diff options
Diffstat (limited to 'drivers/iio/adc/stm32-dfsdm-core.c')
-rw-r--r-- | drivers/iio/adc/stm32-dfsdm-core.c | 523 |
1 files changed, 523 insertions, 0 deletions
diff --git a/drivers/iio/adc/stm32-dfsdm-core.c b/drivers/iio/adc/stm32-dfsdm-core.c new file mode 100644 index 0000000000..0f6ebb3061 --- /dev/null +++ b/drivers/iio/adc/stm32-dfsdm-core.c @@ -0,0 +1,523 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file is part the core part STM32 DFSDM driver + * + * Copyright (C) 2017, STMicroelectronics - All Rights Reserved + * Author(s): Arnaud Pouliquen <arnaud.pouliquen@st.com> for STMicroelectronics. + */ + +#include <linux/bitfield.h> +#include <linux/clk.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/pinctrl/consumer.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/regmap.h> +#include <linux/slab.h> + +#include "stm32-dfsdm.h" + +/** + * struct stm32_dfsdm_dev_data - DFSDM compatible configuration data + * @ipid: DFSDM identification number. Used only if hardware provides identification registers + * @num_filters: DFSDM number of filters. Unused if identification registers are available + * @num_channels: DFSDM number of channels. Unused if identification registers are available + * @regmap_cfg: SAI register map configuration pointer + */ +struct stm32_dfsdm_dev_data { + u32 ipid; + unsigned int num_filters; + unsigned int num_channels; + const struct regmap_config *regmap_cfg; +}; + +#define STM32H7_DFSDM_NUM_FILTERS 4 +#define STM32H7_DFSDM_NUM_CHANNELS 8 + +static bool stm32_dfsdm_volatile_reg(struct device *dev, unsigned int reg) +{ + if (reg < DFSDM_FILTER_BASE_ADR) + return false; + + /* + * Mask is done on register to avoid to list registers of all + * filter instances. + */ + switch (reg & DFSDM_FILTER_REG_MASK) { + case DFSDM_CR1(0) & DFSDM_FILTER_REG_MASK: + case DFSDM_ISR(0) & DFSDM_FILTER_REG_MASK: + case DFSDM_JDATAR(0) & DFSDM_FILTER_REG_MASK: + case DFSDM_RDATAR(0) & DFSDM_FILTER_REG_MASK: + return true; + } + + return false; +} + +static const struct regmap_config stm32h7_dfsdm_regmap_cfg = { + .reg_bits = 32, + .val_bits = 32, + .reg_stride = sizeof(u32), + .max_register = 0x2B8, + .volatile_reg = stm32_dfsdm_volatile_reg, + .fast_io = true, +}; + +static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_data = { + .num_filters = STM32H7_DFSDM_NUM_FILTERS, + .num_channels = STM32H7_DFSDM_NUM_CHANNELS, + .regmap_cfg = &stm32h7_dfsdm_regmap_cfg, +}; + +static const struct regmap_config stm32mp1_dfsdm_regmap_cfg = { + .reg_bits = 32, + .val_bits = 32, + .reg_stride = sizeof(u32), + .max_register = 0x7fc, + .volatile_reg = stm32_dfsdm_volatile_reg, + .fast_io = true, +}; + +static const struct stm32_dfsdm_dev_data stm32mp1_dfsdm_data = { + .ipid = STM32MP15_IPIDR_NUMBER, + .regmap_cfg = &stm32mp1_dfsdm_regmap_cfg, +}; + +struct dfsdm_priv { + struct platform_device *pdev; /* platform device */ + + struct stm32_dfsdm dfsdm; /* common data exported for all instances */ + + unsigned int spi_clk_out_div; /* SPI clkout divider value */ + atomic_t n_active_ch; /* number of current active channels */ + + struct clk *clk; /* DFSDM clock */ + struct clk *aclk; /* audio clock */ +}; + +static inline struct dfsdm_priv *to_stm32_dfsdm_priv(struct stm32_dfsdm *dfsdm) +{ + return container_of(dfsdm, struct dfsdm_priv, dfsdm); +} + +static int stm32_dfsdm_clk_prepare_enable(struct stm32_dfsdm *dfsdm) +{ + struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm); + int