This patch adds support for STMicroelectronics STM32 ADC (analog to digital converter). It's originally based on Linux kernel v4.18-rcs drivers/iio/adc/stm32-adc*. It's composed of: - core driver (UCLASS_SIMPLE_BUS) manages common resources (clk, regu). - child drivers (UCLASS_ADC) declare each ADC, channels and handle conversions. This driver currently supports STM32H7 and STM32MP1 ADC.
Signed-off-by: Fabrice Gasnier fabrice.gasnier@st.com ---
drivers/adc/Kconfig | 16 +++ drivers/adc/Makefile | 1 + drivers/adc/stm32-adc-core.c | 209 +++++++++++++++++++++++++++++++++++ drivers/adc/stm32-adc-core.h | 51 +++++++++ drivers/adc/stm32-adc.c | 257 +++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 534 insertions(+) create mode 100644 drivers/adc/stm32-adc-core.c create mode 100644 drivers/adc/stm32-adc-core.h create mode 100644 drivers/adc/stm32-adc.c
diff --git a/drivers/adc/Kconfig b/drivers/adc/Kconfig index 93e27f1..e719c38 100644 --- a/drivers/adc/Kconfig +++ b/drivers/adc/Kconfig @@ -47,3 +47,19 @@ config SARADC_ROCKCHIP - 2~6 analog input channels - 1O or 12 bits resolution - Up to 1MSPS of sample rate + +config STM32_ADC + bool "Enable STMicroelectronics STM32 ADC driver" + depends on ADC && (STM32H7 || ARCH_STM32MP) + help + This enables driver for STMicroelectronics STM32 analog-to-digital + converter (ADC). + A STM32 ADC block can be composed of several individual ADCs. + Each has its own private registers, but shares some resources: + - clock selection and prescaler + - voltage reference + - common registers area. + STM32 ADC driver is composed of: + - core driver to deal with common resources + - child driver to deal with individual ADC resources (declare ADC + device and associated channels, start/stop conversions) diff --git a/drivers/adc/Makefile b/drivers/adc/Makefile index 95c93d4..cca0fec 100644 --- a/drivers/adc/Makefile +++ b/drivers/adc/Makefile @@ -10,3 +10,4 @@ obj-$(CONFIG_ADC_EXYNOS) += exynos-adc.o obj-$(CONFIG_ADC_SANDBOX) += sandbox.o obj-$(CONFIG_SARADC_ROCKCHIP) += rockchip-saradc.o obj-$(CONFIG_SARADC_MESON) += meson-saradc.o +obj-$(CONFIG_STM32_ADC) += stm32-adc.o stm32-adc-core.o diff --git a/drivers/adc/stm32-adc-core.c b/drivers/adc/stm32-adc-core.c new file mode 100644 index 0000000..a9aa143 --- /dev/null +++ b/drivers/adc/stm32-adc-core.c @@ -0,0 +1,209 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018, STMicroelectronics - All Rights Reserved + * Author: Fabrice Gasnier fabrice.gasnier@st.com + * + * Originally based on the Linux kernel v4.18 drivers/iio/adc/stm32-adc-core.c. + */ + +#include <common.h> +#include <asm/io.h> +#include <power/regulator.h> +#include "stm32-adc-core.h" + +/* STM32H7 - common registers for all ADC instances */ +#define STM32H7_ADC_CCR (STM32_ADCX_COMN_OFFSET + 0x08) + +/* STM32H7_ADC_CCR - bit fields */ +#define STM32H7_PRESC_SHIFT 18 +#define STM32H7_PRESC_MASK GENMASK(21, 18) +#define STM32H7_CKMODE_SHIFT 16 +#define STM32H7_CKMODE_MASK GENMASK(17, 16) + +/* STM32 H7 maximum analog clock rate (from datasheet) */ +#define STM32H7_ADC_MAX_CLK_RATE 36000000 + +/** + * struct stm32h7_adc_ck_spec - specification for stm32h7 adc clock + * @ckmode: ADC clock mode, Async or sync with prescaler. + * @presc: prescaler bitfield for async clock mode + * @div: prescaler division ratio + */ +struct stm32h7_adc_ck_spec { + u32 ckmode; + u32 presc; + int div; +}; + +static const struct stm32h7_adc_ck_spec stm32h7_adc_ckmodes_spec[] = { + /* 00: CK_ADC[1..3]: Asynchronous clock modes */ + { 0, 0, 1 }, + { 0, 1, 2 }, + { 0, 2, 4 }, + { 0, 3, 6 }, + { 0, 4, 8 }, + { 0, 5, 10 }, + { 0, 6, 12 }, + { 0, 7, 16 }, + { 0, 8, 32 }, + { 0, 9, 64 }, + { 0, 10, 128 }, + { 0, 11, 256 }, + /* HCLK used: Synchronous clock modes (1, 2 or 4 prescaler) */ + { 1, 0, 1 }, + { 2, 0, 2 }, + { 3, 0, 4 }, +}; + +static int stm32h7_adc_clk_sel(struct udevice *dev, + struct stm32_adc_common *common) +{ + u32 ckmode, presc; + unsigned long rate; + int i, div; + + /* stm32h7 bus clock is common for all ADC instances (mandatory) */ + if (!clk_valid(&common->bclk)) { + dev_err(dev, "No bclk clock found\n"); + return -ENOENT; + } + + /* + * stm32h7 can use either 'bus' or 'adc' clock for analog circuitry. + * So, choice is to have bus clock mandatory and adc clock optional. + * If optional 'adc' clock has been found, then try to use it first. + */ + if (clk_valid(&common->aclk)) { + /* + * Asynchronous clock modes (e.g. ckmode == 0) + * From spec: PLL output musn't exceed max rate + */ + rate = clk_get_rate(&common->aclk); + if (!rate) { + dev_err(dev, "Invalid aclk rate: 0\n"); + return -EINVAL; + } + + for (i = 0; i < ARRAY_SIZE(stm32h7_adc_ckmodes_spec); i++) { + ckmode = stm32h7_adc_ckmodes_spec[i].ckmode; + presc = stm32h7_adc_ckmodes_spec[i].presc; + div = stm32h7_adc_ckmodes_spec[i].div; + + if (ckmode) + continue; + + if ((rate / div) <= STM32H7_ADC_MAX_CLK_RATE) + goto out; + } + } + + /* Synchronous clock modes (e.g. ckmode is 1, 2 or 3) */ + rate = clk_get_rate(&common->bclk); + if (!rate) { + dev_err(dev, "Invalid bus clock rate: 0\n"); + return -EINVAL; + } + + for (i = 0; i < ARRAY_SIZE(stm32h7_adc_ckmodes_spec); i++) { + ckmode = stm32h7_adc_ckmodes_spec[i].ckmode; + presc = stm32h7_adc_ckmodes_spec[i].presc; + div = stm32h7_adc_ckmodes_spec[i].div; + + if (!ckmode) + continue; + + if ((rate / div) <= STM32H7_ADC_MAX_CLK_RATE) + goto out; + } + + dev_err(dev, "clk selection failed\n"); + return -EINVAL; + +out: + /* rate used later by each ADC instance to control BOOST mode */ + common->rate = rate / div; + + /* Set common clock mode and prescaler */ + clrsetbits_le32(common->base + STM32H7_ADC_CCR, + STM32H7_CKMODE_MASK | STM32H7_PRESC_MASK, + ckmode << STM32H7_CKMODE_SHIFT | + presc << STM32H7_PRESC_SHIFT); + + dev_dbg(dev, "Using %s clock/%d source at %ld kHz\n", + ckmode ? "bus" : "adc", div, common->rate / 1000); + + return 0; +} + +static int stm32_adc_core_probe(struct udevice *dev) +{ + struct stm32_adc_common *common = dev_get_priv(dev); + int ret; + + common->base = dev_read_addr_ptr(dev); + if (!common->base) { + dev_err(dev, "can't get address\n"); + return -ENOENT; + } + + ret = device_get_supply_regulator(dev, "vref-supply", &common->vref); + if (ret) { + dev_err(dev, "can't get vref-supply: %d\n", ret); + return ret; + } + + ret = regulator_get_value(common->vref); + if (ret < 0) { + dev_err(dev, "can't get vref-supply value: %d\n", ret); + return ret; + } + common->vref_uv = ret; + + ret = clk_get_by_name(dev, "adc", &common->aclk); + if (!ret) { + ret = clk_enable(&common->aclk); + if (ret) { + dev_err(dev, "Can't enable aclk: %d\n", ret); + return