linux-kernel - RE: [PATCH v7 RESEND 2/3] thermal: exynos_tmu: Support new hardware and update TMU interface

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Message-ID: <000b01dc5d37$3f6f5e80$be4e1b80$@samsung.com>
Date: Mon, 24 Nov 2025 20:41:16 +0900
From: 손신 <shin.son@...sung.com>
To: "'Tudor Ambarus'" <tudor.ambarus@...aro.org>, "'Daniel Lezcano'"
	<daniel.lezcano@...aro.org>, "'Bartlomiej Zolnierkiewicz'"
	<bzolnier@...il.com>, "'Krzysztof Kozlowski'" <krzk@...nel.org>, "'Rafael J
 . Wysocki'" <rafael@...nel.org>, "'Zhang Rui'" <rui.zhang@...el.com>,
	"'Lukasz	Luba'" <lukasz.luba@....com>, "'Rob Herring'" <robh@...nel.org>,
	"'Conor Dooley'" <conor+dt@...nel.org>, "'Alim Akhtar'"
	<alim.akhtar@...sung.com>
Cc: "'Henrik Grimler'" <henrik@...mler.se>, <linux-pm@...r.kernel.org>,
	<linux-samsung-soc@...r.kernel.org>, <devicetree@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
	"'Peter	Griffin'" <peter.griffin@...aro.org>,
	'André Draszik' <andre.draszik@...aro.org>, "'William
 McVicker'" <willmcvicker@...gle.com>, <jyescas@...gle.com>,
	<shin.son@...sung.com>
Subject: RE: [PATCH v7 RESEND 2/3] thermal: exynos_tmu: Support new hardware
 and update TMU interface

Hello, Tudor Ambarus.

