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Message-ID: <20201113135947.h7cek55eevilay2t@pengutronix.de>
Date: Fri, 13 Nov 2020 14:59:47 +0100
From: Oleksij Rempel <o.rempel@...gutronix.de>
To: Biwen Li <biwen.li@....nxp.com>
Cc: leoyang.li@....com, linux@...pel-privat.de, kernel@...gutronix.de,
wsa@...-dreams.de, shawnguo@...nel.org, s.hauer@...gutronix.de,
festevam@...il.com, aisheng.dong@....com, xiaoning.wang@....com,
linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
jiafei.pan@....com, xiaobo.xie@....com,
linux-arm-kernel@...ts.infradead.org, Biwen Li <biwen.li@....com>
Subject: Re: [v10] i2c: imx: support slave mode for imx I2C driver
On Wed, Nov 11, 2020 at 07:32:55PM +0800, Biwen Li wrote:
> From: Biwen Li <biwen.li@....com>
>
> The patch supports slave mode for imx I2C driver
>
> Signed-off-by: Biwen Li <biwen.li@....com>
Thank you for your work!
Acked-by: Oleksij Rempel <o.rempel@...gutronix.de>
@Wolfram, Christian Eggers I2SR_IAL patches should go before this one.
> ---
> Change in v10:
> - totally remove CONFIG_I2C_SLAVE
> - replace api with i2c_imx_clart_irq()
> - remove robust code
> - place pm_runtime_get in i2c_imx_slave_init()
> to i2c_imx_reg_slave()
> - apply the patch on top of this patch set:
> [PATCH v6 0/3] i2c: imx: Fix handling of arbitration loss
> https://lkml.org/lkml/2020/10/9/407
>
> Change in v9:
> - remove #ifdef after select I2C_SLAVE by default
>
> Change in v8:
> - fix build issue
>
> Change in v7:
> - support auto switch mode between master and slave
> - enable interrupt when idle in slave mode
> - remove #ifdef
>
> Change in v6:
> - delete robust logs and comments
> - not read status register again in master isr.
>
> Change in v5:
> - fix a bug that cannot determine in what mode(master mode or
> slave mode)
>
> Change in v4:
> - add MACRO CONFIG_I2C_SLAVE to fix compilation issue
>
> Change in v3:
> - support layerscape and i.mx platform
>
> Change in v2:
> - remove MACRO CONFIG_I2C_SLAVE
>
> drivers/i2c/busses/Kconfig | 1 +
> drivers/i2c/busses/i2c-imx.c | 219 +++++++++++++++++++++++++++++++----
> 2 files changed, 196 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index a97a9d058198..e2ad62481f25 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -675,6 +675,7 @@ config I2C_IMG
> config I2C_IMX
> tristate "IMX I2C interface"
> depends on ARCH_MXC || ARCH_LAYERSCAPE || COLDFIRE
> + select I2C_SLAVE
> help
> Say Y here if you want to use the IIC bus controller on
> the Freescale i.MX/MXC, Layerscape or ColdFire processors.
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index e6f8d6e45a15..a8e8af57e33f 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -17,6 +17,7 @@
> * Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
> *
> * Copyright 2013 Freescale Semiconductor, Inc.
> + * Copyright 2020 NXP
> *
> */
>
> @@ -73,6 +74,11 @@
> #define IMX_I2C_I2SR 0x03 /* i2c status */
> #define IMX_I2C_I2DR 0x04 /* i2c transfer data */
>
> +/*
> + * All of the layerscape series SoCs support IBIC register.
> + */
> +#define IMX_I2C_IBIC 0x05 /* i2c bus interrupt config */
> +
> #define IMX_I2C_REGSHIFT 2
> #define VF610_I2C_REGSHIFT 0
>
> @@ -91,6 +97,7 @@
> #define I2CR_MSTA 0x20
> #define I2CR_IIEN 0x40
> #define I2CR_IEN 0x80
> +#define IBIC_BIIE 0x80 /* Bus idle interrupt enable */
>
> /* register bits different operating codes definition:
> * 1) I2SR: Interrupt flags clear operation differ between SoCs:
> @@ -201,6 +208,7 @@ 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 = {
> @@ -265,6 +273,11 @@ static inline int is_imx1_i2c(struct imx_i2c_struct *i2c_imx)
> return i2c_imx->hwdata->devtype == IMX1_I2C;
> }
>
> +static inline int is_vf610_i2c(struct imx_i2c_struct *i2c_imx)
> +{
> + return i2c_imx->hwdata->devtype == VF610_I2C;
> +}
> +
> static inline void imx_i2c_write_reg(unsigned int val,
> struct imx_i2c_struct *i2c_imx, unsigned int reg)
> {
> @@ -277,6 +290,27 @@ static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx,
> return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
> }
>
> +static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx, unsigned int bits)
> +{
> + unsigned int temp;
> +
> + /*
> + * i2sr_clr_opcode is the value to clear all interrupts. Here we want to
> + * clear only <bits>, so we write ~i2sr_clr_opcode with just <bits>
> + * toggled. This is required because i.MX needs W0C and Vybrid uses W1C.
