2 * Copyright (C) 2016 Atmel Corporation
3 * Wenyou.Yang <wenyou.yang@atmel.com>
5 * SPDX-License-Identifier: GPL-2.0+
9 #include <clk-uclass.h>
12 #include <mach/at91_pmc.h>
15 DECLARE_GLOBAL_DATA_PTR;
17 #define GENERATED_SOURCE_MAX 6
18 #define GENERATED_MAX_DIV 255
21 * generated_clk_bind() - for the generated clock driver
22 * Recursively bind its children as clk devices.
24 * @return: 0 on success, or negative error code on failure
26 static int generated_clk_bind(struct udevice *dev)
28 return at91_clk_sub_device_bind(dev, "generic-clk");
31 static const struct udevice_id generated_clk_match[] = {
32 { .compatible = "atmel,sama5d2-clk-generated" },
36 U_BOOT_DRIVER(generated_clk) = {
37 .name = "generated-clk",
39 .of_match = generated_clk_match,
40 .bind = generated_clk_bind,
43 /*-------------------------------------------------------------*/
45 struct generic_clk_priv {
49 static ulong generic_clk_get_rate(struct clk *clk)
51 struct pmc_platdata *plat = dev_get_platdata(clk->dev);
52 struct at91_pmc *pmc = plat->reg_base;
56 u8 clock_source, parent_index;
59 writel(clk->id & AT91_PMC_PCR_PID_MASK, &pmc->pcr);
60 tmp = readl(&pmc->pcr);
61 clock_source = (tmp >> AT91_PMC_PCR_GCKCSS_OFFSET) &
62 AT91_PMC_PCR_GCKCSS_MASK;
63 gckdiv = (tmp >> AT91_PMC_PCR_GCKDIV_OFFSET) & AT91_PMC_PCR_GCKDIV_MASK;
65 parent_index = clock_source - 1;
66 ret = clk_get_by_index(dev_get_parent(clk->dev), parent_index, &parent);
70 clk_rate = clk_get_rate(&parent) / (gckdiv + 1);
77 static ulong generic_clk_set_rate(struct clk *clk, ulong rate)
79 struct pmc_platdata *plat = dev_get_platdata(clk->dev);
80 struct at91_pmc *pmc = plat->reg_base;
81 struct generic_clk_priv *priv = dev_get_priv(clk->dev);
82 struct clk parent, best_parent;
83 ulong tmp_rate, best_rate = rate, parent_rate;
84 int tmp_diff, best_diff = -1;
85 u32 div, best_div = 0;
86 u8 best_parent_index, best_clock_source = 0;
91 for (i = 0; i < priv->num_parents; i++) {
92 ret = clk_get_by_index(dev_get_parent(clk->dev), i, &parent);
96 parent_rate = clk_get_rate(&parent);
97 if (IS_ERR_VALUE(parent_rate))
100 for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {
101 tmp_rate = DIV_ROUND_CLOSEST(parent_rate, div);
102 tmp_diff = abs(rate - tmp_rate);
104 if (best_diff < 0 || best_diff > tmp_diff) {
105 best_rate = tmp_rate;
106 best_diff = tmp_diff;
109 best_parent = parent;
110 best_parent_index = i;
111 best_clock_source = best_parent_index + 1;
114 if (!best_diff || tmp_rate < rate)
122 debug("GCK: best parent: %s, best_rate = %ld, best_div = %d\n",
123 best_parent.dev->name, best_rate, best_div);
125 ret = clk_enable(&best_parent);
129 writel(clk->id & AT91_PMC_PCR_PID_MASK, &pmc->pcr);
130 tmp = readl(&pmc->pcr);
131 tmp &= ~(AT91_PMC_PCR_GCKDIV | AT91_PMC_PCR_GCKCSS);
132 tmp |= AT91_PMC_PCR_GCKCSS_(best_clock_source) |
133 AT91_PMC_PCR_CMD_WRITE |
134 AT91_PMC_PCR_GCKDIV_(best_div) |
136 writel(tmp, &pmc->pcr);
138 while (!(readl(&pmc->sr) & AT91_PMC_GCKRDY))
144 static struct clk_ops generic_clk_ops = {
145 .of_xlate = at91_clk_of_xlate,
146 .get_rate = generic_clk_get_rate,
147 .set_rate = generic_clk_set_rate,
150 static int generic_clk_ofdata_to_platdata(struct udevice *dev)
152 struct generic_clk_priv *priv = dev_get_priv(dev);
153 u32 cells[GENERATED_SOURCE_MAX];
156 num_parents = fdtdec_get_int_array_count(gd->fdt_blob,
157 dev_of_offset(dev_get_parent(dev)), "clocks", cells,
158 GENERATED_SOURCE_MAX);
163 priv->num_parents = num_parents;
168 U_BOOT_DRIVER(generic_clk) = {
169 .name = "generic-clk",
171 .probe = at91_clk_probe,
172 .ofdata_to_platdata = generic_clk_ofdata_to_platdata,
173 .priv_auto_alloc_size = sizeof(struct generic_clk_priv),
174 .platdata_auto_alloc_size = sizeof(struct pmc_platdata),
175 .ops = &generic_clk_ops,