struct scpi_clk *clk = to_scpi_clk(hw); |
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int idx = clk->scpi_ops->dvfs_get_idx(clk->id); |
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const struct scpi_opp *opp; |
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if (idx < 0) |
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return 0; |
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opp = clk->info->opps + idx; |
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return opp->freq; |
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} |
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static long scpi_dvfs_round_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 scpi_clk *clk = to_scpi_clk(hw); |
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return __scpi_dvfs_round_rate(clk, rate); |
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} |
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static int __scpi_find_dvfs_index(struct scpi_clk *clk, unsigned long rate) |
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{ |
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int idx, max_opp = clk->info->count; |
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const struct scpi_opp *opp = clk->info->opps; |
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for (idx = 0; idx < max_opp; idx++, opp++) |
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if (opp->freq == rate) |
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return idx; |
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return -EINVAL; |
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} |
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static int scpi_dvfs_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 scpi_clk *clk = to_scpi_clk(hw); |
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int ret = __scpi_find_dvfs_index(clk, rate); |
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if (ret < 0) |
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return ret; |
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return clk->scpi_ops->dvfs_set_idx(clk->id, (u8)ret); |
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} |
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static const struct clk_ops scpi_dvfs_ops = { |
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.recalc_rate = scpi_dvfs_recalc_rate, |
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.round_rate = scpi_dvfs_round_rate, |
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.set_rate = scpi_dvfs_set_rate, |
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}; |
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static const struct of_device_id scpi_clk_match[] __maybe_unused = { |
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{ .compatible = "arm,scpi-dvfs-clocks", .data = &scpi_dvfs_ops, }, |
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{ .compatible = "arm,scpi-variable-clocks", .data = &scpi_clk_ops, }, |
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{} |
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}; |
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static int |
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scpi_clk_ops_init(struct device *dev, const struct of_device_id *match, |
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struct scpi_clk *sclk, const char *name) |
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{ |
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struct clk_init_data init; |
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unsigned long min = 0, max = 0; |
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int ret; |
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init.name = name; |
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init.flags = 0; |
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init.num_parents = 0; |
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init.ops = match->data; |
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sclk->hw.init = &init; |
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sclk->scpi_ops = get_scpi_ops(); |
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if (init.ops == &scpi_dvfs_ops) { |
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sclk->info = sclk->scpi_ops->dvfs_get_info(sclk->id); |
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if (IS_ERR(sclk->info)) |
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return PTR_ERR(sclk->info); |
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} else if (init.ops == &scpi_clk_ops) { |
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if (sclk->scpi_ops->clk_get_range(sclk->id, &min, &max) || !max) |
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return -EINVAL; |
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} else { |
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return -EINVAL; |
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} |
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ret = devm_clk_hw_register(dev, &sclk->hw); |
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if (!ret && max) |
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clk_hw_set_rate_range(&sclk->hw, min, max); |
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return ret; |
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} |
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struct scpi_clk_data { |
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struct scpi_clk **clk; |
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unsigned int clk_num; |
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}; |
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static struct clk_hw * |
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scpi_of_clk_src_get(struct of_phandle_args *clkspec, void *data) |
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{ |
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struct scpi_clk *sclk; |
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struct scpi_clk_data *clk_data = data; |
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unsigned int idx = clkspec->args[0], count; |
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for (count = 0; count < clk_data->clk_num; count++) { |
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sclk = clk_data->clk[count]; |
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if (idx == sclk->id) |
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return &sclk->hw; |
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} |
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return ERR_PTR(-EINVAL); |
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} |
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static int scpi_clk_add(struct device *dev, struct device_node *np, |
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const struct of_device_id *match) |
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{ |
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int idx, count, err; |
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struct scpi_clk_data *clk_data; |
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count = of_property_count_strings(np, "clock-output-names"); |
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if (count < 0) { |
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dev_err(dev, "%pOFn: invalid clock output count\n", np); |
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return -EINVAL; |
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} |
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clk_data = devm_kmalloc(dev, sizeof(*clk_data), GFP_KERNEL); |
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if (!clk_data) |
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return -ENOMEM; |
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clk_data->clk_num = count; |
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clk_data->clk = devm_kcalloc(dev, count, sizeof(*clk_data->clk), |
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GFP_KERNEL); |
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if (!clk_data->clk) |
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return -ENOMEM; |
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for (idx = 0; idx < count; idx++) { |
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struct scpi_clk *sclk; |
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const char *name; |
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u32 val; |
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sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL); |
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if (!sclk) |
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return -ENOMEM; |
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if (of_property_read_string_index(np, "clock-output-names", |
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idx, &name)) { |
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dev_err(dev, "invalid clock name @ %pOFn\n", np); |
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return -EINVAL; |
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} |
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if (of_property_read_u32_index(np, "clock-indices", |
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idx, &val)) { |
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dev_err(dev, "invalid clock index @ %pOFn\n", np); |
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return -EINVAL; |
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} |
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sclk->id = val; |
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err = scpi_clk_ops_init(dev, match, sclk, name); |
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if (err) { |
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dev_err(dev, "failed to register clock '%s'\n", name); |
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return err; |
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} |
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dev_dbg(dev, "Registered clock '%s'\n", name); |
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clk_data->clk[idx] = sclk; |
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} |
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return of_clk_add_hw_provider(np, scpi_of_clk_src_get, clk_data); |
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} |
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static int scpi_clocks_remove(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct device_node *child, *np = dev->of_node; |
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if (cpufreq_dev) { |
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platform_device_unregister(cpufreq_dev); |
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cpufreq_dev = NULL; |
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} |
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for_each_available_child_of_node(np, child) |
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of_clk_del_provider(np); |
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return 0; |
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} |
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static int scpi_clocks_probe(struct platform_device *pdev) |
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{ |
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int ret; |
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struct device *dev = &pdev->dev; |
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struct device_node *child, *np = dev->of_node; |
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const struct of_device_id *match; |
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if (!get_scpi_ops()) |
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return -ENXIO; |
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for_each_available_child_of_node(np, child) { |
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match = of_match_node(scpi_clk_match, child); |
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if (!match) |
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continue; |
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ret = scpi_clk_add(dev, child, match); |
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if (ret) { |
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scpi_clocks_remove(pdev); |
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of_node_put(child); |
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return ret; |
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} |
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if (match->data != &scpi_dvfs_ops) |
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continue; |
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/* Add the virtual cpufreq device if it's DVFS clock provider */ |
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cpufreq_dev = platform_device_register_simple("scpi-cpufreq", |
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-1, NULL, 0); |
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if (IS_ERR(cpufreq_dev)) |
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pr_warn("unable to register cpufreq device"); |
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} |
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return 0; |
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} |
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static const struct of_device_id scpi_clocks_ids[] = { |
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{ .compatible = "arm,scpi-clocks", }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(of, scpi_clocks_ids); |
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static struct platform_driver scpi_clocks_driver = { |
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.driver = { |
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.name = "scpi_clocks", |
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.of_match_table = scpi_clocks_ids, |
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}, |
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.probe = scpi_clocks_probe, |
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.remove = scpi_clocks_remove, |
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}; |
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module_platform_driver(scpi_clocks_driver); |
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MODULE_AUTHOR("Sudeep Holla <[email protected]>"); |
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MODULE_DESCRIPTION("ARM SCPI clock driver"); |
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MODULE_LICENSE("GPL v2");
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