This adds support for the SAR (Successive Approximation Register) ADC on the Amlogic Meson SoCs. The code is based on the public S805 (Meson8b) and S905 (GXBB) datasheets (see [0] and [1]), as well as by reading (various versions of) the vendor driver and by inspecting the registers on the vendor kernels of my testing-hardware. Currently the GXBB, GXL and GXM SoCs are supported. GXBB hardware has 10-bit ADC resolution, while GXL and GXM have 12-bit ADC resolution. The code was written to support older SoCs (Meson8 and Meson8b) as well, but due to lack of actual testing-hardware no of_device_id was added for these. Two "features" from the vendor driver are currently missing: - the vendor driver uses channel #7 for calibration (this improves the accuracy of the results - in my tests the results were less than 3% off without calibration compared to the vendor driver). Adding support for this should be easy, but is not required for most applications. - channel #6 is connected to the SoCs internal temperature sensor. Adding support for this is probably not so easy since (based on the u-boot sources) most SoC versions are using different registers and algorithms for the conversion from "ADC value" to temperature. Supported by the hardware but currently not supported by the driver: - reading multiple channels at the same time (the hardware has a FIFO buffer which stores multiple results) - continuous sampling (this would require a way to enable this individually because otherwise the ADC would be drawing power constantly) - interrupt support (similar to the vendor driver this new driver is polling the results. It is unclear if the IRQ-mode is supported on older (Meson6 or Meson8) hardware as well or if there are any errata) [0] http://dn.odroid.com/S805/Datasheet/S805_Datasheet%20V0.8%2020150126.pdf [1] http://dn.odroid.com/S905/DataSheet/S905_Public_Datasheet_V1.1.4.pdf Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> --- drivers/iio/adc/Kconfig | 12 + drivers/iio/adc/Makefile | 1 + drivers/iio/adc/meson_saradc.c | 893 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 906 insertions(+) create mode 100644 drivers/iio/adc/meson_saradc.c diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index 9c8b558ba19e..86059b9b91bf 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -371,6 +371,18 @@ config MEN_Z188_ADC This driver can also be built as a module. If so, the module will be called men_z188_adc. +config MESON_SARADC + tristate "Amlogic Meson SAR ADC driver" + default ARCH_MESON + depends on OF && COMMON_CLK && (ARCH_MESON || COMPILE_TEST) + select REGMAP_MMIO + help + Say yes here to build support for the SAR ADC found in Amlogic Meson + SoCs. + + To compile this driver as a module, choose M here: the + module will be called meson_saradc. + config MXS_LRADC tristate "Freescale i.MX23/i.MX28 LRADC" depends on (ARCH_MXS || COMPILE_TEST) && HAS_IOMEM diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index d36c4be8d1fc..de05b9e75f8f 100644 --- a/drivers/iio/adc/Makefile +++ b/drivers/iio/adc/Makefile @@ -36,6 +36,7 @@ obj-$(CONFIG_MCP320X) += mcp320x.o obj-$(CONFIG_MCP3422) += mcp3422.o obj-$(CONFIG_MEDIATEK_MT6577_AUXADC) += mt6577_auxadc.o obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o +obj-$(CONFIG_MESON_SARADC) += meson_saradc.o obj-$(CONFIG_MXS_LRADC) += mxs-lradc.o obj-$(CONFIG_NAU7802) += nau7802.o obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c new file mode 100644 index 000000000000..4c189e5fd7cc --- /dev/null +++ b/drivers/iio/adc/meson_saradc.c @@ -0,0 +1,893 @@ +/* + * Amlogic Meson Successive Approximation Register (SAR) A/D Converter + * + * Copyright (C) 2017 Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/bitfield.h> +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/iio/iio.