Re: [PATCH v6 2/4] iio: adc: Add Xilinx AMS driver
From: Jonathan Cameron
Date: Sun Jul 04 2021 - 14:29:18 EST
On Thu, 24 Jun 2021 19:29:37 +0100
Anand Ashok Dumbre <anand.ashok.dumbre@xxxxxxxxxx> wrote:
> The AMS includes an ADC as well as on-chip sensors that can be used to
> sample external voltages and monitor on-die operating conditions, such
> as temperature and supply voltage levels. The AMS has two SYSMON blocks.
> PL-SYSMON block is capable of monitoring off chip voltage and
> temperature.
> PL-SYSMON block has DRP, JTAG and I2C interface to enable monitoring
> from external master. Out of these interface currently only DRP is
> supported.
> Other block PS-SYSMON is memory mapped to PS.
> The AMS can use internal channels to monitor voltage and temperature as
> well as one primary and up to 16 auxiliary channels for measuring
> external voltages.
> The voltage and temperature monitoring channels also have event
> capability which allows to generate an interrupt when their value falls
> below or raises above a set threshold.
>
> Signed-off-by: Manish Narani <manish.narani@xxxxxxxxxx>
> Signed-off-by: Anand Ashok Dumbre <anand.ashok.dumbre@xxxxxxxxxx>
Hi Anand,
A few comments inline from a fresh read.
Only significant one is that the use of separate masks and shifts
differs from how they are normally done in the kernel these days.
FIELD_PREP() and FIELD_GET() allow a single mask definition to be
cleanly used for both the shift and masking in a nice clean way.
Thanks,
Jonathan
> ---
> drivers/iio/adc/Kconfig | 13 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/xilinx-ams.c | 1342 ++++++++++++++++++++++++++++++++++
> 3 files changed, 1356 insertions(+)
> create mode 100644 drivers/iio/adc/xilinx-ams.c
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index c7946c439612..c011ab30ec9a 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -1256,4 +1256,17 @@ config XILINX_XADC
> The driver can also be build as a module. If so, the module will be called
> xilinx-xadc.
>
> +config XILINX_AMS
> + tristate "Xilinx AMS driver"
> + depends on ARCH_ZYNQMP || COMPILE_TEST
> + depends on HAS_IOMEM
> + help
> + Say yes here to have support for the Xilinx AMS.
> +
> + The driver supports Voltage and Temperature monitoring on Xilinx Ultrascale
> + devices.
> +
> + The driver can also be built as a module. If so, the module will be called
> + xilinx-ams.
> +
> endmenu
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index a226657d19c0..99e031f44479 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -112,4 +112,5 @@ obj-$(CONFIG_VF610_ADC) += vf610_adc.o
> obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
> xilinx-xadc-y := xilinx-xadc-core.o xilinx-xadc-events.o
> obj-$(CONFIG_XILINX_XADC) += xilinx-xadc.o
> +obj-$(CONFIG_XILINX_AMS) += xilinx-ams.o
> obj-$(CONFIG_SD_ADC_MODULATOR) += sd_adc_modulator.o
> diff --git a/drivers/iio/adc/xilinx-ams.c b/drivers/iio/adc/xilinx-ams.c
> new file mode 100644
> index 000000000000..463e3162726c
> --- /dev/null
> +++ b/drivers/iio/adc/xilinx-ams.c
> @@ -0,0 +1,1342 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Xilinx AMS driver
> + *
> + * Copyright (C) 2021 Xilinx, Inc.