ret; + + ret = clk_prepare_enable(priv->clk); + if (ret || !priv->aclk) + return ret; + + ret = clk_prepare_enable(priv->aclk); + if (ret) + clk_disable_unprepare(priv->clk); + + return ret; +} + +static void stm32_dfsdm_clk_disable_unprepare(struct stm32_dfsdm *dfsdm) +{ + struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm); + + clk_disable_unprepare(priv->aclk); + clk_disable_unprepare(priv->clk); +} + +/** + * stm32_dfsdm_start_dfsdm - start global dfsdm interface. + * + * Enable interface if n_active_ch is not null. + * @dfsdm: Handle used to retrieve dfsdm context. + */ +int stm32_dfsdm_start_dfsdm(struct stm32_dfsdm *dfsdm) +{ + struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm); + struct device *dev = &priv->pdev->dev; + unsigned int clk_div = priv->spi_clk_out_div, clk_src; + int ret; + + if (atomic_inc_return(&priv->n_active_ch) == 1) { + ret = pm_runtime_resume_and_get(dev); + if (ret < 0) + goto error_ret; + + /* select clock source, e.g. 0 for "dfsdm" or 1 for "audio" */ + clk_src = priv->aclk ? 1 : 0; + ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0), + DFSDM_CHCFGR1_CKOUTSRC_MASK, + DFSDM_CHCFGR1_CKOUTSRC(clk_src)); + if (ret < 0) + goto pm_put; + + /* Output the SPI CLKOUT (if clk_div == 0 clock if OFF) */ + ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0), + DFSDM_CHCFGR1_CKOUTDIV_MASK, + DFSDM_CHCFGR1_CKOUTDIV(clk_div)); + if (ret < 0) + goto pm_put; + + /* Global enable of DFSDM interface */ + ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0), + DFSDM_CHCFGR1_DFSDMEN_MASK, + DFSDM_CHCFGR1_DFSDMEN(1)); + if (ret < 0) + goto pm_put; + } + + dev_dbg(dev, "%s: n_active_ch %d\n", __func__, + atomic_read(&priv->n_active_ch)); + + return 0; + +pm_put: + pm_runtime_put_sync(dev); +error_ret: + atomic_dec(&priv->n_active_ch); + + return ret; +} +EXPORT_SYMBOL_GPL(stm32_dfsdm_start_dfsdm); + +/** + * stm32_dfsdm_stop_dfsdm - stop global DFSDM interface. + * + * Disable interface if n_active_ch is null + * @dfsdm: Handle used to retrieve dfsdm context. + */ +int stm32_dfsdm_stop_dfsdm(struct stm32_dfsdm *dfsdm) +{ + struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm); + int ret; + + if (atomic_dec_and_test(&priv->n_active_ch)) { + /* Global disable of DFSDM interface */ + ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0), + DFSDM_CHCFGR1_DFSDMEN_MASK, + DFSDM_CHCFGR1_DFSDMEN(0)); + if (ret < 0) + return ret; + + /* Stop SPI CLKOUT */ + ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0), + DFSDM_CHCFGR1_CKOUTDIV_MASK, + DFSDM_CHCFGR1_CKOUTDIV(0)); + if (ret < 0) + return ret; + + pm_runtime_put_sync(&priv->pdev->dev); + } + dev_dbg(&priv->pdev->dev, "%s: n_active_ch %d\n", __func__, + atomic_read(&priv->n_active_ch)); + + return 0; +} +EXPORT_SYMBOL_GPL(stm32_dfsdm_stop_dfsdm); + +static int stm32_dfsdm_parse_of(struct platform_device *pdev, + struct dfsdm_priv *priv) +{ + struct device_node *node = pdev->dev.of_node; + struct resource *res; + unsigned long clk_freq, divider; + unsigned int spi_freq, rem; + int ret; + + if (!node) + return -EINVAL; + + priv->dfsdm.base = devm_platform_get_and_ioremap_resource(pdev, 0, + &res); + if (IS_ERR(priv->dfsdm.base)) + return PTR_ERR(priv->dfsdm.base); + + priv->dfsdm.phys_base = res->start; + + /* + * "dfsdm" clock is mandatory for DFSDM peripheral clocking. + * "dfsdm" or "audio" clocks can be used as source clock for + * the SPI clock out signal and