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![Simon Glass](/assets/img/avatar_default.png)
This construct is quite long-winded. In earlier days it made some sense since auto-allocation was a strange concept. But with driver model now used pretty universally, we can shorten this to 'auto'. This reduces verbosity and makes it easier to read. Coincidentally it also ensures that every declaration is on one line, thus making dtoc's job easier. Signed-off-by: Simon Glass <sjg@chromium.org>
214 lines
5.0 KiB
C
214 lines
5.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2018, STMicroelectronics - All Rights Reserved
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* Author: Fabrice Gasnier <fabrice.gasnier@st.com>
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*
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* Originally based on the Linux kernel v4.18 drivers/iio/adc/stm32-adc-core.c.
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*/
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#include <common.h>
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#include <dm.h>
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#include <asm/io.h>
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#include <dm/device_compat.h>
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#include <linux/bitops.h>
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#include <power/regulator.h>
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#include "stm32-adc-core.h"
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/* STM32H7 - common registers for all ADC instances */
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#define STM32H7_ADC_CCR (STM32_ADCX_COMN_OFFSET + 0x08)
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/* STM32H7_ADC_CCR - bit fields */
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#define STM32H7_PRESC_SHIFT 18
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#define STM32H7_PRESC_MASK GENMASK(21, 18)
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#define STM32H7_CKMODE_SHIFT 16
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#define STM32H7_CKMODE_MASK GENMASK(17, 16)
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/* STM32 H7 maximum analog clock rate (from datasheet) */
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#define STM32H7_ADC_MAX_CLK_RATE 36000000
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/**
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* struct stm32h7_adc_ck_spec - specification for stm32h7 adc clock
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* @ckmode: ADC clock mode, Async or sync with prescaler.
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* @presc: prescaler bitfield for async clock mode
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* @div: prescaler division ratio
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*/
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struct stm32h7_adc_ck_spec {
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u32 ckmode;
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u32 presc;
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int div;
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};
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static const struct stm32h7_adc_ck_spec stm32h7_adc_ckmodes_spec[] = {
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/* 00: CK_ADC[1..3]: Asynchronous clock modes */
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{ 0, 0, 1 },
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{ 0, 1, 2 },
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{ 0, 2, 4 },
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{ 0, 3, 6 },
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{ 0, 4, 8 },
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{ 0, 5, 10 },
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{ 0, 6, 12 },
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{ 0, 7, 16 },
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{ 0, 8, 32 },
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{ 0, 9, 64 },
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{ 0, 10, 128 },
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{ 0, 11, 256 },
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/* HCLK used: Synchronous clock modes (1, 2 or 4 prescaler) */
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{ 1, 0, 1 },
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{ 2, 0, 2 },
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{ 3, 0, 4 },
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};
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static int stm32h7_adc_clk_sel(struct udevice *dev,
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struct stm32_adc_common *common)
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{
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u32 ckmode, presc;
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unsigned long rate;
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unsigned int i;
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int div;
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/* stm32h7 bus clock is common for all ADC instances (mandatory) */
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if (!clk_valid(&common->bclk)) {
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dev_err(dev, "No bclk clock found\n");
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return -ENOENT;
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}
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/*
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* stm32h7 can use either 'bus' or 'adc' clock for analog circuitry.
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* So, choice is to have bus clock mandatory and adc clock optional.
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* If optional 'adc' clock has been found, then try to use it first.
