Re: [PATCH] clk: rs9: Fix I2C accessors

[Marek Vasut <marex@denx.de>]

On 9/12/22 08:46, Alexander Stein wrote:

Hi,

[...]

>> +static int rs9_regmap_i2c_read(void *context,
>> +			       unsigned int reg, unsigned int *val)
>> +{
>> +	struct i2c_client *i2c = context;
>> +	struct i2c_msg xfer[2];
>> +	u8 data[2];
>> +	int ret;
>> +
>> +	xfer[0].addr = i2c->addr;
>> +	xfer[0].flags = 0;
>> +	xfer[0].len = 1;
>> +	xfer[0].buf = (void *)®
> 
> This does work only for little-endian machines, right?

Ah, right, fixed in V2.

>> +	xfer[1].addr = i2c->addr;
>> +	xfer[1].flags = I2C_M_RD | I2C_M_RECV_LEN;
>> +	xfer[1].len = 1;
>> +	xfer[1].buf = (void *)data;
>> +
>> +	ret = i2c_transfer(i2c->adapter, xfer, 2);
>> +	if (ret == 2)
>> +		return 0;
> 
> You are missing setting 'val' here.

Fixed in V2

>> +	else if (ret < 0)
>> +		return ret;
>> +	else
>> +		return -EIO;
>> +}
>> +
>>   static const struct regmap_config rs9_regmap_config = {
>>   	.reg_bits = 8,
>>   	.val_bits = 8,
>> @@ -97,6 +140,8 @@ static const struct regmap_config rs9_regmap_config = {
>>   	.max_register = 0x8,
>>   	.rd_table = &rs9_readable_table,
>>   	.wr_table = &rs9_writeable_table,
>> +	.reg_write = rs9_regmap_i2c_write,
>> +	.reg_read = rs9_regmap_i2c_read,
>>   };
>>
>>   static int rs9_get_output_config(struct rs9_driver_data *rs9, int idx)
>> @@ -242,11 +287,17 @@ static int rs9_probe(struct i2c_client *client)
>>   			return ret;
>>   	}
>>
>> -	rs9->regmap = devm_regmap_init_i2c(client, &rs9_regmap_config);
>> +	rs9->regmap = devm_regmap_init(&client->dev, NULL,
>> +				       client,
> &rs9_regmap_config);
>>   	if (IS_ERR(rs9->regmap))
>>   		return dev_err_probe(&client->dev, PTR_ERR(rs9->regmap),
>>   				     "Failed to allocate register
> map\n");
>>
>> +	/* Always read back 1 Byte via I2C */
>> +	ret = regmap_write(rs9->regmap, RS9_REG_BCP, 1);
>> +	if (ret < 0)
>> +		return ret;
>> +
>>   	/* Register clock */
>>   	for (i = 0; i < rs9->chip_info->num_clks; i++) {
>>   		snprintf(name, 5, "DIF%d", i);
> 
> 
> For some reason this doesn't work with cache being enabled. No idea why this
> happens though.

What does this part mean , what does not work with which cache being 
enabled ?