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

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Message-ID: <630b8727-cffa-4118-93e4-2dd8ce97ebde@ti.com>
Date: Mon, 6 Jan 2025 16:18:47 -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 1/4/2025 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.

>> ---
>>  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.
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.