linux-kernel - Re: [PATCH v2 1/6] i2c: i2c-stm32f7: Add 10-bit address support

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Message-ID: <fd463a3d-354c-d4e9-16a8-2829ccc04adc@st.com>
Date:   Mon, 26 Mar 2018 09:56:40 +0200
From:   Pierre Yves MORDRET <pierre-yves.mordret@...com>
To:     Wolfram Sang <wsa@...-dreams.de>
CC:     Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        <linux-i2c@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/6] i2c: i2c-stm32f7: Add 10-bit address support



On 03/24/2018 11:43 PM, Wolfram Sang wrote:
> On Wed, Mar 21, 2018 at 05:48:55PM +0100, Pierre-Yves MORDRET wrote:
>> This patch adds support for 10-bit device address for STM32F7 I2C
>>
>> Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@...il.com>
>> Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@...com>
> 
> Out of curiosity: how did you test this patch? I never managed to find a
> 10-bit client (except for an SoC with 10-bit slave mode).

I don't have a 10-bit device either. For testing 10-bit I'm using 2 I2C
instances from the SoC, one in master mode and the other in slave mode.

> 
>> ---
>>   Version history:
>>      v1:
>>         * Initial
>>      v2:
>> ---
>> ---
>>  drivers/i2c/busses/i2c-stm32f7.c | 22 +++++++++++++++++-----
>>  1 file changed, 17 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
>> index f273e28..ae0d15c 100644
>> --- a/drivers/i2c/busses/i2c-stm32f7.c
>> +++ b/drivers/i2c/busses/i2c-stm32f7.c
>> @@ -65,7 +65,12 @@
>>  #define STM32F7_I2C_CR2_NACK			BIT(15)
>>  #define STM32F7_I2C_CR2_STOP			BIT(14)
>>  #define STM32F7_I2C_CR2_START			BIT(13)
>> +#define STM32F7_I2C_CR2_HEAD10R			BIT(12)
>> +#define STM32F7_I2C_CR2_ADD10			BIT(11)
>>  #define STM32F7_I2C_CR2_RD_WRN			BIT(10)
>> +#define STM32F7_I2C_CR2_SADD10_MASK		GENMASK(9, 0)
>> +#define STM32F7_I2C_CR2_SADD10(n)		(((n) & \
>> +						STM32F7_I2C_CR2_SADD10_MASK))
>>  #define STM32F7_I2C_CR2_SADD7_MASK		GENMASK(7, 1)
>>  #define STM32F7_I2C_CR2_SADD7(n)		(((n) & 0x7f) << 1)
>>  
>> @@ -176,14 +181,14 @@ struct stm32f7_i2c_timings {
>>  
>>  /**
>>   * struct stm32f7_i2c_msg - client specific data
>> - * @addr: 8-bit slave addr, including r/w bit
>> + * @addr: 8-bit or 10-bit slave addr, including r/w bit
>>   * @count: number of bytes to be transferred
>>   * @buf: data buffer
>>   * @result: result of the transfer
>>   * @stop: last I2C msg to be sent, i.e. STOP to be generated
>>   */
>>  struct stm32f7_i2c_msg {
>> -	u8 addr;
>> +	u16 addr;
>>  	u32 count;
>>  	u8 *buf;
>>  	int result;
>> @@ -629,8 +634,15 @@ static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,
>>  		cr2 |= STM32F7_I2C_CR2_RD_WRN;
>>  
>>  	/* Set slave address */
>> -	cr2 &= ~STM32F7_I2C_CR2_SADD7_MASK;
>> -	cr2 |= STM32F7_I2C_CR2_SADD7(f7_msg->addr);
>> +	cr2 &= ~(STM32F7_I2C_CR2_HEAD10R | STM32F7_I2C_CR2_ADD10);
>> +	if (msg->flags & I2C_M_TEN) {
>> +		cr2 &= ~STM32F7_I2C_CR2_SADD10_MASK;
>> +		cr2 |= STM32F7_I2C_CR2_SADD10(f7_msg->addr);
>> +		cr2 |= STM32F7_I2C_CR2_ADD10;
>> +	} else {
>> +		cr2 &= ~STM32F7_I2C_CR2_SADD7_MASK;
>> +		cr2 |= STM32F7_I2C_CR2_SADD7(f7_msg->addr);
>> +	}
>>  
>>  	/* Set nb bytes to transfer and reload if needed */
>>  	cr2 &= ~(STM32F7_I2C_CR2_NBYTES_MASK | STM32F7_I2C_CR2_RELOAD);
>> @@ -798,7 +810,7 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
>>  
>>  static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
>>  {
>> -	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
>> +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
>>  }
>>  
>>  static struct i2c_algorithm stm32f7_i2c_algo = {
>> -- 
>> 2.7.4
>>