ret; + } + } + + ret = clk_get_by_name(dev, "bus", &common->bclk); + if (!ret) { + ret = clk_enable(&common->bclk); + if (ret) { + dev_err(dev, "Can't enable bclk: %d\n", ret); + goto err_aclk_disable; + } + } + + ret = stm32h7_adc_clk_sel(dev, common); + if (ret) + goto err_bclk_disable; + + return ret; + +err_bclk_disable: + if (clk_valid(&common->bclk)) + clk_disable(&common->bclk); + +err_aclk_disable: + if (clk_valid(&common->aclk)) + clk_disable(&common->aclk); + + return ret; +} + +static const struct udevice_id stm32_adc_core_ids[] = { + { .compatible = "st,stm32h7-adc-core" }, + { .compatible = "st,stm32mp1-adc-core" }, + {} +}; + +U_BOOT_DRIVER(stm32_adc_core) = { + .name = "stm32-adc-core", + .id = UCLASS_SIMPLE_BUS, + .of_match = stm32_adc_core_ids, + .probe = stm32_adc_core_probe, + .priv_auto_alloc_size = sizeof(struct stm32_adc_common), +}; diff --git a/drivers/adc/stm32-adc-core.h b/drivers/adc/stm32-adc-core.h new file mode 100644 index 0000000..ba0e10e --- /dev/null +++ b/drivers/adc/stm32-adc-core.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2018, STMicroelectronics - All Rights Reserved + * Author: Fabrice Gasnier fabrice.gasnier@st.com. + * + * Originally based on the Linux kernel v4.18 drivers/iio/adc/stm32-adc-core.h. + */ + +#ifndef __STM32_ADC_H +#define __STM32_ADC_H + +/* + * STM32 - ADC global register map + * ________________________________________________________ + * | Offset | Register | + * -------------------------------------------------------- + * | 0x000 | Master ADC1 | + * -------------------------------------------------------- + * | 0x100 | Slave ADC2 | + * -------------------------------------------------------- + * | 0x200 | Slave ADC3 | + * -------------------------------------------------------- + * | 0x300 | Master & Slave common regs | + * -------------------------------------------------------- + */ +#define STM32_ADC_MAX_ADCS 3 +#define STM32_ADCX_COMN_OFFSET 0x300 + +#include <common.h> +#include <clk.h> +#include <dm.h> + +/** + * struct stm32_adc_common - stm32 ADC driver common data (for all instances) + * @base: control registers base cpu addr + * @rate: clock rate used for analog circuitry + * @aclk: clock for the analog circuitry + * @bclk: bus clock common for all ADCs + * @vref: regulator reference + * @vref_uv: reference supply voltage (uV) + */ +struct stm32_adc_common { + void __iomem *base; + unsigned long rate; + struct clk aclk; + struct clk bclk; + struct udevice *vref; + int vref_uv; +}; + +#endif diff --git a/drivers/adc/stm32-adc.c b/drivers/adc/stm32-adc.c new file mode 100644 index 0000000..e108062 --- /dev/null +++ b/drivers/adc/stm32-adc.c @@ -0,0 +1,257 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018, STMicroelectronics - All Rights Reserved + * Author: Fabrice Gasnier fabrice.gasnier@st.com + * + * Originally based on the Linux kernel v4.18 drivers/iio/adc/stm32-adc.c. + */ + +#include <common.h> +#include <adc.h> +#include <asm/io.h> +#include <linux/iopoll.h> +#include "stm32-adc-core.h" + +/* STM32H7 - Registers for each ADC instance */ +#define STM32H7_ADC_ISR 0x00 +#define STM32H7_ADC_CR 0x08 +#define STM32H7_ADC_CFGR 0x0C +#define STM32H7_ADC_SMPR1 0x14 +#define STM32H7_ADC_SMPR2 0x18 +#define STM32H7_ADC_PCSEL 0x1C +#define STM32H7_ADC_SQR1 0x30 +#define STM32H7_ADC_DR 0x40 +#define STM32H7_ADC_DIFSEL 0xC0 + +/* STM32H7_ADC_ISR - bit fields */ +#define STM32MP1_VREGREADY BIT(12) +#define STM32H7_EOC BIT(2) +#define STM32H7_ADRDY BIT(0) + +/* STM32H7_ADC_CR - bit fields */ +#define STM32H7_DEEPPWD BIT(29) +#define STM32H7_ADVREGEN BIT(28) +#define STM32H7_BOOST BIT(8) +#define STM32H7_ADSTART BIT(2) +#define STM32H7_ADDIS BIT(1) +#define STM32H7_ADEN BIT(0) + +/* STM32H7_ADC_CFGR bit fields */ +#define STM32H7_EXTEN GENMASK(11, 10) +#define STM32H7_DMNGT GENMASK(1, 0) + +/* STM32H7_ADC_SQR1 - bit fields */ +#define STM32H7_SQ1_SHIFT 6 + +/* BOOST bit must be set on STM32H7 when ADC clock is above 20MHz */ +#define STM32H7_BOOST_CLKRATE 20000000UL + +#define STM32_ADC_CH_MAX 20 /* max number of channels */ +#define STM32_ADC_TIMEOUT_US 100000 + +struct stm32_adc_cfg { + unsigned int max_channels; + unsigned int num_bits; + bool has_vregready; +}; + +struct stm32_adc { + void __iomem *regs; + int active_channel; + const struct stm32_adc_cfg *cfg; +}; + +static int stm32_adc_stop(struct udevice *dev) +{ + struct stm32_adc *adc = dev_get_priv(dev); + + setbits_le32(adc->regs + STM32H7_ADC_CR, STM32H7_ADDIS); + clrbits_le32(adc->regs + STM32H7_ADC_CR, STM32H7_BOOST); + /* Setting DEEPPWD disables ADC vreg and clears ADVREGEN */ + setbits_le32(adc->regs + STM32H7_ADC_CR, STM32H7_DEEPPWD); + adc->active_channel = -1; + + return 0; +} + +static int stm32_adc_start_channel(struct udevice *dev, int channel) +{ + struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev); + struct stm32_adc_common *common = dev_get_priv(dev_get_parent(dev)); + struct stm32_adc *adc = dev_get_priv(dev); + int ret; + u32 val; + + /* Exit deep power down, then enable ADC voltage regulator */ + clrbits_le32(adc->regs + STM32H7_ADC_CR, STM32H7_DEEPPWD); + setbits_le32(adc->regs + STM32H7_ADC_CR, STM32H7_ADVREGEN); + if (common->rate > STM32H7_BOOST_CLKRATE) + setbits_le32(adc->regs + STM32H7_ADC_CR, STM32H7_BOOST); + + /* Wait for startup time */ + if (!adc->cfg->has_vregready) { + udelay(20); + } else { + ret = readl_poll_timeout(adc->regs + STM32H7_ADC_ISR, val, + val & STM32MP1_VREGREADY, + STM32_ADC_TIMEOUT_US); + if (ret < 0) { + stm32_adc_stop(dev); + dev_err(dev, "Failed to enable vreg: %d\n", ret); + return ret; + } + } + + /* Only use single ended channels */ + writel(0, adc->regs + STM32H7_ADC_DIFSEL); + + /* Enable ADC, Poll for ADRDY to be set (after adc startup time) */ + setbits_le32(adc->regs + STM32H7_ADC_CR, STM32H7_ADEN); + ret = readl_poll_timeout(adc->regs + STM32H7_ADC_ISR, val, + val & STM32H7_ADRDY, STM32_ADC_TIMEOUT_US); + if (ret < 0) { + stm32_adc_stop(dev); + dev_err(dev, "Failed to enable ADC: %d\n", ret); + return ret; + } + + /* Preselect channels */ + writel(uc_pdata->channel_mask, adc->regs + STM32H7_ADC_PCSEL); + + /* Set sampling time to max value by default */ + writel(0xffffffff, adc->regs + STM32H7_ADC_SMPR1); + writel(0xffffffff, adc->regs + STM32H7_ADC_SMPR2); + + /* Program regular sequence: chan in SQ1 & len = 0 for one channel */ + writel(channel << STM32H7_SQ1_SHIFT, adc->regs + STM32H7_ADC_SQR1); + + /* Trigger detection disabled (conversion can be launched in SW) */ + clrbits_le32(adc->regs + STM32H7_ADC_CFGR, STM32H7_EXTEN | + STM32H7_DMNGT); + adc->active_channel = channel; + + return 0; +} + +static int stm32_adc_channel_data(struct udevice *dev, int channel, + unsigned int *data) +{ + struct stm32_adc *adc = dev_get_priv(dev); + int ret; + u32 val; + + if (channel != adc->active_channel) { + dev_err(dev, "Requested channel is not active!