Re: [PATCH] Add slave mode to Synopsys I2C driver
From: Andy Shevchenko
Date: Tue Oct 11 2016 - 08:49:21 EST
On Tue, 2016-10-11 at 13:18 +0100, Luis.Oliveira@xxxxxxxxxxxx wrote:
> From: Luis Oliveira <lolivei@xxxxxxxxxxxx>
>
> Add support in existing I2C Synopsys Designware Core driver for I2C
> slave mode.
My comments below.
> --- a/drivers/i2c/busses/i2c-designware-core.c
> +++ b/drivers/i2c/busses/i2c-designware-core.c
> @@ -21,6 +21,7 @@
> Â * ------------------------------------------------------------------
> ----------
> Â *
> Â */
> +
Doesn't belong this patch (let's call it indent fix).
> Â#include <linux/export.h>
> Â#include <linux/errno.h>
> Â#include <linux/err.h>
> @@ -85,15 +87,27 @@
> Â#define DW_IC_INTR_STOP_DET 0x200
> Â#define DW_IC_INTR_START_DET 0x400
> Â#define DW_IC_INTR_GEN_CALL 0x800
> -
> -#define DW_IC_INTR_DEFAULT_MASK (DW_IC_INTR_RX_FULL |
> \
> - ÂDW_IC_INTR_TX_EMPTY | \
> - ÂDW_IC_INTR_TX_ABRT | \
> - ÂDW_IC_INTR_STOP_DET)
> +#define DW_IC_INTR_RESTART_DET 0x1000
> +
> +#define DW_IC_INTR_MST_DEFAULT_MASK (DW_IC_INTR_RX_FUL
> L | \
> + ÂÂÂÂDW_IC_INTR_TX_EMPTY | \
> + ÂÂÂÂDW_IC_INTR_TX_ABRT | \
> + ÂÂÂÂDW_IC_INTR_STOP_DET | \
> + ÂÂÂÂDW_IC_INTR_RX_DONE | \
> + ÂÂÂÂDW_IC_INTR_RX_UNDER | \
> + ÂÂÂÂDW_IC_INTR_RD_REQ)
> +
> + #define DW_IC_INTR_SLV_DEFAULT_MASK (DW_IC_INTR_RX_FU
> LL | \
> + ÂÂÂÂDW_IC_INTR_STOP_DET | \
It would be better to keep list in the same order as in other set above.
> + ÂÂÂÂDW_IC_INTR_TX_ABRT | \
> + ÂÂÂÂDW_IC_INTR_RX_DONE | \
> + ÂÂÂÂDW_IC_INTR_RX_UNDER | \
> + ÂÂÂÂDW_IC_INTR_RD_REQ)
> Â
Or even split common part with previous name.
> @@ -107,7 +121,7 @@
> Â */
> Â#define STATUS_IDLE 0x0
> Â#define STATUS_WRITE_IN_PROGRESS 0x1
> -#define STATUS_READ_IN_PROGRESS 0x2
> +#define STATUS_READ_IN_PROGRESS 0x2
Indent fix. Not here.
> @@ -128,6 +142,9 @@
> Â#define ABRT_10B_RD_NORSTRT 10
> Â#define ABRT_MASTER_DIS 11
> Â#define ARB_LOST 12
> +#define ABRT_SLVFLUSH_TXFIFOÂÂÂÂ13
> +#define ABRT_SLV_ARBLOSTÂÂÂÂÂÂÂÂ14
> +#define ABRT_SLVRD_INTXÂÂÂÂÂÂÂÂÂ15
Can we use _SLAVE_ instead? It would be in align with _MASTER_.
Same to above MASK definition.
