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dd7c749474
Add a simple driver for the clocks provided by the MIPS Boston development board. The system provides information about 2 clocks whose rates are fixed by the bitfile flashed in the boards FPGA, and this driver simply reads the rates of these 2 clocks. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reviewed-by: Simon Glass <sjg@chromium.org>
98 lines
2.1 KiB
C
98 lines
2.1 KiB
C
/*
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* Copyright (C) 2016 Imagination Technologies
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*
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* SPDX-License-Identifier: GPL-2.0
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*/
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#include <common.h>
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#include <clk-uclass.h>
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#include <dm.h>
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#include <dt-bindings/clock/boston-clock.h>
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#include <regmap.h>
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#include <syscon.h>
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struct clk_boston {
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struct regmap *regmap;
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};
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#define BOSTON_PLAT_MMCMDIV 0x30
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# define BOSTON_PLAT_MMCMDIV_CLK0DIV (0xff << 0)
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# define BOSTON_PLAT_MMCMDIV_INPUT (0xff << 8)
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# define BOSTON_PLAT_MMCMDIV_MUL (0xff << 16)
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# define BOSTON_PLAT_MMCMDIV_CLK1DIV (0xff << 24)
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static uint32_t ext_field(uint32_t val, uint32_t mask)
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{
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return (val & mask) >> (ffs(mask) - 1);
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}
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static ulong clk_boston_get_rate(struct clk *clk)
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{
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struct clk_boston *state = dev_get_platdata(clk->dev);
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uint32_t in_rate, mul, div;
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uint mmcmdiv;
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int err;
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err = regmap_read(state->regmap, BOSTON_PLAT_MMCMDIV, &mmcmdiv);
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if (err)
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return 0;
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in_rate = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_INPUT);
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mul = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_MUL);
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switch (clk->id) {
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case BOSTON_CLK_SYS:
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div = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_CLK0DIV);
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break;
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case BOSTON_CLK_CPU:
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div = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_CLK1DIV);
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break;
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default:
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return 0;
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}
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return (in_rate * mul * 1000000) / div;
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}
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const struct clk_ops clk_boston_ops = {
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.get_rate = clk_boston_get_rate,
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};
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static int clk_boston_ofdata_to_platdata(struct udevice *dev)
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{
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struct clk_boston *state = dev_get_platdata(dev);
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struct udevice *syscon;
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int err;
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err = uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
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"regmap", &syscon);
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if (err) {
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error("unable to find syscon device\n");
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return err;
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}
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state->regmap = syscon_get_regmap(syscon);
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if (!state->regmap) {
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error("unable to find regmap\n");
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return -ENODEV;
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}
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return 0;
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}
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static const struct udevice_id clk_boston_match[] = {
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{
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.compatible = "img,boston-clock",
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},
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{ /* sentinel */ }
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};
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U_BOOT_DRIVER(clk_boston) = {
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.name = "boston_clock",
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.id = UCLASS_CLK,
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.of_match = clk_boston_match,
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.ofdata_to_platdata = clk_boston_ofdata_to_platdata,
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.platdata_auto_alloc_size = sizeof(struct clk_boston),
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.ops = &clk_boston_ops,
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};
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