Re: [RESEND v2] i2c: imx: support slave mode for imx I2C driver

[Oleksij Rempel <o.rempel@pengutronix.de>]

Hi,

I'm trying to test you patch on i.MX6S RIoTBoard. So far I fail to get it working with 
following setup:
1. register i2c-gpio
2. connect i2c-gpio SCL to i2c-imx SCL pin and i2c-gpio SDA to i2c-imx SDA pin
3. run this command to register i2c slave eeprom on i2c-imx:
echo slave-24c02 0x1064 > /sys/bus/i2c/devices/i2c-3/new_device
4. run "i2cdetect 4" on i2c-gpio to detect eeprom on i2c-imx slave.

So far, nothing was detected and even irq counter of i2c-imx didn't increased.

Do I'm missing some thing? Please, help me to test you patch.

And, please, do not forget to include me in the next patch round, if you wont to get your 
patches mainline.

This devicetree i used for testing:
#include "imx6dl-riotboard.dts"

/ {
         i2c_gpio: i2c-gpio {
                 compatible = "i2c-gpio";
                 #address-cells = <1>;
                 #size-cells = <0>;
                 pinctrl-names = "default";
                 pinctrl-0 = <&pinctrl_i2c_gpio>;
                 gpios = <
                         &gpio4 27 GPIO_ACTIVE_HIGH /* SDA */
                         &gpio4 26 GPIO_ACTIVE_HIGH /* SCL */
                 >;
                 clock-frequency = <10000>;
                 status = "okay";
         };
};

&iomuxc {
         pinctrl-names = "default";

         imx6-riotboard {
                 pinctrl_i2c_gpio: i2c-gpiogrp {
                         fsl,pins = <
                                 MX6QDL_PAD_DISP0_DAT6__GPIO4_IO27 0x4001b8b1
                                 MX6QDL_PAD_DISP0_DAT5__GPIO4_IO26 0x4001b8b1
                         >;
                 };
         };
};

&i2c4 {
                 clock-frequency = <10000>;

};


