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Date:   Fri, 25 Feb 2022 14:36:00 +0100
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Subject: Re: [PATCH v4 1/2] thermal: Add thermal driver for Sunplus SP7021
Content-Language: en-US
To:     Li-hao Kuo <lhjeff911@gmail.com>, rafael@kernel.org,
        amitk@kernel.org, rui.zhang@intel.com, robh+dt@kernel.org,
        linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     wells.lu@sunplus.com, lh.kuo@sunplus.com
References: <cover.1642127137.git.lhjeff911@gmail.com>
 <2847f96335da1c74dfbee7ba67939bdc474ba2a4.1642127137.git.lhjeff911@gmail.com>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
In-Reply-To: <2847f96335da1c74dfbee7ba67939bdc474ba2a4.1642127137.git.lhjeff911@gmail.com>
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On 14/01/2022 03:46, Li-hao Kuo wrote:
> Add thermal driver for Sunplus SP7021.

Please give a detailed description of the sensor so we can refer to the 
changelog to understand the code below.


> Signed-off-by: Li-hao Kuo <lhjeff911@gmail.com>
> ---
> Changes in v4:
>   - Modify yaml file remove reg name and change nvmem name
> 
>   MAINTAINERS                       |   6 ++
>   drivers/thermal/Kconfig           |  10 +++
>   drivers/thermal/Makefile          |   1 +
>   drivers/thermal/sunplus_thermal.c | 157 ++++++++++++++++++++++++++++++++++++++
>   4 files changed, 174 insertions(+)
>   create mode 100644 drivers/thermal/sunplus_thermal.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index dc4a137..e41b265 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -18423,6 +18423,12 @@ L:	netdev@vger.kernel.org
>   S:	Maintained
>   F:	drivers/net/ethernet/dlink/sundance.c
>   
> +SUNPLUS THERMAL DRIVER
> +M:	Li-hao Kuo <lhjeff911@gmail.com>
> +L:	linux-pm@vger.kernel.org
> +S:	Maintained
> +F:	drivers/thermal/sunplus_thermal.c
> +
>   SUPERH
>   M:	Yoshinori Sato <ysato@users.sourceforge.jp>
>   M:	Rich Felker <dalias@libc.org>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index e37691e..98647c7 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -502,4 +502,14 @@ config KHADAS_MCU_FAN_THERMAL
>   	  If you say yes here you get support for the FAN controlled
>   	  by the Microcontroller found on the Khadas VIM boards.
>   
> +config SUNPLUS_THERMAL
> +	tristate "Sunplus thermal drivers"
> +	depends on SOC_SP7021
> +	help
> +	  This the Sunplus SP7021 thermal driver, which supports the primitive
> +	  temperature sensor embedded in Sunplus SP7021 SoC.
> +
> +	  If you have a Sunplus SP7021 platform say Y here and enable this option
> +	  to have support for thermal management
> +
>   endif
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index f0c36a1..2f7417a 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -61,3 +61,4 @@ obj-$(CONFIG_UNIPHIER_THERMAL)	+= uniphier_thermal.o
>   obj-$(CONFIG_AMLOGIC_THERMAL)     += amlogic_thermal.o
>   obj-$(CONFIG_SPRD_THERMAL)	+= sprd_thermal.o
>   obj-$(CONFIG_KHADAS_MCU_FAN_THERMAL)	+= khadas_mcu_fan.o
> +obj-$(CONFIG_SUNPLUS_THERMAL)	+= sunplus_thermal.o
> \ No newline at end of file
> diff --git a/drivers/thermal/sunplus_thermal.c b/drivers/thermal/sunplus_thermal.c
> new file mode 100644
> index 0000000..460c41d
> --- /dev/null
> +++ b/drivers/thermal/sunplus_thermal.c
> @@ -0,0 +1,157 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) Sunplus Inc.
> + * Author: Li-hao Kuo <lhjeff911@gmail.com>
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/cpufreq.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/nvmem-consumer.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +#include <linux/rtc.h>
> +#include <linux/thermal.h>


Please check the headers above. Some are not necessary (eg cpufreq, 
delay, rtc ...) AFAICT

> +#define DISABLE_THREMAL		(BIT(31) | BIT(15))
> +#define ENABLE_THREMAL		BIT(31)
> +#define SP_THREMAL_MASK		GENMASK(10, 0)

THREMAL ?

s/THREMAL/THERMAL/ ?

> +#define TEMP_RATE		608
> +#define TEMP_BASE		3500
> +#define TEMP_OTP_BASE		1518
> +
> +#define SP_THERMAL_CTL0_REG	0x0000
> +#define SP_THERMAL_STS0_REG	0x0030
> +
> +/* common data structures */
> +struct sp_thermal_data {
> +	struct thermal_zone_device *pcb_tz;
> +	struct platform_device *pdev;
> +	enum thermal_device_mode mode;
> +	long sensor_temp;
> +	void __iomem *regs;
> +	int otp_temp0;
> +	int otp_temp1;
> +	u32 id;
> +};
> +
> +static char *sp7021_otp_coef_read(struct device *dev, ssize_t *len)
> +{
> +	char *ret = NULL;
> +	struct nvmem_cell *c = nvmem_cell_get(dev, "calib");
> +
> +	if (IS_ERR_OR_NULL(c))
> +		return NULL;
> +
> +	ret = nvmem_cell_read(c, len);
> +	nvmem_cell_put(c);

That is wrong. Please refer to the documentation driver-api/nvmem.rst

nvmem_cell_put() must be called when the pointer returned by 
nvmem_cell_read() is no longer used.


