Re: [PATCH v2 3/3] hwmon: sparx5: Add Sparx5 SoC temperature driver

From: Lars Povlsen
Date: Tue Jun 09 2020 - 08:20:46 EST


Jonathan Cameron writes:

> On Tue, 9 Jun 2020 09:49:40 +0200
> Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx> wrote:
>
>> This patch adds a temperature sensor driver to the Sparx5 SoC.
>>
>> Reviewed-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
>> Signed-off-by: Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx>
>
> Hi. Quick drive by review whilst waiting for coffee time...
>
> A few minor suggestions inline.
>

Much appreciated!

> Thanks,
>
> Jonathan
>
>> ---
>> drivers/hwmon/Kconfig | 10 +++
>> drivers/hwmon/Makefile | 2 +-
>> drivers/hwmon/sparx5-temp.c | 152 ++++++++++++++++++++++++++++++++++++
>> 3 files changed, 163 insertions(+), 1 deletion(-)
>> create mode 100644 drivers/hwmon/sparx5-temp.c
>>
>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
>> index 288ae9f63588c..ec6bb8b8b12df 100644
>> --- a/drivers/hwmon/Kconfig
>> +++ b/drivers/hwmon/Kconfig
>> @@ -515,6 +515,16 @@ config SENSORS_I5K_AMB
>> This driver can also be built as a module. If so, the module
>> will be called i5k_amb.
>>
>> +config SENSORS_SPARX5
>> + tristate "Sparx5 SoC temperature sensor"
>> + depends on ARCH_SPARX5
> Anything stop this building with COMPILE_TEST?
>
> That will great increase automated build coverage.
>
>> + help
>> + If you say yes here you get support for temperature monitoring
>> + with the Microchip Sparx5 SoC.
>> +
>> + This driver can also be built as a module. If so, the module
>> + will be called sparx5-temp.
>> +
>> config SENSORS_F71805F
>> tristate "Fintek F71805F/FG, F71806F/FG and F71872F/FG"
>> depends on !PPC
>> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
>> index 3e32c21f5efe3..144f09993a3f4 100644
>> --- a/drivers/hwmon/Makefile
>> +++ b/drivers/hwmon/Makefile
>> @@ -66,6 +66,7 @@ obj-$(CONFIG_SENSORS_DS1621) += ds1621.o
>> obj-$(CONFIG_SENSORS_EMC1403) += emc1403.o
>> obj-$(CONFIG_SENSORS_EMC2103) += emc2103.o
>> obj-$(CONFIG_SENSORS_EMC6W201) += emc6w201.o
>> +obj-$(CONFIG_SENSORS_SPARX5) += sparx5-temp.o
>> obj-$(CONFIG_SENSORS_F71805F) += f71805f.o
>> obj-$(CONFIG_SENSORS_F71882FG) += f71882fg.o
>> obj-$(CONFIG_SENSORS_F75375S) += f75375s.o
>> @@ -193,4 +194,3 @@ obj-$(CONFIG_SENSORS_OCC) += occ/
>> obj-$(CONFIG_PMBUS) += pmbus/
>>
>> ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG
>> -
>> diff --git a/drivers/hwmon/sparx5-temp.c b/drivers/hwmon/sparx5-temp.c
>> new file mode 100644
>> index 0000000000000..2e754462b6010
>> --- /dev/null
>> +++ b/drivers/hwmon/sparx5-temp.c
>> @@ -0,0 +1,152 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/* Sparx5 SoC temperature sensor driver
>> + *
>> + * Copyright (C) 2020 Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/init.h>
>> +#include <linux/hwmon.h>
>> +#include <linux/io.h>
>> +#include <linux/of_device.h>
> I think you only have this to define the id table?
>
> If so, perhaps better to include mod_devicetable.h and not include
> the of header.

Well, I ended up needed other, so it became:

-#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/mod_devicetable.h>

Other of these drivers seem to use "linux/of_device.h" as well?