> + *
> + * Manish Narani <mnarani@xxxxxxxxxx>
> + * Rajnikant Bhojani <rajnikant.bhojani@xxxxxxxxxx>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#include <linux/iio/events.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +static const unsigned int AMS_UNMASK_TIMEOUT_MS = 500;
> +
> +/* AMS registers definitions */
> +#define AMS_ISR_0 0x010
> +#define AMS_ISR_1 0x014
> +#define AMS_IER_0 0x020
> +#define AMS_IER_1 0x024
> +#define AMS_IDR_0 0x028
> +#define AMS_IDR_1 0x02c
> +#define AMS_PS_CSTS 0x040
> +#define AMS_PL_CSTS 0x044
> +
> +#define AMS_VCC_PSPLL0 0x060
> +#define AMS_VCC_PSPLL3 0x06C
> +#define AMS_VCCINT 0x078
> +#define AMS_VCCBRAM 0x07C
> +#define AMS_VCCAUX 0x080
> +#define AMS_PSDDRPLL 0x084
> +#define AMS_PSINTFPDDR 0x09C
> +
> +#define AMS_VCC_PSPLL0_CH 48
> +#define AMS_VCC_PSPLL3_CH 51
> +#define AMS_VCCINT_CH 54
> +#define AMS_VCCBRAM_CH 55
> +#define AMS_VCCAUX_CH 56
> +#define AMS_PSDDRPLL_CH 57
> +#define AMS_PSINTFPDDR_CH 63
> +
> +#define AMS_REG_CONFIG0 0x100
> +#define AMS_REG_CONFIG1 0x104
> +#define AMS_REG_CONFIG3 0x10C
> +#define AMS_REG_SEQ_CH0 0x120
> +#define AMS_REG_SEQ_CH1 0x124
> +#define AMS_REG_SEQ_CH2 0x118
> +
> +#define AMS_TEMP 0x000
> +#define AMS_SUPPLY1 0x004
> +#define AMS_SUPPLY2 0x008
> +#define AMS_VP_VN 0x00c
> +#define AMS_VREFP 0x010
> +#define AMS_VREFN 0x014
> +#define AMS_SUPPLY3 0x018
> +#define AMS_SUPPLY4 0x034
> +#define AMS_SUPPLY5 0x038
> +#define AMS_SUPPLY6 0x03c
> +#define AMS_SUPPLY7 0x200
> +#define AMS_SUPPLY8 0x204
> +#define AMS_SUPPLY9 0x208
> +#define AMS_SUPPLY10 0x20c
> +#define AMS_VCCAMS 0x210
> +#define AMS_TEMP_REMOTE 0x214
> +
> +#define AMS_REG_VAUX(x) (0x40 + 4 * (x))
> +
> +#define AMS_PS_RESET_VALUE 0xFFFF
> +#define AMS_PL_RESET_VALUE 0xFFFF
> +
> +#define AMS_CONF0_CHANNEL_NUM_MASK GENMASK(6, 0)
> +
> +#define AMS_CONF1_SEQ_MASK GENMASK(15, 12)
> +#define AMS_CONF1_SEQ_DEFAULT (0 << 12)
> +#define AMS_CONF1_SEQ_CONTINUOUS (2 << 12)
> +#define AMS_CONF1_SEQ_SINGLE_CHANNEL (3 << 12)
FIELD_PREP(AMS_CONFG1_SEQ_MASK, 0) or even better, define
the values as not shifted and have
FIELD_PREP(AMS_CONFIG1_SEQ_MASK, AMS_CONF1_SEQ_DEFAULT)
etc in the relevant places inline.
> +
> +#define AMS_REG_SEQ0_MASK 0xFFFF
> +#define AMS_REG_SEQ2_MASK 0x003F
> +#define AMS_REG_SEQ1_MASK 0xFFFF
> +#define AMS_REG_SEQ2_MASK_SHIFT 16
> +#define AMS_REG_SEQ1_MASK_SHIFT 22
As below, combine mask and shift into a shifted mask
then you can use FIELD_PREP() to do the magic for you.
