Hi Carlos,
Quite a different patch this v2.
On Mon, Jul 24, 2023 at 06:55:45PM +0800, carlos.song@xxxxxxx wrote:
> From: Carlos Song <carlos.song@xxxxxxx>
>
> Add bus recovery feature for LPI2C.
> Need add gpio pinctrl, scl-gpios and sda-gpios configuration in dts.
mmhhh... I already asked you in the previous version to update
the commit log... where is the DTS?
> Signed-off-by: Clark Wang <xiaoning.wang@xxxxxxx>
> Signed-off-by: Carlos Song <carlos.song@xxxxxxx>
> ---
> drivers/i2c/busses/i2c-imx-lpi2c.c | 51 ++++++++++++++++++++++++++++++
> 1 file changed, 51 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
> index 158de0b7f030..e93ff3b5373c 100644
> --- a/drivers/i2c/busses/i2c-imx-lpi2c.c
> +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
> @@ -107,6 +107,7 @@ struct lpi2c_imx_struct {
> unsigned int txfifosize;
> unsigned int rxfifosize;
> enum lpi2c_imx_mode mode;
> + struct i2c_bus_recovery_info rinfo;
if this is in the i2c_adapter, why do you also need it here? You
keep this place allocated even if it is optional.
> };
>
> static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx,
> @@ -134,6 +135,8 @@ static int lpi2c_imx_bus_busy(struct lpi2c_imx_struct *lpi2c_imx)
>
> if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
> dev_dbg(&lpi2c_imx->adapter.dev, "bus not work\n");
> + if (lpi2c_imx->adapter.bus_recovery_info)
> + i2c_recover_bus(&lpi2c_imx->adapter);
what is the recover_bus() function that will get called?
> return -ETIMEDOUT;
> }
> schedule();
> @@ -191,6 +194,8 @@ static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx)
>
> if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
> dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n");
> + if (lpi2c_imx->adapter.bus_recovery_info)
> + i2c_recover_bus(&lpi2c_imx->adapter);
> break;
> }
> schedule();
> @@ -323,6 +328,8 @@ static int lpi2c_imx_txfifo_empty(struct lpi2c_imx_struct *lpi2c_imx)
>
> if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
> dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n");
> + if (lpi2c_imx->adapter.bus_recovery_info)
> + i2c_recover_bus(&lpi2c_imx->adapter);
> return -ETIMEDOUT;
> }
> schedule();
> @@ -525,6 +532,44 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> +/*
> + * We switch SCL and SDA to their GPIO function and do some bitbanging
> + * for bus recovery. These alternative pinmux settings can be
> + * described in the device tree by a separate pinctrl state "gpio". If
What is the description in the device tree?
> + * this is missing this is not a big problem, the only implication is
> + * that we can't do bus recovery.
> + */
> +static int lpi2c_imx_init_recovery_info(struct lpi2c_imx_struct *lpi2c_imx,
> + struct platform_device *pdev)
> +{
> + struct i2c_bus_recovery_info *rinfo = &lpi2c_imx->rinfo;
> +
> + /*
> + * When there is no pinctrl state "gpio" in device tree, it means i2c
> + * recovery function is not needed, so it is not a problem even if
> + * pinctrl state "gpio" is missing. Just do not initialize the I2C bus
> + * recovery information.
> + */
> + rinfo->pinctrl = devm_pinctrl_get(&pdev->dev);
> + if (IS_ERR(rinfo->pinctrl)) {
> + if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> + dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n");
nit: "can't get pinctrl..." sounds like error and this is not an
error. Just "bus recovery not supported" is more a friendly
message.
> + return PTR_ERR(rinfo->pinctrl);
> + } else if (!rinfo->pinctrl) {
> + return -ENODEV;
this is the unsupported case and here I would return '0' as it's
not an error.
> + }
> +
> + if (IS_ERR(pinctrl_lookup_state(rinfo->pinctrl, "gpio"))) {
> + dev_dbg(&pdev->dev, "recovery information incomplete\n");
> + return 0;
> + }
> +
> + lpi2c_imx->adapter.bus_recovery_info = rinfo;
> +
> + return 0;
> +}
> +
> static u32 lpi2c_imx_func(struct i2c_adapter *adapter)
> {
> return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
> @@ -603,6 +648,12 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
> lpi2c_imx->txfifosize = 1 << (temp & 0x0f);
> lpi2c_imx->rxfifosize = 1 << ((temp >> 8) & 0x0f);
>
> + /* Init optional bus recovery function */
> + ret = lpi2c_imx_init_recovery_info(lpi2c_imx, pdev);
> + /* Give it another chance if pinctrl used is not ready yet */
> + if (ret == -EPROBE_DEFER)
> + goto rpm_disable;
what about other errors like -ENOMEM?
Andi
> ret = i2c_add_adapter(&lpi2c_imx->adapter);
> if (ret)
> goto rpm_disable;
> --
> 2.34.1
>
