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Date:   Thu, 14 Apr 2022 09:12:14 +0200
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Subject: Re: [PATCH v7 1/2] thermal: Add thermal driver for Sunplus SP7021
Content-Language: en-US
To:     Li-hao Kuo <lhjeff911@gmail.com>, krzk@kernel.org,
        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.1649662002.git.lhjeff911@gmail.com>
 <c59e0a5c53f055b7159bc896083538d1f8ac9ad8.1649662002.git.lhjeff911@gmail.com>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
In-Reply-To: <c59e0a5c53f055b7159bc896083538d1f8ac9ad8.1649662002.git.lhjeff911@gmail.com>
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On 11/04/2022 10:52, Li-hao Kuo wrote:
> Add thermal driver for Sunplus SP7021.

Already asked previously : please give a more detailed description of 
the sensor

I've commented again this patch. There are some comments which are not 
taken into account from my previous review on v4


> Signed-off-by: Li-hao Kuo <lhjeff911@gmail.com>
> ---
> Changes in v7:
>   - Modify yaml file.
> 
>   MAINTAINERS                       |   6 ++
>   drivers/thermal/Kconfig           |  10 +++
>   drivers/thermal/Makefile          |   1 +
>   drivers/thermal/sunplus_thermal.c | 139 ++++++++++++++++++++++++++++++++++++++
>   4 files changed, 156 insertions(+)
>   create mode 100644 drivers/thermal/sunplus_thermal.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 61d9f11..307570c 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -18885,6 +18885,12 @@ S:	Maintained
>   F:	Documentation/devicetree/bindings/spi/spi-sunplus-sp7021.yaml
>   F:	drivers/spi/spi-sunplus-sp7021.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
> +
>   SUNPLUS UART DRIVER
>   M:	Hammer Hsieh <hammerh0314@gmail.com>
>   S:	Maintained
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index e37691e..66316c3 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 || COMPILE_TEST
> +	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..38a76f9 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
> diff --git a/drivers/thermal/sunplus_thermal.c b/drivers/thermal/sunplus_thermal.c
> new file mode 100644
> index 0000000..9a9b348
> --- /dev/null
> +++ b/drivers/thermal/sunplus_thermal.c
> @@ -0,0 +1,139 @@
> +// 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/delay.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/thermal.h>

Already commented, check the headers above.

> +#define DISABLE_THERMAL		(BIT(31) | BIT(15))
> +#define ENABLE_THERMAL		BIT(31)
> +#define SP_THERMAL_MASK		GENMASK(10, 0)
> +#define SP_TCODE_HIGH_MASK	GENMASK(10, 8)
> +#define SP_TCODE_LOW_MASK	GENMASK(7, 0)
> +
> +#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;

field not used outside of the function checking the return code of 
sensor register

> +	struct platform_device *pdev;

field not used

> +	enum thermal_device_mode mode;

field not used

> +	void __iomem *regs;
> +	int otp_temp0;
> +	u32 id;
> +};
> +
> +static int sp7021_get_otp_temp_coef(struct sp_thermal_data *sp_data, struct device *dev)
> +{
> +	struct nvmem_cell *cell;
> +	ssize_t otp_l;
> +	char *otp_v;
> +
> +	cell = nvmem_cell_get(dev, "calib");
> +	if (IS_ERR(cell))
> +		return PTR_ERR(cell);
> +
> +	otp_v = nvmem_cell_read(cell, &otp_l);
> +	nvmem_cell_put(cell);

See my previous comments in v4, this is wrong. Move the nvmem_cell_put() 
after FIELD_PREP() ... below where otp_v is no longer used.

> +	if (otp_l < 3)
> +		return -EINVAL;

Please replace '3' by a macro

Why this check is needed by the way ? Sounds like only 0 and 1 indexes 
are used here.

> +	sp_data->otp_temp0 = FIELD_PREP(SP_TCODE_LOW_MASK, otp_v[0]) |
> +			     FIELD_PREP(SP_TCODE_HIGH_MASK, otp_v[1]);
> +	if (sp_data->otp_temp0 == 0)
> +		sp_data->otp_temp0 = TEMP_OTP_BASE;
> +	return 0;
> +}
> +
> +/*
> + *When remanufacturing, the 35 degree T_CODE will be read and stored in nvcell.
> + *TEMP_RATE is the SP7021 temperature slope.
> + *T_CODE : 11 digits in total
> + */

nit: space after '*'

Please elaborate the comment, it is still unclear

> +
> +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_THERMAL_MASK, t_code);
> +	*temp = ((sp_data->otp_temp0 - t_code) * 10000 / TEMP_RATE) + TEMP_BASE;
> +	*temp *= 10;
> +	return 0;
> +}
> +
> +static const 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)

Adding a function to wrap another function is pointless in this case. It 
is simpler to directly call devm_thermal_zone_of_sensor_register() from 
the probe function

> +{
> +	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 PTR_ERR(data->pcb_tz);
> +	return 0;
> +}
> +
> +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;
> +
> +	sp_data->regs = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(sp_data->regs)) {
> +		dev_err(&pdev->dev, "resource get fail\n");
> +		return PTR_ERR(sp_data->regs);
> +	}
> +
> +	writel(ENABLE_THERMAL, sp_data->regs + SP_THERMAL_CTL0_REG);
> +
> +	platform_set_drvdata(pdev, sp_data);
> +	ret = sp7021_get_otp_temp_coef(sp_data, &pdev->dev);
> +	if (ret)
> +		return ret;

Add some space to let the code easier to read

> +	ret = sp_thermal_register_sensor(pdev, sp_data, 0);
> +	return ret;
> +}
> +
> +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,

and .remove ?

> +	.driver	= {
> +		.name	= "sp7021-thermal",
> +		.of_match_table = 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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