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> + +#define SAR_ADC_REG0 0x00 + #define SAR_ADC_REG0_PANEL_DETECT BIT(31) + #define SAR_ADC_REG0_BUSY_MASK GENMASK(30, 28) + #define SAR_ADC_REG0_DELTA_BUSY BIT(30) + #define SAR_ADC_REG0_AVG_BUSY BIT(29) + #define SAR_ADC_REG0_SAMPLE_BUSY BIT(28) + #define SAR_ADC_REG0_FIFO_FULL BIT(27) + #define SAR_ADC_REG0_FIFO_EMPTY BIT(26) + #define SAR_ADC_REG0_FIFO_COUNT_MASK GENMASK(25, 21) + #define SAR_ADC_REG0_ADC_BIAS_CTRL_MASK GENMASK(20, 19) + #define SAR_ADC_REG0_CURR_CHAN_ID_MASK GENMASK(18, 16) + #define SAR_ADC_REG0_ADC_TEMP_SEN_SEL BIT(15) + #define SAR_ADC_REG0_SAMPLING_STOP BIT(14) + #define SAR_ADC_REG0_CHAN_DELTA_EN_MASK GENMASK(13, 12) + #define SAR_ADC_REG0_DETECT_IRQ_POL BIT(10) + #define SAR_ADC_REG0_DETECT_IRQ_EN BIT(9) + #define SAR_ADC_REG0_FIFO_CNT_IRQ_MASK GENMASK(8, 4) + #define SAR_ADC_REG0_FIFO_IRQ_EN BIT(3) + #define SAR_ADC_REG0_SAMPLING_START BIT(2) + #define SAR_ADC_REG0_CONTINUOUS_EN BIT(1) + #define SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE BIT(0) + +#define SAR_ADC_CHAN_LIST 0x04 + #define SAR_ADC_CHAN_LIST_MAX_INDEX_MASK GENMASK(26, 24) + #define SAR_ADC_CHAN_CHAN_ENTRY_MASK(_chan) \ + (GENMASK(2, 0) << (_chan * 3)) + +#define SAR_ADC_AVG_CNTL 0x08 + #define SAR_ADC_AVG_CNTL_AVG_MODE_SHIFT(_chan) \ + (16 + (_chan * 2)) + #define SAR_ADC_AVG_CNTL_AVG_MODE_MASK(_chan) \ + (GENMASK(17, 16) << (_chan * 2)) + #define SAR_ADC_AVG_CNTL_NUM_SAMPLES_SHIFT(_chan) \ + (0 + (_chan * 2)) + #define SAR_ADC_AVG_CNTL_NUM_SAMPLES_MASK(_chan) \ + (GENMASK(1, 0) << (_chan * 2)) + +#define SAR_ADC_REG3 0x0c + #define SAR_ADC_REG3_CNTL_USE_SC_DLY BIT(31) + #define SAR_ADC_REG3_CLK_EN BIT(30) + #define SAR_ADC_REG3_BL30_INITIALIZED BIT(28) + #define SAR_ADC_REG3_CTRL_CONT_RING_COUNTER_EN BIT(27) + #define SAR_ADC_REG3_CTRL_SAMPLING_CLOCK_PHASE BIT(26) + #define SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK GENMASK(25, 23) + #define SAR_ADC_REG3_DETECT_EN BIT(22) + #define SAR_ADC_REG3_ADC_EN BIT(21) + #define SAR_ADC_REG3_PANEL_DETECT_COUNT_MASK GENMASK(20, 18) + #define SAR_ADC_REG3_PANEL_DETECT_FILTER_TB_MASK GENMASK(17, 16) + #define SAR_ADC_REG3_ADC_CLK_DIV_SHIFT 10 + #define SAR_ADC_REG3_ADC_CLK_DIV_WIDTH 5 + #define SAR_ADC_REG3_ADC_CLK_DIV_MASK GENMASK(15, 10) + #define SAR_ADC_REG3_BLOCK_DLY_SEL_MASK GENMASK(9, 8) + #define SAR_ADC_REG3_BLOCK_DLY_MASK GENMASK(7, 0) + +#define SAR_ADC_DELAY 0x10 + #define SAR_ADC_DELAY_INPUT_DLY_SEL_MASK GENMASK(25, 24) + #define SAR_ADC_DELAY_BL30_BUSY BIT(15) + #define SAR_ADC_DELAY_KERNEL_BUSY BIT(14) + #define SAR_ADC_DELAY_INPUT_DLY_CNT_MASK GENMASK(23, 16) + #define SAR_ADC_DELAY_SAMPLE_DLY_SEL_MASK GENMASK(9, 8) + #define SAR_ADC_DELAY_SAMPLE_DLY_CNT_MASK GENMASK(7, 0) + +#define SAR_ADC_LAST_RD 0x14 + #define SAR_ADC_LAST_RD_LAST_CHANNEL1_MASK GENMASK(23, 16) + #define SAR_ADC_LAST_RD_LAST_CHANNEL0_MASK GENMASK(9, 0) + +#define SAR_ADC_FIFO_RD 0x18 + #define SAR_ADC_FIFO_RD_CHAN_ID_MASK GENMASK(14, 12) + #define SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK GENMASK(11, 0) + +#define SAR_ADC_AUX_SW 0x1c + #define SAR_ADC_AUX_SW_MUX_SEL_CHAN_MASK(_chan) \ + (GENMASK(10, 8) << ((_chan - 2) * 2)) + #define SAR_ADC_AUX_SW_VREF_P_MUX BIT(6) + #define SAR_ADC_AUX_SW_VREF_N_MUX BIT(5) + #define SAR_ADC_AUX_SW_MODE_SEL BIT(4) + #define SAR_ADC_AUX_SW_YP_DRIVE_SW BIT(3) + #define SAR_ADC_AUX_SW_XP_DRIVE_SW BIT(2) + #define SAR_ADC_AUX_SW_YM_DRIVE_SW BIT(1) + #define SAR_ADC_AUX_SW_XM_DRIVE_SW BIT(0) + +#define SAR_ADC_CHAN_10_SW 0x20 + #define SAR_ADC_CHAN_10_SW_CHAN1_MUX_SEL_MASK GENMASK(25, 23) + #define SAR_ADC_CHAN_10_SW_CHAN1_VREF_P_MUX BIT(22) + #define SAR_ADC_CHAN_10_SW_CHAN1_VREF_N_MUX BIT(21) + #define