> +
> +#define AMS_REGCFG1_ALARM_MASK 0xF0F
> +#define AMS_REGCFG3_ALARM_MASK 0x3F
> +
> +#define AMS_ALARM_TEMP 0x140
> +#define AMS_ALARM_SUPPLY1 0x144
> +#define AMS_ALARM_SUPPLY2 0x148
> +#define AMS_ALARM_SUPPLY3 0x160
> +#define AMS_ALARM_SUPPLY4 0x164
> +#define AMS_ALARM_SUPPLY5 0x168
> +#define AMS_ALARM_SUPPLY6 0x16c
> +#define AMS_ALARM_SUPPLY7 0x180
> +#define AMS_ALARM_SUPPLY8 0x184
> +#define AMS_ALARM_SUPPLY9 0x188
> +#define AMS_ALARM_SUPPLY10 0x18c
> +#define AMS_ALARM_VCCAMS 0x190
> +#define AMS_ALARM_TEMP_REMOTE 0x194
> +#define AMS_ALARM_THRESHOLD_OFF_10 0x10
> +#define AMS_ALARM_THRESHOLD_OFF_20 0x20
> +
> +#define AMS_ALARM_THR_DIRECT_MASK 0x01
> +#define AMS_ALARM_THR_MIN 0x0000
> +#define AMS_ALARM_THR_MAX 0xffff
> +
> +#define AMS_NO_OF_ALARMS 32
> +#define AMS_PL_ALARM_START 16
> +#define AMS_ISR0_ALARM_MASK 0xFFFFFFFFU
> +#define AMS_ISR1_ALARM_MASK 0xE000001FU
> +#define AMS_ISR1_EOC_MASK 0x00000008U
> +#define AMS_ISR1_INTR_MASK_SHIFT 32
> +#define AMS_ISR0_ALARM_2_TO_0_MASK 0x07
> +#define AMS_ISR0_ALARM_6_TO_3_MASK 0x78
> +#define AMS_ISR0_ALARM_12_TO_7_MASK 0x3F
> +#define AMS_CONF1_ALARM_2_TO_0_SHIFT 1
Can we handle these via a single mask that includes the shift
and FIELD_PREP() etc? That tends to make it easier to
review by ensuring we don't have multiple defines to deal with.
> +#define AMS_CONF1_ALARM_6_TO_3_SHIFT 5
> +#define AMS_CONF3_ALARM_12_TO_7_SHIFT 8
> +
> +#define AMS_PS_CSTS_PS_READY 0x08010000U
> +#define AMS_PL_CSTS_ACCESS_MASK 0x00000001U
> +
> +#define AMS_PL_MAX_FIXED_CHANNEL 10
> +#define AMS_PL_MAX_EXT_CHANNEL 20
> +
> +#define AMS_INIT_TIMEOUT_US 10000
> +
> +/*
> + * Following scale and offset value is derived from
> + * UG580 (v1.7) December 20, 2016
> + */
> +#define AMS_SUPPLY_SCALE_1VOLT 1000
> +#define AMS_SUPPLY_SCALE_3VOLT 3000
> +#define AMS_SUPPLY_SCALE_6VOLT 6000
> +#define AMS_SUPPLY_SCALE_DIV_BIT 16
> +
> +#define AMS_TEMP_SCALE 509314
> +#define AMS_TEMP_SCALE_DIV_BIT 16
> +#define AMS_TEMP_OFFSET -((280230L << 16) / 509314)
> +
> +enum ams_alarm_bit {
> + AMS_ALARM_BIT_TEMP,
> + AMS_ALARM_BIT_SUPPLY1,
> + AMS_ALARM_BIT_SUPPLY2,
> + AMS_ALARM_BIT_SUPPLY3,
> + AMS_ALARM_BIT_SUPPLY4,
> + AMS_ALARM_BIT_SUPPLY5,
> + AMS_ALARM_BIT_SUPPLY6,
> + AMS_ALARM_BIT_RESERVED,
> + AMS_ALARM_BIT_SUPPLY7,
> + AMS_ALARM_BIT_SUPPLY8,
> + AMS_ALARM_BIT_SUPPLY9,
> + AMS_ALARM_BIT_SUPPLY10,
> + AMS_ALARM_BIT_VCCAMS,
> + AMS_ALARM_BIT_TEMP_REMOTE
> +};
> +
> +enum ams_seq {
> + AMS_SEQ_VCC_PSPLL,
> + AMS_SEQ_VCC_PSBATT,