Regards,
Oleksij

On 09.10.19 12:18, Biwen Li wrote:
> The patch supports slave mode for imx I2C driver
> 
> Signed-off-by: Biwen Li <biwen.li@nxp.com>
> ---
> Change in v2:
> 	- remove MACRO CONFIG_I2C_SLAVE
> 
>   drivers/i2c/busses/i2c-imx.c | 180 ++++++++++++++++++++++++++++++++---
>   1 file changed, 166 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index a3b61336fe55..d9858bc63656 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -203,6 +203,7 @@ struct imx_i2c_struct {
>   	struct pinctrl_state *pinctrl_pins_gpio;
>   
>   	struct imx_i2c_dma	*dma;
> +	struct i2c_client	*slave;
>   };
>   
>   static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
> @@ -588,23 +589,38 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
>   	imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
>   }
>   
> -static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
> +/* Clear interrupt flag bit */
> +static void i2c_imx_clr_if_bit(struct imx_i2c_struct *i2c_imx)
>   {
> -	struct imx_i2c_struct *i2c_imx = dev_id;
> -	unsigned int temp;
> +	unsigned int status;
>   
> -	temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> -	if (temp & I2SR_IIF) {
> -		/* save status register */
> -		i2c_imx->i2csr = temp;
> -		temp &= ~I2SR_IIF;
> -		temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
> -		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
> -		wake_up(&i2c_imx->queue);
> -		return IRQ_HANDLED;
> -	}
> +	status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> +	status &= ~I2SR_IIF;
> +	status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
> +	imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR);
> +}
>   
> -	return IRQ_NONE;
> +/* Clear arbitration lost bit */
> +static void i2c_imx_clr_al_bit(struct imx_i2c_struct *i2c_imx)
> +{
> +	unsigned int status;
> +
> +	status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> +	status &= ~I2SR_IAL;
> +	imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR);
> +}
> +
> +static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx)
> +{
> +	unsigned int status;
> +
> +	/* Save status register */
> +	status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> +	i2c_imx->i2csr = status | I2SR_IIF;
> +
> +	wake_up(&i2c_imx->queue);
> +
> +	return IRQ_HANDLED;
>   }
>   
>   static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx,
> @@ -1048,11 +1064,147 @@ static u32 i2c_imx_func(struct i2c_adapter *adapter)
>   		| I2C_FUNC_SMBUS_READ_BLOCK_DATA;
>   }
>   
> +static void i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx)
> +{
> +	unsigned int temp;
> +
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
> +
> +	/* Set slave addr. */
> +	imx_i2c_write_reg((i2c_imx->slave->addr << 1), i2c_imx, IMX_I2C_IADR);
> +
> +	/* Disable i2c module */
> +	temp = i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN;
> +	imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> +
> +	/* Reset status register */
> +	imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx,
> +			  IMX_I2C_I2SR);
> +
> +	/* Enable module and enable interrupt from i2c module */
> +	temp = i2c_imx->hwdata->i2cr_ien_opcode | I2CR_IIEN;
> +	imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> +
> +	/* Wait controller to be stable */
> +	usleep_range(50, 150);
> +}
> +
> +static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx)
> +{
> +	unsigned int status, ctl;
> +	u8 value;
> +
> +	if (!i2c_imx->slave) {
> +		dev_err(&i2c_imx->adapter.dev, "cannot deal with slave irq,i2c_imx->slave is null");
> +		return IRQ_NONE;
> +	}
> +
> +	status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> +	ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
> +	if (status & I2SR_IAL) { /* Arbitration lost */
> +		i2c_imx_clr_al_bit(i2c_imx);
> +	} else if (status & I2SR_IAAS) { /* Addressed as a slave */
> +		if (status & I2SR_SRW) { /* Master wants to read from us*/
> +			dev_dbg(&i2c_imx->adapter.dev, "read requested");
> +			i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_REQUESTED, &value);
> +
> +			/* Slave transmit */
> +			ctl |= I2CR_MTX;
> +			imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
> +
> +			/* Send data */
> +			imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
> +		} else { /* Master wants to write to us */
> +			dev_dbg(&i2c_imx->adapter.dev, "write requested");
> +			i2c_slave_event(i2c_imx->slave,	I2C_SLAVE_WRITE_REQUESTED, &value);
> +
> +			/* Slave receive */
> +			ctl &= ~I2CR_MTX;
> +			imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
> +			/* Dummy read */
> +			imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
> +		}
> +	} else if (!(ctl & I2CR_MTX)) { /* Receive mode */
> +			if (status & I2SR_IBB) { /* No STOP signal detected */
> +				ctl &= ~I2CR_MTX;
> +				imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
> +
> +				value = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
> +				i2c_slave_event(i2c_imx->slave,	I2C_SLAVE_WRITE_RECEIVED, &value);
> +			} else { /* STOP signal is detected */
> +				dev_dbg(&i2c_imx->adapter.dev,
> +					"STOP signal detected");
> +				i2c_slave_event(i2c_imx->slave, I2C_SLAVE_STOP, &value);
> +			}
> +	} else if (!(status & I2SR_RXAK)) {	/* Transmit mode received ACK */
> +		ctl |= I2CR_MTX;
> +		imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
> +
> +		i2c_slave_event(i2c_imx->slave,	I2C_SLAVE_READ_PROCESSED, &value);
> +
> +		imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
> +	} else { /* Transmit mode received NAK */
> +		ctl &= ~I2CR_MTX;
> +		imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
> +		imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
> +	}
> +	return IRQ_HANDLED;
> +}
> +
> +static int i2c_imx_reg_slave(struct i2c_client *client)
> +{
> +	struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter);
> +
> +	if (i2c_imx->slave)
> +		return -EBUSY;
> +
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
> +	i2c_imx->slave = client;
> +
> +	i2c_imx_slave_init(i2c_imx);
> +
> +	return 0;
> +}
> +
> +static int i2c_imx_unreg_slave(struct i2c_client *client)
> +{
> +	struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter);
> +
> +	if (!i2c_imx->slave)
> +		return -EINVAL;
> +
> +	i2c_imx->slave = NULL;
> +
> +	return 0;
> +}
> +
>   static const struct i2c_algorithm i2c_imx_algo = {
>   	.master_xfer	= i2c_imx_xfer,
>   	.functionality	= i2c_imx_func,
> +	.reg_slave	= i2c_imx_reg_slave,
> +	.unreg_slave	= i2c_imx_unreg_slave,
>   };
>   
> +static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
> +{
> +	struct imx_i2c_struct *i2c_imx = dev_id;
> +	unsigned int status, ctl;
> +	irqreturn_t irq_status = IRQ_NONE;
> +
> +	status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> +	ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
> +
> +	if (status & I2SR_IIF) {
> +		i2c_imx_clr_if_bit(i2c_imx);
> +		if (ctl & I2CR_MSTA)
> +			irq_status = i2c_imx_master_isr(i2c_imx);
> +		else
> +			irq_status = i2c_imx_slave_isr(i2c_imx);
> +	}
> +
> +	return irq_status;
> +}
> +
>   static int i2c_imx_probe(struct platform_device *pdev)
>   {
>   	struct imx_i2c_struct *i2c_imx;
> 

Kind regards,
Oleksij Rempel

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