> @@ -140,6 +157,9 @@
> Â#define DW_IC_TX_ABRT_10B_RD_NORSTRT (1UL <<
> ABRT_10B_RD_NORSTRT)
> Â#define DW_IC_TX_ABRT_MASTER_DIS (1UL << ABRT_MASTER_DIS)
> Â#define DW_IC_TX_ARB_LOST (1UL << ARB_LOST)
> +#define DW_IC_RX_ABRT_SLVRD_INTXÂÂÂÂÂÂÂÂ(1UL << ABRT_SLVRD_INTX)
> +#define DW_IC_RX_ABRT_SLV_ARBLOSTÂÂÂÂÂÂÂ(1UL << ABRT_SLV_ARBLOST)
> +#define DW_IC_RX_ABRT_SLVFLUSH_TXFIFOÂÂÂ(1UL << ABRT_SLVFLUSH_TXFIFO)
Ditto.
> @@ -343,8 +369,8 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
> Â /* Configure register access mode 16bit */
> Â dev->accessor_flags |= ACCESS_16BIT;
> Â } else if (reg != DW_IC_COMP_TYPE_VALUE) {
> - dev_err(dev->dev, "Unknown Synopsys component type: "
> - "0x%08x\n", reg);
> + dev_err(dev->dev, "Unknown Synopsys component type:
> 0x%08x\n",
> + reg);
Indent fix. Not here.
> @@ -431,12 +457,30 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
> Â "Hardware too old to adjust SDA hold
> time.\n");
> Â }
> Â
> - /* Configure Tx/Rx FIFO threshold levels */
> - dw_writel(dev, dev->tx_fifo_depth / 2, DW_IC_TX_TL);
> - dw_writel(dev, 0, DW_IC_RX_TL);
> -
> - /* configure the i2c master */
> - dw_writel(dev, dev->master_cfg , DW_IC_CON);
> + if ((dev->master_cfg & DW_IC_CON_MASTER) &&
> + (dev->master_cfg & DW_IC_CON_SLAVE_DISABLE)) {
> + /* IF master */
> +
> + /* Configure Tx/Rx FIFO threshold levels */
> + dw_writel(dev, dev->tx_fifo_depth / 2, DW_IC_TX_TL);
> + dw_writel(dev, 0, DW_IC_RX_TL);
> +
> + /* configure the i2c master */
> + dw_writel(dev, dev->master_cfg, DW_IC_CON);
> + dw_writel(dev, DW_IC_INTR_MST_DEFAULT_MASK,
> DW_IC_INTR_MASK);
> + } else if (!(dev->master_cfg & DW_IC_CON_MASTER) &&
> + !(dev->master_cfg & DW_IC_CON_SLAVE_DISABLE)) {
> + /*IF slave */
> +
> + /* Configure Tx/Rx FIFO threshold levels */
> + dw_writel(dev, 0, DW_IC_TX_TL);
> + dw_writel(dev, 0, DW_IC_RX_TL);
> +
> + /* configure the i2c slave */
> + dw_writel(dev, dev->slave_cfg, DW_IC_CON);
> + dw_writel(dev, DW_IC_INTR_SLV_DEFAULT_MASK,
> DW_IC_INTR_MASK);
> + } else
> + return -EAGAIN;
Regarding to such blocks. Perhaps you may refactor code first to split
*_master() functions out of existing ones and add *_slave() in sequent
patch?
Same to all similar pieces in the patch.
> @@ -772,12 +816,64 @@ done_nolock:
> Âstatic u32 i2c_dw_func(struct i2c_adapter *adap)
> Â{
> Â struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> +
Indent fix. Not here.
> Â return dev->functionality;
> Â}
>
> Â
> +static int i2c_dw_reg_slave(struct i2c_client *slave)
> +{
> + struct dw_i2c_dev *dev =ÂÂi2c_get_adapdata(slave->adapter);
> +
> + if (dev->slave)
> + return -EBUSY;
+ empty line.
> + if (slave->flags & I2C_CLIENT_TEN)
> + return -EAFNOSUPPORT;
> + /* set slave address in the IC_SAR register,
> + * the address to which the DW_apb_i2c responds
> + */
No, multi-line comment style is different and please indent it
correctly.
