Re: [PATCH v3 2/3] hwmon: da9063: HWMON driver

Guenter Roeck
2021-07-10T16:08:21Z

On Wed, Jul 07, 2021 at 01:25:03PM +0000, Vincent Pelletier wrote:
> Add the HWMON driver for DA9063
>
> Originally-from: Opensource [Steve Twiss] <stwiss.opensource@diasemi.com>
> Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>
> ---
> Changes in v3:
> - changed original author's Signed-off-by into an Originally-from.
> - dropped license boilerplate
> - only return ETIMEOUT if ADC result is not ready by the time the IRQ
> either triggered or timed out
> - removed unnecessary lists
> - changed a duplicate init_comptetion into a more useful reinit_completion
> - dropped unused platform_set_drvdata
> - moved temperature offset reading from mfd driver
>
> Changes in v2:
> - drop of_match_table: this should be meaningless in such sub-function
> driver (at least judging by other sub-function drivers for the da9063)
> - sort includes
> - switch to devm_hwmon_device_register_with_info
> - registers.h changes moved to patch 1
> - add SPDX header
>
> This patch depends on patch 1/3.
> Originally submitted by Steve Twiss in 2014:
> https://marc.info/?l=linux-kernel&m=139560868309857&w=2
>
> drivers/hwmon/Kconfig | 10 ++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/da9063-hwmon.c | 260 +++++++++++++++++++++++++++++++++++
> 3 files changed, 271 insertions(+)
> create mode 100644 drivers/hwmon/da9063-hwmon.c
>
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 87624902ea80..17244cfaa855 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -515,6 +515,16 @@ config SENSORS_DA9055
> This driver can also be built as a module. If so, the module
> will be called da9055-hwmon.
>
> +config SENSORS_DA9063
> + tristate "Dialog Semiconductor DA9063"
> + depends on MFD_DA9063
> + help
> + If you say yes here you get support for the hardware
> + monitoring features of the DA9063 Power Management IC.
> +
> + This driver can also be built as a module. If so, the module
> + will be called da9063-hwmon.
> +
> config SENSORS_I5K_AMB
> tristate "FB-DIMM AMB temperature sensor on Intel 5000 series chipsets"
> depends on PCI
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 59e78bc212cf..6855711ed9ec 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -60,6 +60,7 @@ obj-$(CONFIG_SENSORS_CORSAIR_CPRO) += corsair-cpro.o
> obj-$(CONFIG_SENSORS_CORSAIR_PSU) += corsair-psu.o
> obj-$(CONFIG_SENSORS_DA9052_ADC)+= da9052-hwmon.o
> obj-$(CONFIG_SENSORS_DA9055)+= da9055-hwmon.o
> +obj-$(CONFIG_SENSORS_DA9063) += da9063-hwmon.o
> obj-$(CONFIG_SENSORS_DELL_SMM) += dell-smm-hwmon.o
> obj-$(CONFIG_SENSORS_DME1737) += dme1737.o
> obj-$(CONFIG_SENSORS_DRIVETEMP) += drivetemp.o
> diff --git a/drivers/hwmon/da9063-hwmon.c b/drivers/hwmon/da9063-hwmon.c
> new file mode 100644
> index 000000000000..6367685536a1
> --- /dev/null
> +++ b/drivers/hwmon/da9063-hwmon.c
> @@ -0,0 +1,260 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/* da9063-hwmon.c - Hardware monitor support for DA9063
> + * Copyright (C) 2014 Dialog Semiconductor Ltd.
> + * Copyright (C) 2021 Vincent Pelletier <plr.vincent@gmail.com>
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>

Unnecessary include.

> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/da9063/core.h>
> +#include <linux/mod_devicetable.h>

I don't immediately see where this include is needed. Is this a
leftover ?

> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>

Same here.

> +
> +#define DA9063_ADC_RES (1 << (DA9063_ADC_RES_L_BITS + DA9063_ADC_RES_M_BITS))
> +#define DA9063_ADC_MAX (DA9063_ADC_RES - 1)
> +#define DA9063_2V5 2500
> +#define DA9063_5V0 5000
> +#define DA9063_5V5 5500
> +#define DA9063_TJUNC_M -398

It doesn't matter here (I think), but it would be better to surround the
above with () to ensure that the '-' is not interpreted as arithmetic
operator.

