Re: [PATCH 3/3] hwmon: sparx5: Add Sparx5 SoC temperature driver
From: Guenter Roeck
Date: Wed May 13 2020 - 11:20:22 EST
On Wed, May 13, 2020 at 03:41:40PM +0200, Lars Povlsen 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>
> ---
> drivers/hwmon/Kconfig | 10 +++
> drivers/hwmon/Makefile | 2 +-
> drivers/hwmon/sparx5-temp.c | 154 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 165 insertions(+), 1 deletion(-)
> create mode 100644 drivers/hwmon/sparx5-temp.c
>
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 4c62f900bf7e8..130cb1f1748ff 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -480,6 +480,16 @@ 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
> + 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 b0b9c8e571762..28a09986b7a62 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -64,6 +64,7 @@ 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
> @@ -190,4 +191,3 @@ 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..bf9dd102a9825
> --- /dev/null
> +++ b/drivers/hwmon/sparx5-temp.c
> @@ -0,0 +1,154 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/* Sparx5 SoC temperature sensor driver
> + *
> + * Copyright (C) 2020 Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx>
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
Unnecessary include
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +
> +#define TEMP_CTRL 0
> +#define TEMP_CFG 4
> +#define TEMP_CFG_CYCLES GENMASK(24, 15)
> +#define TEMP_CFG_CYCLES_OFF 15
> +#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) {
> + value = (stat & TEMP_STAT_TEMP);
Unnecessary ( )
> + value = DIV_ROUND_CLOSEST(value * 3522, 4096) - 1094;
> + value *= 100;
> + *temp = value;
> + } else
> + rc = -EINVAL;
-EINVAL is for bad used input. -EIO, maybe, unless there is a better error.
Also,
if (!(stat & TEMP_STAT_VALID))
return -EIO;
...
would be easier to read (and not result in a checkpatch warning).
> + 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),
> + 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 = 0;
Unnecessary initialization
> +
> + 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;
> +
> + 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");
> --
> 2.26.2