> +
> + __i2c_dw_enable(dev, false);
> +
> + dw_writel(dev, slave->addr, DW_IC_SAR);
> +
> + pm_runtime_forbid(dev->dev);
Why? Add a comment and how it recovers (returns back) from this.
> +
> + dev->slave = slave;
> +
> + __i2c_dw_enable(dev, true);
> +
> + dev->cmd_err = 0;
> + dev->msg_write_idx = 0;
> + dev->msg_read_idx = 0;
> + dev->msg_err = 0;
> + dev->status = STATUS_IDLE;
> + dev->abort_source = 0;
> + dev->rx_outstanding = 0;
> +
> + return 0;
> +}
> +
> +static int i2c_dw_unreg_slave(struct i2c_client *slave)
> +{
> + struct dw_i2c_dev *dev =ÂÂi2c_get_adapdata(slave->adapter);
> +
> + WARN_ON(!dev->slave);
I doubt i2c core will allow such. Same to above.
> +
> + i2c_dw_disable_int(dev);
> + i2c_dw_disable(dev);
> +
> + dev->slave =ÂÂNULL;
> +
> + pm_runtime_allow(dev->dev);
> +
> + return 0;
> +}
> +
> Âstatic struct i2c_algorithm i2c_dw_algo = {
> Â .master_xfer = i2c_dw_xfer,
> Â .functionality = i2c_dw_func,
> + .reg_slave = i2c_dw_reg_slave,
> + .unreg_slave = i2c_dw_unreg_slave,
> @@ -839,19 +933,129 @@ static u32 i2c_dw_read_clear_intrbits(struct
> dw_i2c_dev *dev)
> Â * Interrupt service routine. This gets called whenever an I2C
> interrupt
> Â * occurs.
> Â */
> +
> +static bool i2c_dw_slave_irq_handler(struct dw_i2c_dev *dev)
_irq_handler_slave()
> +{
> + u32 raw_stat, stat, enabled;
> + u8 val;
> + u8 slv_act;
Reversed tree. slv -> slave.
> +
> + statÂÂÂÂÂ= dw_readl(dev, DW_IC_INTR_STAT);
> + enabledÂÂ= dw_readl(dev, DW_IC_ENABLE);
> + raw_stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
> +
> + if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY))
(!(enabled && (raw_stat & ~DW_IC...))) ?
> + return false;
> +
> + slv_act = ((dw_readl(dev, DW_IC_STATUS) &
> + DW_IC_STATUS_SLV_ACTIVITY)>>6);
> +
> + dev_dbg(dev->dev,
> + Â"%s: %#x SLAVE_ACTV=%#x : RAW_INTR_STAT=%#x :
> INTR_STAT=%#x\n",
> + Â__func__, enabled, slv_act, raw_stat, stat);
Indent lines properly.
> + if ((stat & DW_IC_INTR_RX_FULL) && (stat &
> DW_IC_INTR_STOP_DET)) {
> + dev_dbg(dev->dev, "First write\n");
Is this useful?
> + i2c_slave_event(dev->slave,
> I2C_SLAVE_WRITE_REQUESTED, &val);
> + }
> +
> + if (slv_act) {
> + dev_dbg(dev->dev, "I2C GET\n");
Or this?
> +
> + if (stat & DW_IC_INTR_RD_REQ) {
> + 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_dbg(dev->dev, "Byte %X
> acked! ", val);
>
> + ;
What's that?
> + }
> + dev_dbg(dev->dev, "I2C GET + add");
> + dw_readl(dev, DW_IC_CLR_RD_REQ);
> + stat =
> i2c_dw_read_clear_intrbits(dev);
> + } else {
> + dev_dbg(dev->dev, "I2C GET + 0x00");
> + dw_readl(dev, DW_IC_CLR_RD_REQ);
> + dw_readl(dev, DW_IC_CLR_RX_UNDER);
> + stat =
> i2c_dw_read_clear_intrbits(dev);
> + }
> + if (!i2c_slave_event(dev->slave,
> + I2C_SLAVE_READ_REQUESTED,
> &val))
> + dw_writel(dev, (0x0 << 8 | val),
0 << (x) == 0. What the intention?