SAR_ADC_CHAN_10_SW_CHAN1_MODE_SEL BIT(20) + #define SAR_ADC_CHAN_10_SW_CHAN1_YP_DRIVE_SW BIT(19) + #define SAR_ADC_CHAN_10_SW_CHAN1_XP_DRIVE_SW BIT(18) + #define SAR_ADC_CHAN_10_SW_CHAN1_YM_DRIVE_SW BIT(17) + #define SAR_ADC_CHAN_10_SW_CHAN1_XM_DRIVE_SW BIT(16) + #define SAR_ADC_CHAN_10_SW_CHAN0_MUX_SEL_MASK GENMASK(9, 7) + #define SAR_ADC_CHAN_10_SW_CHAN0_VREF_P_MUX BIT(6) + #define SAR_ADC_CHAN_10_SW_CHAN0_VREF_N_MUX BIT(5) + #define SAR_ADC_CHAN_10_SW_CHAN0_MODE_SEL BIT(4) + #define SAR_ADC_CHAN_10_SW_CHAN0_YP_DRIVE_SW BIT(3) + #define SAR_ADC_CHAN_10_SW_CHAN0_XP_DRIVE_SW BIT(2) + #define SAR_ADC_CHAN_10_SW_CHAN0_YM_DRIVE_SW BIT(1) + #define SAR_ADC_CHAN_10_SW_CHAN0_XM_DRIVE_SW BIT(0) + +#define SAR_ADC_DETECT_IDLE_SW 0x24 + #define SAR_ADC_DETECT_IDLE_SW_DETECT_SW_EN BIT(26) + #define SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_MUX_MASK GENMASK(25, 23) + #define SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_VREF_P_MUX BIT(22) + #define SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_VREF_N_MUX BIT(21) + #define SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_SEL BIT(20) + #define SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_YP_DRIVE_SW BIT(19) + #define SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_XP_DRIVE_SW BIT(18) + #define SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_YM_DRIVE_SW BIT(17) + #define SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_XM_DRIVE_SW BIT(16) + #define SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_MUX_SEL_MASK GENMASK(9, 7) + #define SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_VREF_P_MUX BIT(6) + #define SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_VREF_N_MUX BIT(5) + #define SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_SEL BIT(4) + #define SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_YP_DRIVE_SW BIT(3) + #define SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_XP_DRIVE_SW BIT(2) + #define SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_YM_DRIVE_SW BIT(1) + #define SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_XM_DRIVE_SW BIT(0) + +#define SAR_ADC_DELTA_10 0x28 + #define SAR_ADC_DELTA_10_TEMP_SEL BIT(27) + #define SAR_ADC_DELTA_10_TS_REVE1 BIT(26) + #define SAR_ADC_DELTA_10_CHAN1_DELTA_VALUE_SHIFT 16 + #define SAR_ADC_DELTA_10_CHAN1_DELTA_VALUE_MASK GENMASK(25, 16) + #define SAR_ADC_DELTA_10_TS_REVE0 BIT(15) + #define SAR_ADC_DELTA_10_TS_C_SHIFT 11 + #define SAR_ADC_DELTA_10_TS_C_MASK GENMASK(14, 11) + #define SAR_ADC_DELTA_10_TS_VBG_EN BIT(10) + #define SAR_ADC_DELTA_10_CHAN0_DELTA_VALUE_SHIFT 0 + #define SAR_ADC_DELTA_10_CHAN0_DELTA_VALUE_MASK GENMASK(9, 0) + +/* + * NOTE: registers from here are undocumented (the vendor Linux kernel driver + * and u-boot source served as reference). These only seem to be relevant on + * GXBB and newer. + */ +#define SAR_ADC_REG11 0x2c + #define SAR_ADC_REG11_BANDGAP_EN BIT(13) + +#define SAR_ADC_REG13 0x34 + #define SAR_ADC_REG13_12BIT_CALIBRATION_MASK GENMASK(13, 8) + +#define SAR_ADC_MAX_FIFO_SIZE 32 + +#define MESON_SAR_ADC_CHAN(_chan, _type) { \ + .type = _type, \ + .indexed = true, \ + .channel = _chan, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ + BIT(IIO_CHAN_INFO_AVERAGE_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .datasheet_name = "SAR_ADC_CH"#_chan, \ +} + +/* + * TODO: the hardware supports IIO_TEMP for channel 6 as well which is + * currently not supported by this driver. + */ +static const struct iio_chan_spec meson_saradc_iio_channels[] = { + MESON_SAR_ADC_CHAN(0, IIO_VOLTAGE), + MESON_SAR_ADC_CHAN(1, IIO_VOLTAGE), + MESON_SAR_ADC_CHAN(2, IIO_VOLTAGE), + MESON_SAR_ADC_CHAN(3, IIO_VOLTAGE), + MESON_SAR_ADC_CHAN(4, IIO_VOLTAGE), + MESON_SAR_ADC_CHAN(5, IIO_VOLTAGE), + MESON_SAR_ADC_CHAN(6, IIO_VOLTAGE), + MESON_SAR_ADC_CHAN(7, IIO_VOLTAGE), + IIO_CHAN_SOFT_TIMESTAMP(8), +}; + +enum