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Diffstat (limited to '')
| -rw-r--r-- | drivers/iio/adc/stm32-adc.c | 1934 |
1 files changed, 1934 insertions, 0 deletions
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c new file mode 100644 index 000000000..59fd8b620 --- /dev/null +++ b/drivers/iio/adc/stm32-adc.c @@ -0,0 +1,1934 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file is part of STM32 ADC driver + * + * Copyright (C) 2016, STMicroelectronics - All Rights Reserved + * Author: Fabrice Gasnier <fabrice.gasnier@st.com>. + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/dma-mapping.h> +#include <linux/dmaengine.h> +#include <linux/iio/iio.h> +#include <linux/iio/buffer.h> +#include <linux/iio/timer/stm32-lptim-trigger.h> +#include <linux/iio/timer/stm32-timer-trigger.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/of.h> +#include <linux/of_device.h> + +#include "stm32-adc-core.h" + +/* Number of linear calibration shadow registers / LINCALRDYW control bits */ +#define STM32H7_LINCALFACT_NUM 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_CH_SZ 10 /* max channel name size */ +#define STM32_ADC_MAX_SQ 16 /* SQ1..SQ16 */ +#define STM32_ADC_MAX_SMP 7 /* SMPx range is [0..7] */ +#define STM32_ADC_TIMEOUT_US 100000 +#define STM32_ADC_TIMEOUT (msecs_to_jiffies(STM32_ADC_TIMEOUT_US / 1000)) + +#define STM32_DMA_BUFFER_SIZE PAGE_SIZE + +/* External trigger enable */ +enum stm32_adc_exten { + STM32_EXTEN_SWTRIG, + STM32_EXTEN_HWTRIG_RISING_EDGE, + STM32_EXTEN_HWTRIG_FALLING_EDGE, + STM32_EXTEN_HWTRIG_BOTH_EDGES, +}; + +/* extsel - trigger mux selection value */ +enum stm32_adc_extsel { + STM32_EXT0, + STM32_EXT1, + STM32_EXT2, + STM32_EXT3, + STM32_EXT4, + STM32_EXT5, + STM32_EXT6, + STM32_EXT7, + STM32_EXT8, + STM32_EXT9, + STM32_EXT10, + STM32_EXT11, + STM32_EXT12, + STM32_EXT13, + STM32_EXT14, + STM32_EXT15, + STM32_EXT16, + STM32_EXT17, + STM32_EXT18, + STM32_EXT19, + STM32_EXT20, +}; + +/** + * struct stm32_adc_trig_info - ADC trigger info + * @name: name of the trigger, corresponding to its source + * @extsel: trigger selection + */ +struct stm32_adc_trig_info { + const char *name; + enum stm32_adc_extsel extsel; +}; + +/** + * struct stm32_adc_calib - optional adc calibration data + * @calfact_s: Calibration offset for single ended channels + * @calfact_d: Calibration offset in differential + * @lincalfact: Linearity calibration factor + */ +struct stm32_adc_calib { + u32 calfact_s; + u32 calfact_d; + u32 lincalfact[STM32H7_LINCALFACT_NUM]; +}; + +/** + * stm32_adc_regs - stm32 ADC misc registers & bitfield desc + * @reg: register offset + * @mask: bitfield mask + * @shift: left shift + */ +struct stm32_adc_regs { + int reg; + int mask; + int shift; +}; + +/** + * stm32_adc_regspec - stm32 registers definition, compatible dependent data + * @dr: data register offset + * @ier_eoc: interrupt enable register & eocie bitfield + * @isr_eoc: interrupt status register & eoc bitfield + * @sqr: reference to sequence registers array + * @exten: trigger control register & bitfield + * @extsel: trigger selection register & bitfield + * @res: resolution selection register & bitfield + * @smpr: smpr1 & smpr2 registers offset array + * @smp_bits: smpr1 & smpr2 index and bitfields + */ +struct stm32_adc_regspec { + const u32 dr; + const struct stm32_adc_regs ier_eoc; + const struct stm32_adc_regs isr_eoc; + const struct stm32_adc_regs *sqr; + const struct stm32_adc_regs exten; + const struct stm32_adc_regs extsel; + const struct stm32_adc_regs res; + const u32 smpr[2]; + const struct stm32_adc_regs *smp_bits; +}; + +struct stm32_adc; + +/** + * stm32_adc_cfg - stm32 compatible configuration data + * @regs: registers descriptions + * @adc_info: per instance input channels definitions + * @trigs: external trigger sources + * @clk_required: clock is required + * @has_vregready: vregready status flag presence + * @selfcalib: optional routine for self-calibration + * @prepare: optional prepare routine (power-up, enable) + * @start_conv: routine to start conversions + * @stop_conv: routine to stop conversions + * @unprepare: optional unprepare routine (disable, power-down) + * @smp_cycles: programmable sampling time (ADC clock cycles) + */ +struct stm32_adc_cfg { + const struct stm32_adc_regspec *regs; + const struct stm32_adc_info *adc_info; + struct stm32_adc_trig_info *trigs; + bool clk_required; + bool has_vregready; + int (*selfcalib)(struct stm32_adc *); + int (*prepare)(struct stm32_adc *); + void (*start_conv)(struct stm32_adc *, bool dma); + void (*stop_conv)(struct stm32_adc *); + void (*unprepare)(struct stm32_adc *); + const unsigned int *smp_cycles; +}; + +/** + * struct stm32_adc - private data of each ADC IIO instance + * @common: reference to ADC block common data + * @offset: ADC instance register offset in ADC block + * @cfg: compatible configuration data + * @completion: end of single conversion completion + * @buffer: data buffer + * @clk: clock for this adc instance + * @irq: interrupt for this adc instance + * @lock: spinlock + * @bufi: data buffer index + * @num_conv: expected number of scan conversions + * @res: data resolution (e.g. RES bitfield value) + * @trigger_polarity: external trigger polarity (e.g. exten) + * @dma_chan: dma channel + * @rx_buf: dma rx buffer cpu address + * @rx_dma_buf: dma rx buffer bus address + * @rx_buf_sz: dma rx buffer size + * @difsel bitmask to set single-ended/differential channel + * @pcsel bitmask to preselect channels on some devices + * @smpr_val: sampling time settings (e.g. smpr1 / smpr2) + * @cal: optional calibration data on some devices + * @chan_name: channel name array + */ +struct stm32_adc { + struct stm32_adc_common *common; + u32 offset; + const struct stm32_adc_cfg *cfg; + struct completion completion; + u16 buffer[STM32_ADC_MAX_SQ]; + struct clk *clk; + int irq; + spinlock_t lock; /* interrupt lock */ + unsigned int bufi; + unsigned int num_conv; + u32 res; + u32 trigger_polarity; + struct dma_chan *dma_chan; + u8 *rx_buf; + dma_addr_t rx_dma_buf; + unsigned int rx_buf_sz; + u32 difsel; + u32 pcsel; + u32 smpr_val[2]; + struct stm32_adc_calib cal; + char chan_name[STM32_ADC_CH_MAX][STM32_ADC_CH_SZ]; +}; + +struct stm32_adc_diff_channel { + u32 vinp; + u32 vinn; +}; + +/** + * struct stm32_adc_info - stm32 ADC, per instance config data + * @max_channels: Number of channels + * @resolutions: available resolutions + * @num_res: number of available resolutions + */ +struct stm32_adc_info { + int max_channels; + const unsigned int *resolutions; + const unsigned int num_res; +}; + +static const unsigned int stm32f4_adc_resolutions[] = { + /* sorted values so the index matches RES[1:0] in STM32F4_ADC_CR1 */ + 12, 10, 8, 6, +}; + +/* stm32f4 