> DW_IC_DATA_CMD);
> + }
> + }
> + if (stat & DW_IC_INTR_RX_DONE) {
>
> +
Redundant.
> + 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);
> + dev_dbg(dev->dev, "Transmission Complete.");
> + stat = i2c_dw_read_clear_intrbits(dev);
> +
> + goto done;
> + }
> +
> + if (stat & DW_IC_INTR_RX_FULL) {
> + dev_dbg(dev->dev, "I2C SET");
> + val = dw_readl(dev, DW_IC_DATA_CMD);
> + if (!i2c_slave_event(dev->slave,
> + I2C_SLAVE_WRITE_RECEIVED, &val)) {
> + dev_dbg(dev->dev, "Byte %X acked! ", val);
> + ;
> + }
> + } else {
> + i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
> + dev_dbg(dev->dev, "Transmission Complete.");
> + stat = i2c_dw_read_clear_intrbits(dev);
> + }
> +
> + if (stat & DW_IC_INTR_TX_OVER) {
> + dw_readl(dev, DW_IC_CLR_TX_OVER);
> + return true;
> + }
>
> +done:
Useless label. Return directly.
> + return true;
> +}
The function might need a refactoring.
> +
> Âstatic irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
> Â{
> Â struct dw_i2c_dev *dev = dev_id;
> - u32 stat, enabled;
> + u32 stat, enabled, mode;
> Â
> Â enabled = dw_readl(dev, DW_IC_ENABLE);
> + mode = dw_readl(dev, DW_IC_CON);
> Â stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
> - dev_dbg(dev->dev, "%s: enabled=%#x stat=%#x\n", __func__,
> enabled, stat);
> +
> + stat = i2c_dw_read_clear_intrbits(dev);
> +
> + dev_dbg(dev->dev,
> + "%s: enabled=%#x stat=%#x\n", __func__, enabled,
> stat);
> +
> Â if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
> Â return IRQ_NONE;
> Â
> Â stat = i2c_dw_read_clear_intrbits(dev);
> Â
> + if (!(mode & DW_IC_CON_MASTER) && !(mode &
> DW_IC_CON_SLAVE_DISABLE)) {
> +
>
> + /* slaveÂÂmode*/
Hmm... Besides style does it really help?
> + if (!i2c_dw_slave_irq_handler(dev))
> + return IRQ_NONE;
> +
> + complete(&dev->cmd_complete);
> + return IRQ_HANDLED;
> + }
> +
> --- a/drivers/i2c/busses/i2c-designware-core.h
> +++ b/drivers/i2c/busses/i2c-designware-core.h
> @@ -28,9 +28,13 @@
> Â#define DW_IC_CON_SPEED_FAST 0x4
> Â#define DW_IC_CON_SPEED_HIGH 0x6
> Â#define DW_IC_CON_SPEED_MASK 0x6
> +#define DW_IC_CON_10BITADDR_SLAVEÂÂÂÂÂÂÂ0x8
> Â#define DW_IC_CON_10BITADDR_MASTER 0x10
> Â#define DW_IC_CON_RESTART_EN 0x20
> Â#define DW_IC_CON_SLAVE_DISABLE 0x40
> +#define DW_IC_CON_STOP_DET_IFADDRESSEDÂÂ0x80
> +#define DW_IC_CON_TX_EMPTY_CTRL 0x100
> +#define DW_IC_CON_RX_FIFO_FULL_HLD_CTRL 0x200
> Â
> Â
> Â/**
> @@ -80,7 +84,8 @@ struct dw_i2c_dev {
> Â void __iomem *base;
> Â struct completion cmd_complete;
> Â struct clk *clk;
> - u32 (*get_clk_rate_khz) (struct
> dw_i2c_dev *dev);
> + struct i2c_client *slave;
>
> + u32 (*get_clk_rate_khz)(struct
> dw_i2c_dev *dev);
What happened to this member? Indentation fix? Not here.
