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Sender: Guenter Roeck <groeck7@gmail.com>
Message-ID: <cddebb5a-3b83-e89d-db00-9a59ddbd6741@roeck-us.net>
Date:   Tue, 30 Aug 2022 22:36:58 -0700
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Subject: Re: [PATCH v3 02/19] hwmon: (mr75203) fix VM sensor allocation when
 "intel,vm-map" not defined
Content-Language: en-US
To:     Eliav Farber <farbere@amazon.com>, jdelvare@suse.com,
        robh+dt@kernel.org, p.zabel@pengutronix.de, rtanwar@maxlinear.com,
        linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     talel@amazon.com, hhhawa@amazon.com, jonnyc@amazon.com,
        hanochu@amazon.com, ronenk@amazon.com, itamark@amazon.com,
        shellykz@amazon.com, shorer@amazon.com, amitlavi@amazon.com,
        almogbs@amazon.com, dkl@amazon.com, rahul.tanwar@linux.intel.com,
        andriy.shevchenko@intel.com
References: <20220830192212.28570-1-farbere@amazon.com>
 <20220830192212.28570-3-farbere@amazon.com>
From:   Guenter Roeck <linux@roeck-us.net>
In-Reply-To: <20220830192212.28570-3-farbere@amazon.com>
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Precedence: bulk

On 8/30/22 12:21, Eliav Farber wrote:
> Bug fix - in case "intel,vm-map" is missing in device-tree ,'num' is set
> to 0, and no voltage channel infos are allocated.
> 
> Signed-off-by: Eliav Farber <farbere@amazon.com>
> ---
>   drivers/hwmon/mr75203.c | 28 ++++++++++++----------------
>   1 file changed, 12 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
> index 046523d47c29..0e29877a1a9c 100644
> --- a/drivers/hwmon/mr75203.c
> +++ b/drivers/hwmon/mr75203.c
> @@ -580,8 +580,6 @@ static int mr75203_probe(struct platform_device *pdev)
>   	}
>   
>   	if (vm_num) {
> -		u32 num = vm_num;
> -
>   		ret = pvt_get_regmap(pdev, "vm", pvt);
>   		if (ret)
>   			return ret;
> @@ -594,30 +592,28 @@ static int mr75203_probe(struct platform_device *pdev)
>   		ret = device_property_read_u8_array(dev, "intel,vm-map",
>   						    pvt->vm_idx, vm_num);
>   		if (ret) {
> -			num = 0;
> +			/*
> +			 * Incase intel,vm-map property is not defined, we
> +			 * assume incremental channel numbers.
> +			 */
> +			for (i = 0; i < vm_num; i++)
> +				pvt->vm_idx[i] = i;
>   		} else {
>   			for (i = 0; i < vm_num; i++)
>   				if (pvt->vm_idx[i] >= vm_num ||
> -				    pvt->vm_idx[i] == 0xff) {
> -					num = i;
> +				    pvt->vm_idx[i] == 0xff)
>   					break;

So all vm_idx values from 0x00 to 0xfe would be acceptable ?
Does the chip really have that many registers (0x200 + 0x40 + 0x200 * 0xfe) ?
Is that documented somewhere ?

Thanks,
Guenter

> -				}
> -		}
>   
> -		/*
> -		 * Incase intel,vm-map property is not defined, we assume
> -		 * incremental channel numbers.
> -		 */
> -		for (i = num; i < vm_num; i++)
> -			pvt->vm_idx[i] = i;
> +			vm_num = i;
> +		}
>   
> -		in_config = devm_kcalloc(dev, num + 1,
> +		in_config = devm_kcalloc(dev, vm_num + 1,
>   					 sizeof(*in_config), GFP_KERNEL);
>   		if (!in_config)
>   			return -ENOMEM;
>   
> -		memset32(in_config, HWMON_I_INPUT, num);
> -		in_config[num] = 0;
> +		memset32(in_config, HWMON_I_INPUT, vm_num);
> +		in_config[vm_num] = 0;
>   		pvt_in.config = in_config;
>   
>   		pvt_info[index++] = &pvt_in;