can have up to 16 channels */ +static const struct stm32_adc_info stm32f4_adc_info = { + .max_channels = 16, + .resolutions = stm32f4_adc_resolutions, + .num_res = ARRAY_SIZE(stm32f4_adc_resolutions), +}; + +static const unsigned int stm32h7_adc_resolutions[] = { + /* sorted values so the index matches RES[2:0] in STM32H7_ADC_CFGR */ + 16, 14, 12, 10, 8, +}; + +/* stm32h7 can have up to 20 channels */ +static const struct stm32_adc_info stm32h7_adc_info = { + .max_channels = STM32_ADC_CH_MAX, + .resolutions = stm32h7_adc_resolutions, + .num_res = ARRAY_SIZE(stm32h7_adc_resolutions), +}; + +/** + * stm32f4_sq - describe regular sequence registers + * - L: sequence len (register & bit field) + * - SQ1..SQ16: sequence entries (register & bit field) + */ +static const struct stm32_adc_regs stm32f4_sq[STM32_ADC_MAX_SQ + 1] = { + /* L: len bit field description to be kept as first element */ + { STM32F4_ADC_SQR1, GENMASK(23, 20), 20 }, + /* SQ1..SQ16 registers & bit fields (reg, mask, shift) */ + { STM32F4_ADC_SQR3, GENMASK(4, 0), 0 }, + { STM32F4_ADC_SQR3, GENMASK(9, 5), 5 }, + { STM32F4_ADC_SQR3, GENMASK(14, 10), 10 }, + { STM32F4_ADC_SQR3, GENMASK(19, 15), 15 }, + { STM32F4_ADC_SQR3, GENMASK(24, 20), 20 }, + { STM32F4_ADC_SQR3, GENMASK(29, 25), 25 }, + { STM32F4_ADC_SQR2, GENMASK(4, 0), 0 }, + { STM32F4_ADC_SQR2, GENMASK(9, 5), 5 }, + { STM32F4_ADC_SQR2, GENMASK(14, 10), 10 }, + { STM32F4_ADC_SQR2, GENMASK(19, 15), 15 }, + { STM32F4_ADC_SQR2, GENMASK(24, 20), 20 }, + { STM32F4_ADC_SQR2, GENMASK(29, 25), 25 }, + { STM32F4_ADC_SQR1, GENMASK(4, 0), 0 }, + { STM32F4_ADC_SQR1, GENMASK(9, 5), 5 }, + { STM32F4_ADC_SQR1, GENMASK(14, 10), 10 }, + { STM32F4_ADC_SQR1, GENMASK(19, 15), 15 }, +}; + +/* STM32F4 external trigger sources for all instances */ +static struct stm32_adc_trig_info stm32f4_adc_trigs[] = { + { TIM1_CH1, STM32_EXT0 }, + { TIM1_CH2, STM32_EXT1 }, + { TIM1_CH3, STM32_EXT2 }, + { TIM2_CH2, STM32_EXT3 }, + { TIM2_CH3, STM32_EXT4 }, + { TIM2_CH4, STM32_EXT5 }, + { TIM2_TRGO, STM32_EXT6 }, + { TIM3_CH1, STM32_EXT7 }, + { TIM3_TRGO, STM32_EXT8 }, + { TIM4_CH4, STM32_EXT9 }, + { TIM5_CH1, STM32_EXT10 }, + { TIM5_CH2, STM32_EXT11 }, + { TIM5_CH3, STM32_EXT12 }, + { TIM8_CH1, STM32_EXT13 }, + { TIM8_TRGO, STM32_EXT14 }, + {}, /* sentinel */ +}; + +/** + * stm32f4_smp_bits[] - describe sampling time register index & bit fields + * Sorted so it can be indexed by channel number. + */ +static const struct stm32_adc_regs stm32f4_smp_bits[] = { + /* STM32F4_ADC_SMPR2: smpr[] index, mask, shift for SMP0 to SMP9 */ + { 1, GENMASK(2, 0), 0 }, + { 1, GENMASK(5, 3), 3 }, + { 1, GENMASK(8, 6), 6 }, + { 1, GENMASK(11, 9), 9 }, + { 1, GENMASK(14, 12), 12 }, + { 1, GENMASK(17, 15), 15 }, + { 1, GENMASK(20, 18), 18 }, + { 1, GENMASK(23, 21), 21 }, + { 1, GENMASK(26, 24), 24 }, + { 1, GENMASK(29, 27), 27 }, + /* STM32F4_ADC_SMPR1, smpr[] index, mask, shift for SMP10 to SMP18 */ + { 0, GENMASK(2, 0), 0 }, + { 0, GENMASK(5, 3), 3 }, + { 0, GENMASK(8, 6), 6 }, + { 0, GENMASK(11, 9), 9 }, + { 0, GENMASK(14, 12), 12 }, + { 0, GENMASK(17, 15), 15 }, + { 0, GENMASK(20, 18), 18 }, + { 0, GENMASK(23, 21), 21 }, + { 0, GENMASK(26, 24), 24 }, +}; + +/* STM32F4 programmable sampling time (ADC clock cycles) */ +static const unsigned int stm32f4_adc_smp_cycles[STM32_ADC_MAX_SMP + 1] = { + 3, 15, 28, 56, 84, 112, 144, 480, +}; + +static const struct stm32_adc_regspec stm32f4_adc_regspec = { + .dr = STM32F4_ADC_DR, + .ier_eoc = { STM32F4_ADC_CR1, STM32F4_EOCIE }, + .isr_eoc = { STM32F4_ADC_SR, STM32F4_EOC }, + .sqr = stm32f4_sq, + .exten = { STM32F4_ADC_CR2, STM32F4_EXTEN_MASK, STM32F4_EXTEN_SHIFT }, + .extsel = { STM32F4_ADC_CR2, STM32F4_EXTSEL_MASK, + STM32F4_EXTSEL_SHIFT }, + .res = { STM32F4_ADC_CR1, STM32F4_RES_MASK, STM32F4_RES_SHIFT }, + .smpr = { STM32F4_ADC_SMPR1, STM32F4_ADC_SMPR2 }, + .smp_bits = stm32f4_smp_bits, +}; + +static const struct stm32_adc_regs stm32h7_sq[STM32_ADC_MAX_SQ + 1] = { + /* L: len bit field description to be kept as first element */ + { STM32H7_ADC_SQR1, GENMASK(3, 0), 0 }, + /* SQ1..SQ16 registers & bit fields (reg, mask, shift) */ + { STM32H7_ADC_SQR1, GENMASK(10, 6), 6 }, + { STM32H7_ADC_SQR1, GENMASK(16, 12), 12 }, + { STM32H7_ADC_SQR1, GENMASK(22, 18), 18 }, + { STM32H7_ADC_SQR1, GENMASK(28, 24), 24 }, + { STM32H7_ADC_SQR2, GENMASK(4, 0), 0 }, + { STM32H7_ADC_SQR2, GENMASK(10, 6), 6 }, + { STM32H7_ADC_SQR2, GENMASK(16, 12), 12 }, + { STM32H7_ADC_SQR2, GENMASK(22, 18), 18 }, + { STM32H7_ADC_SQR2, GENMASK(28, 24), 24 }, + { STM32H7_ADC_SQR3, GENMASK(4, 0), 0 }, + { STM32H7_ADC_SQR3, GENMASK(10, 6), 6 }, + { STM32H7_ADC_SQR3, GENMASK(16, 12), 12 }, + { STM32H7_ADC_SQR3, GENMASK(22, 18), 18 }, + { STM32H7_ADC_SQR3, GENMASK(28, 24), 24 }, + { STM32H7_ADC_SQR4, GENMASK(4, 0), 0 }, + { STM32H7_ADC_SQR4, GENMASK(10, 6), 6 }, +}; + +/* STM32H7 external trigger sources for all instances */ +static struct stm32_adc_trig_info stm32h7_adc_trigs[] = { + { TIM1_CH1, STM32_EXT0 }, + { TIM1_CH2, STM32_EXT1 }, + { TIM1_CH3, STM32_EXT2 }, + { TIM2_CH2, STM32_EXT3 }, + { TIM3_TRGO, STM32_EXT4 }, + { TIM4_CH4, STM32_EXT5 }, + { TIM8_TRGO, STM32_EXT7 }, + { TIM8_TRGO2, STM32_EXT8 }, + { TIM1_TRGO, STM32_EXT9 }, + { TIM1_TRGO2, STM32_EXT10 }, + { TIM2_TRGO, STM32_EXT11 }, + { TIM4_TRGO, STM32_EXT12 }, + { TIM6_TRGO, STM32_EXT13 }, + { TIM15_TRGO, STM32_EXT14 }, + { TIM3_CH4, STM32_EXT15 }, + { LPTIM1_OUT, STM32_EXT18 }, + { LPTIM2_OUT, STM32_EXT19 }, + { LPTIM3_OUT, STM32_EXT20 }, + {}, +}; + +/** + * stm32h7_smp_bits - describe sampling time register index & bit fields + * Sorted so it can be indexed by channel number. + */ +static const struct stm32_adc_regs stm32h7_smp_bits[] = { + /* STM32H7_ADC_SMPR1, smpr[] index, mask, shift for SMP0 to SMP9 */ + { 0, GENMASK(2, 0), 0 }, + { 0, GENMASK(5, 3), 3 }, + { 0, GENMASK(8, 6), 6 }, + { 0, GENMASK(11, 9), 9 }, + { 0, GENMASK(14, 12), 12 }, + { 0, GENMASK(17, 15), 15 }, + { 0, GENMASK(20, 18), 18 }, + { 0, GENMASK(23, 21), 21 }, + { 0, GENMASK(26, 24), 24 }, + { 0, GENMASK(29, 27), 27 }, + /* STM32H7_ADC_SMPR2, smpr[] index, mask, shift for SMP10 to SMP19 */ + { 1, GENMASK(2, 0), 0 }, + { 1, GENMASK(5, 3), 3 }, + { 1, GENMASK(8, 6), 6 }, + { 1, GENMASK(11, 9), 9 }, + { 1, GENMASK(14, 12), 12 }, + { 1, GENMASK(17, 15), 15 }, + { 1, GENMASK(20, 18), 18 }, + { 1, GENMASK(23, 21), 21 }, + { 1, GENMASK(26, 24), 24 }, + { 1, GENMASK(29, 27), 27 }, +}; + +/* STM32H7 programmable sampling time (ADC clock cycles, rounded down) */ +static const unsigned int stm32h7_adc_smp_cycles[STM32_ADC_MAX_SMP + 1] = { + 1, 2, 8, 16, 32, 64, 387, 810, +}; + +static const struct stm32_adc_regspec stm32h7_adc_regspec = { + .dr = STM32H7_ADC_DR, + .ier_eoc = { STM32H7_ADC_IER, STM32H7_EOCIE }, + .isr_eoc = { STM32H7_ADC_ISR, STM32H7_EOC }, + .sqr = stm32h7_sq, + .exten = { STM32H7_ADC_CFGR, STM32H7_EXTEN_MASK, STM32H7_EXTEN_SHIFT }, + .extsel = { STM32H7_ADC_CFGR, STM32H7_EXTSEL_MASK, + STM32H7_EXTSEL_SHIFT }, + .res = { STM32H7_ADC_CFGR, STM32H7_RES_MASK, STM32H7_RES_SHIFT }, + .smpr = { STM32H7_ADC_SMPR1, STM32H7_ADC_SMPR2 }, + .smp_bits = stm32h7_smp_bits, +}; + +/** + * STM32 ADC registers access routines + * @adc: stm32 adc instance + * @reg: reg offset in adc instance + * + * Note: All instances share same base, with 0x0, 0x100 or 0x200 offset resp. + * for adc1, adc2 and adc3. + */ +static u32 stm32_adc_readl(struct stm32_adc *adc, u32 reg) +{ + return readl_relaxed(adc->common->base + adc->offset + reg); +} + +#define stm32_adc_readl_addr(addr) stm32_adc_readl(adc, addr) + +#define stm32_adc_readl_poll_timeout(reg, val, cond, sleep_us, timeout_us) \ + readx_poll_timeout(stm32_adc_readl_addr, reg, val, \ + cond, sleep_us, timeout_us) + +static u16 stm32_adc_readw(struct stm32_adc *adc, u32 reg) +{ + return readw_relaxed(adc->common->base + adc->offset + reg); +} + +static void stm32_adc_writel(struct stm32_adc *adc, u32 reg, u32 val) +{ + writel_relaxed(val, adc->common->base + adc->offset + reg); +} + +static void stm32_adc_set_bits(struct stm32_adc *adc, u32 reg, u32 bits) +{ + unsigned long flags; + + spin_lock_irqsave(&adc->lock, flags); + stm32_adc_writel(adc, reg, stm32_adc_readl(adc, reg) | bits); + spin_unlock_irqrestore(&adc->lock, flags); +} + +static void stm32_adc_clr_bits(struct stm32_adc *adc, u32 reg, u32 bits) +{ + unsigned long flags; + + spin_lock_irqsave(&adc->lock, flags); + stm32_adc_writel(adc, reg, stm32_adc_readl(adc, reg) & ~bits); + spin_unlock_irqrestore(&adc->lock, flags); +} + +/** + * stm32_adc_conv_irq_enable() - Enable end of conversion interrupt + * @adc: stm32 adc instance + */ +static void stm32_adc_conv_irq_enable(struct stm32_adc *adc) +{ + stm32_adc_set_bits(adc, adc->cfg->regs->ier_eoc.reg, + adc->cfg->regs->ier_eoc.mask); +}; + +/** + * stm32_adc_conv_irq_disable() - Disable end of conversion interrupt + * @adc: stm32 adc instance + */ +static void stm32_adc_conv_irq_disable(struct stm32_adc *adc) +{ + stm32_adc_clr_bits(adc, adc->cfg->regs->ier_eoc.reg, + adc->cfg->regs->ier_eoc.mask); +} + +static void stm32_adc_set_res(struct stm32_adc *adc) +{ + const struct stm32_adc_regs *res = &adc->cfg->regs->res; + u32 val; + + val = stm32_adc_readl(adc, res->reg); + val = (val & ~res->mask) | (adc->res << res->shift); + stm32_adc_writel(adc, res->reg, val); +} + +/** + * stm32f4_adc_start_conv() - Start conversions for regular channels. + * @adc: stm32 adc instance + * @dma: use dma to transfer conversion result + * + * Start conversions for regular channels. + * Also take care of normal or DMA mode. Circular DMA may be used for regular + * conversions, in IIO buffer modes. Otherwise, use ADC interrupt with direct + * DR read instead (e.g. read_raw, or triggered buffer mode without DMA). + */ +static void stm32f4_adc_start_conv(struct stm32_adc *adc, bool dma) +{ + stm32_adc_set_bits(adc, STM32F4_ADC_CR1, STM32F4_SCAN); + + if (dma) + stm32_adc_set_bits(adc, STM32F4_ADC_CR2, + STM32F4_DMA | STM32F4_DDS); + + stm32_adc_set_bits(adc, STM32F4_ADC_CR2, STM32F4_EOCS | STM32F4_ADON); + + /* Wait for Power-up time (tSTAB from datasheet) */ + usleep_range(2, 3); + + /* Software start ? (e.g. trigger detection disabled ?) */ + if (!(stm32_adc_readl(adc, STM32F4_ADC_CR2) & STM32F4_EXTEN_MASK)) + stm32_adc_set_bits(adc, STM32F4_ADC_CR2, STM32F4_SWSTART); +} + +static void stm32f4_adc_stop_conv(struct stm32_adc *adc) +{ + stm32_adc_clr_bits(adc, STM32F4_ADC_CR2, STM32F4_EXTEN_MASK); + stm32_adc_clr_bits(adc, STM32F4_ADC_SR, STM32F4_STRT); + + stm32_adc_clr_bits(adc, STM32F4_ADC_CR1, STM32F4_SCAN); + stm32_adc_clr_bits(adc, STM32F4_ADC_CR2, + STM32F4_ADON | STM32F4_DMA | STM32F4_DDS); +} + +static void stm32h7_adc_start_conv(struct stm32_adc *adc, bool dma) +{ + enum stm32h7_adc_dmngt dmngt; + unsigned long flags; + u32 val; + + if (dma) + dmngt = STM32H7_DMNGT_DMA_CIRC; + else + dmngt = STM32H7_DMNGT_DR_ONLY; + + spin_lock_irqsave(&adc->lock, flags); + val = stm32_adc_readl(adc, STM32H7_ADC_CFGR); + val = (val & ~STM32H7_DMNGT_MASK) | (dmngt << STM32H7_DMNGT_SHIFT); + stm32_adc_writel(adc, STM32H7_ADC_CFGR, val); + spin_unlock_irqrestore(&adc->lock, flags); + + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTART); +} + +static void stm32h7_adc_stop_conv(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int ret; + u32 val; + + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTP); + + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & (STM32H7_ADSTART)), + 100, STM32_ADC_TIMEOUT_US); + if (ret) + dev_warn(&indio_dev->dev, "stop failed\n"); + + stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR, STM32H7_DMNGT_MASK); +} + +static int stm32h7_adc_exit_pwr_down(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int ret; + u32 val; + + /* Exit deep power down, then enable ADC voltage regulator */ + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD); + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADVREGEN); + + if (adc->common->rate > STM32H7_BOOST_CLKRATE) + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST); + + /* Wait for startup time */ + if (!adc->cfg->has_vregready) { + usleep_range(10, 20); + return 0; + } + + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_ISR, val, + val & STM32MP1_VREGREADY, 100, + STM32_ADC_TIMEOUT_US); + if (ret) { + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD); + dev_err(&indio_dev->dev, "Failed to exit power down\n"); + } + + return ret; +} + +static void stm32h7_adc_enter_pwr_down(struct stm32_adc *adc) +{ + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST); + + /* Setting DEEPPWD disables ADC vreg and clears ADVREGEN */ + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD); +} + +static int stm32h7_adc_enable(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int ret; + u32 val; + + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADEN); + + /* Poll for ADRDY to be set (after adc startup time) */ + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_ISR, val, + val & STM32H7_ADRDY, + 100, STM32_ADC_TIMEOUT_US); + if (ret) { + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS); + dev_err(&indio_dev->dev, "Failed to enable ADC\n"); + } else { + /* Clear ADRDY by writing one */ + stm32_adc_set_bits(adc, STM32H7_ADC_ISR, STM32H7_ADRDY); + } + + return ret; +} + +static void stm32h7_adc_disable(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int ret; + u32 val; + + /* Disable ADC and wait until it's effectively disabled */ + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS); + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & STM32H7_ADEN), 