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -21,6 +21,7 @@
> Â * ------------------------------------------------------------------
> ----------
> Â *
> Â */
> +
Ditto.
> Â#include <linux/kernel.h>
> Â#include <linux/module.h>
> Â#include <linux/delay.h>
> @@ -158,6 +159,7 @@ static int dw_i2c_plat_probe(struct
> platform_device *pdev)
> Â struct resource *mem;
> Â int irq, r;
> Â u32 acpi_speed, ht = 0;
> + bool isslave = false;
isslave -> is_slave.
> Â
> Â irq = platform_get_irq(pdev, 0);
> Â if (irq < 0)
> @@ -190,6 +192,7 @@ static int dw_i2c_plat_probe(struct
> platform_device *pdev)
> Â Â&dev->scl_falling_time);
> Â device_property_read_u32(&pdev->dev, "clock-
> frequency",
> Â Â&dev->clk_freq);
> + isslave = device_property_read_bool(&pdev->dev,
> "isslave");
This needs a separate patch against device bindings.
Moreover, check if:
- there is already standard property for such functionality
- it can/can't be discovered automatically
- consequences of use this on ACPI-enabled platforms
> @@ -216,24 +219,46 @@ static int dw_i2c_plat_probe(struct
> platform_device *pdev)
> Â
> Â dev->functionality =
> Â I2C_FUNC_I2C |
> - I2C_FUNC_10BIT_ADDR |
> Â I2C_FUNC_SMBUS_BYTE |
> Â I2C_FUNC_SMBUS_BYTE_DATA |
> Â I2C_FUNC_SMBUS_WORD_DATA |
> Â I2C_FUNC_SMBUS_I2C_BLOCK;
> Â
> - dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE
> |
> + if (!isslave) {
> + dev->master_cfg = DW_IC_CON_MASTER |
> DW_IC_CON_SLAVE_DISABLE |
> Â ÂÂDW_IC_CON_RESTART_EN;
> + dev->functionality |= I2C_FUNC_10BIT_ADDR;
> + dev_info(&pdev->dev, "I am registed as a I2C
> Master!\n");
> + switch (dev->clk_freq) {
> + case 100000:
> + dev->master_cfg |= DW_IC_CON_SPEED_STD;
> + break;
> + case 3400000:
> + dev->master_cfg |= DW_IC_CON_SPEED_HIGH;
> + break;
> + default:
> + dev->master_cfg |= DW_IC_CON_SPEED_FAST;
> + }
> + } else {
> + dev->slave_cfg = DW_IC_CON_RX_FIFO_FULL_HLD_CTRL |
> + ÂÂDW_IC_CON_RESTART_EN |
> DW_IC_CON_STOP_DET_IFADDRESSED |
> + ÂÂDW_IC_CON_SPEED_FAST;
> +
> + dev->functionality |= I2C_FUNC_SLAVE;
> + dev->functionality &= ~I2C_FUNC_10BIT_ADDR;
> + dev_info(&pdev->dev, "I am registed as a I2C
> Slave!\n");
> +
> + switch (dev->clk_freq) {
> + case 100000:
> + dev->slave_cfg |= DW_IC_CON_SPEED_STD;
> +
> + case 3400000:
> + dev->slave_cfg |= DW_IC_CON_SPEED_HIGH;
> + break;
> + default:
> + dev->slave_cfg |= DW_IC_CON_SPEED_FAST;
> Â
> - switch (dev->clk_freq) {
> - case 100000:
> - dev->master_cfg |= DW_IC_CON_SPEED_STD;
> - break;
> - case 3400000:
> - dev->master_cfg |= DW_IC_CON_SPEED_HIGH;
> - break;
> - default:
> - dev->master_cfg |= DW_IC_CON_SPEED_FAST;
> + }
Factor out _master() part first.
In summary I see 4 patches here:
- factor out _master() parts
- enable slave
- device bindings
- indentation fix
--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy