linux-kernel - Re: [PATCH v2 2/2] mfd: tps65215: Remove regmap

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Message-ID: <48d409b5-6e2d-493f-8ce4-e6510061c854@ti.com>
Date: Tue, 7 Jan 2025 12:45:20 -0600
From: Shree Ramamoorthy <s-ramamoorthy@...com>
To: Roger Quadros <rogerq@...nel.org>, <aaro.koskinen@....fi>,
        <andreas@...nade.info>, <khilman@...libre.com>, <tony@...mide.com>,
        <lee@...nel.org>, <linux-omap@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC: <m-leonard@...com>, <praneeth@...com>, <christophe.jaillet@...adoo.fr>
Subject: Re: [PATCH v2 2/2] mfd: tps65215: Remove regmap_read check

Hi,


On 1/7/25 6:47 AM, Roger Quadros wrote:
>
> On 07/01/2025 00:18, Shree Ramamoorthy wrote:
>> Hi,
>>
>> On 1/4/2025 12:16 PM, Roger Quadros wrote:
>>> On 04/01/2025 00:57, Shree Ramamoorthy wrote:
>>>> The chipid macro/variable and regmap_read function call is not needed
>>>> because the TPS65219_REG_TI_DEV_ID register value is not a consistent value
>>>> across TPS65219 PMIC config versions. Reading from the DEV_ID register
>>>> without a consistent value to compare it to isn't useful. There isn't a
>>>> way to verify the match data ID is the same ID read from the DEV_ID device
>>>> register. 0xF0 isn't a DEV_ID value consistent across TPS65219 NVM
>>>> configurations.
>>>>
>>>> For TPS65215, there is a consistent value in bits 5-0 of the DEV_ID
>>>> register. However, there are other error checks in place within probe()
>>>> that apply to both PMICs rather than keeping this isolated check for one
>>>> PMIC.
>>>>
>>>> Signed-off-by: Shree Ramamoorthy <s-ramamoorthy@...com>
>>> In that case this could be squashed with 1?
>> Since this change does not have to do with TPS65215 support directly
>> and is a different type of change, I wanted to keep this patch separate.
>> I can instead have this patch be first, then the MFD add TPS65215 support
>> will follow this to avoid any confusion about regmap_read being modified then removed.
>>
> OK thanks.
>
>>>> ---
>>>>   drivers/mfd/tps65219.c       | 6 ------
>>>>   include/linux/mfd/tps65219.h | 2 --
>>>>   2 files changed, 8 deletions(-)
>>>>
>>>> diff --git a/drivers/mfd/tps65219.c b/drivers/mfd/tps65219.c
>>>> index 816b271990a2..d3267bf7cd77 100644
>>>> --- a/drivers/mfd/tps65219.c
>>>> +++ b/drivers/mfd/tps65219.c
>>>> @@ -382,12 +382,6 @@ static int tps65219_probe(struct i2c_client *client)
>>>>   	if (ret)
>>>>   		return ret;
>>>>   
>>>> -	ret = regmap_read(tps->regmap, TPS65219_REG_TI_DEV_ID, &tps->chip_id);
>>>> -	if (ret) {
>>>> -		dev_err(tps->dev, "Failed to read device ID: %d\n", ret);
>>>> -		return ret;
>>>> -	}
>>>> -
>>>>   	ret = devm_mfd_add_devices(tps->dev, PLATFORM_DEVID_AUTO,
>>>>   				   pmic->cells, pmic->n_cells,
>>>>   				   NULL, 0, regmap_irq_get_domain(tps->irq_data));
>>>> diff --git a/include/linux/mfd/tps65219.h b/include/linux/mfd/tps65219.h
>>>> index 9892b6e4c85c..535115bfa4a4 100644
>>>> --- a/include/linux/mfd/tps65219.h
>>>> +++ b/include/linux/mfd/tps65219.h
>>>> @@ -15,8 +15,6 @@
>>>>   #include <linux/regmap.h>
>>>>   #include <linux/regulator/driver.h>
>>>>   
>>>> -/* TPS chip id list */
>>>> -#define TPS65219					0xF0
>>>>   /* Chip id list*/
>>>>   enum pmic_id {
>>>>   	TPS65215,
>>> Looking at TRM, TPS65215 device_id is 0x15 and TPS6521901 device_id is 0x00.
>>>
>>> shouldn't we use that here as well?
>> The device_id value set varies across TPS65219 hardware versions.
> Do you foresee any software quirks being applied for specific versions of
> TPS65219? If not then probably not worth the effort to keep track of all the
> versions.

I don't foresee any sw quirks that would need to be support for TPS65219,
since there haven't been any since the driver was released.

>> Having the device_id as the chip_id differentiator will fail for TPS65219,
>> even though the system engineers have now kept the TPS65215 device_id value
>> consistent across all hardware versions.
>>

-- 
Best,
Shree Ramamoorthy
PMIC Software Engineer