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Date:   Wed, 24 Jun 2020 14:10:38 -0700
From:   Guenter Roeck <linux@roeck-us.net>
To:     Lars Povlsen <lars.povlsen@microchip.com>
Cc:     Jean Delvare <jdelvare@suse.com>,
        Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>,
        linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Alexandre Belloni <alexandre.belloni@bootlin.com>
Subject: Re: [PATCH v4 3/3] hwmon: sparx5: Add Sparx5 SoC temperature driver
Message-ID: <20200624211038.GA72859@roeck-us.net>
References: <20200618135951.25441-1-lars.povlsen@microchip.com>
 <20200618135951.25441-4-lars.povlsen@microchip.com>
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On Thu, Jun 18, 2020 at 03:59:51PM +0200, Lars Povlsen wrote:
> This patch adds a temperature sensor driver to the Sparx5 SoC.
> 
> Signed-off-by: Lars Povlsen <lars.povlsen@microchip.com>

Sorry for the long delay.

We'll still need approval from DT for DT properties.

> ---
>  Documentation/hwmon/sparx5-temp.rst |  33 ++++++

Nitpick: The new file needs to be added to index.rst.

Other than that, for my reference:

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

>  drivers/hwmon/Kconfig               |  10 ++
>  drivers/hwmon/Makefile              |   1 +
>  drivers/hwmon/sparx5-temp.c         | 168 ++++++++++++++++++++++++++++
>  4 files changed, 212 insertions(+)
>  create mode 100644 Documentation/hwmon/sparx5-temp.rst
>  create mode 100644 drivers/hwmon/sparx5-temp.c
> 
> diff --git a/Documentation/hwmon/sparx5-temp.rst b/Documentation/hwmon/sparx5-temp.rst
> new file mode 100644
> index 0000000000000..0140809089542
> --- /dev/null
> +++ b/Documentation/hwmon/sparx5-temp.rst
> @@ -0,0 +1,33 @@
> +.. SPDX-License-Identifier: GPL-2.0-only
> +
> +Microchip SparX-5 SoC
> +=====================
> +
> +Supported chips:
> +
> +  * VSC7546, VSC7549, VSC755, VSC7556, and VSC7558 (Sparx5 series)
> +
> +    Prefix: 'sparx5-temp'
> +
> +    Addresses scanned: -
> +
> +    Datasheet: Provided by Microchip upon request and under NDA
> +
> +Author: Lars Povlsen <lars.povlsen@microchip.com>
> +
> +Description
> +-----------
> +
> +The Sparx5 SoC contains a temperature sensor based on the MR74060
> +Moortec IP.
> +
> +The sensor has a range of -40?C to +125?C and an accuracy of +/-5?C.
> +
> +Sysfs entries
> +-------------
> +
> +The following attributes are supported.
> +
> +======================= ========================================================
> +temp1_input		Die temperature (in millidegree Celsius.)
> +======================= ========================================================
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 288ae9f63588c..7fb5e0c6c6306 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 || COMPILE_TEST
> +	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..857293f650412 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -167,6 +167,7 @@ obj-$(CONFIG_SENSORS_SMM665)	+= smm665.o
>  obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
>  obj-$(CONFIG_SENSORS_SMSC47M1)	+= smsc47m1.o
>  obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
> +obj-$(CONFIG_SENSORS_SPARX5)	+= sparx5-temp.o
>  obj-$(CONFIG_SENSORS_STTS751)	+= stts751.o
>  obj-$(CONFIG_SENSORS_AMC6821)	+= amc6821.o
>  obj-$(CONFIG_SENSORS_TC74)	+= tc74.o
> diff --git a/drivers/hwmon/sparx5-temp.c b/drivers/hwmon/sparx5-temp.c
> new file mode 100644
> index 0000000000000..7d7a060259a80
> --- /dev/null
> +++ b/drivers/hwmon/sparx5-temp.c
> @@ -0,0 +1,168 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/* Sparx5 SoC temperature sensor driver
> + *
> + * Copyright (C) 2020 Lars Povlsen <lars.povlsen@microchip.com>
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/hwmon.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +#define TEMP_CTRL		0
> +#define TEMP_CFG		4
> +#define  TEMP_CFG_CYCLES	GENMASK(24, 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;
> +	struct clk *clk;
> +};
> +
> +static void s5_temp_clk_disable(void *data)
> +{
> +	struct clk *clk = data;
> +
> +	clk_disable_unprepare(clk);
> +}
> +
> +static void s5_temp_enable(struct s5_hwmon *hwmon)
> +{
> +	u32 val = readl(hwmon->base + TEMP_CFG);
> +	u32 clk = clk_get_rate(hwmon->clk) / USEC_PER_SEC;
> +
> +	val &= ~TEMP_CFG_CYCLES;
> +	val |= FIELD_PREP(TEMP_CFG_CYCLES, clk);
> +	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;
> +		/*
> +		 * From register documentation:
> +		 * Temp(C) = TEMP_SENSOR_STAT.TEMP / 4096 * 352.2 - 109.4
> +		 */
> +		value = DIV_ROUND_CLOSEST(value * 3522, 4096) - 1094;
> +		/*
> +		 * Scale down by 10 from above and multiply by 1000 to
> +		 * have millidegrees as specified by the hwmon sysfs
> +		 * interface.
> +		 */
> +		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),
> +	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 ret;
> +
> +	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);
> +
> +	hwmon->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(hwmon->clk))
> +		return PTR_ERR(hwmon->clk);
> +
> +	ret = clk_prepare_enable(hwmon->clk);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_add_action_or_reset(&pdev->dev, s5_temp_clk_disable,
> +				       hwmon->clk);
> +	if (ret)
> +		return ret;
> +
> +	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@microchip.com>");
> +MODULE_DESCRIPTION("Sparx5 SoC temperature sensor driver");
> +MODULE_LICENSE("GPL");