internal processing, depending + * on use case. + */ + priv->clk = devm_clk_get(&pdev->dev, "dfsdm"); + if (IS_ERR(priv->clk)) + return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk), + "Failed to get clock\n"); + + priv->aclk = devm_clk_get(&pdev->dev, "audio"); + if (IS_ERR(priv->aclk)) + priv->aclk = NULL; + + if (priv->aclk) + clk_freq = clk_get_rate(priv->aclk); + else + clk_freq = clk_get_rate(priv->clk); + + /* SPI clock out frequency */ + ret = of_property_read_u32(pdev->dev.of_node, "spi-max-frequency", + &spi_freq); + if (ret < 0) { + /* No SPI master mode */ + return 0; + } + + divider = div_u64_rem(clk_freq, spi_freq, &rem); + /* Round up divider when ckout isn't precise, not to exceed spi_freq */ + if (rem) + divider++; + + /* programmable divider is in range of [2:256] */ + if (divider < 2 || divider > 256) { + dev_err(&pdev->dev, "spi-max-frequency not achievable\n"); + return -EINVAL; + } + + /* SPI clock output divider is: divider = CKOUTDIV + 1 */ + priv->spi_clk_out_div = divider - 1; + priv->dfsdm.spi_master_freq = clk_freq / (priv->spi_clk_out_div + 1); + + if (rem) { + dev_warn(&pdev->dev, "SPI clock not accurate\n"); + dev_warn(&pdev->dev, "%ld = %d * %d + %d\n", + clk_freq, spi_freq, priv->spi_clk_out_div + 1, rem); + } + + return 0; +}; + +static const struct of_device_id stm32_dfsdm_of_match[] = { + { + .compatible = "st,stm32h7-dfsdm", + .data = &stm32h7_dfsdm_data, + }, + { + .compatible = "st,stm32mp1-dfsdm", + .data = &stm32mp1_dfsdm_data, + }, + {} +}; +MODULE_DEVICE_TABLE(of, stm32_dfsdm_of_match); + +static int stm32_dfsdm_probe_identification(struct platform_device *pdev, + struct dfsdm_priv *priv, + const struct stm32_dfsdm_dev_data *dev_data) +{ + struct device_node *np = pdev->dev.of_node; + struct device_node *child; + struct stm32_dfsdm *dfsdm = &priv->dfsdm; + const char *compat; + int ret, count = 0; + u32 id, val; + + if (!dev_data->ipid) { + dfsdm->num_fls = dev_data->num_filters; + dfsdm->num_chs = dev_data->num_channels; + return 0; + } + + ret = regmap_read(dfsdm->regmap, DFSDM_IPIDR, &id); + if (ret) + return ret; + + if (id != dev_data->ipid) { + dev_err(&pdev->dev, "Unexpected IP version: 0x%x", id); + return -EINVAL; + } + + for_each_child_of_node(np, child) { + ret = of_property_read_string(child, "compatible", &compat); + if (ret) + continue; + /* Count only child nodes with dfsdm compatible */ + if (strstr(compat, "dfsdm")) + count++; + } + + ret = regmap_read(dfsdm->regmap, DFSDM_HWCFGR, &val); + if (ret) + return ret; + + dfsdm->num_fls = FIELD_GET(DFSDM_HWCFGR_NBF_MASK, val); + dfsdm->num_chs = FIELD_GET(DFSDM_HWCFGR_NBT_MASK, val); + + if (count > dfsdm->num_fls) { + dev_err(&pdev->dev, "Unexpected child number: %d", count); + return -EINVAL; + } + + ret = regmap_read(dfsdm->regmap, DFSDM_VERR, &val); + if (ret) + return ret; + + dev_dbg(&pdev->dev, "DFSDM version: %lu.%lu. %d channels/%d filters\n", + FIELD_GET(DFSDM_VERR_MAJREV_MASK, val), + FIELD_GET(DFSDM_VERR_MINREV_MASK, val), + dfsdm->num_chs, dfsdm->num_fls); + + return 0; +} + +static int stm32_dfsdm_probe(struct platform_device *pdev) +{ + struct dfsdm_priv *priv; + const struct stm32_dfsdm_dev_data *dev_data; + struct stm32_dfsdm *dfsdm; + int ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->pdev = pdev; + + dev_data = of_device_get_match_data(&pdev->dev); + + dfsdm = &priv->dfsdm; + + ret = stm32_dfsdm_parse_of(pdev, priv); + if (ret < 0) + return