100, + STM32_ADC_TIMEOUT_US); + if (ret) + dev_warn(&indio_dev->dev, "Failed to disable\n"); +} + +/** + * stm32h7_adc_read_selfcalib() - read calibration shadow regs, save result + * @adc: stm32 adc instance + */ +static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int i, ret; + u32 lincalrdyw_mask, val; + + /* Enable adc so LINCALRDYW1..6 bits are writable */ + ret = stm32h7_adc_enable(adc); + if (ret) + return ret; + + /* Read linearity calibration */ + lincalrdyw_mask = STM32H7_LINCALRDYW6; + for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) { + /* Clear STM32H7_LINCALRDYW[6..1]: transfer calib to CALFACT2 */ + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask); + + /* Poll: wait calib data to be ready in CALFACT2 register */ + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & lincalrdyw_mask), + 100, STM32_ADC_TIMEOUT_US); + if (ret) { + dev_err(&indio_dev->dev, "Failed to read calfact\n"); + goto disable; + } + + val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2); + adc->cal.lincalfact[i] = (val & STM32H7_LINCALFACT_MASK); + adc->cal.lincalfact[i] >>= STM32H7_LINCALFACT_SHIFT; + + lincalrdyw_mask >>= 1; + } + + /* Read offset calibration */ + val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT); + adc->cal.calfact_s = (val & STM32H7_CALFACT_S_MASK); + adc->cal.calfact_s >>= STM32H7_CALFACT_S_SHIFT; + adc->cal.calfact_d = (val & STM32H7_CALFACT_D_MASK); + adc->cal.calfact_d >>= STM32H7_CALFACT_D_SHIFT; + +disable: + stm32h7_adc_disable(adc); + + return ret; +} + +/** + * stm32h7_adc_restore_selfcalib() - Restore saved self-calibration result + * @adc: stm32 adc instance + * Note: ADC must be enabled, with no on-going conversions. + */ +static int stm32h7_adc_restore_selfcalib(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int i, ret; + u32 lincalrdyw_mask, val; + + val = (adc->cal.calfact_s << STM32H7_CALFACT_S_SHIFT) | + (adc->cal.calfact_d << STM32H7_CALFACT_D_SHIFT); + stm32_adc_writel(adc, STM32H7_ADC_CALFACT, val); + + lincalrdyw_mask = STM32H7_LINCALRDYW6; + for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) { + /* + * Write saved calibration data to shadow registers: + * Write CALFACT2, and set LINCALRDYW[6..1] bit to trigger + * data write. Then poll to wait for complete transfer. + */ + val = adc->cal.lincalfact[i] << STM32H7_LINCALFACT_SHIFT; + stm32_adc_writel(adc, STM32H7_ADC_CALFACT2, val); + stm32_adc_set_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask); + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + val & lincalrdyw_mask, + 100, STM32_ADC_TIMEOUT_US); + if (ret) { + dev_err(&indio_dev->dev, "Failed to write calfact\n"); + return ret; + } + + /* + * Read back calibration data, has two effects: + * - It ensures bits LINCALRDYW[6..1] are kept cleared + * for next time calibration needs to be restored. + * - BTW, bit clear triggers a read, then check data has been + * correctly written. + */ + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask); + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & lincalrdyw_mask), + 100, STM32_ADC_TIMEOUT_US); + if (ret) { + dev_err(&indio_dev->dev, "Failed to read calfact\n"); + return ret; + } + val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2); + if (val != adc->cal.lincalfact[i] << STM32H7_LINCALFACT_SHIFT) { + dev_err(&indio_dev->dev, "calfact not consistent\n"); + return -EIO; + } + + lincalrdyw_mask >>= 1; + } + + return 0; +} + +/** + * Fixed timeout value for ADC calibration. + * worst cases: + * - low clock frequency + * - maximum prescalers + * Calibration requires: + * - 131,072 ADC clock cycle for the linear calibration + * - 20 ADC clock cycle for the offset calibration + * + * Set to 100ms for now + */ +#define STM32H7_ADC_CALIB_TIMEOUT_US 100000 + +/** + * stm32h7_adc_selfcalib() - Procedure to calibrate ADC (from power down) + * @adc: stm32 adc instance + * Exit from power down, calibrate ADC, then return to power down. + */ +static int stm32h7_adc_selfcalib(struct stm32_adc *adc) +{ + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + int ret; + u32 val; + + ret = stm32h7_adc_exit_pwr_down(adc); + if (ret) + return ret; + + /* + * Select calibration mode: + * - Offset calibration for single ended inputs + * - No linearity calibration (do it later, before reading it) + */ + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADCALDIF); + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADCALLIN); + + /* Start calibration, then wait for completion */ + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADCAL); + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & STM32H7_ADCAL), 100, + STM32H7_ADC_CALIB_TIMEOUT_US); + if (ret) { + dev_err(&indio_dev->dev, "calibration failed\n"); + goto pwr_dwn; + } + + /* + * Select calibration mode, then start calibration: + * - Offset calibration for differential input + * - Linearity calibration (needs to be done only once for single/diff) + * will run simultaneously with offset calibration. + */ + stm32_adc_set_bits(adc, STM32H7_ADC_CR, + STM32H7_ADCALDIF | STM32H7_ADCALLIN); + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADCAL); + ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val, + !(val & STM32H7_ADCAL), 100, + STM32H7_ADC_CALIB_TIMEOUT_US); + if (ret) { + dev_err(&indio_dev->dev, "calibration failed\n"); + goto pwr_dwn; + } + + stm32_adc_clr_bits(adc, STM32H7_ADC_CR, + STM32H7_ADCALDIF | STM32H7_ADCALLIN); + + /* Read calibration result for future reference */ + ret = stm32h7_adc_read_selfcalib(adc); + +pwr_dwn: + stm32h7_adc_enter_pwr_down(adc); + + return ret; +} + +/** + * stm32h7_adc_prepare() - Leave power down mode to enable ADC. + * @adc: stm32 adc instance + * Leave power down mode. + * Configure channels as single ended or differential before enabling ADC. + * Enable ADC. + * Restore calibration data. + * Pre-select channels that may be used in PCSEL (required by input MUX / IO): + * - Only one input is selected for single ended (e.g. 'vinp') + * - Two inputs are selected for differential channels (e.g. 