meson_saradc_avg_mode { + NO_AVERAGING = 0x0, + MEAN_AVERAGING = 0x1, + MEDIAN_AVERAGING = 0x2, +}; + +enum meson_saradc_num_samples { + ONE_SAMPLE = 0x0, + TWO_SAMPLES = 0x1, + FOUR_SAMPLES = 0x2, + EIGHT_SAMPLES = 0x3, +}; + +enum meson_saradc_chan7_mux_sel { + CHAN7_MUX_VSS = 0x0, + CHAN7_MUX_VDD_DIV4 = 0x1, + CHAN7_MUX_VDD_DIV2 = 0x2, + CHAN7_MUX_VDD_MUL3_DIV4 = 0x3, + CHAN7_MUX_VDD = 0x4, + CHAN7_MUX_CH7_INPUT = 0x7, +}; + +struct meson_saradc_data { + unsigned int resolution; + const char *name; +}; + +struct meson_saradc_priv { + struct regmap *regmap; + struct regulator *vref; + const struct meson_saradc_data *data; + struct clk *clkin; + struct clk *core_clk; + struct clk *sana_clk; + struct clk *adc_sel_clk; + struct clk *adc_clk; + struct clk_gate clk_gate; + struct clk *adc_div_clk; + struct clk_divider clk_div; +}; + +static const struct regmap_config meson_saradc_regmap_config = { + .reg_bits = 8, + .val_bits = 32, + .reg_stride = 4, + .max_register = SAR_ADC_REG13, +}; + +static unsigned int meson_saradc_get_fifo_count(struct iio_dev *indio_dev) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + u32 regval; + + regmap_read(priv->regmap, SAR_ADC_REG0, ®val); + + return FIELD_GET(SAR_ADC_REG0_FIFO_COUNT_MASK, regval); +} + +static int meson_saradc_wait_busy_clear(struct iio_dev *indio_dev) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + int regval, timeout = 10000; + + /* + * NOTE: we need a small delay before reading the status, otherwise + * the sample engine may not have started internally (which would + * seem to us that sampling is already finished). + */ + do { + udelay(1); + regmap_read(priv->regmap, SAR_ADC_REG0, ®val); + } while (FIELD_GET(SAR_ADC_REG0_BUSY_MASK, regval) && timeout--); + + if (timeout < 0) + return -ETIMEDOUT; + + return 0; +} + +static int meson_saradc_read_raw_sample(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + int *val) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + int ret, regval, fifo_chan, fifo_val, sum = 0, count = 0; + + ret = meson_saradc_wait_busy_clear(indio_dev); + if (ret) + return ret; + + while (meson_saradc_get_fifo_count(indio_dev) > 0 && + count < SAR_ADC_MAX_FIFO_SIZE) { + regmap_read(priv->regmap, SAR_ADC_FIFO_RD, ®val); + + fifo_chan = FIELD_GET(SAR_ADC_FIFO_RD_CHAN_ID_MASK, regval); + if (fifo_chan == chan->channel) { + fifo_val = FIELD_GET(SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK, + regval); + fifo_val &= (BIT(priv->data->resolution) - 1); + + sum += fifo_val; + count++; + } + } + + if (!count) + return -ENOENT; + + *val = sum / count; + + return 0; +} + +static void meson_saradc_set_averaging(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum meson_saradc_avg_mode mode, + enum meson_saradc_num_samples samples) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + u32 val; + + val = samples << SAR_ADC_AVG_CNTL_NUM_SAMPLES_SHIFT(chan->channel); + regmap_update_bits(priv->regmap, SAR_ADC_AVG_CNTL, + SAR_ADC_AVG_CNTL_NUM_SAMPLES_MASK(chan->channel), + val); + + val = mode << SAR_ADC_AVG_CNTL_AVG_MODE_SHIFT(chan->channel); + regmap_update_bits(priv->regmap, SAR_ADC_AVG_CNTL, + SAR_ADC_AVG_CNTL_AVG_MODE_MASK(chan->channel), val); +} + +static void meson_saradc_enable_channel(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + u32 regval; + + /* the SAR ADC engine allows sampling multiple channels at the same + * time. to keep it simple we're only working with one *internal* + * channel, which starts counting at index 0 (which means: count = 1). + */ + regval = FIELD_PREP(SAR_ADC_CHAN_LIST_MAX_INDEX_MASK, 