> +#define DA9063_TJUNC_O 330000
> +#define DA9063_VBBAT_M 2048
> +
> +enum da9063_adc {
> + DA9063_CHAN_VSYS = DA9063_ADC_MUX_VSYS,
> + DA9063_CHAN_ADCIN1 = DA9063_ADC_MUX_ADCIN1,
> + DA9063_CHAN_ADCIN2 = DA9063_ADC_MUX_ADCIN2,
> + DA9063_CHAN_ADCIN3 = DA9063_ADC_MUX_ADCIN3,
> + DA9063_CHAN_TJUNC = DA9063_ADC_MUX_T_SENSE,
> + DA9063_CHAN_VBBAT = DA9063_ADC_MUX_VBBAT,
> + DA9063_CHAN_LDO_G1 = DA9063_ADC_MUX_LDO_G1,
> + DA9063_CHAN_LDO_G2 = DA9063_ADC_MUX_LDO_G2,
> + DA9063_CHAN_LDO_G3 = DA9063_ADC_MUX_LDO_G3

Many of the above defines are not used. Do you plan a follow-up commit
to use them ? Otherwise please drop unused defines.

> +};
> +
> +struct da9063_hwmon {
> + struct da9063 *da9063;
> + struct mutex hwmon_mutex;
> + struct completion adc_ready;
> + signed char tjunc_offset;

I am curious: 'char' implies 'signed'. Any reason for using 'signed' ?

Also, note that on most architectures the resulting code is more complex
when using 'char' instead of 'int'. This is seen easily by compiling the
driver for arm64: Replacing the above 'signed char' with 'int' reduces
code size by 32 bytes.

> +};
> +
> +static int da9063_adc_manual_read(struct da9063_hwmon *hwmon, int channel)
> +{
> + int ret;
> + unsigned char val;
> + unsigned char data[2];
> + int adc_man;

Should this be unsigned int ?

> +
> + mutex_lock(&hwmon->hwmon_mutex);
> +
> + val = (channel & DA9063_ADC_MUX_MASK) | DA9063_ADC_MAN;
> + ret = regmap_update_bits(hwmon->da9063->regmap, DA9063_REG_ADC_MAN,
> + DA9063_ADC_MUX_MASK | DA9063_ADC_MAN, val);
> + if (ret < 0)
> + goto err_mread;
> +
> + ret = wait_for_completion_timeout(&hwmon->adc_ready,
> + msecs_to_jiffies(100));
> + reinit_completion(&hwmon->adc_ready);

This is unusual. Normally I see init_completion() or reinit_completion()
ahead of calls to wait functions.

If a request timed out and an interrupt happened after the timeout,
the next request would return immediately with the previous result,
since complete() would be called on the re-initialized completion
handler. That doesn't seem to be correct to me.

