Received-SPF: pass (google.com: domain of linux-kernel+bounces-77941-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
Message-ID: <1fe2c4b3-9dd2-a961-4198-45aca3449c36@axis.com>
Date: Fri, 23 Feb 2024 16:40:18 +0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.2.2
Subject: Re: [PATCH] power: supply: bq27xxx: Introduce parameter to config
 cache regs
To: Sebastian Reichel <sebastian.reichel@collabora.com>,
 Hermes Zhang <Hermes.Zhang@axis.com>
Cc: kernel@axis.com, =?UTF-8?Q?Pali_Roh=c3=a1r?= <pali@kernel.org>,
 linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20240219100541.48453-1-Hermes.Zhang@axis.com>
 <eh34cvorgnrw4v5a6emzjk2p6om2ybkn627bpmh775z4ubw63h@nbxgpm767u4x>
From: Hermes Zhang <chenhuiz@axis.com>
In-Reply-To: <eh34cvorgnrw4v5a6emzjk2p6om2ybkn627bpmh775z4ubw63h@nbxgpm767u4x>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0:
	=?utf-8?B?anRVekRGUUtZd053TTBCU2VYbS9QM0x6TGZjTmd2VFcwaHpXcTAzQzhqVXda?=
 =?utf-8?B?VkVPKzZrU09DbkYvQnFFY2ZpWndZT3Z5QW9ud1ozSGZpZHRsdjRPV3gwWVZ1?=
 =?utf-8?B?S2dIYk1LMFFna0liL1hKd1AyaXZvcTluVWlKNmVScUtDTzc5U2twVjhSOGIw?=
 =?utf-8?B?QTJ1aHVkMVFwYTN6eEYwKzBFYk5oK0VXb25uaVpVQkIwaW5ZOHdXWGhnZXdo?=
 =?utf-8?B?S3NFWHdnSDhCOEtqVFNQamRMTEdUbFpzWkxvNktuaDJQYmxVaXhyRUYwSlVU?=
 =?utf-8?B?WTMrK29OS2VXbXF1NFVnRFJSdHJOSEZjOW1FT2xubnlLYUp0YUx6QmtkZmV5?=
 =?utf-8?B?dUVCTDIxZEFBTUN2cDRvOXFBZDdzd0RKZWx1M2Y2VU9uYVlZWDdXeHQyZDJT?=
 =?utf-8?B?bFlEZitIZUV0Z3hOTTRSZllGQ0VCaWZlNzU4THJCZnNqczJoR0F1NE1TVlIr?=
 =?utf-8?B?eTQwUUdMUEEwaUFBUThnSnFmcGc2WTFSQks2MENtS05LNmM2R28zSlhaMWpN?=
 =?utf-8?B?clZLN2RvME1ubnRTdHhHay8vUFlpbnZ2QTdRY1NSVFY3UlFydmFBYnNuSERZ?=
 =?utf-8?B?VFQwa2VVb3c5V0UyaVZYZVlaUUxZbTE1Q0xzRGpGSnNWemo5bVpwNnhOc2Vv?=
 =?utf-8?B?MHBmSFNCR3o1Q1Y3cGZiTXVqU0d6MGFEMC9UUnJWWXhuZ25uV1hvdlNyL2F4?=
 =?utf-8?B?bktveWVkdGhhVktzamxQVE1lSkZuRGhjTTJWZTVoWnVrVndDRjFPaHhmNE5I?=
 =?utf-8?B?b3o5YUpvY25XeHFZZXlwOThSYVRVVVpGNjQrV1RLOE81ZGxIQW9wWDRhVXZr?=
 =?utf-8?B?bkRBenFWTy9MWkIxaFBRcTEvbDFRZTRoS2ljaDNzUnZuSHFNVDZkYmJhZ1ZM?=
 =?utf-8?B?OXpkd25MZGo5QXZYdTJEdXR0QTd3eGh3TkFPN3k0MEhuVjRxS1R4ZTFMSHJU?=
 =?utf-8?B?cDVkOEdNSHNjSHlPS1RTNUx6NW9OampBNzFxbWNGUlFXR2R5OU9ZMm5pYXQ3?=
 =?utf-8?B?bGF6NVZjYlRhQzlLQit2NXBHT2huc2VaWGZpRlZKWHJrSCtpVi9MT0lralg5?=
 =?utf-8?B?MDZTVEhlMTZ6ZkVWUVZKclEwQmZLcm9JRkMrQ2RwVXNFMVlrZ1h5bHh2dkg5?=
 =?utf-8?B?Njk0UEFsbjZZYS83aC9aWG8weG1iSGdYMXRUN2dTM1F1aml5VFRYcCtqVG92?=
 =?utf-8?B?bHJwdkJIY25uQ1g3Ui9pc3IvWVlzNzlId1MvaGdoVUJOQ3RMS1lRRU5lblZH?=
 =?utf-8?B?WlZGc3EzbVhqbjNzU0N0cG1DWlN6WGd4MFpsTlFKZjBnT2ZTTWZlazExU2I0?=
 =?utf-8?B?TVg0ak1OTEJTSFNSL0hZTDFFeWNkVXE3TXZtOVF3Wm5GNDZaWjRGSGVuSDJP?=
