1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
4 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>
6 * Originally based on the Linux kernel v4.18 drivers/iio/adc/stm32-adc-core.c.
11 #include <dm/device_compat.h>
12 #include <power/regulator.h>
13 #include "stm32-adc-core.h"
15 /* STM32H7 - common registers for all ADC instances */
16 #define STM32H7_ADC_CCR (STM32_ADCX_COMN_OFFSET + 0x08)
18 /* STM32H7_ADC_CCR - bit fields */
19 #define STM32H7_PRESC_SHIFT 18
20 #define STM32H7_PRESC_MASK GENMASK(21, 18)
21 #define STM32H7_CKMODE_SHIFT 16
22 #define STM32H7_CKMODE_MASK GENMASK(17, 16)
24 /* STM32 H7 maximum analog clock rate (from datasheet) */
25 #define STM32H7_ADC_MAX_CLK_RATE 36000000
28 * struct stm32h7_adc_ck_spec - specification for stm32h7 adc clock
29 * @ckmode: ADC clock mode, Async or sync with prescaler.
30 * @presc: prescaler bitfield for async clock mode
31 * @div: prescaler division ratio
33 struct stm32h7_adc_ck_spec {
39 static const struct stm32h7_adc_ck_spec stm32h7_adc_ckmodes_spec[] = {
40 /* 00: CK_ADC[1..3]: Asynchronous clock modes */
53 /* HCLK used: Synchronous clock modes (1, 2 or 4 prescaler) */
59 static int stm32h7_adc_clk_sel(struct udevice *dev,
60 struct stm32_adc_common *common)
67 /* stm32h7 bus clock is common for all ADC instances (mandatory) */
68 if (!clk_valid(&common->bclk)) {
69 dev_err(dev, "No bclk clock found\n");
74 * stm32h7 can use either 'bus' or 'adc' clock for analog circuitry.
75 * So, choice is to have bus clock mandatory and adc clock optional.
76 * If optional 'adc' clock has been found, then try to use it first.
78 if (clk_valid(&common->aclk)) {
80 * Asynchronous clock modes (e.g. ckmode == 0)
81 * From spec: PLL output musn't exceed max rate
83 rate = clk_get_rate(&common->aclk);
85 dev_err(dev, "Invalid aclk rate: 0\n");
89 for (i = 0; i < ARRAY_SIZE(stm32h7_adc_ckmodes_spec); i++) {
90 ckmode = stm32h7_adc_ckmodes_spec[i].ckmode;
91 presc = stm32h7_adc_ckmodes_spec[i].presc;
92 div = stm32h7_adc_ckmodes_spec[i].div;
97 if ((rate / div) <= STM32H7_ADC_MAX_CLK_RATE)
102 /* Synchronous clock modes (e.g. ckmode is 1, 2 or 3) */
103 rate = clk_get_rate(&common->bclk);
105 dev_err(dev, "Invalid bus clock rate: 0\n");
109 for (i = 0; i < ARRAY_SIZE(stm32h7_adc_ckmodes_spec); i++) {
110 ckmode = stm32h7_adc_ckmodes_spec[i].ckmode;
111 presc = stm32h7_adc_ckmodes_spec[i].presc;
112 div = stm32h7_adc_ckmodes_spec[i].div;
117 if ((rate / div) <= STM32H7_ADC_MAX_CLK_RATE)
121 dev_err(dev, "clk selection failed\n");
125 /* rate used later by each ADC instance to control BOOST mode */
126 common->rate = rate / div;
128 /* Set common clock mode and prescaler */
129 clrsetbits_le32(common->base + STM32H7_ADC_CCR,
130 STM32H7_CKMODE_MASK | STM32H7_PRESC_MASK,
131 ckmode << STM32H7_CKMODE_SHIFT |
132 presc << STM32H7_PRESC_SHIFT);
134 dev_dbg(dev, "Using %s clock/%d source at %ld kHz\n",
135 ckmode ? "bus" : "adc", div, common->rate / 1000);
140 static int stm32_adc_core_probe(struct udevice *dev)
142 struct stm32_adc_common *common = dev_get_priv(dev);
145 common->base = dev_read_addr_ptr(dev);
147 dev_err(dev, "can't get address\n");
151 ret = device_get_supply_regulator(dev, "vref-supply", &common->vref);
153 dev_err(dev, "can't get vref-supply: %d\n", ret);
157 ret = regulator_get_value(common->vref);
159 dev_err(dev, "can't get vref-supply value: %d\n", ret);
162 common->vref_uv = ret;
164 ret = clk_get_by_name(dev, "adc", &common->aclk);
166 ret = clk_enable(&common->aclk);
168 dev_err(dev, "Can't enable aclk: %d\n", ret);
173 ret = clk_get_by_name(dev, "bus", &common->bclk);
175 ret = clk_enable(&common->bclk);
177 dev_err(dev, "Can't enable bclk: %d\n", ret);
178 goto err_aclk_disable;
182 ret = stm32h7_adc_clk_sel(dev, common);
184 goto err_bclk_disable;
189 if (clk_valid(&common->bclk))
190 clk_disable(&common->bclk);
193 if (clk_valid(&common->aclk))
194 clk_disable(&common->aclk);
199 static const struct udevice_id stm32_adc_core_ids[] = {
200 { .compatible = "st,stm32h7-adc-core" },
201 { .compatible = "st,stm32mp1-adc-core" },
205 U_BOOT_DRIVER(stm32_adc_core) = {
206 .name = "stm32-adc-core",
207 .id = UCLASS_SIMPLE_BUS,
208 .of_match = stm32_adc_core_ids,
209 .probe = stm32_adc_core_probe,
210 .priv_auto_alloc_size = sizeof(struct stm32_adc_common),