> + */
> + temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ bits;
> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
> +}
> +
> +/* Set up i2c controller register and i2c status register to default value. */
> +static void i2c_imx_reset_regs(struct imx_i2c_struct *i2c_imx)
> +{
> + imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
> + i2c_imx, IMX_I2C_I2CR);
> + i2c_imx_clear_irq(i2c_imx, I2SR_IIF | I2SR_IAL);
> +}
> +
> /* Functions for DMA support */
> static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
> dma_addr_t phy_addr)
> @@ -412,19 +446,6 @@ static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx)
> dma->chan_using = NULL;
> }
>
> -static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx, unsigned int bits)
> -{
> - unsigned int temp;
> -
> - /*
> - * i2sr_clr_opcode is the value to clear all interrupts. Here we want to
> - * clear only <bits>, so we write ~i2sr_clr_opcode with just <bits>
> - * toggled. This is required because i.MX needs W0C and Vybrid uses W1C.
> - */
> - temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ bits;
> - imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
> -}
> -
> static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy, bool atomic)
> {
> unsigned long orig_jiffies = jiffies;
> @@ -638,18 +659,165 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx, bool atomic)
> imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> }
>
> +/*
> + * Enable bus idle interrupts
> + * Note: IBIC register will be cleared after disabled i2c module.
> + * All of layerscape series SoCs support IBIC register.
> + */
> +static void i2c_imx_enable_bus_idle(struct imx_i2c_struct *i2c_imx)
> +{
> + if (is_vf610_i2c(i2c_imx)) {
> + unsigned int temp;
> +
> + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_IBIC);
> + temp |= IBIC_BIIE;
> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_IBIC);
> + }
> +}
> +
> +static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx,
> + unsigned int status, unsigned int ctl)
> +{
> + u8 value;
> +
> + if (status & I2SR_IAL) { /* Arbitration lost */
> + i2c_imx_clear_irq(i2c_imx, I2SR_IAL);
> + if (!(status & I2SR_IAAS))
> + return IRQ_HANDLED;
> + }
> +
> + 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 */
> + 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 void i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx)
> +{
> + int temp;
> +
> + /* Set slave addr. */
> + imx_i2c_write_reg((i2c_imx->slave->addr << 1), i2c_imx, IMX_I2C_IADR);
> +
> + i2c_imx_reset_regs(i2c_imx);
> +
> + /* Enable module */
> + temp = i2c_imx->hwdata->i2cr_ien_opcode;
> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> +
> + /* Enable interrupt from i2c module */
> + temp |= I2CR_IIEN;
> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> +
> + i2c_imx_enable_bus_idle(i2c_imx);
> +}
> +
> +static int i2c_imx_reg_slave(struct i2c_client *client)
> +{
> + struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter);
> + int ret;
> +
> + if (i2c_imx->slave)
> + return -EBUSY;
> +
> + i2c_imx->slave = client;
> +
> + /* Resume */
> + ret = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
> + if (ret < 0) {
> + dev_err(&i2c_imx->adapter.dev, "failed to resume i2c controller");
> + return ret;
> + }
> +
> + 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);
> + int ret;
> +
> + if (!i2c_imx->slave)
> + return -EINVAL;
> +
> + /* Reset slave address. */
> + imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR);
> +
> + i2c_imx_reset_regs(i2c_imx);
> +
> + i2c_imx->slave = NULL;
> +
> + /* Suspend */
> + ret = pm_runtime_put_sync(i2c_imx->adapter.dev.parent);
> + if (ret < 0)
> + dev_err(&i2c_imx->adapter.dev, "failed to suspend i2c controller");
> +
> + return ret;
> +}
> +
> +static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx, unsigned int status)
> +{
> + /* save status register */
> + i2c_imx->i2csr = status;
> + wake_up(&i2c_imx->queue);
> +
> + return IRQ_HANDLED;
> +}
> +
> static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
> {
> struct imx_i2c_struct *i2c_imx = dev_id;
> - unsigned int temp;
> + unsigned int ctl, status;
>
> - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> - if (temp & I2SR_IIF) {
> - /* save status register */
> - i2c_imx->i2csr = temp;
> + 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_clear_irq(i2c_imx, I2SR_IIF);
> - wake_up(&i2c_imx->queue);
> - return IRQ_HANDLED;
> + if (i2c_imx->slave && !(ctl & I2CR_MSTA))
> + return i2c_imx_slave_isr(i2c_imx, status, ctl);
> + return i2c_imx_master_isr(i2c_imx, status);
> }
>
> return IRQ_NONE;
> @@ -1027,6 +1195,10 @@ static int i2c_imx_xfer_common(struct i2c_adapter *adapter,
> dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
> (result < 0) ? "error" : "success msg",
> (result < 0) ? result : num);
> + /* After data is transferred, switch to slave mode(as a receiver) */
> + if (i2c_imx->slave)
> + i2c_imx_slave_init(i2c_imx);
> +
> return (result < 0) ? result : num;
> }
>
> @@ -1140,6 +1312,8 @@ static const struct i2c_algorithm i2c_imx_algo = {
> .master_xfer = i2c_imx_xfer,
> .master_xfer_atomic = i2c_imx_xfer_atomic,
> .functionality = i2c_imx_func,
> + .reg_slave = i2c_imx_reg_slave,
> + .unreg_slave = i2c_imx_unreg_slave,
> };
>
> static int i2c_imx_probe(struct platform_device *pdev)
> @@ -1233,10 +1407,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
> clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb);
> i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));
>
> - /* Set up chip registers to defaults */
> - imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
> - i2c_imx, IMX_I2C_I2CR);
> - imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
> + i2c_imx_reset_regs(i2c_imx);
>
> /* Init optional bus recovery function */
> ret = i2c_imx_init_recovery_info(i2c_imx, pdev);
> --
> 2.17.1
>
>
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