ret; + + dfsdm->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "dfsdm", + dfsdm->base, + dev_data->regmap_cfg); + if (IS_ERR(dfsdm->regmap)) { + ret = PTR_ERR(dfsdm->regmap); + dev_err(&pdev->dev, "%s: Failed to allocate regmap: %d\n", + __func__, ret); + return ret; + } + + ret = stm32_dfsdm_probe_identification(pdev, priv, dev_data); + if (ret < 0) + return ret; + + dfsdm->fl_list = devm_kcalloc(&pdev->dev, dfsdm->num_fls, + sizeof(*dfsdm->fl_list), GFP_KERNEL); + if (!dfsdm->fl_list) + return -ENOMEM; + + dfsdm->ch_list = devm_kcalloc(&pdev->dev, dfsdm->num_chs, + sizeof(*dfsdm->ch_list), GFP_KERNEL); + if (!dfsdm->ch_list) + return -ENOMEM; + + platform_set_drvdata(pdev, dfsdm); + + ret = stm32_dfsdm_clk_prepare_enable(dfsdm); + if (ret) { + dev_err(&pdev->dev, "Failed to start clock\n"); + return ret; + } + + pm_runtime_get_noresume(&pdev->dev); + pm_runtime_set_active(&pdev->dev); + pm_runtime_enable(&pdev->dev); + + ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev); + if (ret) + goto pm_put; + + pm_runtime_put(&pdev->dev); + + return 0; + +pm_put: + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); + pm_runtime_put_noidle(&pdev->dev); + stm32_dfsdm_clk_disable_unprepare(dfsdm); + + return ret; +} + +static int stm32_dfsdm_core_remove(struct platform_device *pdev) +{ + struct stm32_dfsdm *dfsdm = platform_get_drvdata(pdev); + + pm_runtime_get_sync(&pdev->dev); + of_platform_depopulate(&pdev->dev); + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); + pm_runtime_put_noidle(&pdev->dev); + stm32_dfsdm_clk_disable_unprepare(dfsdm); + + return 0; +} + +static int stm32_dfsdm_core_suspend(struct device *dev) +{ + struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev); + struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm); + int ret; + + ret = pm_runtime_force_suspend(dev); + if (ret) + return ret; + + /* Balance devm_regmap_init_mmio_clk() clk_prepare() */ + clk_unprepare(priv->clk); + + return pinctrl_pm_select_sleep_state(dev); +} + +static int stm32_dfsdm_core_resume(struct device *dev) +{ + struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev); + struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm); + int ret; + + ret = pinctrl_pm_select_default_state(dev); + if (ret) + return ret; + + ret = clk_prepare(priv->clk); + if (ret) + return ret; + + return pm_runtime_force_resume(dev); +} + +static int stm32_dfsdm_core_runtime_suspend(struct device *dev) +{ + struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev); + + stm32_dfsdm_clk_disable_unprepare(dfsdm); + + return 0; +} + +static int stm32_dfsdm_core_runtime_resume(struct device *dev) +{ + struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev); + + return stm32_dfsdm_clk_prepare_enable(dfsdm); +} + +static const struct dev_pm_ops stm32_dfsdm_core_pm_ops = { + SYSTEM_SLEEP_PM_OPS(stm32_dfsdm_core_suspend, stm32_dfsdm_core_resume) + RUNTIME_PM_OPS(stm32_dfsdm_core_runtime_suspend, + stm32_dfsdm_core_runtime_resume, + NULL) +}; + +static struct platform_driver stm32_dfsdm_driver = { + .probe = stm32_dfsdm_probe, + .remove = stm32_dfsdm_core_remove, + .driver = { + .name = "stm32-dfsdm", + .of_match_table = stm32_dfsdm_of_match, + .pm = pm_ptr(&stm32_dfsdm_core_pm_ops), + }, +}; + +module_platform_driver(stm32_dfsdm_driver); + +MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>"); +MODULE_DESCRIPTION("STMicroelectronics STM32 dfsdm driver"); +MODULE_LICENSE("GPL v2"); |