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*/
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if (clk_valid(&common->aclk)) {
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/*
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* Asynchronous clock modes (e.g. ckmode == 0)
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* From spec: PLL output musn't exceed max rate
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*/
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rate = clk_get_rate(&common->aclk);
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if (!rate) {
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dev_err(dev, "Invalid aclk rate: 0\n");
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return -EINVAL;
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}
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for (i = 0; i < ARRAY_SIZE(stm32h7_adc_ckmodes_spec); i++) {
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ckmode = stm32h7_adc_ckmodes_spec[i].ckmode;
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presc = stm32h7_adc_ckmodes_spec[i].presc;
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div = stm32h7_adc_ckmodes_spec[i].div;
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if (ckmode)
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continue;
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if ((rate / div) <= STM32H7_ADC_MAX_CLK_RATE)
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goto out;
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}
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}
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/* Synchronous clock modes (e.g. ckmode is 1, 2 or 3) */
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rate = clk_get_rate(&common->bclk);
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if (!rate) {
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dev_err(dev, "Invalid bus clock rate: 0\n");
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return -EINVAL;
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}
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for (i = 0; i < ARRAY_SIZE(stm32h7_adc_ckmodes_spec); i++) {
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ckmode = stm32h7_adc_ckmodes_spec[i].ckmode;
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presc = stm32h7_adc_ckmodes_spec[i].presc;
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div = stm32h7_adc_ckmodes_spec[i].div;
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if (!ckmode)
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continue;
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if ((rate / div) <= STM32H7_ADC_MAX_CLK_RATE)
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goto out;
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}
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dev_err(dev, "clk selection failed\n");
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return -EINVAL;
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out:
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/* rate used later by each ADC instance to control BOOST mode */
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common->rate = rate / div;
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/* Set common clock mode and prescaler */
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clrsetbits_le32(common->base + STM32H7_ADC_CCR,
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STM32H7_CKMODE_MASK | STM32H7_PRESC_MASK,
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ckmode << STM32H7_CKMODE_SHIFT |
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presc << STM32H7_PRESC_SHIFT);
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dev_dbg(dev, "Using %s clock/%d source at %ld kHz\n",
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ckmode ? "bus" : "adc", div, common->rate / 1000);
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return 0;
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}
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static int stm32_adc_core_probe(struct udevice *dev)
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{
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struct stm32_adc_common *common = dev_get_priv(dev);
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int ret;
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common->base = dev_read_addr_ptr(dev);
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if (!common->base) {
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dev_err(dev, "can't get address\n");
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return -ENOENT;
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}
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ret = device_get_supply_regulator(dev, "vref-supply", &common->vref);
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if (ret) {
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dev_err(dev, "can't get vref-supply: %d\n", ret);
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return ret;
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}
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ret = regulator_get_value(common->vref);
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if (ret < 0) {
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dev_err(dev, "can't get vref-supply value: %d\n", ret);
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return ret;
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}
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common->vref_uv = ret;
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ret = clk_get_by_name(dev, "adc", &common->aclk);
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if (!ret) {
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ret = clk_enable(&common->aclk);
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if (ret) {
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dev_err(dev, "Can't enable aclk: %d\n", ret);
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return ret;
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}
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}
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ret = clk_get_by_name(dev, "bus", &common->bclk);
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if (!ret) {
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ret = clk_enable(&common->bclk);
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if (ret) {
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dev_err(dev, "Can't enable bclk: %d\n", ret);
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goto err_aclk_disable;
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}
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}
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ret = stm32h7_adc_clk_sel(dev, common);
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if (ret)
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goto err_bclk_disable;
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return ret;
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err_bclk_disable:
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if (clk_valid(&common->bclk))
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clk_disable(&common->bclk);
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err_aclk_disable:
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if (clk_valid(&common->aclk))
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clk_disable(&common->aclk);
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return ret;
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}
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static const struct udevice_id stm32_adc_core_ids[] = {
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{ .compatible = "st,stm32h7-adc-core" },
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{ .compatible = "st,stm32mp1-adc-core" },
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{}
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};
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U_BOOT_DRIVER(stm32_adc_core) = {
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.name = "stm32-adc-core",
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.id = UCLASS_SIMPLE_BUS,
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.of_match = stm32_adc_core_ids,
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.probe = stm32_adc_core_probe,
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.priv_auto = sizeof(struct stm32_adc_common),
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};
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