// SPDX-License-Identifier: GPL-2.0-only /* * Aspeed AST2400/2500/2600 ADC * * Copyright (C) 2017 Google, Inc. * Copyright (C) 2021 Aspeed Technology Inc. * * ADC clock formula: * Ast2400/Ast2500: * clock period = period of PCLK * 2 * (ADC0C[31:17] + 1) * (ADC0C[9:0] + 1) * Ast2600: * clock period = period of PCLK * 2 * (ADC0C[15:0] + 1) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define ASPEED_RESOLUTION_BITS 10 #define ASPEED_CLOCKS_PER_SAMPLE 12 #define ASPEED_REG_ENGINE_CONTROL 0x00 #define ASPEED_REG_INTERRUPT_CONTROL 0x04 #define ASPEED_REG_VGA_DETECT_CONTROL 0x08 #define ASPEED_REG_CLOCK_CONTROL 0x0C #define ASPEED_REG_COMPENSATION_TRIM 0xC4 /* * The register offset between 0xC8~0xCC can be read and won't affect the * hardware logic in each version of ADC. */ #define ASPEED_REG_MAX 0xD0 #define ASPEED_ADC_ENGINE_ENABLE BIT(0) #define ASPEED_ADC_OP_MODE GENMASK(3, 1) #define ASPEED_ADC_OP_MODE_PWR_DOWN 0 #define ASPEED_ADC_OP_MODE_STANDBY 1 #define ASPEED_ADC_OP_MODE_NORMAL 7 #define ASPEED_ADC_CTRL_COMPENSATION BIT(4) #define ASPEED_ADC_AUTO_COMPENSATION BIT(5) /* * Bit 6 determines not only the reference voltage range but also the dividing * circuit for battery sensing. */ #define ASPEED_ADC_REF_VOLTAGE GENMASK(7, 6) #define ASPEED_ADC_REF_VOLTAGE_2500mV 0 #define ASPEED_ADC_REF_VOLTAGE_1200mV 1 #define ASPEED_ADC_REF_VOLTAGE_EXT_HIGH 2 #define ASPEED_ADC_REF_VOLTAGE_EXT_LOW 3 #define ASPEED_ADC_BAT_SENSING_DIV BIT(6) #define ASPEED_ADC_BAT_SENSING_DIV_2_3 0 #define ASPEED_ADC_BAT_SENSING_DIV_1_3 1 #define ASPEED_ADC_CTRL_INIT_RDY BIT(8) #define ASPEED_ADC_CH7_MODE BIT(12) #define ASPEED_ADC_CH7_NORMAL 0 #define ASPEED_ADC_CH7_BAT 1 #define ASPEED_ADC_BAT_SENSING_ENABLE BIT(13) #define ASPEED_ADC_CTRL_CHANNEL GENMASK(31, 16) #define ASPEED_ADC_CTRL_CHANNEL_ENABLE(ch) FIELD_PREP(ASPEED_ADC_CTRL_CHANNEL, BIT(ch)) #define ASPEED_ADC_INIT_POLLING_TIME 500 #define ASPEED_ADC_INIT_TIMEOUT 500000 /* * When the sampling rate is too high, the ADC may not have enough charging * time, resulting in a low voltage value. Thus, the default uses a slow * sampling rate for most use cases. */ #define ASPEED_ADC_DEF_SAMPLING_RATE 65000 struct aspeed_adc_trim_locate { const unsigned int offset; const unsigned int field; }; struct aspeed_adc_model_data { const char *model_name; unsigned int min_sampling_rate; // Hz unsigned int max_sampling_rate; // Hz unsigned int vref_fixed_mv; bool wait_init_sequence; bool need_prescaler; bool bat_sense_sup; u8 scaler_bit_width; unsigned int num_channels; const struct aspeed_adc_trim_locate *trim_locate; }; struct adc_gain { u8 mult; u8 div; }; struct aspeed_adc_data { struct device *dev; const struct aspeed_adc_model_data *model_data; void __iomem *base; spinlock_t clk_lock; struct clk_hw *fixed_div_clk; struct clk_hw *clk_prescaler; struct clk_hw *clk_scaler; struct reset_control *rst; int vref_mv; u32 sample_period_ns; int cv; bool battery_sensing; struct adc_gain battery_mode_gain; }; #define ASPEED_CHAN(_idx, _data_reg_addr) { \ .type = IIO_VOLTAGE, \ .indexed = 1, \ .channel = (_idx), \ .address = (_data_reg_addr), \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ BIT(IIO_CHAN_INFO_SAMP_FREQ) | \ BIT(IIO_CHAN_INFO_OFFSET), \ } static const struct iio_chan_spec aspeed_adc_iio_channels[] = { ASPEED_CHAN(0, 0x10), ASPEED_CHAN(1, 0x12), ASPEED_CHAN(2, 0x14), ASPEED_CHAN(3, 0x16), ASPEED_CHAN(4, 0x18), ASPEED_CHAN(5, 0x1A), ASPEED_CHAN(6, 0x1C), ASPEED_CHAN(7, 0x1E), ASPEED_CHAN(8, 0x20), ASPEED_CHAN(9, 0x22), ASPEED_CHAN(10, 0x24), ASPEED_CHAN(11, 0x26), ASPEED_CHAN(12, 0x28), ASPEED_CHAN(13, 0x2A), ASPEED_CHAN(14, 0x2C), ASPEED_CHAN(15, 0x2E), }; #define ASPEED_BAT_CHAN(_idx, _data_reg_addr) { \ .type = IIO_VOLTAGE, \ .indexed = 1, \ .channel = (_idx), \ .address = (_data_reg_addr), \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ BIT(IIO_CHAN_INFO_OFFSET), \ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ BIT(IIO_CHAN_INFO_SAMP_FREQ), \ } static const struct iio_chan_spec aspeed_adc_iio_bat_channels[] = { ASPEED_CHAN(0, 0x10), ASPEED_CHAN(1, 0x12), ASPEED_CHAN(2, 0x14), ASPEED_CHAN(3, 0x16), ASPEED_CHAN(4, 0x18), ASPEED_CHAN(5, 0x1A), ASPEED_CHAN(6, 0x1C), ASPEED_BAT_CHAN(7, 0x1E), }; static int aspeed_adc_set_trim_data(struct iio_dev *indio_dev) { struct device_node *syscon; struct regmap *scu; u32 scu_otp, trimming_val; struct aspeed_adc_data *data = iio_priv(indio_dev); syscon = of_find_node_by_name(NULL, "syscon"); if (syscon == NULL) { dev_warn(data->dev, "Couldn't find syscon node\n"); return -EOPNOTSUPP; } scu = syscon_node_to_regmap(syscon); of_node_put(syscon); if (IS_ERR(scu)) { dev_warn(data->dev, "Failed to get syscon regmap\n"); return -EOPNOTSUPP; } if (data->model_data->trim_locate) { if (regmap_read(scu, data->model_data->trim_locate->offset, &scu_otp)) { dev_warn(data->dev, "Failed to get adc trimming data\n"); trimming_val = 0x8; } else { trimming_val = ((scu_otp) & (data->model_data->trim_locate->field)) >> __ffs(data->model_data->trim_locate->field); if (!trimming_val) trimming_val = 0x8; } dev_dbg(data->dev, "trimming val = %d, offset = %08x, fields = %08x\n", trimming_val, data->model_data->trim_locate->offset, data->model_data->trim_locate->field); writel(trimming_val, data->base + ASPEED_REG_COMPENSATION_TRIM); } return 0; } static int aspeed_adc_compensation(struct iio_dev *indio_dev) { struct aspeed_adc_data *data = iio_priv(indio_dev); u32 index, adc_raw = 0; u32 adc_engine_control_reg_val; adc_engine_control_reg_val = readl(data->base + ASPEED_REG_ENGINE_CONTROL); adc_engine_control_reg_val &= ~ASPEED_ADC_OP_MODE; adc_engine_control_reg_val |= (FIELD_PREP(ASPEED_ADC_OP_MODE, ASPEED_ADC_OP_MODE_NORMAL) | ASPEED_ADC_ENGINE_ENABLE); /* * Enable compensating sensing: * After that, the input voltage of ADC will force to half of the reference * voltage. So the expected reading raw data will become half of the max * value. We can get compensating value = 0x200 - ADC read raw value. * It is recommended to average at least 10 samples to get a final CV. */ writel(adc_engine_control_reg_val | ASPEED_ADC_CTRL_COMPENSATION | ASPEED_ADC_CTRL_CHANNEL_ENABLE(0), data->base + ASPEED_REG_ENGINE_CONTROL); /* * After enable compensating sensing mode need to wait some time for ADC stable * Experiment result is 1ms. */ mdelay(1); for (index = 0; index < 16; index++) { /* * Waiting for the sampling period ensures that the value acquired * is fresh each time. */ ndelay(data->sample_period_ns); adc_raw += readw(data->base + aspeed_adc_iio_channels[0].address); } adc_raw >>= 4; data->cv = BIT(ASPEED_RESOLUTION_BITS - 1) - adc_raw; writel(adc_engine_control_reg_val, data->base + ASPEED_REG_ENGINE_CONTROL); dev_dbg(data->dev, "Compensating value = %d\n", data->cv); return 0; } static int aspeed_adc_set_sampling_rate(struct iio_dev *indio_dev, u32 rate) { struct aspeed_adc_data *data = iio_priv(indio_dev); if (rate < data->model_data->min_sampling_rate || rate > data->model_data->max_sampling_rate) return -EINVAL; /* Each sampling needs 12 clocks to convert.*/ clk_set_rate(data->clk_scaler->clk, rate * ASPEED_CLOCKS_PER_SAMPLE); rate = clk_get_rate(data->clk_scaler->clk); data->sample_period_ns = DIV_ROUND_UP_ULL( (u64)NSEC_PER_SEC * ASPEED_CLOCKS_PER_SAMPLE, rate); dev_dbg(data->dev, "Adc clock = %d sample period = %d ns", rate, data->sample_period_ns); return 0; } static int aspeed_adc_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct aspeed_adc_data *data = iio_priv(indio_dev); u32 adc_engine_control_reg_val; switch (mask) { case IIO_CHAN_INFO_RAW: if (data->battery_sensing && chan->channel == 7) { adc_engine_control_reg_val = readl(data->base + ASPEED_REG_ENGINE_CONTROL); writel(adc_engine_control_reg_val | FIELD_PREP(ASPEED_ADC_CH7_MODE, ASPEED_ADC_CH7_BAT) | ASPEED_ADC_BAT_SENSING_ENABLE, data->base + ASPEED_REG_ENGINE_CONTROL); /* * After enable battery sensing mode need to wait some time for adc stable * Experiment result is 1ms. */ mdelay(1); *val = readw(data->base + chan->address); *val = (*val * data->battery_mode_gain.mult) / data->battery_mode_gain.div; /* Restore control register value */ writel(adc_engine_control_reg_val, data->base + ASPEED_REG_ENGINE_CONTROL); } else *val = readw(data->base + chan->address); return IIO_VAL_INT; case IIO_CHAN_INFO_OFFSET: if (data->battery_sensing && chan->channel == 7) *val = (data->cv * data->battery_mode_gain.mult) / data->battery_mode_gain.div; else *val = data->cv; return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: *val = data->vref_mv; *val2 = ASPEED_RESOLUTION_BITS; return IIO_VAL_FRACTIONAL_LOG2; case IIO_CHAN_INFO_SAMP_FREQ: *val = clk_get_rate(data->clk_scaler->clk) / ASPEED_CLOCKS_PER_SAMPLE; return IIO_VAL_INT; default: return -EINVAL; } } static int aspeed_adc_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) { switch (mask) { case IIO_CHAN_INFO_SAMP_FREQ: return aspeed_adc_set_sampling_rate(indio_dev, val); case IIO_CHAN_INFO_SCALE: case IIO_CHAN_INFO_RAW: /* * Technically, these could be written but the only reasons * for doing so seem better handled in userspace. EPERM is * returned to signal this is a policy choice rather than a * hardware limitation. */ return -EPERM; default: return -EINVAL; } } static int aspeed_adc_reg_access(struct iio_dev *indio_dev, unsigned int reg, unsigned int writeval, unsigned int *readval) { struct aspeed_adc_data *data = iio_priv(indio_dev); if (!readval || reg % 4 || reg > ASPEED_REG_MAX) return -EINVAL; *readval = readl(data->base + reg); return 0; } static const struct iio_info aspeed_adc_iio_info = { .read_raw = aspeed_adc_read_raw, .write_raw = aspeed_adc_write_raw, .debugfs_reg_access = aspeed_adc_reg_access, }; static void aspeed_adc_unregister_fixed_divider(void *data) { struct clk_hw *clk = data; clk_hw_unregister_fixed_factor(clk); } static void aspeed_adc_reset_assert(void *data) { struct reset_control *rst = data; reset_control_assert(rst); } static void aspeed_adc_clk_disable_unprepare(void *data) { struct clk *clk = data; clk_disable_unprepare(clk); } static void aspeed_adc_power_down(void *data) { struct aspeed_adc_data *priv_data = data; writel(FIELD_PREP(ASPEED_ADC_OP_MODE, ASPEED_ADC_OP_MODE_PWR_DOWN), priv_data->base + ASPEED_REG_ENGINE_CONTROL); } static int aspeed_adc_vref_config(struct iio_dev *indio_dev) { struct aspeed_adc_data *data = iio_priv(indio_dev); int ret; u32 adc_engine_control_reg_val; if (data->model_data->vref_fixed_mv) { data->vref_mv = data->model_data->vref_fixed_mv; return 0; } adc_engine_control_reg_val = readl(data->base + ASPEED_REG_ENGINE_CONTROL); ret = devm_regulator_get_enable_read_voltage(data->dev, "vref"); if (ret < 0 && ret != -ENODEV) return ret; if (ret != -ENODEV) { data->vref_mv = ret / 1000; if ((data->vref_mv >= 1550) && (data->vref_mv <= 2700)) writel(adc_engine_control_reg_val | FIELD_PREP( ASPEED_ADC_REF_VOLTAGE, ASPEED_ADC_REF_VOLTAGE_EXT_HIGH), data->base + ASPEED_REG_ENGINE_CONTROL); else if ((data->vref_mv >= 900) && (data->vref_mv <= 1650)) writel(adc_engine_control_reg_val | FIELD_PREP( ASPEED_ADC_REF_VOLTAGE, ASPEED_ADC_REF_VOLTAGE_EXT_LOW), data->base + ASPEED_REG_ENGINE_CONTROL); else { dev_err(data->dev, "Regulator voltage %d not support", data->vref_mv); return -EOPNOTSUPP; } } else { data->vref_mv = 2500000; of_property_read_u32(data->dev->of_node, "aspeed,int-vref-microvolt", &data->vref_mv); /* Conversion from uV to mV */ data->vref_mv /= 1000; if (data->vref_mv == 2500) writel(adc_engine_control_reg_val | FIELD_PREP(ASPEED_ADC_REF_VOLTAGE, ASPEED_ADC_REF_VOLTAGE_2500mV), data->base + ASPEED_REG_ENGINE_CONTROL); else if (data->vref_mv == 1200) writel(adc_engine_control_reg_val | FIELD_PREP(ASPEED_ADC_REF_VOLTAGE, ASPEED_ADC_REF_VOLTAGE_1200mV), data->base + ASPEED_REG_ENGINE_CONTROL); else { dev_err(data->dev, "Voltage %d not support", data->vref_mv); return -EOPNOTSUPP; } } return 0; } static int aspeed_adc_probe(struct platform_device *pdev) { struct iio_dev *indio_dev; struct aspeed_adc_data *data; int ret; u32 adc_engine_control_reg_val; unsigned long scaler_flags = 0; char clk_name[32], clk_parent_name[32]; indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*data)); if (!indio_dev) return -ENOMEM; data = iio_priv(indio_dev); data->dev = &pdev->dev; data->model_data = of_device_get_match_data(&pdev->dev); platform_set_drvdata(pdev, indio_dev); data->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(data->base)) return PTR_ERR(data->base); /* Register ADC clock prescaler with source specified by device tree. */ spin_lock_init(&data->clk_lock); snprintf(clk_parent_name, ARRAY_SIZE(clk_parent_name), "%s", of_clk_get_parent_name(pdev->dev.of_node, 0)); snprintf(clk_name, ARRAY_SIZE(clk_name), "%s-fixed-div", data->model_data->model_name); data->fixed_div_clk = clk_hw_register_fixed_factor( &pdev->dev, clk_name, clk_parent_name, 0, 1, 2); if (IS_ERR(data->fixed_div_clk)) return PTR_ERR(data->fixed_div_clk); ret = devm_add_action_or_reset(data->dev, aspeed_adc_unregister_fixed_divider, data->fixed_div_clk); if (ret) return ret; snprintf(clk_parent_name, ARRAY_SIZE(clk_parent_name), clk_name); if (data->model_data->need_prescaler) { snprintf(clk_name, ARRAY_SIZE(clk_name), "%s-prescaler", data->model_data->model_name); data->clk_prescaler = devm_clk_hw_register_divider( &pdev->dev, clk_name, clk_parent_name, 0, data->base + ASPEED_REG_CLOCK_CONTROL, 17, 15, 0, &data->clk_lock); if (IS_ERR(data->clk_prescaler)) return PTR_ERR(data->clk_prescaler); snprintf(clk_parent_name, ARRAY_SIZE(clk_parent_name), clk_name); scaler_flags = CLK_SET_RATE_PARENT; } /* * Register ADC clock scaler downstream from the prescaler. Allow rate * setting to adjust the prescaler as well. */ snprintf(clk_name, ARRAY_SIZE(clk_name), "%s-scaler", data->model_data->model_name); data->clk_scaler = devm_clk_hw_register_divider( &pdev->dev, clk_name, clk_parent_name, scaler_flags, data->base + ASPEED_REG_CLOCK_CONTROL, 0, data->model_data->scaler_bit_width, data->model_data->need_prescaler ? CLK_DIVIDER_ONE_BASED : 0, &data->clk_lock); if (IS_ERR(data->clk_scaler)) return PTR_ERR(data->clk_scaler); data->rst = devm_reset_control_get_shared(&pdev->dev, NULL); if (IS_ERR(data->rst)) { dev_err(&pdev->dev, "invalid or missing reset controller device tree entry"); return PTR_ERR(data->rst); } reset_control_deassert(data->rst); ret = devm_add_action_or_reset(data->dev, aspeed_adc_reset_assert, data->rst); if (ret) return ret; ret = aspeed_adc_vref_config(indio_dev); if (ret) return ret; ret = aspeed_adc_set_trim_data(indio_dev); if (ret) return ret; if (of_property_present(data->dev->of_node, "aspeed,battery-sensing")) { if (data->model_data->bat_sense_sup) { data->battery_sensing = 1; if (readl(data->base + ASPEED_REG_ENGINE_CONTROL) & ASPEED_ADC_BAT_SENSING_DIV) { data->battery_mode_gain.mult = 3; data->battery_mode_gain.div = 1; } else { data->battery_mode_gain.mult = 3; data->battery_mode_gain.div = 2; } } else dev_warn(&pdev->dev, "Failed to enable battery-sensing mode\n"); } ret = clk_prepare_enable(data->clk_scaler->clk); if (ret) return ret; ret = devm_add_action_or_reset(data->dev, aspeed_adc_clk_disable_unprepare, data->clk_scaler->clk); if (ret) return ret; ret = aspeed_adc_set_sampling_rate(indio_dev, ASPEED_ADC_DEF_SAMPLING_RATE); if (ret) return ret; adc_engine_control_reg_val = readl(data->base + ASPEED_REG_ENGINE_CONTROL); adc_engine_control_reg_val |= FIELD_PREP(ASPEED_ADC_OP_MODE, ASPEED_ADC_OP_MODE_NORMAL) | ASPEED_ADC_ENGINE_ENABLE; /* Enable engine in normal mode. */ writel(adc_engine_control_reg_val, data->base + ASPEED_REG_ENGINE_CONTROL); ret = devm_add_action_or_reset(data->dev, aspeed_adc_power_down, data); if (ret) return ret; if (data->model_data->wait_init_sequence) { /* Wait for initial sequence complete. */ ret = readl_poll_timeout(data->base + ASPEED_REG_ENGINE_CONTROL, adc_engine_control_reg_val, adc_engine_control_reg_val & ASPEED_ADC_CTRL_INIT_RDY, ASPEED_ADC_INIT_POLLING_TIME, ASPEED_ADC_INIT_TIMEOUT); if (ret) return ret; } aspeed_adc_compensation(indio_dev); /* Start all channels in normal mode. */ adc_engine_control_reg_val = readl(data->base + ASPEED_REG_ENGINE_CONTROL); adc_engine_control_reg_val |= ASPEED_ADC_CTRL_CHANNEL; writel(adc_engine_control_reg_val, data->base + ASPEED_REG_ENGINE_CONTROL); indio_dev->name = data->model_data->model_name; indio_dev->info = &aspeed_adc_iio_info; indio_dev->modes = INDIO_DIRECT_MODE; indio_dev->channels = data->battery_sensing ? aspeed_adc_iio_bat_channels : aspeed_adc_iio_channels; indio_dev->num_channels = data->model_data->num_channels; ret = devm_iio_device_register(data->dev, indio_dev); return ret; } static const struct aspeed_adc_trim_locate ast2500_adc_trim = { .offset = 0x154, .field = GENMASK(31, 28), }; static const struct aspeed_adc_trim_locate ast2600_adc0_trim = { .offset = 0x5d0, .field = GENMASK(3, 0), }; static const struct aspeed_adc_trim_locate ast2600_adc1_trim = { .offset = 0x5d0, .field = GENMASK(7, 4), }; static const struct aspeed_adc_model_data ast2400_model_data = { .model_name = "ast2400-adc", .vref_fixed_mv = 2500, .min_sampling_rate = 10000, .max_sampling_rate = 500000, .need_prescaler = true, .scaler_bit_width = 10, .num_channels = 16, }; static const struct aspeed_adc_model_data ast2500_model_data = { .model_name = "ast2500-adc", .vref_fixed_mv = 1800, .min_sampling_rate = 1, .max_sampling_rate = 1000000, .wait_init_sequence = true, .need_prescaler = true, .scaler_bit_width = 10, .num_channels = 16, .trim_locate = &ast2500_adc_trim, }; static const struct aspeed_adc_model_data ast2600_adc0_model_data = { .model_name = "ast2600-adc0", .min_sampling_rate = 10000, .max_sampling_rate = 500000, .wait_init_sequence = true, .bat_sense_sup = true, .scaler_bit_width = 16, .num_channels = 8, .trim_locate = &ast2600_adc0_trim, }; static const struct aspeed_adc_model_data ast2600_adc1_model_data = { .model_name = "ast2600-adc1", .min_sampling_rate = 10000, .max_sampling_rate = 500000, .wait_init_sequence = true, .bat_sense_sup = true, .scaler_bit_width = 16, .num_channels = 8, .trim_locate = &ast2600_adc1_trim, }; static const struct of_device_id aspeed_adc_matches[] = { { .compatible = "aspeed,ast2400-adc", .data = &ast2400_model_data }, { .compatible = "aspeed,ast2500-adc", .data = &ast2500_model_data }, { .compatible = "aspeed,ast2600-adc0", .data = &ast2600_adc0_model_data }, { .compatible = "aspeed,ast2600-adc1", .data = &ast2600_adc1_model_data }, { } }; MODULE_DEVICE_TABLE(of, aspeed_adc_matches); static struct platform_driver aspeed_adc_driver = { .probe = aspeed_adc_probe, .driver = { .name = KBUILD_MODNAME, .of_match_table = aspeed_adc_matches, } }; module_platform_driver(aspeed_adc_driver); MODULE_AUTHOR("Rick Altherr "); MODULE_DESCRIPTION("Aspeed AST2400/2500/2600 ADC Driver"); MODULE_LICENSE("GPL");