linux-kernel - Re: [PATCH v1 07/10] thermal: tsens: Check if the IP is correctly enabled by firmware

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Message-ID: <20180809203735.GO160295@google.com>
Date:   Thu, 9 Aug 2018 13:37:35 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Amit Kucheria <amit.kucheria@...aro.org>
Cc:     linux-kernel@...r.kernel.org, rnayak@...eaurora.org,
        linux-arm-msm@...r.kernel.org, bjorn.andersson@...aro.org,
        edubezval@...il.com, smohanad@...eaurora.org,
        andy.gross@...aro.org, dianders@...omium.org,
        Zhang Rui <rui.zhang@...el.com>, linux-pm@...r.kernel.org
Subject: Re: [PATCH v1 07/10] thermal: tsens: Check if the IP is correctly
 enabled by firmware

On Thu, Aug 09, 2018 at 06:02:39PM +0530, Amit Kucheria wrote:
> The SROT registers are initialised by the secure firmware at boot. We
> don't have write access to the registers. Check if the block is enabled
> before continuing.
> 
> Signed-off-by: Amit Kucheria <amit.kucheria@...aro.org>
> ---
>  drivers/thermal/qcom/tsens-common.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/thermal/qcom/tsens-common.c b/drivers/thermal/qcom/tsens-common.c
> index 0b8a793f15f4..d250b757d1f0 100644
> --- a/drivers/thermal/qcom/tsens-common.c
> +++ b/drivers/thermal/qcom/tsens-common.c
> @@ -12,6 +12,11 @@
>  #include <linux/regmap.h>
>  #include "tsens.h"
>  
> +/* SROT */
> +#define CTRL_OFFSET		0x4
> +#define TSENS_EN		BIT(0)
> +
> +/* TM */
>  #define STATUS_OFFSET		0x30
>  #define SN_ADDR_OFFSET		0x4
>  #define SN_ST_TEMP_MASK		0x3ff
> @@ -119,6 +124,8 @@ int __init init_common(struct tsens_device *tmdev)
>  {
>  	void __iomem *tm_base, *srot_base;
>  	struct resource *res;
> +	u32 code;
> +	int ret;
>  	struct platform_device *op = of_find_device_by_node(tmdev->dev->of_node);
>  
>  	if (!op)
> @@ -151,5 +158,15 @@ int __init init_common(struct tsens_device *tmdev)
>  	if (IS_ERR(tmdev->tm_map))
>  		return PTR_ERR(tmdev->tm_map);
>  
> +	if (tmdev->srot_map) {
> +		ret = regmap_read(tmdev->srot_map, CTRL_OFFSET, &code);
> +		if (ret)
> +			return ret;
> +		if (!(code & TSENS_EN)) {
> +			dev_err(tmdev->dev, "tsens device is not enabled\n");
> +			return -ENODEV;
> +		}
> +	}
> +
>  	return 0;
>  }

Reviewed-by: Matthias Kaehlcke <mka@...omium.org>