> + if (ret == 0)
> + dev_dbg(hwmon->da9063->dev,
> + "Timeout while waiting for ADC completion IRQ\n");
> +
> + ret = regmap_read(hwmon->da9063->regmap, DA9063_REG_ADC_MAN, &adc_man);
> + if (ret < 0)
> + goto err_mread;
> +
> + /* data value is not ready */
> + if (adc_man & DA9063_ADC_MAN) {
> + ret = -ETIMEDOUT;
> + goto err_mread;
> + }
> +
> + ret = regmap_bulk_read(hwmon->da9063->regmap,
> + DA9063_REG_ADC_RES_L, data, 2);
> + if (ret < 0)
> + goto err_mread;
> +
> + ret = (data[0] & DA9063_ADC_RES_L_MASK) >> DA9063_ADC_RES_L_SHIFT;
> + ret |= data[1] << DA9063_ADC_RES_L_BITS;
> +err_mread:
> + mutex_unlock(&hwmon->hwmon_mutex);
> + return ret;
> +}
> +
> +static irqreturn_t da9063_hwmon_irq_handler(int irq, void *irq_data)
> +{
> + struct da9063_hwmon *hwmon = irq_data;
> +
> + complete(&hwmon->adc_ready);
> + return IRQ_HANDLED;
> +}
> +
> +static umode_t da9063_is_visible(const void *drvdata, enum
> + hwmon_sensor_types type, u32 attr, int channel)
> +{
> + return 0444;
> +}
> +
> +static const enum da9063_adc da9063_in_index[] = {
> + DA9063_CHAN_VSYS, DA9063_CHAN_VBBAT
> +};
> +
> +static int da9063_read(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long *val)
> +{
> + struct da9063_hwmon *hwmon = dev_get_drvdata(dev);
> + enum da9063_adc adc_channel;
> + int tmp;
> +
> + switch (type) {
> + case hwmon_in:
> + if (attr != hwmon_in_input)
> + return -EOPNOTSUPP;
> + adc_channel = da9063_in_index[channel];
> + break;
> + case hwmon_temp:
> + if (attr != hwmon_temp_input)
> + return -EOPNOTSUPP;
> + adc_channel = DA9063_CHAN_TJUNC;
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + tmp = da9063_adc_manual_read(hwmon, adc_channel);
> + if (tmp < 0)
> + return tmp;
> +
> + switch (adc_channel) {
> + case DA9063_CHAN_VSYS:
> + *val = ((DA9063_5V5 - DA9063_2V5) * tmp) / DA9063_ADC_MAX +
> + DA9063_2V5;
> + break;
> + case DA9063_CHAN_TJUNC:
> + tmp -= hwmon->tjunc_offset;
> + *val = DA9063_TJUNC_M * tmp + DA9063_TJUNC_O;
> + break;
> + case DA9063_CHAN_VBBAT:
> + *val = (DA9063_5V0 * tmp) / DA9063_ADC_MAX;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static const char * const da9063_in_name[] = {
> + "VSYS", "VBBAT"
> +};
> +
> +static int da9063_read_string(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, const char **str)
> +{
> + switch (type) {
> + case hwmon_in:
> + if (attr != hwmon_in_label)
> + return -EOPNOTSUPP;
> + *str = da9063_in_name[channel];
> + break;
> + case hwmon_temp:
> + if (attr != hwmon_temp_label)
> + return -EOPNOTSUPP;
> + *str = "TJUNC";
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + return 0;
> +}
> +
> +static const struct hwmon_ops da9063_ops = {
> + .is_visible = da9063_is_visible,
> + .read = da9063_read,
> + .read_string = da9063_read_string,
> +};
> +
> +static const struct hwmon_channel_info *da9063_channel_info[] = {
> + HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
> + HWMON_CHANNEL_INFO(in,
> + HWMON_I_INPUT | HWMON_I_LABEL,
> + HWMON_I_INPUT | HWMON_I_LABEL),
> + HWMON_CHANNEL_INFO(temp,
> + HWMON_T_INPUT | HWMON_T_LABEL),
> + NULL
> +};
> +
> +static const struct hwmon_chip_info da9063_chip_info = {
> + .ops = &da9063_ops,
> + .info = da9063_channel_info,
> +};
> +
> +static int da9063_hwmon_probe(struct platform_device *pdev)
> +{
> + struct da9063 *da9063 = dev_get_drvdata(pdev->dev.parent);
> + struct da9063_hwmon *hwmon;
> + struct device *hwmon_dev;
> + unsigned int tmp;
> + int irq;
> + int ret;
> +
> + hwmon = devm_kzalloc(&pdev->dev, sizeof(struct da9063_hwmon),
> + GFP_KERNEL);
> + if (!hwmon)
> + return -ENOMEM;
> +
> + mutex_init(&hwmon->hwmon_mutex);
> + init_completion(&hwmon->adc_ready);
> + hwmon->da9063 = da9063;
> +
> + irq = platform_get_irq_byname(pdev, DA9063_DRVNAME_HWMON);
> + if (irq < 0)
> + return irq;
> +
> + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
> + da9063_hwmon_irq_handler,
> + IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> + "HWMON", hwmon);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to request IRQ.\n");
> + return ret;
> + }
> +
> + ret = regmap_read(da9063->regmap, DA9063_REG_T_OFFSET, &tmp);
> + if (ret < 0) {
> + tmp = 0;
> + dev_warn(&pdev->dev,
> + "Temperature trimming value cannot be read (defaulting to 0)\n");
> + }
> + hwmon->tjunc_offset = (signed char) tmp;

Nit: Unnecessary space after typecast (checkpatch --strict would tell you).

Also, I am curious: The temperature offset is a standard hwmon attribute.
Is it an oversight to not report it, or is it on purpose ?

> +
> + hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, "da9063",
> + hwmon,
> + &da9063_chip_info,
> + NULL);
> +
> + return PTR_ERR_OR_ZERO(hwmon_dev);
> +}
> +
> +static struct platform_driver da9063_hwmon_driver = {
> + .probe = da9063_hwmon_probe,
> + .driver = {
> + .name = DA9063_DRVNAME_HWMON,
> + },
> +};
> +module_platform_driver(da9063_hwmon_driver);
> +
> +MODULE_DESCRIPTION("Hardware monitor support device driver for Dialog DA9063");
> +MODULE_AUTHOR("Vincent Pelletier <plr.vincent@gmail.com>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" DA9063_DRVNAME_HWMON);