> + AMS_SEQ_VCCINT,
> + AMS_SEQ_VCCBRAM,
> + AMS_SEQ_VCCAUX,
> + AMS_SEQ_PSDDRPLL,
> + AMS_SEQ_INTDDR
> +};
> +
> +enum ams_ps_pl_seq {
> + AMS_SEQ_CALIB,
> + AMS_SEQ_RSVD_1,
> + AMS_SEQ_RSVD_2,
> + AMS_SEQ_TEST,
> + AMS_SEQ_RSVD_4,
> + AMS_SEQ_SUPPLY4,
> + AMS_SEQ_SUPPLY5,
> + AMS_SEQ_SUPPLY6,
> + AMS_SEQ_TEMP,
> + AMS_SEQ_SUPPLY2,
> + AMS_SEQ_SUPPLY1,
> + AMS_SEQ_VP_VN,
> + AMS_SEQ_VREFP,
> + AMS_SEQ_VREFN,
> + AMS_SEQ_SUPPLY3,
> + AMS_SEQ_CURRENT_MON,
> + AMS_SEQ_SUPPLY7,
> + AMS_SEQ_SUPPLY8,
> + AMS_SEQ_SUPPLY9,
> + AMS_SEQ_SUPPLY10,
> + AMS_SEQ_VCCAMS,
> + AMS_SEQ_TEMP_REMOTE,
> + AMS_SEQ_MAX
> +};
> +
> +#define AMS_SEQ(x) (AMS_SEQ_MAX + (x))
> +#define AMS_VAUX_SEQ(x) (AMS_SEQ_MAX + (x))
> +
> +#define AMS_PS_SEQ_MAX AMS_SEQ_MAX
> +#define PS_SEQ(x) (x)
> +#define PL_SEQ(x) (AMS_PS_SEQ_MAX + (x))
> +
> +#define AMS_CHAN_TEMP(_scan_index, _addr) { \
> + .type = IIO_TEMP, \
> + .indexed = 1, \
> + .address = (_addr), \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> + BIT(IIO_CHAN_INFO_SCALE) | \
> + BIT(IIO_CHAN_INFO_OFFSET), \
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> + .event_spec = ams_temp_events, \
> + .num_event_specs = ARRAY_SIZE(ams_temp_events), \
> + .scan_index = (_scan_index), \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 12, \
> + .storagebits = 16, \
> + .shift = 4, \
> + .endianness = IIO_CPU, \
Currently these are only documentation i think as no support for using them
in this driver (buffered modes). You could drop them until you need them
in some future patch.
> + }, \
> +}
> +
...
> +static int ams_enable_single_channel(struct ams *ams, unsigned int offset)
> +{
> + u8 channel_num = 0;
> +
> + switch (offset) {
> + case AMS_VCC_PSPLL0:
> + channel_num = AMS_VCC_PSPLL0_CH;
> + break;
> + case AMS_VCC_PSPLL3:
> + channel_num = AMS_VCC_PSPLL3_CH;
> + break;
> + case AMS_VCCINT:
> + channel_num = AMS_VCCINT_CH;
> + break;
> + case AMS_VCCBRAM:
> + channel_num = AMS_VCCBRAM_CH;
> + break;
> + case AMS_VCCAUX:
> + channel_num = AMS_VCCAUX_CH;
> + break;
> + case AMS_PSDDRPLL:
> + channel_num = AMS_PSDDRPLL_CH;
> + break;
> + case AMS_PSINTFPDDR:
> + channel_num = AMS_PSINTFPDDR_CH;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + /* set single channel, sequencer off mode */
> + ams_ps_update_reg(ams, AMS_REG_CONFIG1, AMS_CONF1_SEQ_MASK,
> + AMS_CONF1_SEQ_SINGLE_CHANNEL);
> +
> + /* write the channel number */
> + ams_ps_update_reg(ams, AMS_REG_CONFIG0, AMS_CONF0_CHANNEL_NUM_MASK,
> + channel_num);
nitpick: Blank line here.
