diff options
Diffstat (limited to 'drivers/clk/at91/clk-generated.c')
| -rw-r--r-- | drivers/clk/at91/clk-generated.c | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c new file mode 100644 index 0000000..f6164cc --- /dev/null +++ b/drivers/clk/at91/clk-generated.c @@ -0,0 +1,162 @@ +/* + * Copyright (C) 2016 Atmel Corporation + * Wenyou.Yang <wenyou.yang@atmel.com> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.h> +#include <clk-uclass.h> +#include <dm/device.h> +#include <linux/io.h> +#include <mach/at91_pmc.h> +#include "pmc.h" + +DECLARE_GLOBAL_DATA_PTR; + +#define GENERATED_SOURCE_MAX 6 +#define GENERATED_MAX_DIV 255 + +struct generated_clk_priv { + u32 num_parents; +}; + +static ulong generated_clk_get_rate(struct clk *clk) +{ + struct pmc_platdata *plat = dev_get_platdata(clk->dev); + struct at91_pmc *pmc = plat->reg_base; + struct clk parent; + u32 tmp, gckdiv; + u8 parent_id; + int ret; + + writel(clk->id & AT91_PMC_PCR_PID_MASK, &pmc->pcr); + tmp = readl(&pmc->pcr); + parent_id = (tmp >> AT91_PMC_PCR_GCKCSS_OFFSET) & + AT91_PMC_PCR_GCKCSS_MASK; + gckdiv = (tmp >> AT91_PMC_PCR_GCKDIV_OFFSET) & AT91_PMC_PCR_GCKDIV_MASK; + + ret = clk_get_by_index(clk->dev, parent_id, &parent); + if (ret) + return 0; + + return clk_get_rate(&parent) / (gckdiv + 1); +} + +static ulong generated_clk_set_rate(struct clk *clk, ulong rate) +{ + struct pmc_platdata *plat = dev_get_platdata(clk->dev); + struct at91_pmc *pmc = plat->reg_base; + struct generated_clk_priv *priv = dev_get_priv(clk->dev); + struct clk parent, best_parent; + ulong tmp_rate, best_rate = rate, parent_rate; + int tmp_diff, best_diff = -1; + u32 div, best_div = 0; + u8 best_parent_id = 0; + u8 i; + u32 tmp; + int ret; + + for (i = 0; i < priv->num_parents; i++) { + ret = clk_get_by_index(clk->dev, i, &parent); + if (ret) + return ret; + + parent_rate = clk_get_rate(&parent); + if (IS_ERR_VALUE(parent_rate)) + return parent_rate; + + for (div = 1; div < GENERATED_MAX_DIV + 2; div++) { + tmp_rate = DIV_ROUND_CLOSEST(parent_rate, div); + if (rate < tmp_rate) + continue; + tmp_diff = rate - tmp_rate; + + if (best_diff < 0 || best_diff > tmp_diff) { + best_rate = tmp_rate; + best_diff = tmp_diff; + + best_div = div - 1; + best_parent = parent; + best_parent_id = i; + } + + if (!best_diff || tmp_rate < rate) + break; + } + + if (!best_diff) + break; + } + + debug("GCK: best parent: %s, best_rate = %ld, best_div = %d\n", + best_parent.dev->name, best_rate, best_div); + + ret = clk_enable(&best_parent); + if (ret) + return ret; + + writel(clk->id & AT91_PMC_PCR_PID_MASK, &pmc->pcr); + tmp = readl(&pmc->pcr); + tmp &= ~(AT91_PMC_PCR_GCKDIV | AT91_PMC_PCR_GCKCSS); + tmp |= AT91_PMC_PCR_GCKCSS_(best_parent_id) | + AT91_PMC_PCR_CMD_WRITE | + AT91_PMC_PCR_GCKDIV_(best_div) | + AT91_PMC_PCR_GCKEN; + writel(tmp, &pmc->pcr); + + while (!(readl(&pmc->sr) & AT91_PMC_GCKRDY)) + ; + + return 0; +} + +static struct clk_ops generated_clk_ops = { + .get_rate = generated_clk_get_rate, + .set_rate = generated_clk_set_rate, +}; + +static int generated_clk_ofdata_to_platdata(struct udevice *dev) +{ + struct generated_clk_priv *priv = dev_get_priv(dev); + u32 cells[GENERATED_SOURCE_MAX]; + u32 num_parents; + + num_parents = fdtdec_get_int_array_count(gd->fdt_blob, dev->of_offset, + "clocks", cells, + GENERATED_SOURCE_MAX); + + if (!num_parents) + return -1; + + priv->num_parents = num_parents; + + return 0; +} + +static int generated_clk_bind(struct udevice *dev) +{ + return at91_pmc_clk_node_bind(dev); +} + +static int generated_clk_probe(struct udevice *dev) +{ + return at91_pmc_core_probe(dev); +} + +static const struct udevice_id generated_clk_match[] = { + { .compatible = "atmel,sama5d2-clk-generated" }, + {} +}; + +U_BOOT_DRIVER(generated_clk) = { + .name = "generated-clk", + .id = UCLASS_CLK, + .of_match = generated_clk_match, + .bind = generated_clk_bind, + .probe = generated_clk_probe, + .ofdata_to_platdata = generated_clk_ofdata_to_platdata, + .priv_auto_alloc_size = sizeof(struct generated_clk_priv), + .platdata_auto_alloc_size = sizeof(struct pmc_platdata), + .ops = &generated_clk_ops, +}; |