>
>> +
>> +#define TEMP_CTRL 0
>> +#define TEMP_CFG 4
>> +#define TEMP_CFG_CYCLES GENMASK(24, 15)
>> +#define TEMP_CFG_CYCLES_OFF 15
>
> Could you used FIELD_PREP etc to avoid having to have both
> the mask and offset defined here?
>
>> +#define TEMP_CFG_ENA BIT(0)
>> +#define TEMP_STAT 8
>> +#define TEMP_STAT_VALID BIT(12)
>> +#define TEMP_STAT_TEMP GENMASK(11, 0)
>> +
>> +struct s5_hwmon {
>> + void __iomem *base;
>> +};
>> +
>> +static void s5_temp_enable(struct s5_hwmon *hwmon)
>> +{
>> + u32 val = readl(hwmon->base + TEMP_CFG);
>> + u32 clk = 250;
>> +
>> + val &= ~TEMP_CFG_CYCLES;
>> + val |= (clk << TEMP_CFG_CYCLES_OFF);
>> + val |= TEMP_CFG_ENA;
>> +
>> + writel(val, hwmon->base + TEMP_CFG);
>> +}
>> +
>> +static void s5_temp_disable(void *data)
>> +{
>> + struct s5_hwmon *hwmon = data;
>> + u32 val = readl(hwmon->base + TEMP_CFG);
>> +
>> + val &= ~TEMP_CFG_ENA;
>> +
>> + writel(val, hwmon->base + TEMP_CFG);
>> +}
>> +
>> +static int s5_read(struct device *dev, enum hwmon_sensor_types type,
>> + u32 attr, int channel, long *temp)
>> +{
>> + struct s5_hwmon *hwmon = dev_get_drvdata(dev);
>> + int rc = 0, value;
>> + u32 stat;
>> +
>> + switch (attr) {
>> + case hwmon_temp_input:
>> + stat = readl_relaxed(hwmon->base + TEMP_STAT);
>> + if (!(stat & TEMP_STAT_VALID))
>> + return -EIO;
>> + value = stat & TEMP_STAT_TEMP;
>> + value = DIV_ROUND_CLOSEST(value * 3522, 4096) - 1094;
>> + value *= 100;
>> + *temp = value;
>> + break;
>> + default:
>> + rc = -EOPNOTSUPP;
>> + break;
>> + }
>> +
>> + return rc;
>> +}
>> +
>> +static umode_t s5_is_visible(const void *_data, enum hwmon_sensor_types type,
>> + u32 attr, int channel)
>> +{
>> + if (type != hwmon_temp)
>> + return 0;
>> +
>> + switch (attr) {
>> + case hwmon_temp_input:
>> + return 0444;
>> + default:
>> + return 0;
>> + }
>> +}
>> +
>> +static const struct hwmon_channel_info *s5_info[] = {
>> + HWMON_CHANNEL_INFO(chip,
>> + HWMON_C_REGISTER_TZ),
>> + HWMON_CHANNEL_INFO(temp,
>> + HWMON_T_INPUT),
>
> Excess line breaks. The above 2 would be more readable on one line each.
>

Right.

>> + NULL
>> +};
>> +
>> +static const struct hwmon_ops s5_hwmon_ops = {
>> + .is_visible = s5_is_visible,
>> + .read = s5_read,
>> +};
>> +
>> +static const struct hwmon_chip_info s5_chip_info = {
>> + .ops = &s5_hwmon_ops,
>> + .info = s5_info,
>> +};
>> +
>> +static int s5_temp_probe(struct platform_device *pdev)
>> +{
>> + struct device *hwmon_dev;
>> + struct s5_hwmon *hwmon;
>> + int err;
>> +
>> + hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
>> + if (!hwmon)
>> + return -ENOMEM;
>> +
>> + hwmon->base = devm_platform_ioremap_resource(pdev, 0);
>> + if (IS_ERR(hwmon->base))
>> + return PTR_ERR(hwmon->base);
>> +
>> + err = devm_add_action(&pdev->dev, s5_temp_disable, hwmon);
>> + if (err)
>> + return err;
>
> Probably just my linear way of thinking, but unusual to put error
> handling / remove stuff in place _before_ the thing it's unwinding.
>
> We have devm_add_action_or_reset to make it safe to call this after
> the thing it unwinds.
>

Seems I got this "backwardness" from ltq-cputemp.c. However, its totally
unneeded here, so I'll just remove it.

Thanks!

---Lars

>> +
>> + s5_temp_enable(hwmon);
>> +
>> + hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
>> + "s5_temp",
>> + hwmon,
>> + &s5_chip_info,
>> + NULL);
>> +
>> + return PTR_ERR_OR_ZERO(hwmon_dev);
>> +}
>> +
>> +const struct of_device_id s5_temp_match[] = {
>> + { .compatible = "microchip,sparx5-temp" },
>> + {},
>> +};
>> +MODULE_DEVICE_TABLE(of, s5_temp_match);
>> +
>> +static struct platform_driver s5_temp_driver = {
>> + .probe = s5_temp_probe,
>> + .driver = {
>> + .name = "sparx5-temp",
>> + .of_match_table = s5_temp_match,
>> + },
>> +};
>> +
>> +module_platform_driver(s5_temp_driver);
>> +
>> +MODULE_AUTHOR("Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx>");
>> +MODULE_DESCRIPTION("Sparx5 SoC temperature sensor driver");
>> +MODULE_LICENSE("GPL");
>> --
>> 2.27.0
>>
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--
Lars Povlsen,
Microchip