> -----Original Message-----
> From: Tudor Ambarus [mailto:tudor.ambarus@...aro.org]
> Sent: Monday, November 24, 2025 7:43 PM
> To: 손신 <shin.son@...sung.com>; 'Daniel Lezcano'
> <daniel.lezcano@...aro.org>; 'Bartlomiej Zolnierkiewicz'
> <bzolnier@...il.com>; 'Krzysztof Kozlowski' <krzk@...nel.org>; 'Rafael J .
> Wysocki' <rafael@...nel.org>; 'Zhang Rui' <rui.zhang@...el.com>; 'Lukasz
> Luba' <lukasz.luba@....com>; 'Rob Herring' <robh@...nel.org>; 'Conor
> Dooley' <conor+dt@...nel.org>; 'Alim Akhtar' <alim.akhtar@...sung.com>
> Cc: 'Henrik Grimler' <henrik@...mler.se>; linux-pm@...r.kernel.org; linux-
> samsung-soc@...r.kernel.org; devicetree@...r.kernel.org; linux-arm-
> kernel@...ts.infradead.org; linux-kernel@...r.kernel.org; Peter Griffin
> <peter.griffin@...aro.org>; André Draszik <andre.draszik@...aro.org>;
> William McVicker <willmcvicker@...gle.com>; jyescas@...gle.com
> Subject: Re: [PATCH v7 RESEND 2/3] thermal: exynos_tmu: Support new
> hardware and update TMU interface
> 
> Hi, Shin,
> 
> On 11/24/25 12:06 PM, 손신 wrote:
> >>> +static void update_con_reg(struct exynos_tmu_data *data) {
> >>> +	u32 val, t_buf_vref_sel, t_buf_slope_sel;
> >>> +
> >>> +	val = readl(data->base + EXYNOS_TMU_REG_TRIMINFO);
> >>> +	t_buf_vref_sel = (val >> EXYNOSAUTOV920_TMU_T_BUF_VREF_SEL_SHIFT)
> >>> +				& EXYNOSAUTOV920_TMU_T_BUF_VREF_SEL_MASK;
> >>> +	t_buf_slope_sel = (val >> EXYNOSAUTOV920_TMU_T_BUF_SLOPE_SEL_SHIFT)
> >>> +				& EXYNOSAUTOV920_TMU_T_BUF_SLOPE_SEL_MASK;
> >>> +
> >>> +	val = readl(data->base +  EXYNOSAUTOV920_TMU_REG_CONTROL);
> >>> +	val &= ~(EXYNOS_TMU_REF_VOLTAGE_MASK <<
> >> EXYNOS_TMU_REF_VOLTAGE_SHIFT);
> >>> +	val |= (t_buf_vref_sel << EXYNOS_TMU_REF_VOLTAGE_SHIFT);
> >>> +	val &= ~(EXYNOS_TMU_BUF_SLOPE_SEL_MASK <<
> >> EXYNOS_TMU_BUF_SLOPE_SEL_SHIFT);
> >>> +	val |= (t_buf_slope_sel << EXYNOS_TMU_BUF_SLOPE_SEL_SHIFT);
> >>> +	writel(val, data->base + EXYNOSAUTOV920_TMU_REG_CONTROL);
> >>> +
> >>> +	val = readl(data->base + EXYNOSAUTOV920_TMU_REG_CONTROL1);
> >>> +	val &= ~(EXYNOSAUTOV920_TMU_NUM_PROBE_MASK <<
> >> EXYNOSAUTOV920_TMU_NUM_PROBE_SHIFT);
> >>> +	val &= ~(EXYNOSAUTOV920_TMU_LPI_MODE_MASK <<
> >> EXYNOSAUTOV920_TMU_LPI_MODE_SHIFT);
> >>> +	val |= (data->sensor_count << EXYNOSAUTOV920_TMU_NUM_PROBE_SHIFT);
> >>> +	writel(val, data->base + EXYNOSAUTOV920_TMU_REG_CONTROL1);
> >>> +
> >>> +	writel(1, data->base + EXYNOSAUTOV920_TMU_SAMPLING_INTERVAL);
> >>> +	writel(EXYNOSAUTOV920_TMU_AVG_CON_UPDATE, data->base +
> >> EXYNOSAUTOV920_TMU_REG_AVG_CONTROL);
> >>> +	writel(EXYNOSAUTOV920_TMU_COUNTER_VALUE0_UPDATE,
> >>> +	       data->base + EXYNOSAUTOV920_TMU_REG_COUNTER_VALUE0);
> >>> +	writel(EXYNOSAUTOV920_TMU_COUNTER_VALUE1_UPDATE,
> >>> +	       data->base + EXYNOSAUTOV920_TMU_REG_COUNTER_VALUE1);
> >>> +}
> >>> +
> >> This is unreadable; please make it understandable for those who don’t
> >> have the documentation (explicit static inline functions, comments,
> etc ...).
> > I'll restructure this code by introducing explicit static inline helper
> functions and proper comments to improve readability.
> 
> We likely shouldn't use inlines here, see Linus's reply from 2006:
> https://lore.kernel.org/all/Pine.LNX.4.64.0601021105000.3668@g5.osdl.org/T
> /#u
> 
> I guess you can make this easier to read if you use FIELD_GET/SET from
> bitfield.h. Other improvement would be using the regmap api.
> 
> Shin, a bit unrelated with the patch, but I wanted to let you know that I
> started looking at the GS101 TMU. I assume it's very similar with the TMU
> on exynosautov920. Do you know if they share the same IP version?
> 
> I noticed GS101 uses ACPM calls to communicate with the TMU. Why did you
> choose to not use ACPM for exynosautov920 TMU?
> 
> Thanks!
> ta

I will adopt FIELD_GET/FIELD_PREP to simplify the bitfield handling, and I will avoid using inline functions excessively as suggested.

Regarding ACPM, I did not introduce it earlier because I was trying to align the implementation with the existing framework.
However, if we move toward a separate driver, I will reconsider whether ACPM integration makes sense there.
Would it be possible to get your feedback again when I prepare the next revision of the driver?

Plus, the GS101 TMU driver isn't upstream yet, right?
Could you share where I can find the example code you mentioned? Thank you in advance.

Best regards,
Shin