0); + regmap_update_bits(priv->regmap, SAR_ADC_CHAN_LIST, + SAR_ADC_CHAN_LIST_MAX_INDEX_MASK, regval); + + /* map channel index 0 to the channel which we want to read */ + regval = FIELD_PREP(SAR_ADC_CHAN_CHAN_ENTRY_MASK(0), chan->channel); + regmap_update_bits(priv->regmap, SAR_ADC_CHAN_LIST, + SAR_ADC_CHAN_CHAN_ENTRY_MASK(0), regval); + + regval = FIELD_PREP(SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_MUX_MASK, + chan->channel); + regmap_update_bits(priv->regmap, SAR_ADC_DETECT_IDLE_SW, + SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_MUX_MASK, + regval); + + regval = FIELD_PREP(SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_MUX_SEL_MASK, + chan->channel); + regmap_update_bits(priv->regmap, SAR_ADC_DETECT_IDLE_SW, + SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_MUX_SEL_MASK, + regval); + + if (chan->channel == 6) + regmap_update_bits(priv->regmap, SAR_ADC_DELTA_10, + SAR_ADC_DELTA_10_TEMP_SEL, 0); +} + +static void meson_saradc_set_channel7_mux(struct iio_dev *indio_dev, + enum meson_saradc_chan7_mux_sel sel) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + u32 regval; + + regval = FIELD_PREP(SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK, sel); + regmap_update_bits(priv->regmap, SAR_ADC_REG3, + SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK, regval); + + usleep_range(10, 20); +} + +static void meson_saradc_start_sample_engine(struct iio_dev *indio_dev) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + + regmap_update_bits(priv->regmap, SAR_ADC_REG0, + SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE, + SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE); + + regmap_update_bits(priv->regmap, SAR_ADC_REG0, + SAR_ADC_REG0_SAMPLING_START, + SAR_ADC_REG0_SAMPLING_START); +} + +static void meson_saradc_stop_sample_engine(struct iio_dev *indio_dev) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + + regmap_update_bits(priv->regmap, SAR_ADC_REG0, + SAR_ADC_REG0_SAMPLING_STOP, + SAR_ADC_REG0_SAMPLING_STOP); + + /* wait until all modules are stopped */ + meson_saradc_wait_busy_clear(indio_dev); + + regmap_update_bits(priv->regmap, SAR_ADC_REG0, + SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE, 0); +} + +static void meson_saradc_lock(struct iio_dev *indio_dev) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + int val; + + mutex_lock(&indio_dev->mlock); + + /* prevent BL30 from using the SAR ADC while we are using it */ + regmap_update_bits(priv->regmap, SAR_ADC_DELAY, + SAR_ADC_DELAY_KERNEL_BUSY, + SAR_ADC_DELAY_KERNEL_BUSY); + + /* wait until BL30 releases it's lock (so we can use the SAR ADC) */ + do { + udelay(1); + regmap_read(priv->regmap, SAR_ADC_DELAY, &val); + } while (val & SAR_ADC_DELAY_BL30_BUSY); +} + +static void meson_saradc_unlock(struct iio_dev *indio_dev) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + + /* allow BL30 to use the SAR ADC again */ + regmap_update_bits(priv->regmap, SAR_ADC_DELAY, + SAR_ADC_DELAY_KERNEL_BUSY, 0); + + mutex_unlock(&indio_dev->mlock); +} + +static void meson_saradc_clear_fifo(struct iio_dev *indio_dev) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + int count; + + for (count = 0; count < SAR_ADC_MAX_FIFO_SIZE; count++) { + if (!meson_saradc_get_fifo_count(indio_dev)) + break; + + regmap_read(priv->regmap, SAR_ADC_FIFO_RD, 0); + } +} + +static int meson_saradc_get_sample(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum meson_saradc_avg_mode avg_mode, + enum meson_saradc_num_samples avg_samples, + int *val) +{ + int ret; + + meson_saradc_lock(indio_dev); + + /* clear the FIFO to make sure we're not reading old values */ + meson_saradc_clear_fifo(indio_dev); + + meson_saradc_set_averaging(indio_dev, chan, avg_mode, avg_samples); + + meson_saradc_enable_channel(indio_dev, chan); + + meson_saradc_start_sample_engine(indio_dev); + ret = meson_saradc_read_raw_sample(indio_dev, chan, val); + meson_saradc_stop_sample_engine(indio_dev); + + meson_saradc_unlock(indio_dev); + + if (ret) { + dev_warn(indio_dev->dev.parent, + "failed to read sample for channel %d: %d\n", + chan->channel, ret); + return ret; + } + + return IIO_VAL_INT; +} + +static int meson_saradc_iio_info_read_raw(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + int *val, int *val2, long mask) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + return meson_saradc_get_sample(indio_dev, chan, NO_AVERAGING, + ONE_SAMPLE, val); + break; + + case IIO_CHAN_INFO_AVERAGE_RAW: + return meson_saradc_get_sample(indio_dev, chan, MEAN_AVERAGING, + EIGHT_SAMPLES, val); + break; + + case IIO_CHAN_INFO_SCALE: + ret = regulator_get_voltage(priv->vref); + if (ret < 0) { + dev_err(indio_dev->dev.parent, + "failed to get vref voltage: %d\n", ret); + return ret; + } + + *val = ret / 1000; + *val2 = priv->data->resolution; + return IIO_VAL_FRACTIONAL_LOG2; + + default: + return -EINVAL; + } +} + +static int meson_saradc_clk_init(struct iio_dev *indio_dev, void __iomem *base) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + struct clk_init_data init; + const char *clk_parents[1]; + + init.name = devm_kasprintf(&indio_dev->dev, GFP_KERNEL, "%s#adc_div", + of_node_full_name(indio_dev->dev.of_node)); + init.flags = 0; + init.ops = &clk_divider_ops; + clk_parents[0] = __clk_get_name(priv->clkin); + init.parent_names = clk_parents; + init.num_parents = 1; + + priv->clk_div.reg = base + SAR_ADC_REG3; + priv->clk_div.shift = SAR_ADC_REG3_ADC_CLK_DIV_SHIFT; + priv->clk_div.width = SAR_ADC_REG3_ADC_CLK_DIV_WIDTH; + priv->clk_div.hw.init = &init; + priv->clk_div.flags = 0; + + priv->adc_div_clk = devm_clk_register(&indio_dev->dev, + &priv->clk_div.hw); + if (WARN_ON(IS_ERR(priv->adc_div_clk))) + return PTR_ERR(priv->adc_div_clk); + + init.name = devm_kasprintf(&indio_dev->dev, GFP_KERNEL, "%s#adc_en", + of_node_full_name(indio_dev->dev.of_node)); + init.flags = CLK_SET_RATE_PARENT; + init.ops = &clk_gate_ops; + clk_parents[0] = __clk_get_name(priv->adc_div_clk); + init.parent_names = clk_parents; + init.num_parents = 1; + + priv->clk_gate.reg = base + SAR_ADC_REG3; + priv->clk_gate.bit_idx = fls(SAR_ADC_REG3_CLK_EN); + priv->clk_gate.hw.init = &init; + + priv->adc_clk = devm_clk_register(&indio_dev->dev, &priv->clk_gate.hw); + if (WARN_ON(IS_ERR(priv->adc_clk))) + return PTR_ERR(priv->adc_clk); + + return 0; +} + +static int meson_saradc_init(struct iio_dev *indio_dev) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + int regval, ret; + + /* + * make sure we start at CH7 input since the other muxes are only used + * for internal calibration. + */ + meson_saradc_set_channel7_mux(indio_dev, CHAN7_MUX_CH7_INPUT); + + /* + * leave sampling delay and the input clocks as configured by BL30 to + * make sure BL30 gets the values it expects when reading the + * temperature sensor. + */ + regmap_read(priv->regmap, SAR_ADC_REG3, ®val); + if (regval & SAR_ADC_REG3_BL30_INITIALIZED) + return 0; + + meson_saradc_stop_sample_engine(indio_dev); + + /* update the channel 6 MUX to select the temperature sensor */ + regmap_update_bits(priv->regmap, SAR_ADC_REG0, + SAR_ADC_REG0_ADC_TEMP_SEN_SEL, + SAR_ADC_REG0_ADC_TEMP_SEN_SEL); + + /* disable all channels by default */ + regmap_write(priv->regmap, SAR_ADC_CHAN_LIST, 0x0); + + regmap_update_bits(priv->regmap, SAR_ADC_REG3, + SAR_ADC_REG3_CTRL_SAMPLING_CLOCK_PHASE, 0); + regmap_update_bits(priv->regmap, SAR_ADC_REG3, + SAR_ADC_REG3_CNTL_USE_SC_DLY, + SAR_ADC_REG3_CNTL_USE_SC_DLY); + + /* delay between two samples = (10+1) * 1uS */ + regmap_update_bits(priv->regmap, SAR_ADC_DELAY, + SAR_ADC_DELAY_INPUT_DLY_CNT_MASK, + FIELD_PREP(SAR_ADC_DELAY_SAMPLE_DLY_CNT_MASK, 10)); + regmap_update_bits(priv->regmap, SAR_ADC_DELAY, + SAR_ADC_DELAY_SAMPLE_DLY_SEL_MASK, + FIELD_PREP(SAR_ADC_DELAY_SAMPLE_DLY_SEL_MASK, 0)); + + /* delay between two samples = (10+1) * 1uS */ + regmap_update_bits(priv->regmap, SAR_ADC_DELAY, + SAR_ADC_DELAY_INPUT_DLY_CNT_MASK, + FIELD_PREP(SAR_ADC_DELAY_INPUT_DLY_CNT_MASK, 10)); + regmap_update_bits(priv->regmap, SAR_ADC_DELAY, + SAR_ADC_DELAY_INPUT_DLY_SEL_MASK, + FIELD_PREP(SAR_ADC_DELAY_INPUT_DLY_SEL_MASK, 1)); + + ret = clk_set_parent(priv->adc_sel_clk, priv->clkin); + if (ret) { + dev_err(indio_dev->dev.parent, + "failed to set adc parent to clkin\n"); + return ret; + } + + ret = clk_set_rate(priv->adc_clk, 1200000); + if (ret) { + dev_err(indio_dev->dev.parent, + "failed to set adc clock rate\n"); + return ret; + } + + return 0; +} + +static int meson_saradc_hw_enable(struct iio_dev *indio_dev) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + int ret; + + meson_saradc_lock(indio_dev); + + ret = regulator_enable(priv->vref); + if (ret < 0) { + dev_err(indio_dev->dev.parent, + "failed to enable vref regulator\n"); + goto err_vref; + } + + ret = clk_prepare_enable(priv->core_clk); + if (ret) { + dev_err(indio_dev->dev.parent, "failed to enable core clk\n"); + goto err_core_clk; + } + + ret = clk_prepare_enable(priv->sana_clk); + if (ret) { + dev_err(indio_dev->dev.parent, "failed to enable sana clk\n"); + goto err_sana_clk; + } + + regmap_update_bits(priv->regmap, SAR_ADC_REG11, + SAR_ADC_REG11_BANDGAP_EN, SAR_ADC_REG11_BANDGAP_EN); + regmap_update_bits(priv->regmap, SAR_ADC_REG3, SAR_ADC_REG3_ADC_EN, + SAR_ADC_REG3_ADC_EN); + + udelay(5); + + ret = clk_prepare_enable(priv->adc_clk); + if (ret) { + dev_err(indio_dev->dev.parent, "failed to enable adc clk\n"); + goto err_adc_clk; + } + + meson_saradc_unlock(indio_dev); + + return 0; + +err_adc_clk: + regmap_update_bits(priv->regmap, SAR_ADC_REG3, SAR_ADC_REG3_ADC_EN, 0); + regmap_update_bits(priv->regmap, SAR_ADC_REG11, + SAR_ADC_REG11_BANDGAP_EN, 0); + clk_disable_unprepare(priv->sana_clk); +err_sana_clk: + clk_disable_unprepare(priv->core_clk); +err_core_clk: + regulator_disable(priv->vref); +err_vref: + meson_saradc_unlock(indio_dev); + return ret; +} + +static void meson_saradc_hw_disable(struct iio_dev *indio_dev) +{ + struct meson_saradc_priv *priv = iio_priv(indio_dev); + + meson_saradc_lock(indio_dev); + + clk_disable_unprepare(priv->adc_clk); + + regmap_update_bits(priv->regmap, SAR_ADC_REG3, SAR_ADC_REG3_ADC_EN, 0); + regmap_update_bits(priv->regmap, SAR_ADC_REG11, + SAR_ADC_REG11_BANDGAP_EN, 0); + + clk_disable_unprepare(priv->sana_clk); + clk_disable_unprepare(priv->core_clk); + + regulator_disable(priv->vref); + + meson_saradc_unlock(indio_dev); +} + +static const struct iio_info meson_saradc_iio_info = { + .read_raw = meson_saradc_iio_info_read_raw, + .driver_module = THIS_MODULE, +}; + +struct meson_saradc_data meson_saradc_gxbb_data = { + .resolution = 10, + .name = "meson-gxbb-saradc", +}; + +struct meson_saradc_data meson_saradc_gxl_data = { + .resolution = 12, + .name = "meson-gxl-saradc", +}; + +static const struct of_device_id meson_saradc_of_match[] = { + { + .compatible = "amlogic,meson-gxbb-saradc", + .data = &meson_saradc_gxbb_data, + }, { + .compatible = "amlogic,meson-gxl-saradc", + .data = &meson_saradc_gxl_data, + }, + {}, +}; +MODULE_DEVICE_TABLE(of, meson_saradc_of_match); + +static int meson_saradc_probe(struct platform_device *pdev) +{ + struct meson_saradc_priv *priv; + struct iio_dev *indio_dev; + struct resource *res; + void __iomem *base; + const struct of_device_id *match; + int ret; + + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv)); + if (!indio_dev) { + dev_err(&pdev->dev, "failed allocating iio device\n"); + return -ENOMEM; + } + + priv = iio_priv(indio_dev); + + match = of_match_device(meson_saradc_of_match, &pdev->dev); + priv->data = match->data; + + indio_dev->name = priv->data->name; + indio_dev->dev.parent = &pdev->dev; + indio_dev->dev.of_node = pdev->dev.of_node; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &meson_saradc_iio_info; + + indio_dev->channels = meson_saradc_iio_channels; + indio_dev->num_channels = ARRAY_SIZE(meson_saradc_iio_channels); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(base)) + return PTR_ERR(base); + + priv->regmap = devm_regmap_init_mmio(&pdev->dev, base, + &meson_saradc_regmap_config); + if (IS_ERR(priv->regmap)) + return PTR_ERR(priv->regmap); + + priv->clkin = devm_clk_get(&pdev->dev, "clkin"); + if (IS_ERR(priv->clkin)) { + dev_err(&pdev->dev, "failed to get clkin\n"); + return PTR_ERR(priv->clkin); + } + + priv->core_clk = devm_clk_get(&pdev->dev, "core"); + if (IS_ERR(priv->core_clk)) { + dev_err(&pdev->dev, "failed to get core clk\n"); + return PTR_ERR(priv->core_clk); + } + + priv->sana_clk = devm_clk_get(&pdev->dev, "sana"); + if (IS_ERR(priv->sana_clk)) { + if (PTR_ERR(priv->sana_clk) == -ENOENT) { + priv->sana_clk = NULL; + } else { + dev_err(&pdev->dev, "failed to get sana clk\n"); + return PTR_ERR(priv->sana_clk); + } + } + + priv->adc_clk = devm_clk_get(&pdev->dev, "adc_clk"); + if (IS_ERR(priv->adc_clk)) { + if (PTR_ERR(priv->adc_clk) == -ENOENT) { + priv->adc_clk = NULL; + } else { + dev_err(&pdev->dev, "failed to get adc clk\n"); + return PTR_ERR(priv->adc_clk); + } + } + + priv->adc_sel_clk = devm_clk_get(&pdev->dev, "adc_sel"); + if (IS_ERR(priv->adc_sel_clk)) { + if (PTR_ERR(priv->adc_sel_clk) == -ENOENT) { + priv->adc_sel_clk = NULL; + } else { + dev_err(&pdev->dev, "failed to get adc_sel clk\n"); + return PTR_ERR(priv->adc_sel_clk); + } + } + + /* on pre-GXBB SoCs the SAR ADC itself provides the ADC clock: */ + if (!priv->adc_clk) { + ret = meson_saradc_clk_init(indio_dev, base); + if (ret) + return ret; + } + + priv->vref = devm_regulator_get(&pdev->dev, "vref"); + if (IS_ERR(priv->vref)) { + dev_err(&pdev->dev, "failed to get vref regulator\n"); + return PTR_ERR(priv->vref); + } + + ret = meson_saradc_init(indio_dev); + if (ret) + goto err; + + ret = meson_saradc_hw_enable(indio_dev); + if (ret) + goto err; + + platform_set_drvdata(pdev, indio_dev); + + ret = iio_device_register(indio_dev); + if (ret) + goto err_hw; + + return 0; + +err_hw: + meson_saradc_hw_disable(indio_dev); +err: + return ret; +} + +static int meson_saradc_remove(struct platform_device *pdev) +{ + struct iio_dev *indio_dev = platform_get_drvdata(pdev); + + meson_saradc_hw_disable(indio_dev); + iio_device_unregister(indio_dev); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int meson_saradc_suspend(struct device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + + meson_saradc_hw_disable(indio_dev); + + return 0; +} + +static int meson_saradc_resume(struct device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + + return meson_saradc_hw_enable(indio_dev); +} +#endif /* CONFIG_PM_SLEEP */ + +static SIMPLE_DEV_PM_OPS(meson_saradc_pm_ops, + meson_saradc_suspend, meson_saradc_resume); + +static struct platform_driver meson_saradc_driver = { + .probe = meson_saradc_probe, + .remove = meson_saradc_remove, + .driver = { + .name = "meson-saradc", + .of_match_table = meson_saradc_of_match, + .pm = &meson_saradc_pm_ops, + }, +}; + +module_platform_driver(meson_saradc_driver); + +MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>"); +MODULE_DESCRIPTION("Amlogic Meson SAR ADC driver"); +MODULE_LICENSE("GPL v2"); -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
