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From: "Jernej Škrabec" <jernej.skrabec@gmail.com>
To: Vasily Khoruzhick <anarsoul@gmail.com>,
	Yangtao Li <tiny.windzz@gmail.com>, Chen-Yu Tsai <wens@csie.org>,
	Samuel Holland <samuel@sholland.org>,
	Andre Przywara <andre.przywara@arm.com>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Zhang Rui <rui.zhang@intel.com>,
	Lukasz Luba <lukasz.luba@arm.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Martin Botka <martin.botka@somainline.org>,
	Maksim Kiselev <bigunclemax@gmail.com>,
	Bob McChesney <bob@electricworry.net>,
	linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-sunxi@lists.linux.dev
Subject: Re: [PATCH v4 5/7] thermal: sun8i: add SRAM register access code
Date: Thu, 15 Feb 2024 22:24:54 +0100	[thread overview]
Message-ID: <4543691.LvFx2qVVIh@jernej-laptop> (raw)
In-Reply-To: <20240209144221.3602382-6-andre.przywara@arm.com>

Dne petek, 09. februar 2024 ob 15:42:19 CET je Andre Przywara napisal(a):
> The Allwinner H616 SoC needs to clear a bit in one register in the SRAM
> controller, to report reasonable temperature values. On reset, bit 16 in
> register 0x3000000 is set, which leads to the driver reporting
> temperatures around 200C. Clearing this bit brings the values down to the
> expected range. The BSP code does a one-time write in U-Boot, with a
> comment just mentioning the effect on the THS, but offering no further
> explanation.
> 
> To not rely on firmware to set things up for us, add code that queries
> the SRAM controller device via a DT phandle link, then clear just this
> single bit.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  drivers/thermal/sun8i_thermal.c | 50 +++++++++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
> 
> diff --git a/drivers/thermal/sun8i_thermal.c b/drivers/thermal/sun8i_thermal.c
> index c919b0fd5e169..8a9d2bdc71ece 100644
> --- a/drivers/thermal/sun8i_thermal.c
> +++ b/drivers/thermal/sun8i_thermal.c
> @@ -15,6 +15,7 @@
>  #include <linux/module.h>
>  #include <linux/nvmem-consumer.h>
>  #include <linux/of.h>
> +#include <linux/of_platform.h>
>  #include <linux/platform_device.h>
>  #include <linux/regmap.h>
>  #include <linux/reset.h>
> @@ -66,6 +67,7 @@ struct tsensor {
>  struct ths_thermal_chip {
>  	bool            has_mod_clk;
>  	bool            has_bus_clk_reset;
> +	bool		needs_sram;
>  	int		sensor_num;
>  	int		offset;
>  	int		scale;
> @@ -83,6 +85,7 @@ struct ths_device {
>  	const struct ths_thermal_chip		*chip;
>  	struct device				*dev;
>  	struct regmap				*regmap;
> +	struct regmap_field			*sram_regmap_field;
>  	struct reset_control			*reset;
>  	struct clk				*bus_clk;
>  	struct clk                              *mod_clk;
> @@ -337,6 +340,34 @@ static void sun8i_ths_reset_control_assert(void *data)
>  	reset_control_assert(data);
>  }
>  
> +static struct regmap *sun8i_ths_get_sram_regmap(struct device_node *node)
> +{
> +	struct device_node *sram_node;
> +	struct platform_device *sram_pdev;
> +	struct regmap *regmap = NULL;
> +
> +	sram_node = of_parse_phandle(node, "allwinner,sram", 0);
> +	if (!sram_node)
> +		return ERR_PTR(-ENODEV);
> +
> +	sram_pdev = of_find_device_by_node(sram_node);
> +	if (!sram_pdev) {
> +		/* platform device might not be probed yet */
> +		regmap = ERR_PTR(-EPROBE_DEFER);
> +		goto out_put_node;
> +	}
> +
> +	/* If no regmap is found then the other device driver is at fault */
> +	regmap = dev_get_regmap(&sram_pdev->dev, NULL);
> +	if (!regmap)
> +		regmap = ERR_PTR(-EINVAL);
> +
> +	platform_device_put(sram_pdev);
> +out_put_node:
> +	of_node_put(sram_node);
> +	return regmap;
> +}
> +
>  static int sun8i_ths_resource_init(struct ths_device *tmdev)
>  {
>  	struct device *dev = tmdev->dev;
> @@ -381,6 +412,21 @@ static int sun8i_ths_resource_init(struct ths_device *tmdev)
>  	if (ret)
>  		return ret;
>  
> +	if (tmdev->chip->needs_sram) {
> +		const struct reg_field sun8i_sram_reg_field =
> +			REG_FIELD(0x0, 16, 16);

What about global static constant for a field? Many drivers do so and code 
would be simpler.

Best regards,
Jernej

> +		struct regmap *regmap;
> +
> +		regmap = sun8i_ths_get_sram_regmap(dev->of_node);
> +		if (IS_ERR(regmap))
> +			return PTR_ERR(regmap);
> +		tmdev->sram_regmap_field = devm_regmap_field_alloc(dev,
> +						      regmap,
> +						      sun8i_sram_reg_field);
> +		if (IS_ERR(tmdev->sram_regmap_field))
> +			return PTR_ERR(tmdev->sram_regmap_field);
> +	}
> +
>  	ret = sun8i_ths_calibrate(tmdev);
>  	if (ret)
>  		return ret;
> @@ -427,6 +473,10 @@ static int sun50i_h6_thermal_init(struct ths_device *tmdev)
>  {
>  	int val;
>  
> +	/* The H616 needs to have a bit in the SRAM control register cleared. */
> +	if (tmdev->sram_regmap_field)
> +		regmap_field_write(tmdev->sram_regmap_field, 0);
> +
>  	/*
>  	 * The manual recommends an overall sample frequency of 50 KHz (20us,
>  	 * 480 cycles at 24 MHz), which provides plenty of time for both the
> 





  reply	other threads:[~2024-02-15 21:25 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-09 14:42 [PATCH v4 0/7] add support for H616 thermal system Andre Przywara
2024-02-09 14:42 ` [PATCH v4 1/7] soc: sunxi: sram: export register 0 for THS on H616 Andre Przywara
2024-02-14 20:29   ` Jernej Škrabec
2024-02-15  1:28     ` Andre Przywara
2024-02-15 21:18       ` Jernej Škrabec
2024-02-09 14:42 ` [PATCH v4 2/7] dt-bindings: thermal: sun8i: Add H616 THS controller Andre Przywara
2024-02-11 16:31   ` Krzysztof Kozlowski
2024-02-09 14:42 ` [PATCH v4 3/7] thermal: sun8i: explain unknown H6 register value Andre Przywara
2024-02-14 20:31   ` Jernej Škrabec
2024-02-09 14:42 ` [PATCH v4 4/7] thermal: sun8i: extend H6 calibration to support 4 sensors Andre Przywara
2024-02-14 20:35   ` Jernej Škrabec
2024-02-09 14:42 ` [PATCH v4 5/7] thermal: sun8i: add SRAM register access code Andre Przywara
2024-02-15 21:24   ` Jernej Škrabec [this message]
2024-02-09 14:42 ` [PATCH v4 6/7] thermal: sun8i: add support for H616 THS controller Andre Przywara
2024-02-09 14:42 ` [PATCH v4 7/7] arm64: dts: allwinner: h616: Add thermal sensor and zones Andre Przywara

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