\n"); + return -EINVAL; + } + + setbits_le32(adc->regs + STM32H7_ADC_CR, STM32H7_ADSTART); + ret = readl_poll_timeout(adc->regs + STM32H7_ADC_ISR, val, + val & STM32H7_EOC, STM32_ADC_TIMEOUT_US); + if (ret < 0) { + dev_err(dev, "conversion timed out: %d\n", ret); + return ret; + } + + *data = readl(adc->regs + STM32H7_ADC_DR); + + return 0; +} + +static int stm32_adc_chan_of_init(struct udevice *dev) +{ + struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev); + struct stm32_adc *adc = dev_get_priv(dev); + u32 chans[STM32_ADC_CH_MAX]; + int i, num_channels, ret; + + /* Retrieve single ended channels listed in device tree */ + num_channels = dev_read_size(dev, "st,adc-channels"); + if (num_channels < 0) { + dev_err(dev, "can't get st,adc-channels: %d\n", num_channels); + return num_channels; + } + num_channels /= sizeof(u32); + + if (num_channels > adc->cfg->max_channels) { + dev_err(dev, "too many st,adc-channels: %d\n", num_channels); + return -EINVAL; + } + + ret = dev_read_u32_array(dev, "st,adc-channels", chans, num_channels); + if (ret < 0) { + dev_err(dev, "can't read st,adc-channels: %d\n", ret); + return ret; + } + + for (i = 0; i < num_channels; i++) { + if (chans[i] >= adc->cfg->max_channels) { + dev_err(dev, "bad channel %u\n", chans[i]); + return -EINVAL; + } + uc_pdata->channel_mask |= 1 << chans[i]; + } + + uc_pdata->data_mask = (1 << adc->cfg->num_bits) - 1; + uc_pdata->data_format = ADC_DATA_FORMAT_BIN; + uc_pdata->data_timeout_us = 100000; + + return 0; +} + +static int stm32_adc_probe(struct udevice *dev) +{ + struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev); + struct stm32_adc_common *common = dev_get_priv(dev_get_parent(dev)); + struct stm32_adc *adc = dev_get_priv(dev); + int offset; + + offset = dev_read_u32_default(dev, "reg", -ENODATA); + if (offset < 0) { + dev_err(dev, "Can't read reg property\n"); + return offset; + } + adc->regs = common->base + offset; + adc->cfg = (const struct stm32_adc_cfg *)dev_get_driver_data(dev); + + /* VDD supplied by common vref pin */ + uc_pdata->vdd_supply = common->vref; + uc_pdata->vdd_microvolts = common->vref_uv; + uc_pdata->vss_microvolts = 0; + + return stm32_adc_chan_of_init(dev); +} + +static const struct adc_ops stm32_adc_ops = { + .start_channel = stm32_adc_start_channel, + .channel_data = stm32_adc_channel_data, + .stop = stm32_adc_stop, +}; + +static const struct stm32_adc_cfg stm32h7_adc_cfg = { + .num_bits = 16, + .max_channels = STM32_ADC_CH_MAX, +}; + +static const struct stm32_adc_cfg stm32mp1_adc_cfg = { + .num_bits = 16, + .max_channels = STM32_ADC_CH_MAX, + .has_vregready = true, +}; + +static const struct udevice_id stm32_adc_ids[] = { + { .compatible = "st,stm32h7-adc", + .data = (ulong)&stm32h7_adc_cfg }, + { .compatible = "st,stm32mp1-adc", + .data = (ulong)&stm32mp1_adc_cfg }, + {} +}; + +U_BOOT_DRIVER(stm32_adc) = { + .name = "stm32-adc", + .id = UCLASS_ADC, + .of_match = stm32_adc_ids, + .probe = stm32_adc_probe, + .ops = &stm32_adc_ops, + .priv_auto_alloc_size = sizeof(struct stm32_adc), +};