1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2014 Free Electrons 4 * 5 * Author: Boris BREZILLON <boris.brezillon@free-electrons.com> 6 * 7 * Allwinner A31 AR100 clock driver 8 */ 9 10 #include <linux/bitops.h> 11 #include <linux/clk-provider.h> 12 #include <linux/init.h> 13 #include <linux/of.h> 14 #include <linux/platform_device.h> 15 #include <linux/spinlock.h> 16 17 #include "clk-factors.h" 18 19 /* 20 * sun6i_get_ar100_factors - Calculates factors p, m for AR100 21 * 22 * AR100 rate is calculated as follows 23 * rate = (parent_rate >> p) / (m + 1); 24 */ 25 static void sun6i_get_ar100_factors(struct factors_request *req) 26 { 27 unsigned long div; 28 int shift; 29 30 /* clock only divides */ 31 if (req->rate > req->parent_rate) 32 req->rate = req->parent_rate; 33 34 div = DIV_ROUND_UP(req->parent_rate, req->rate); 35 36 if (div < 32) 37 shift = 0; 38 else if (div >> 1 < 32) 39 shift = 1; 40 else if (div >> 2 < 32) 41 shift = 2; 42 else 43 shift = 3; 44 45 div >>= shift; 46 47 if (div > 32) 48 div = 32; 49 50 req->rate = (req->parent_rate >> shift) / div; 51 req->m = div - 1; 52 req->p = shift; 53 } 54 55 static const struct clk_factors_config sun6i_ar100_config = { 56 .mwidth = 5, 57 .mshift = 8, 58 .pwidth = 2, 59 .pshift = 4, 60 }; 61 62 static const struct factors_data sun6i_ar100_data = { 63 .mux = 16, 64 .muxmask = GENMASK(1, 0), 65 .table = &sun6i_ar100_config, 66 .getter = sun6i_get_ar100_factors, 67 }; 68 69 static DEFINE_SPINLOCK(sun6i_ar100_lock); 70 71 static int sun6i_a31_ar100_clk_probe(struct platform_device *pdev) 72 { 73 struct device_node *np = pdev->dev.of_node; 74 void __iomem *reg; 75 struct clk *clk; 76 77 reg = devm_platform_ioremap_resource(pdev, 0); 78 if (IS_ERR(reg)) 79 return PTR_ERR(reg); 80 81 clk = sunxi_factors_register(np, &sun6i_ar100_data, &sun6i_ar100_lock, 82 reg); 83 if (!clk) 84 return -ENOMEM; 85 86 platform_set_drvdata(pdev, clk); 87 88 return 0; 89 } 90 91 static const struct of_device_id sun6i_a31_ar100_clk_dt_ids[] = { 92 { .compatible = "allwinner,sun6i-a31-ar100-clk" }, 93 { /* sentinel */ } 94 }; 95 96 static struct platform_driver sun6i_a31_ar100_clk_driver = { 97 .driver = { 98 .name = "sun6i-a31-ar100-clk", 99 .of_match_table = sun6i_a31_ar100_clk_dt_ids, 100 .suppress_bind_attrs = true, 101 }, 102 .probe = sun6i_a31_ar100_clk_probe, 103 }; 104 builtin_platform_driver(sun6i_a31_ar100_clk_driver); 105