clk/versatile/clk-vexpress-osc.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  *
0004  * Copyright (C) 2012 ARM Limited
0005  */
0006
0007 #include <linux/clkdev.h>
0008 #include <linux/clk-provider.h>
0009 #include <linux/err.h>
0010 #include <linux/module.h>
0011 #include <linux/of.h>
0012 #include <linux/platform_device.h>
0013 #include <linux/slab.h>
0014 #include <linux/vexpress.h>
0015
0016 struct vexpress_osc {
0017     struct regmap *reg;
0018     struct clk_hw hw;
0019     unsigned long rate_min;
0020     unsigned long rate_max;
0021 };
0022
0023 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
0024
0025 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
0026         unsigned long parent_rate)
0027 {
0028     struct vexpress_osc *osc = to_vexpress_osc(hw);
0029     u32 rate;
0030
0031     regmap_read(osc->reg, 0, &rate);
0032
0033     return rate;
0034 }
0035
0036 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
0037         unsigned long *parent_rate)
0038 {
0039     struct vexpress_osc *osc = to_vexpress_osc(hw);
0040
0041     if (osc->rate_min && rate < osc->rate_min)
0042         rate = osc->rate_min;
0043
0044     if (osc->rate_max && rate > osc->rate_max)
0045         rate = osc->rate_max;
0046
0047     return rate;
0048 }
0049
0050 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
0051         unsigned long parent_rate)
0052 {
0053     struct vexpress_osc *osc = to_vexpress_osc(hw);
0054
0055     return regmap_write(osc->reg, 0, rate);
0056 }
0057
0058 static const struct clk_ops vexpress_osc_ops = {
0059     .recalc_rate = vexpress_osc_recalc_rate,
0060     .round_rate = vexpress_osc_round_rate,
0061     .set_rate = vexpress_osc_set_rate,
0062 };
0063
0064
0065 static int vexpress_osc_probe(struct platform_device *pdev)
0066 {
0067     struct clk_init_data init;
0068     struct vexpress_osc *osc;
0069     u32 range[2];
0070     int ret;
0071
0072     osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
0073     if (!osc)
0074         return -ENOMEM;
0075
0076     osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
0077     if (IS_ERR(osc->reg))
0078         return PTR_ERR(osc->reg);
0079
0080     if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
0081             ARRAY_SIZE(range)) == 0) {
0082         osc->rate_min = range[0];
0083         osc->rate_max = range[1];
0084     }
0085
0086     if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
0087             &init.name) != 0)
0088         init.name = dev_name(&pdev->dev);
0089
0090     init.ops = &vexpress_osc_ops;
0091     init.flags = 0;
0092     init.num_parents = 0;
0093
0094     osc->hw.init = &init;
0095
0096     ret = devm_clk_hw_register(&pdev->dev, &osc->hw);
0097     if (ret < 0)
0098         return ret;
0099
0100     devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_simple_get, &osc->hw);
0101     clk_hw_set_rate_range(&osc->hw, osc->rate_min, osc->rate_max);
0102
0103     dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
0104
0105     return 0;
0106 }
0107
0108 static const struct of_device_id vexpress_osc_of_match[] = {
0109     { .compatible = "arm,vexpress-osc", },
0110     {}
0111 };
0112 MODULE_DEVICE_TABLE(of, vexpress_osc_of_match);
0113
0114 static struct platform_driver vexpress_osc_driver = {
0115     .driver = {
0116         .name = "vexpress-osc",
0117         .of_match_table = vexpress_osc_of_match,
0118     },
0119     .probe = vexpress_osc_probe,
0120 };
0121 module_platform_driver(vexpress_osc_driver);
0122 MODULE_LICENSE("GPL v2");