> +	return ret;
> +}
> +
> +static void sp7021_get_otp_temp_coef(struct sp_thermal_data *sp_data, struct device *_d)
> +{
> +	ssize_t otp_l = 0;
> +	char *otp_v;
> +
> +	otp_v = sp7021_otp_coef_read(_d, &otp_l);
> +	if (otp_l < 3)
> +		return;
> +	if (IS_ERR_OR_NULL(otp_v))
> +		return;
> +	sp_data->otp_temp0 = otp_v[0] | (otp_v[1] << 8);

What do you expect by 8bits shifting a char here ?

> +	sp_data->otp_temp0 = otp_v[0] | (otp_v[1] << 8);

duplicate line

> +	sp_data->otp_temp0 = FIELD_GET(SP_THREMAL_MASK, sp_data->otp_temp0);
> +	sp_data->otp_temp1 = (otp_v[1] >> 3) | (otp_v[2] << 5);
> +	sp_data->otp_temp1 = FIELD_GET(SP_THREMAL_MASK, sp_data->otp_temp1);
> +	if (sp_data->otp_temp0 == 0)
> +		sp_data->otp_temp0 = TEMP_OTP_BASE;

Can you add a comment explaining how is stored the coef in the nvcell, 
so we can understand the above actions ?


> +}
> +
> +static int sp_thermal_get_sensor_temp(void *data, int *temp)
> +{
> +	struct sp_thermal_data *sp_data = data;
> +	int t_code;
> +
> +	t_code = readl(sp_data->regs + SP_THERMAL_STS0_REG);
> +	t_code = FIELD_GET(SP_THREMAL_MASK, t_code);
> +	*temp = ((sp_data->otp_temp0 - t_code) * 10000 / TEMP_RATE) + TEMP_BASE;
> +	*temp *= 10;

A comment would be welcome here also

> +	return 0;
> +}
> +
> +static struct thermal_zone_of_device_ops sp_of_thermal_ops = {
> +	.get_temp = sp_thermal_get_sensor_temp,
> +};
> +
> +static int sp_thermal_register_sensor(struct platform_device *pdev, struct sp_thermal_data *data,
> +				       int index)
> +{
> +	int ret;
> +
> +	data->id = index;
> +	data->pcb_tz = devm_thermal_zone_of_sensor_register(&pdev->dev,
> +					data->id, data, &sp_of_thermal_ops);
> +	if (!IS_ERR_OR_NULL(data->pcb_tz))
> +		return 0;
> +	ret = PTR_ERR(data->pcb_tz);
> +	data->pcb_tz = NULL;
> +	return ret;

Usually the logic is inverted

	data->pcb_tz = devm_thermal_zone_of_sensor_register();
	if (IS_ERR_OR_NULL(data->pcb_tz))
		return PTR_ERR(data->pcb_tz);

	return 0;

No need to set pcb_tz to NULL

> +}
> +
> +static int sp7021_thermal_probe(struct platform_device *pdev)
> +{
> +	struct sp_thermal_data *sp_data;
> +	struct resource *res;
> +	int ret;
> +
> +	sp_data = devm_kzalloc(&(pdev->dev), sizeof(*sp_data), GFP_KERNEL);
> +	if (!sp_data)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (IS_ERR(res))
> +		return dev_err_probe(&(pdev->dev), PTR_ERR(res), "resource get fail\n");

Use an intermediate 'dev' variable to shorten the line

> +	sp_data->regs = devm_ioremap(&(pdev->dev), res->start, resource_size(res));
> +	if (IS_ERR(sp_data->regs))
> +		return dev_err_probe(&(pdev->dev), PTR_ERR(sp_data->regs), "mas_base get fail\n");

typo: mas_base -> ioremap

> +	writel(ENABLE_THREMAL, sp_data->regs + SP_THERMAL_CTL0_REG);
> +
> +	platform_set_drvdata(pdev, sp_data);
> +	sp7021_get_otp_temp_coef(sp_data, &pdev->dev);
> +	ret = sp_thermal_register_sensor(pdev, sp_data, 0);

	return sp_thermal_register_sensor(...);
> +

> +	return ret;
> +}
> +
> +static int sp7021_thermal_remove(struct platform_device *_pd)
> +{
> +	return 0;
> +}
> +
> +static const struct of_device_id of_sp7021_thermal_ids[] = {
> +	{ .compatible = "sunplus,sp7021-thermal" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, of_sp7021_thermal_ids);
> +
> +static struct platform_driver sp7021_thermal_driver = {
> +	.probe	= sp7021_thermal_probe,
> +	.remove	= sp7021_thermal_remove,
> +	.driver	= {
> +		.name	= "sp7021-thermal",
> +		.of_match_table = of_match_ptr(of_sp7021_thermal_ids),
> +		},
> +};
> +module_platform_driver(sp7021_thermal_driver);
> +
> +MODULE_AUTHOR("Li-hao Kuo <lhjeff911@gmail.com>");
> +MODULE_DESCRIPTION("Thermal driver for SP7021 SoC");
> +MODULE_LICENSE("GPL");


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