Re: [PATCH v9 5/6] i2c: designware: add SLAVE mode functions

[Luis Oliveira]

On 08-May-17 17:53, Andy Shevchenko wrote:
> On Mon, 2017-05-08 at 11:37 +0100, Luis Oliveira wrote:
>> - Changes in Kconfig to enable I2C_DESIGNWARE_SLAVE support
>> - Slave functions added to core library file
>> - Slave abort sources added to common source file
>> - New driver: i2c-designware-slave added
>> - Changes in the Makefile to compile the I2C_DESIGNWARE_SLAVE module
>>   when supported by the architecture.
>>
>> All the SLAVE flow is added but it is not enabled via platform
>> driver.
> 
> My comments below.
> Overall entire series looks much much better than first version.
> 
>> @@ -41,6 +41,7 @@ obj-$(CONFIG_I2C_CPM)		+= i2c-cpm.o
>>  obj-$(CONFIG_I2C_DAVINCI)	+= i2c-davinci.o
>>  obj-$(CONFIG_I2C_DESIGNWARE_CORE)	+= i2c-designware-core.o
>>  i2c-designware-core-objs := i2c-designware-common.o i2c-designware-
>> master.o
> 
>> +i2c-designware-core-$(CONFIG_I2C_DESIGNWARE_SLAVE) += i2c-designware-
>> slave.o
> 
> What is your intention here?
> 
> AFAIUC it should be like
> 
> ifneq ($(CONFIG_I2C_DESIGNWARE_SLAVE),n)
> i2c-designware-core-objs += i2c-designware-slave.o
> endif
> 

Ok, I will change it in the next patchset.

>> +/**
>> + * i2c_dw_init_slave() - Initialize the designware i2c slave hardware
>> + * @dev: device private data
>> + *
>> + * This functions configures and enables the I2C.
> 
> functions -> function
> I2C -> I2C in slave mode
> 
Yes.

>> + * This function is called during I2C init function, and in case of
>> timeout at
>> + * run time.
>> + */
>> +int i2c_dw_init_slave(struct dw_i2c_dev *dev)
>> +{
>> +	u32 sda_falling_time, scl_falling_time;
>> +	u32 reg, comp_param1;
>> +	u32 hcnt, lcnt;
>> +	int ret;
>> +
>> +	ret = i2c_dw_acquire_lock(dev);
>> +	if (ret)
>> +		return ret;
>> +
>> +	reg = dw_readl(dev, DW_IC_COMP_TYPE);
>> +	if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
>> +		/* Configure register endianness access. */
>> +		dev->flags |= ACCESS_SWAP;
> 
>> +	} else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) {
> 
> GENMASK(15, 0)
> 
I think I will leave it as it is. As Jarkko said it has more readability this way.

>> +		/* Configure register access mode 16bit. */
>> +		dev->flags |= ACCESS_16BIT;
>> +	} else if (reg != DW_IC_COMP_TYPE_VALUE) {
>> +		dev_err(dev->dev,
>> +			"Unknown Synopsys component type: 0x%08x\n",
>> reg);
>> +		i2c_dw_release_lock(dev);
>> +		return -ENODEV;
>> +	}
> 
>> +/*
>> + * Interrupt service routine. This gets called whenever an I2C slave
>> interrupt
>> + * occurs.
>> + */
>> +
>> +static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
>> +{
>> +	u32 raw_stat, stat, enabled;
>> +	u8 val, slave_activity;
>> +
>> +	stat = dw_readl(dev, DW_IC_INTR_STAT);
>> +	enabled = dw_readl(dev, DW_IC_ENABLE);
>> +	raw_stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
>> +	slave_activity = ((dw_readl(dev, DW_IC_STATUS) &
>> +		DW_IC_STATUS_SLAVE_ACTIVITY) >> 6);
>> +
>> +	if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY))
>> +		return 0;
>> +
>> +	dev_dbg(dev->dev,
>> +		"%#x SLAVE_ACTV=%#x : RAW_INTR_STAT=%#x :
>> INTR_STAT=%#x\n",
> 
> SLAVE_ACTV -> STATUS_SLAVE_ACTIVITY

Ok.

> 
>> +		enabled, slave_activity, raw_stat, stat);
>> +
> 
>> +	if (slave_activity) {
>> +		if (stat & DW_IC_INTR_RD_REQ) {
> 
> Looking into next condition (stat & DW_IC_INTR_RX_DONE) I would 
> exchange these lines
> 

By order? I don't think I understood your point. Please elaborate a little more.

>> +			if (stat & DW_IC_INTR_RX_FULL) {
>> +				val = dw_readl(dev, DW_IC_DATA_CMD);
>> +				if (!i2c_slave_event(dev->slave,
>> +				I2C_SLAVE_WRITE_RECEIVED, &val)) {
>> +					dev_vdbg(dev->dev, "Byte %X
>> acked!",
>> +					val);
>> +					}
>> +				dw_readl(dev, DW_IC_CLR_RD_REQ);
>> +				stat =
>> i2c_dw_read_clear_intrbits_slave(dev);
>> +			} else {
>> +				dw_readl(dev, DW_IC_CLR_RD_REQ);
>> +				dw_readl(dev, DW_IC_CLR_RX_UNDER);
>> +				stat =
>> i2c_dw_read_clear_intrbits_slave(dev);
>> +			}
>> +			if (!i2c_slave_event(dev->slave,
>> +					I2C_SLAVE_READ_REQUESTED,
>> &val))
>> +				dw_writel(dev, val, DW_IC_DATA_CMD);
>> +		}
>> +	}
>> +
>> +	if (stat & DW_IC_INTR_RX_DONE) {
>> +		if (!i2c_slave_event(dev->slave,
>> I2C_SLAVE_READ_PROCESSED,
>> +			&val))
>> +			dw_readl(dev, DW_IC_CLR_RX_DONE);
>> +
>> +		i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
>> +		stat = i2c_dw_read_clear_intrbits_slave(dev);
>> +		return 1;
>> +	}
>> +
>> +	if (stat & DW_IC_INTR_RX_FULL) {
>> +		val = dw_readl(dev, DW_IC_DATA_CMD);
>> +		if (!i2c_slave_event(dev->slave,
>> I2C_SLAVE_WRITE_RECEIVED,
>> +			&val))
>> +			dev_vdbg(dev->dev, "Byte %X acked!", val);
>> +	} else {
>> +		i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
>> +		stat = i2c_dw_read_clear_intrbits_slave(dev);
>> +	}
>> +
>> +	if (stat & DW_IC_INTR_TX_OVER)
>> +		dw_readl(dev, DW_IC_CLR_TX_OVER);
>> +
>> +	return 1;
>> +}
> 
>> +static irqreturn_t i2c_dw_isr_slave(int this_irq, void *dev_id)
>> +{
>> +	struct dw_i2c_dev *dev = dev_id;
>> +	int ret;
>> +
>> +	i2c_dw_read_clear_intrbits_slave(dev);
>> +	ret = i2c_dw_irq_handler_slave(dev);
> 
>> +
> 
> I would remove this line.

Ok. Thank you.
> 
>> +	if (ret > 0)
>> +		complete(&dev->cmd_complete);
>> +
>> +	return IRQ_RETVAL(ret);
>> +}
>