> + return 0;
> +}
> +
...
> +static int ams_get_ext_chan(struct device_node *chan_node,
> + struct iio_chan_spec *channels, int num_channels)
> +{
> + struct device_node *child;
> + unsigned int reg;
> + int ret;
> +
> + for_each_child_of_node(chan_node, child) {
> + ret = of_property_read_u32(child, "reg", ®);
> + if (ret || reg > (AMS_PL_MAX_EXT_CHANNEL + 30))
> + continue;
> +
> + memcpy(&channels[num_channels], &ams_pl_channels[reg +
> + AMS_PL_MAX_FIXED_CHANNEL - 30], sizeof(*channels));
> +
> + if (of_property_read_bool(child,
> + "xlnx,bipolar"))
Above fits on one line easily.
> + channels[num_channels].scan_type.sign = 's';
> +
> + num_channels++;
> + }
> +
> + return num_channels;
> +}
> +
...
> +
> +static int ams_probe(struct platform_device *pdev)
> +{
> + struct iio_dev *indio_dev;
> + struct ams *ams;
> + struct resource *res;
> + int ret;
> +
> + if (!pdev->dev.of_node)
> + return -ENODEV;
> +
> + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*ams));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + ams = iio_priv(indio_dev);
> + mutex_init(&ams->lock);
> +
> + indio_dev->name = "xilinx-ams";
> +
> + indio_dev->info = &iio_ams_info;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + ams->base = devm_ioremap_resource(&pdev->dev, res);
devm_platform_ioremap_resource()
Slight reduction in boilerplate.
> + if (IS_ERR(ams->base))
> + return PTR_ERR(ams->base);
> +
> + ams->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(ams->clk))
> + return PTR_ERR(ams->clk);
> + clk_prepare_enable(ams->clk);
> + devm_add_action_or_reset(&pdev->dev, (void *)clk_disable_unprepare,
> + ams->clk);
> +
> + INIT_DELAYED_WORK(&ams->ams_unmask_work, ams_unmask_worker);
> + devm_add_action_or_reset(&pdev->dev, (void *)cancel_delayed_work,
I'm not keen on casting away the function pointer type. Normally we'd
just wrap it in a local function, to make it clear it was deliberate and avoid
potential nasty problems if the signature of the function ever changes.
It's 3 lines of boilerplate, but will give me warm fuzzy feelings!
Same for the other case above. The fact this isn't done in exising kernel
code make this particularly risky.
> + &ams->ams_unmask_work);
> +
> + ret = ams_init_device(ams);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to initialize AMS\n");
> + return ret;
> + }
> +
> + ret = ams_parse_dt(indio_dev, pdev);
> + if (ret) {
> + dev_err(&pdev->dev, "failure in parsing DT\n");
> + return ret;
> + }
> +
> + ams_enable_channel_sequence(indio_dev);
> +
> + ams->irq = platform_get_irq(pdev, 0);
platform_get_irq () can return errors, in particular -EPROBE_DEFER so I'd check
that and return before you call devm_request_irq()
I'm not sure devm_request_irq() will not eat that error code.
> + ret = devm_request_irq(&pdev->dev, ams->irq, &ams_irq, 0, "ams-irq",
> + indio_dev);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to register interrupt\n");
> + return ret;
> + }
> +
> + platform_set_drvdata(pdev, indio_dev);
> +
> + return iio_device_register(indio_dev);
> +}
> +
> +static int ams_remove(struct platform_device *pdev)
> +{
> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +
> + iio_device_unregister(indio_dev);
If this is all you have in remove, then you can use devm_iio_device_register()
in probe() and not need an remove() callback at all.
> +
> + return 0;
> +}
> +
...