1// SPDX-License-Identifier: GPL-2.0 2/* 3 * System Control and Power Interface (SCMI) Protocol based clock driver 4 * 5 * Copyright (C) 2018 ARM Ltd. 6 */ 7 8#include <linux/clk-provider.h> 9#include <linux/device.h> 10#include <linux/err.h> 11#include <linux/of.h> 12#include <linux/module.h> 13#include <linux/scmi_protocol.h> 14#include <asm/div64.h> 15 16struct scmi_clk { 17 u32 id; 18 struct clk_hw hw; 19 const struct scmi_clock_info *info; 20 const struct scmi_handle *handle; 21}; 22 23#define to_scmi_clk(clk) container_of(clk, struct scmi_clk, hw) 24 25static unsigned long scmi_clk_recalc_rate(struct clk_hw *hw, 26 unsigned long parent_rate) 27{ 28 int ret; 29 u64 rate; 30 struct scmi_clk *clk = to_scmi_clk(hw); 31 32 ret = clk->handle->clk_ops->rate_get(clk->handle, clk->id, &rate); 33 if (ret) 34 return 0; 35 return rate; 36} 37 38static long scmi_clk_round_rate(struct clk_hw *hw, unsigned long rate, 39 unsigned long *parent_rate) 40{ 41 u64 fmin, fmax, ftmp; 42 struct scmi_clk *clk = to_scmi_clk(hw); 43 44 /* 45 * We can't figure out what rate it will be, so just return the 46 * rate back to the caller. scmi_clk_recalc_rate() will be called 47 * after the rate is set and we'll know what rate the clock is 48 * running at then. 49 */ 50 if (clk->info->rate_discrete) 51 return rate; 52 53 fmin = clk->info->range.min_rate; 54 fmax = clk->info->range.max_rate; 55 if (rate <= fmin) 56 return fmin; 57 else if (rate >= fmax) 58 return fmax; 59 60 ftmp = rate - fmin; 61 ftmp += clk->info->range.step_size - 1; /* to round up */ 62 do_div(ftmp, clk->info->range.step_size); 63 64 return ftmp * clk->info->range.step_size + fmin; 65} 66 67static int scmi_clk_set_rate(struct clk_hw *hw, unsigned long rate, 68 unsigned long parent_rate) 69{ 70 struct scmi_clk *clk = to_scmi_clk(hw); 71 72 return clk->handle->clk_ops->rate_set(clk->handle, clk->id, rate); 73} 74 75static int scmi_clk_enable(struct clk_hw *hw) 76{ 77 struct scmi_clk *clk = to_scmi_clk(hw); 78 79 return clk->handle->clk_ops->enable(clk->handle, clk->id); 80} 81 82static void scmi_clk_disable(struct clk_hw *hw) 83{ 84 struct scmi_clk *clk = to_scmi_clk(hw); 85 86 clk->handle->clk_ops->disable(clk->handle, clk->id); 87} 88 89static const struct clk_ops scmi_clk_ops = { 90 .recalc_rate = scmi_clk_recalc_rate, 91 .round_rate = scmi_clk_round_rate, 92 .set_rate = scmi_clk_set_rate, 93 /* 94 * We can't provide enable/disable callback as we can't perform the same 95 * in atomic context. Since the clock framework provides standard API 96 * clk_prepare_enable that helps cases using clk_enable in non-atomic 97 * context, it should be fine providing prepare/unprepare. 98 */ 99 .prepare = scmi_clk_enable, 100 .unprepare = scmi_clk_disable, 101}; 102 103static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk) 104{ 105 int ret; 106 unsigned long min_rate, max_rate; 107 108 struct clk_init_data init = { 109 .flags = CLK_GET_RATE_NOCACHE, 110 .num_parents = 0, 111 .ops = &scmi_clk_ops, 112 .name = sclk->info->name, 113 }; 114 115 sclk->hw.init = &init; 116 ret = devm_clk_hw_register(dev, &sclk->hw); 117 if (ret) 118 return ret; 119 120 if (sclk->info->rate_discrete) { 121 int num_rates = sclk->info->list.num_rates; 122 123 if (num_rates <= 0) 124 return -EINVAL; 125 126 min_rate = sclk->info->list.rates[0]; 127 max_rate = sclk->info->list.rates[num_rates - 1]; 128 } else { 129 min_rate = sclk->info->range.min_rate; 130 max_rate = sclk->info->range.max_rate; 131 } 132 133 clk_hw_set_rate_range(&sclk->hw, min_rate, max_rate); 134 return ret; 135} 136 137static int scmi_clocks_probe(struct scmi_device *sdev) 138{ 139 int idx, count, err; 140 struct clk_hw **hws; 141 struct clk_hw_onecell_data *clk_data; 142 struct device *dev = &sdev->dev; 143 struct device_node *np = dev->of_node; 144 const struct scmi_handle *handle = sdev->handle; 145 146 if (!handle || !handle->clk_ops) 147 return -ENODEV; 148 149 count = handle->clk_ops->count_get(handle); 150 if (count < 0) { 151 dev_err(dev, "%pOFn: invalid clock output count\n", np); 152 return -EINVAL; 153 } 154 155 clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, count), 156 GFP_KERNEL); 157 if (!clk_data) 158 return -ENOMEM; 159 160 clk_data->num = count; 161 hws = clk_data->hws; 162 163 for (idx = 0; idx < count; idx++) { 164 struct scmi_clk *sclk; 165 166 sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL); 167 if (!sclk) 168 return -ENOMEM; 169 170 sclk->info = handle->clk_ops->info_get(handle, idx); 171 if (!sclk->info) { 172 dev_dbg(dev, "invalid clock info for idx %d\n", idx); 173 devm_kfree(dev, sclk); 174 continue; 175 } 176 177 sclk->id = idx; 178 sclk->handle = handle; 179 180 err = scmi_clk_ops_init(dev, sclk); 181 if (err) { 182 dev_err(dev, "failed to register clock %d\n", idx); 183 devm_kfree(dev, sclk); 184 hws[idx] = NULL; 185 } else { 186 dev_dbg(dev, "Registered clock:%s\n", sclk->info->name); 187 hws[idx] = &sclk->hw; 188 } 189 } 190 191 return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, 192 clk_data); 193} 194 195static const struct scmi_device_id scmi_id_table[] = { 196 { SCMI_PROTOCOL_CLOCK, "clocks" }, 197 { }, 198}; 199MODULE_DEVICE_TABLE(scmi, scmi_id_table); 200 201static struct scmi_driver scmi_clocks_driver = { 202 .name = "scmi-clocks", 203 .probe = scmi_clocks_probe, 204 .id_table = scmi_id_table, 205}; 206module_scmi_driver(scmi_clocks_driver); 207 208MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); 209MODULE_DESCRIPTION("ARM SCMI clock driver"); 210MODULE_LICENSE("GPL v2"); 211