 =?utf-8?B?WXN6NzlhTVUwUG9kelZ5S0Q2MVZtV0pIc2U0M1VUVnhzRkNKbGJ5U3UwQ1U0?=
 =?utf-8?B?YlcrQzlsdUNWc2NQdEFQTTZadGNybXdOa2dYcUUzbitRMVlIMy8ydHRpNDZF?=
 =?utf-8?B?cXNLS1UyT243QVlDVWRLL1FRRkdPc2MwR1pRLzdiSWd2Y3FCR2RFNmlINXk0?=
 =?utf-8?B?VUJDL2cvKzBlaGpRZERvR2xoeEsyK090bk1HM1g4M2o5M2pSTFQyb0NzdERK?=
 =?utf-8?B?NGdENkd6dlFFTy94dldOQ25KQ0VqRWN6MlVNZVlMa1UwbzJiWFNHeXpmalp6?=
 =?utf-8?B?bXBubGJDalBZYmlPa3ZwdS9jL0dqcVF4NDRIL1BWVit0allxbWpqakFEKzhI?=
 =?utf-8?B?NDA5NEMyUnk2MlZSTjdtbDR3VHp1cCtQODlpVzJrS2VVRjltcktLT1NPWEVs?=
 =?utf-8?B?ZnZiWVhtSytPSk13YU5raVdIYndXZ1dXMURzUVNhaUM1T0tzRGNtaGcvQVFx?=
 =?utf-8?B?Q3lEaU9wOVROOEtDR2VSRTJkd3VMMTE3Z2o4V2xxenBBV2hub3FMMnFlM3di?=
 =?utf-8?B?MTk1YnVwNDFvaWU4RDJvalpzL0hXWVdXc2FwbTQ4aVpsMXljdGJQMGdYVkxL?=
 =?utf-8?B?WlJ1NHhvMkwxVEpzb1lOYnlIcVFxdkFYMXl5OUs4SDVDaWFVdHJtUHp4RHA2?=
 =?utf-8?B?cmtBMFZxK3hUazRhK1diYVYwYzN1RjFGdjVrK3JVanBOQlJuekgxeHN4SjdV?=
 =?utf-8?Q?N+ehUfV+/z9OcHVec13BvAlVk?=
X-OriginatorOrg: axis.com
X-MS-Exchange-CrossTenant-Network-Message-Id: a59c554c-7595-4e96-0b87-08dc344b14e9
X-MS-Exchange-CrossTenant-AuthSource: VI0PR02MB10536.eurprd02.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Feb 2024 08:40:25.8788
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 78703d3c-b907-432f-b066-88f7af9ca3af
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: +lzksganwtsBEOSWs62eKmAPq3bsKZmJWMlgte++DeTs/xPVmWYZJ/13KWDqhKe+pTfsRPzbUzdLfh5JTA70YQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PAXPR02MB7182

Hi,

On 2024/2/22 7:03, Sebastian Reichel wrote:
> Hi,
>
> On Mon, Feb 19, 2024 at 06:05:40PM +0800, Hermes Zhang wrote:
>> Since all of the regs in the bq27xxx_reg_cache are now cached, a simple
>> property read (such as temperature) will need nine I2C transmissions.
>> Introduce a new module parameter to enable the reg cache to be configured,
>> which decrease the amount of unnecessary I2C transmission and preventing
>> the error -16 (EBUSY) happen when working on an I2C bus that is shared by
>> many devices.
> So the problem is not the caching, but the grouping. So instead
> of adding this hack, please change the code to do the caching
> per register. That way you can just keep the caching enabled and
> don't need any custom module parameters.

Thanks for the reply. Yes, the key is the grouping. So do you suggest to 
drop the bq27xxx_reg_cache struct totally and handle the cache for each 
register in e.g. bq27xxx_battery_get_property()? Then it will require an 
extra time info for each register, will that be a big cost? Or am I 
misunderstanding?

Best Regards,

Hermes