'vinp' & 'vinn') + */ +static int stm32h7_adc_prepare(struct stm32_adc *adc) +{ + int ret; + + ret = stm32h7_adc_exit_pwr_down(adc); + if (ret) + return ret; + + stm32_adc_writel(adc, STM32H7_ADC_DIFSEL, adc->difsel); + + ret = stm32h7_adc_enable(adc); + if (ret) + goto pwr_dwn; + + ret = stm32h7_adc_restore_selfcalib(adc); + if (ret) + goto disable; + + stm32_adc_writel(adc, STM32H7_ADC_PCSEL, adc->pcsel); + + return 0; + +disable: + stm32h7_adc_disable(adc); +pwr_dwn: + stm32h7_adc_enter_pwr_down(adc); + + return ret; +} + +static void stm32h7_adc_unprepare(struct stm32_adc *adc) +{ + stm32h7_adc_disable(adc); + stm32h7_adc_enter_pwr_down(adc); +} + +/** + * stm32_adc_conf_scan_seq() - Build regular channels scan sequence + * @indio_dev: IIO device + * @scan_mask: channels to be converted + * + * Conversion sequence : + * Apply sampling time settings for all channels. + * Configure ADC scan sequence based on selected channels in scan_mask. + * Add channels to SQR registers, from scan_mask LSB to MSB, then + * program sequence len. + */ +static int stm32_adc_conf_scan_seq(struct iio_dev *indio_dev, + const unsigned long *scan_mask) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + const struct stm32_adc_regs *sqr = adc->cfg->regs->sqr; + const struct iio_chan_spec *chan; + u32 val, bit; + int i = 0; + + /* Apply sampling time settings */ + stm32_adc_writel(adc, adc->cfg->regs->smpr[0], adc->smpr_val[0]); + stm32_adc_writel(adc, adc->cfg->regs->smpr[1], adc->smpr_val[1]); + + for_each_set_bit(bit, scan_mask, indio_dev->masklength) { + chan = indio_dev->channels + bit; + /* + * Assign one channel per SQ entry in regular + * sequence, starting with SQ1. + */ + i++; + if (i > STM32_ADC_MAX_SQ) + return -EINVAL; + + dev_dbg(&indio_dev->dev, "%s chan %d to SQ%d\n", + __func__, chan->channel, i); + + val = stm32_adc_readl(adc, sqr[i].reg); + val &= ~sqr[i].mask; + val |= chan->channel << sqr[i].shift; + stm32_adc_writel(adc, sqr[i].reg, val); + } + + if (!i) + return -EINVAL; + + /* Sequence len */ + val = stm32_adc_readl(adc, sqr[0].reg); + val &= ~sqr[0].mask; + val |= ((i - 1) << sqr[0].shift); + stm32_adc_writel(adc, sqr[0].reg, val); + + return 0; +} + +/** + * stm32_adc_get_trig_extsel() - Get external trigger selection + * @trig: trigger + * + * Returns trigger extsel value, if trig matches, -EINVAL otherwise. + */ +static int stm32_adc_get_trig_extsel(struct iio_dev *indio_dev, + struct iio_trigger *trig) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + int i; + + /* lookup triggers registered by stm32 timer trigger driver */ + for (i = 0; adc->cfg->trigs[i].name; i++) { + /** + * Checking both stm32 timer trigger type and trig name + * should be safe against arbitrary trigger names. + */ + if ((is_stm32_timer_trigger(trig) || + is_stm32_lptim_trigger(trig)) && + !strcmp(adc->cfg->trigs[i].name, trig->name)) { + return adc->cfg->trigs[i].extsel; + } + } + + return -EINVAL; +} + +/** + * stm32_adc_set_trig() - Set a regular trigger + * @indio_dev: IIO device + * @trig: IIO trigger + * + * Set trigger source/polarity (e.g. SW, or HW with polarity) : + * - if HW trigger disabled (e.g. trig == NULL, conversion launched by sw) + * - if HW trigger enabled, set source & polarity + */ +static int stm32_adc_set_trig(struct iio_dev *indio_dev, + struct iio_trigger *trig) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + u32 val, extsel = 0, exten = STM32_EXTEN_SWTRIG; + unsigned long flags; + int ret; + + if (trig) { + ret = stm32_adc_get_trig_extsel(indio_dev, trig); + if (ret < 0) + return ret; + + /* set trigger source and polarity (default to rising edge) */ + extsel = ret; + exten = adc->trigger_polarity + STM32_EXTEN_HWTRIG_RISING_EDGE; + } + + spin_lock_irqsave(&adc->lock, flags); + val = stm32_adc_readl(adc, adc->cfg->regs->exten.reg); + val &= ~(adc->cfg->regs->exten.mask | adc->cfg->regs->extsel.mask); + val |= exten << adc->cfg->regs->exten.shift; + val |= extsel << adc->cfg->regs->extsel.shift; + stm32_adc_writel(adc, adc->cfg->regs->exten.reg, val); + spin_unlock_irqrestore(&adc->lock, flags); + + return 0; +} + +static int stm32_adc_set_trig_pol(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + unsigned int type) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + + adc->trigger_polarity = type; + + return 0; +} + +static int stm32_adc_get_trig_pol(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + + return adc->trigger_polarity; +} + +static const char * const stm32_trig_pol_items[] = { + "rising-edge", "falling-edge", "both-edges", +}; + +static const struct iio_enum stm32_adc_trig_pol = { + .items = stm32_trig_pol_items, + .num_items = ARRAY_SIZE(stm32_trig_pol_items), + .get = stm32_adc_get_trig_pol, + .set = stm32_adc_set_trig_pol, +}; + +/** + * stm32_adc_single_conv() - Performs a single conversion + * @indio_dev: IIO device + * @chan: IIO channel + * @res: conversion result + * + * The function performs a single conversion on a given channel: + * - Apply sampling time settings + * - Program sequencer with one channel (e.g. in SQ1 with len = 1) + * - Use SW trigger + * - Start conversion, then wait for interrupt completion. + */ +static int stm32_adc_single_conv(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + int *res) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + const struct stm32_adc_regspec *regs = adc->cfg->regs; + long timeout; + u32 val; + int ret; + + reinit_completion(&adc->completion); + + adc->bufi = 0; + + if (adc->cfg->prepare) { + ret = adc->cfg->prepare(adc); + if (ret) + return ret; + } + + /* Apply sampling time settings */ + stm32_adc_writel(adc, regs->smpr[0], adc->smpr_val[0]); + stm32_adc_writel(adc, regs->smpr[1], adc->smpr_val[1]); + + /* Program chan number in regular sequence (SQ1) */ + val = stm32_adc_readl(adc, regs->sqr[1].reg); + val &= ~regs->sqr[1].mask; + val |= chan->channel << regs->sqr[1].shift; + stm32_adc_writel(adc, regs->sqr[1].reg, val); + + /* Set regular sequence len (0 for 1 conversion) */ + stm32_adc_clr_bits(adc, regs->sqr[0].reg, regs->sqr[0].mask); + + /* Trigger detection disabled (conversion can be launched in SW) */ + stm32_adc_clr_bits(adc, regs->exten.reg, regs->exten.mask); + + stm32_adc_conv_irq_enable(adc); + + adc->cfg->start_conv(adc, false); + + timeout = wait_for_completion_interruptible_timeout( + &adc->completion, STM32_ADC_TIMEOUT); + if (timeout == 0) { + ret = -ETIMEDOUT; + } else if (timeout < 0) { + ret = timeout; + } else { + *res = adc->buffer[0]; + ret = IIO_VAL_INT; + } + + adc->cfg->stop_conv(adc); + + stm32_adc_conv_irq_disable(adc); + + if (adc->cfg->unprepare) + adc->cfg->unprepare(adc); + + return ret; +} + +static int stm32_adc_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + if (chan->type == IIO_VOLTAGE) + ret = stm32_adc_single_conv(indio_dev, chan, val); + else + ret = -EINVAL; + iio_device_release_direct_mode(indio_dev); + return ret; + + case IIO_CHAN_INFO_SCALE: + if (chan->differential) { + *val = adc->common->vref_mv * 2; + *val2 = chan->scan_type.realbits; + } else { + *val = adc->common->vref_mv; + *val2 = chan->scan_type.realbits; + } + return IIO_VAL_FRACTIONAL_LOG2; + + case IIO_CHAN_INFO_OFFSET: + if (chan->differential) + /* ADC_full_scale / 2 */ + *val = -((1 << chan->scan_type.realbits) / 2); + else + *val = 0; + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +static irqreturn_t stm32_adc_isr(int irq, void *data) +{ + struct stm32_adc *adc = data; + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + const struct stm32_adc_regspec *regs = adc->cfg->regs; + u32 status = stm32_adc_readl(adc, regs->isr_eoc.reg); + + if (status & regs->isr_eoc.mask) { + /* Reading DR also clears EOC status flag */ + adc->buffer[adc->bufi] = stm32_adc_readw(adc, regs->dr); + if (iio_buffer_enabled(indio_dev)) { + adc->bufi++; + if (adc->bufi >= adc->num_conv) { + stm32_adc_conv_irq_disable(adc); + iio_trigger_poll(indio_dev->trig); + } + } else { + complete(&adc->completion); + } + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +/** + * stm32_adc_validate_trigger() - validate trigger for stm32 adc + * @indio_dev: IIO device + * @trig: new trigger + * + * Returns: 0 if trig matches one of the triggers registered by stm32 adc + * driver, -EINVAL otherwise. + */ +static int stm32_adc_validate_trigger(struct iio_dev *indio_dev, + struct iio_trigger *trig) +{ + return stm32_adc_get_trig_extsel(indio_dev, trig) < 0 ? -EINVAL : 0; +} + +static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + unsigned int watermark = STM32_DMA_BUFFER_SIZE / 2; + unsigned int rx_buf_sz = STM32_DMA_BUFFER_SIZE; + + /* + * dma cyclic transfers are used, buffer is split into two periods. + * There should be : + * - always one buffer (period) dma is working on + * - one buffer (period) driver can push with iio_trigger_poll(). + */ + watermark = min(watermark, val * (unsigned)(sizeof(u16))); + adc->rx_buf_sz = min(rx_buf_sz, watermark * 2 * adc->num_conv); + + return 0; +} + +static int stm32_adc_update_scan_mode(struct iio_dev *indio_dev, + const unsigned long *scan_mask) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + int ret; + + adc->num_conv = bitmap_weight(scan_mask, indio_dev->masklength); + + ret = stm32_adc_conf_scan_seq(indio_dev, scan_mask); + if (ret) + return ret; + + return 0; +} + +static int stm32_adc_of_xlate(struct iio_dev *indio_dev, + const struct of_phandle_args *iiospec) +{ + int i; + + for (i = 0; i < indio_dev->num_channels; i++) + if (indio_dev->channels[i].channel == iiospec->args[0]) + return i; + + return -EINVAL; +} + +/** + * stm32_adc_debugfs_reg_access - read or write register value + * + * To read a value from an ADC register: + * echo [ADC reg offset] > direct_reg_access + * cat direct_reg_access + * + * To write a value in a ADC register: + * echo [ADC_reg_offset] [value] > direct_reg_access + */ +static int stm32_adc_debugfs_reg_access(struct iio_dev *indio_dev, + unsigned reg, unsigned writeval, + unsigned *readval) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + + if (!readval) + stm32_adc_writel(adc, reg, writeval); + else + *readval = stm32_adc_readl(adc, reg); + + return 0; +} + +static const struct iio_info stm32_adc_iio_info = { + .read_raw = stm32_adc_read_raw, + .validate_trigger = stm32_adc_validate_trigger, + .hwfifo_set_watermark = stm32_adc_set_watermark, + .update_scan_mode = stm32_adc_update_scan_mode, + .debugfs_reg_access = stm32_adc_debugfs_reg_access, + .of_xlate = stm32_adc_of_xlate, +}; + +static unsigned int stm32_adc_dma_residue(struct stm32_adc *adc) +{ + struct dma_tx_state state; + enum dma_status status; + + status = dmaengine_tx_status(adc->dma_chan, + adc->dma_chan->cookie, + &state); + if (status == DMA_IN_PROGRESS) { + /* Residue is size in bytes from end of buffer */ + unsigned int i = adc->rx_buf_sz - state.residue; + unsigned int size; + + /* Return available bytes */ + if (i >= adc->bufi) + size = i - adc->bufi; + else + size = adc->rx_buf_sz + i - adc->bufi; + + return size; + } + + return 0; +} + +static void stm32_adc_dma_buffer_done(void *data) +{ + struct iio_dev *indio_dev = data; + struct stm32_adc *adc = iio_priv(indio_dev); + int residue = stm32_adc_dma_residue(adc); + + /* + * In DMA mode the trigger services of IIO are not used + * (e.g. no call to iio_trigger_poll). + * Calling irq handler associated to the hardware trigger is not + * relevant as the conversions have already been done. Data + * transfers are performed directly in DMA callback instead. + * This implementation avoids to call trigger irq handler that + * may sleep, in an atomic context (DMA irq handler context). + */ + dev_dbg(&indio_dev->dev, "%s bufi=%d\n", __func__, adc->bufi); + + while (residue >= indio_dev->scan_bytes) { + u16 *buffer = (u16 *)&adc->rx_buf[adc->bufi]; + + iio_push_to_buffers(indio_dev, buffer); + + residue -= indio_dev->scan_bytes; + adc->bufi += indio_dev->scan_bytes; + if (adc->bufi >= adc->rx_buf_sz) + adc->bufi = 0; + } +} + +static int stm32_adc_dma_start(struct iio_dev *indio_dev) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + struct dma_async_tx_descriptor *desc; + dma_cookie_t cookie; + int ret; + + if (!adc->dma_chan) + return 0; + + dev_dbg(&indio_dev->dev, "%s size=%d watermark=%d\n", __func__, + adc->rx_buf_sz, adc->rx_buf_sz / 2); + + /* Prepare a DMA cyclic transaction */ + desc = dmaengine_prep_dma_cyclic(adc->dma_chan, + adc->rx_dma_buf, + adc->rx_buf_sz, adc->rx_buf_sz / 2, + DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT); + if (!desc) + return -EBUSY; + + desc->callback = stm32_adc_dma_buffer_done; + desc->callback_param = indio_dev; + + cookie = dmaengine_submit(desc); + ret = dma_submit_error(cookie); + if (ret) { + dmaengine_terminate_sync(adc->dma_chan); + return ret; + } + + /* Issue pending DMA requests */ + dma_async_issue_pending(adc->dma_chan); + + return 0; +} + +static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + int ret; + + if (adc->cfg->prepare) { + ret = adc->cfg->prepare(adc); + if (ret) + return ret; + } + + ret = stm32_adc_set_trig(indio_dev, indio_dev->trig); + if (ret) { + dev_err(&indio_dev->dev, "Can't set trigger\n"); + goto err_unprepare; + } + + ret = stm32_adc_dma_start(indio_dev); + if (ret) { + dev_err(&indio_dev->dev, "Can't start dma\n"); + goto err_clr_trig; + } + + ret = iio_triggered_buffer_postenable(indio_dev); + if (ret < 0) + goto err_stop_dma; + + /* Reset adc buffer index */ + adc->bufi = 0; + + if (!adc->dma_chan) + stm32_adc_conv_irq_enable(adc); + + adc->cfg->start_conv(adc, !!adc->dma_chan); + + return 0; + +err_stop_dma: + if (adc->dma_chan) + dmaengine_terminate_all(adc->dma_chan); +err_clr_trig: + stm32_adc_set_trig(indio_dev, NULL); +err_unprepare: + if (adc->cfg->unprepare) + adc->cfg->unprepare(adc); + + return ret; +} + +static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + int ret; + + adc->cfg->stop_conv(adc); + if (!adc->dma_chan) + stm32_adc_conv_irq_disable(adc); + + ret = iio_triggered_buffer_predisable(indio_dev); + if (ret < 0) + dev_err(&indio_dev->dev, "predisable failed\n"); + + if (adc->dma_chan) + dmaengine_terminate_sync(adc->dma_chan); + + if (stm32_adc_set_trig(indio_dev, NULL)) + dev_err(&indio_dev->dev, "Can't clear trigger\n"); + + if (adc->cfg->unprepare) + adc->cfg->unprepare(adc); + + return ret; +} + +static const struct iio_buffer_setup_ops stm32_adc_buffer_setup_ops = { + .postenable = &stm32_adc_buffer_postenable, + .predisable = &stm32_adc_buffer_predisable, +}; + +static irqreturn_t stm32_adc_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct stm32_adc *adc = iio_priv(indio_dev); + + dev_dbg(&indio_dev->dev, "%s bufi=%d\n", __func__, adc->bufi); + + if (!adc->dma_chan) { + /* reset buffer index */ + adc->bufi = 0; + iio_push_to_buffers_with_timestamp(indio_dev, adc->buffer, + pf->timestamp); + } else { + int residue = stm32_adc_dma_residue(adc); + + while (residue >= indio_dev->scan_bytes) { + u16 *buffer = (u16 *)&adc->rx_buf[adc->bufi]; + + iio_push_to_buffers_with_timestamp(indio_dev, buffer, + pf->timestamp); + residue -= indio_dev->scan_bytes; + adc->bufi += indio_dev->scan_bytes; + if (adc->bufi >= adc->rx_buf_sz) + adc->bufi = 0; + } + } + + iio_trigger_notify_done(indio_dev->trig); + + /* re-enable eoc irq */ + if (!adc->dma_chan) + stm32_adc_conv_irq_enable(adc); + + return IRQ_HANDLED; +} + +static const struct iio_chan_spec_ext_info stm32_adc_ext_info[] = { + IIO_ENUM("trigger_polarity", IIO_SHARED_BY_ALL, &stm32_adc_trig_pol), + { + .name = "trigger_polarity_available", + .shared = IIO_SHARED_BY_ALL, + .read = iio_enum_available_read, + .private = (uintptr_t)&stm32_adc_trig_pol, + }, + {}, +}; + +static int stm32_adc_of_get_resolution(struct iio_dev *indio_dev) +{ + struct device_node *node = indio_dev->dev.of_node; + struct stm32_adc *adc = iio_priv(indio_dev); + unsigned int i; + u32 res; + + if (of_property_read_u32(node, "assigned-resolution-bits", &res)) + res = adc->cfg->adc_info->resolutions[0]; + + for (i = 0; i < adc->cfg->adc_info->num_res; i++) + if (res == adc->cfg->adc_info->resolutions[i]) + break; + if (i >= adc->cfg->adc_info->num_res) { + dev_err(&indio_dev->dev, "Bad resolution: %u bits\n", res); + return -EINVAL; + } + + dev_dbg(&indio_dev->dev, "Using %u bits resolution\n", res); + adc->res = i; + + return 0; +} + +static void stm32_adc_smpr_init(struct stm32_adc *adc, int channel, u32 smp_ns) +{ + const struct stm32_adc_regs *smpr = &adc->cfg->regs->smp_bits[channel]; + u32 period_ns, shift = smpr->shift, mask = smpr->mask; + unsigned int smp, r = smpr->reg; + + /* Determine sampling time (ADC clock cycles) */ + period_ns = NSEC_PER_SEC / adc->common->rate; + for (smp = 0; smp <= STM32_ADC_MAX_SMP; smp++) + if ((period_ns * adc->cfg->smp_cycles[smp]) >= smp_ns) + break; + if (smp > STM32_ADC_MAX_SMP) + smp = STM32_ADC_MAX_SMP; + + /* pre-build sampling time registers (e.g. smpr1, smpr2) */ + adc->smpr_val[r] = (adc->smpr_val[r] & ~mask) | (smp << shift); +} + +static void stm32_adc_chan_init_one(struct iio_dev *indio_dev, + struct iio_chan_spec *chan, u32 vinp, + u32 vinn, int scan_index, bool differential) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + char *name = adc->chan_name[vinp]; + + chan->type = IIO_VOLTAGE; + chan->channel = vinp; + if (differential) { + chan->differential = 1; + chan->channel2 = vinn; + snprintf(name, STM32_ADC_CH_SZ, "in%d-in%d", vinp, vinn); + } else { + snprintf(name, STM32_ADC_CH_SZ, "in%d", vinp); + } + chan->datasheet_name = name; + chan->scan_index = scan_index; + chan->indexed = 1; + chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); + chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_OFFSET); + chan->scan_type.sign = 'u'; + chan->scan_type.realbits = adc->cfg->adc_info->resolutions[adc->res]; + chan->scan_type.storagebits = 16; + chan->ext_info = stm32_adc_ext_info; + + /* pre-build selected channels mask */ + adc->pcsel |= BIT(chan->channel); + if (differential) { + /* pre-build diff channels mask */ + adc->difsel |= BIT(chan->channel); + /* Also add negative input to pre-selected channels */ + adc->pcsel |= BIT(chan->channel2); + } +} + +static int stm32_adc_chan_of_init(struct iio_dev *indio_dev) +{ + struct device_node *node = indio_dev->dev.of_node; + struct stm32_adc *adc = iio_priv(indio_dev); + const struct stm32_adc_info *adc_info = adc->cfg->adc_info; + struct stm32_adc_diff_channel diff[STM32_ADC_CH_MAX]; + struct property *prop; + const __be32 *cur; + struct iio_chan_spec *channels; + int scan_index = 0, num_channels = 0, num_diff = 0, ret, i; + u32 val, smp = 0; + + ret = of_property_count_u32_elems(node, "st,adc-channels"); + if (ret > adc_info->max_channels) { + dev_err(&indio_dev->dev, "Bad st,adc-channels?\n"); + return -EINVAL; + } else if (ret > 0) { + num_channels += ret; + } + + ret = of_property_count_elems_of_size(node, "st,adc-diff-channels", + sizeof(*diff)); + if (ret > adc_info->max_channels) { + dev_err(&indio_dev->dev, "Bad st,adc-diff-channels?\n"); + return -EINVAL; + } else if (ret > 0) { + int size = ret * sizeof(*diff) / sizeof(u32); + + num_diff = ret; + num_channels += ret; + ret = of_property_read_u32_array(node, "st,adc-diff-channels", + (u32 *)diff, size); + if (ret) + return ret; + } + + if (!num_channels) { + dev_err(&indio_dev->dev, "No channels configured\n"); + return -ENODATA; + } + + /* Optional sample time is provided either for each, or all channels */ + ret = of_property_count_u32_elems(node, "st,min-sample-time-nsecs"); + if (ret > 1 && ret != num_channels) { + dev_err(&indio_dev->dev, "Invalid st,min-sample-time-nsecs\n"); + return -EINVAL; + } + + channels = devm_kcalloc(&indio_dev->dev, num_channels, + sizeof(struct iio_chan_spec), GFP_KERNEL); + if (!channels) + return -ENOMEM; + + of_property_for_each_u32(node, "st,adc-channels", prop, cur, val) { + if (val >= adc_info->max_channels) { + dev_err(&indio_dev->dev, "Invalid channel %d\n", val); + return -EINVAL; + } + + /* Channel can't be configured both as single-ended & diff */ + for (i = 0; i < num_diff; i++) { + if (val == diff[i].vinp) { + dev_err(&indio_dev->dev, + "channel %d miss-configured\n", val); + return -EINVAL; + } + } + stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val, + 0, scan_index, false); + scan_index++; + } + + for (i = 0; i < num_diff; i++) { + if (diff[i].vinp >= adc_info->max_channels || + diff[i].vinn >= adc_info->max_channels) { + dev_err(&indio_dev->dev, "Invalid channel in%d-in%d\n", + diff[i].vinp, diff[i].vinn); + return -EINVAL; + } + stm32_adc_chan_init_one(indio_dev, &channels[scan_index], + diff[i].vinp, diff[i].vinn, scan_index, + true); + scan_index++; + } + + for (i = 0; i < scan_index; i++) { + /* + * Using of_property_read_u32_index(), smp value will only be + * modified if valid u32 value can be decoded. This allows to + * get either no value, 1 shared value for all indexes, or one + * value per channel. + */ + of_property_read_u32_index(node, "st,min-sample-time-nsecs", + i, &smp); + /* Prepare sampling time settings */ + stm32_adc_smpr_init(adc, channels[i].channel, smp); + } + + indio_dev->num_channels = scan_index; + indio_dev->channels = channels; + + return 0; +} + +static int stm32_adc_dma_request(struct device *dev, struct iio_dev *indio_dev) +{ + struct stm32_adc *adc = iio_priv(indio_dev); + struct dma_slave_config config; + int ret; + + adc->dma_chan = dma_request_chan(dev, "rx"); + if (IS_ERR(adc->dma_chan)) { + ret = PTR_ERR(adc->dma_chan); + if (ret != -ENODEV) { + if (ret != -EPROBE_DEFER) + dev_err(dev, + "DMA channel request failed with %d\n", + ret); + return ret; + } + + /* DMA is optional: fall back to IRQ mode */ + adc->dma_chan = NULL; + return 0; + } + + adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev, + STM32_DMA_BUFFER_SIZE, + &adc->rx_dma_buf, GFP_KERNEL); + if (!adc->rx_buf) { + ret = -ENOMEM; + goto err_release; + } + + /* Configure DMA channel to read data register */ + memset(&config, 0, sizeof(config)); + config.src_addr = (dma_addr_t)adc->common->phys_base; + config.src_addr += adc->offset + adc->cfg->regs->dr; + config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES; + + ret = dmaengine_slave_config(adc->dma_chan, &config); + if (ret) + goto err_free; + + return 0; + +err_free: + dma_free_coherent(adc->dma_chan->device->dev, STM32_DMA_BUFFER_SIZE, + adc->rx_buf, adc->rx_dma_buf); +err_release: + dma_release_channel(adc->dma_chan); + + return ret; +} + +static int stm32_adc_probe(struct platform_device *pdev) +{ + struct iio_dev *indio_dev; + struct device *dev = &pdev->dev; + irqreturn_t (*handler)(int irq, void *p) = NULL; + struct stm32_adc *adc; + int ret; + + if (!pdev->dev.of_node) + return -ENODEV; + + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc)); + if (!indio_dev) + return -ENOMEM; + + adc = iio_priv(indio_dev); + adc->common = dev_get_drvdata(pdev->dev.parent); + spin_lock_init(&adc->lock); + init_completion(&adc->completion); + adc->cfg = (const struct stm32_adc_cfg *) + of_match_device(dev->driver->of_match_table, dev)->data; + + indio_dev->name = dev_name(&pdev->dev); + indio_dev->dev.parent = &pdev->dev; + indio_dev->dev.of_node = pdev->dev.of_node; + indio_dev->info = &stm32_adc_iio_info; + indio_dev->modes = INDIO_DIRECT_MODE | INDIO_HARDWARE_TRIGGERED; + + platform_set_drvdata(pdev, adc); + + ret = of_property_read_u32(pdev->dev.of_node, "reg", &adc->offset); + if (ret != 0) { + dev_err(&pdev->dev, "missing reg property\n"); + return -EINVAL; + } + + adc->irq = platform_get_irq(pdev, 0); + if (adc->irq < 0) { + dev_err(&pdev->dev, "failed to get irq\n"); + return adc->irq; + } + + ret = devm_request_irq(&pdev->dev, adc->irq, stm32_adc_isr, + 0, pdev->name, adc); + if (ret) { + dev_err(&pdev->dev, "failed to request IRQ\n"); + return ret; + } + + adc->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(adc->clk)) { + ret = PTR_ERR(adc->clk); + if (ret == -ENOENT && !adc->cfg->clk_required) { + adc->clk = NULL; + } else { + dev_err(&pdev->dev, "Can't get clock\n"); + return ret; + } + } + + if (adc->clk) { + ret = clk_prepare_enable(adc->clk); + if (ret < 0) { + dev_err(&pdev->dev, "clk enable failed\n"); + return ret; + } + } + + ret = stm32_adc_of_get_resolution(indio_dev); + if (ret < 0) + goto err_clk_disable; + stm32_adc_set_res(adc); + + if (adc->cfg->selfcalib) { + ret = adc->cfg->selfcalib(adc); + if (ret) + goto err_clk_disable; + } + + ret = stm32_adc_chan_of_init(indio_dev); + if (ret < 0) + goto err_clk_disable; + + ret = stm32_adc_dma_request(dev, indio_dev); + if (ret < 0) + goto err_clk_disable; + + if (!adc->dma_chan) + handler = &stm32_adc_trigger_handler; + + ret = iio_triggered_buffer_setup(indio_dev, + &iio_pollfunc_store_time, handler, + &stm32_adc_buffer_setup_ops); + if (ret) { + dev_err(&pdev->dev, "buffer setup failed\n"); + goto err_dma_disable; + } + + ret = iio_device_register(indio_dev); + if (ret) { + dev_err(&pdev->dev, "iio dev register failed\n"); + goto err_buffer_cleanup; + } + + return 0; + +err_buffer_cleanup: + iio_triggered_buffer_cleanup(indio_dev); + +err_dma_disable: + if (adc->dma_chan) { + dma_free_coherent(adc->dma_chan->device->dev, + STM32_DMA_BUFFER_SIZE, + adc->rx_buf, adc->rx_dma_buf); + dma_release_channel(adc->dma_chan); + } +err_clk_disable: + if (adc->clk) + clk_disable_unprepare(adc->clk); + + return ret; +} + +static int stm32_adc_remove(struct platform_device *pdev) +{ + struct stm32_adc *adc = platform_get_drvdata(pdev); + struct iio_dev *indio_dev = iio_priv_to_dev(adc); + + iio_device_unregister(indio_dev); + iio_triggered_buffer_cleanup(indio_dev); + if (adc->dma_chan) { + dma_free_coherent(adc->dma_chan->device->dev, + STM32_DMA_BUFFER_SIZE, + adc->rx_buf, adc->rx_dma_buf); + dma_release_channel(adc->dma_chan); + } + if (adc->clk) + clk_disable_unprepare(adc->clk); + + return 0; +} + +static const struct stm32_adc_cfg stm32f4_adc_cfg = { + .regs = &stm32f4_adc_regspec, + .adc_info = &stm32f4_adc_info, + .trigs = stm32f4_adc_trigs, + .clk_required = true, + .start_conv = stm32f4_adc_start_conv, + .stop_conv = stm32f4_adc_stop_conv, + .smp_cycles = stm32f4_adc_smp_cycles, +}; + +static const struct stm32_adc_cfg stm32h7_adc_cfg = { + .regs = &stm32h7_adc_regspec, + .adc_info = &stm32h7_adc_info, + .trigs = stm32h7_adc_trigs, + .selfcalib = stm32h7_adc_selfcalib, + .start_conv = stm32h7_adc_start_conv, + .stop_conv = stm32h7_adc_stop_conv, + .prepare = stm32h7_adc_prepare, + .unprepare = stm32h7_adc_unprepare, + .smp_cycles = stm32h7_adc_smp_cycles, +}; + +static const struct stm32_adc_cfg stm32mp1_adc_cfg = { + .regs = &stm32h7_adc_regspec, + .adc_info = &stm32h7_adc_info, + .trigs = stm32h7_adc_trigs, + .has_vregready = true, + .selfcalib = stm32h7_adc_selfcalib, + .start_conv = stm32h7_adc_start_conv, + .stop_conv = stm32h7_adc_stop_conv, + .prepare = stm32h7_adc_prepare, + .unprepare = stm32h7_adc_unprepare, + .smp_cycles = stm32h7_adc_smp_cycles, +}; + +static const struct of_device_id stm32_adc_of_match[] = { + { .compatible = "st,stm32f4-adc", .data = (void *)&stm32f4_adc_cfg }, + { .compatible = "st,stm32h7-adc", .data = (void *)&stm32h7_adc_cfg }, + { .compatible = "st,stm32mp1-adc", .data = (void *)&stm32mp1_adc_cfg }, + {}, +}; +MODULE_DEVICE_TABLE(of, stm32_adc_of_match); + +static struct platform_driver stm32_adc_driver = { + .probe = stm32_adc_probe, + .remove = stm32_adc_remove, + .driver = { + .name = "stm32-adc", + .of_match_table = stm32_adc_of_match, + }, +}; +module_platform_driver(stm32_adc_driver); + +MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); +MODULE_DESCRIPTION("STMicroelectronics STM32 ADC IIO driver"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:stm32-adc"); |