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Date: Fri, 21 May 2021 06:44:40 +0000
From: Aisheng Dong <aisheng.dong@....com>
To: Clark Wang <xiaoning.wang@....com>,
"robh+dt@...nel.org" <robh+dt@...nel.org>,
"shawnguo@...nel.org" <shawnguo@...nel.org>,
"s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
"festevam@...il.com" <festevam@...il.com>
CC: "kernel@...gutronix.de" <kernel@...gutronix.de>,
dl-linux-imx <linux-imx@....com>,
"linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH V2 10/18] i2c: imx-lpi2c: add bus recovery feature
> From: Clark Wang <xiaoning.wang@....com>
> Sent: Tuesday, April 6, 2021 7:33 PM
>
> Add bus recovery feature for LPI2C.
> Need add gpio pinctrl, scl-gpios and sda-gpios configuration in dts.
>
> Signed-off-by: Clark Wang <xiaoning.wang@....com>
> ---
> V2 changes:
> - No change. Add dt-bindings in the next patch.
Dt binding patch should be sent before driver change
> ---
> drivers/i2c/busses/i2c-imx-lpi2c.c | 83 ++++++++++++++++++++++++++++++
> 1 file changed, 83 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c
> b/drivers/i2c/busses/i2c-imx-lpi2c.c
> index 77ceb743b282..77dd6ee5a4a8 100644
> --- a/drivers/i2c/busses/i2c-imx-lpi2c.c
> +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
> @@ -18,6 +18,7 @@
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> +#include <linux/of_gpio.h>
> #include <linux/pinctrl/consumer.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> @@ -108,6 +109,11 @@ struct lpi2c_imx_struct {
> unsigned int txfifosize;
> unsigned int rxfifosize;
> enum lpi2c_imx_mode mode;
> +
> + struct i2c_bus_recovery_info rinfo;
> + struct pinctrl *pinctrl;
> + struct pinctrl_state *pinctrl_pins_default;
> + struct pinctrl_state *pinctrl_pins_gpio;
> };
>
> static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx, @@ -135,6
> +141,8 @@ 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);
> return -ETIMEDOUT;
> }
> schedule();
> @@ -192,6 +200,8 @@ 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();
> @@ -329,6 +339,8 @@ 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();
> @@ -528,6 +540,71 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> +static void lpi2c_imx_prepare_recovery(struct i2c_adapter *adap) {
> + struct lpi2c_imx_struct *lpi2c_imx;
> +
> + lpi2c_imx = container_of(adap, struct lpi2c_imx_struct, adapter);
> +
> + pinctrl_select_state(lpi2c_imx->pinctrl,
> +lpi2c_imx->pinctrl_pins_gpio); }
> +
> +static void lpi2c_imx_unprepare_recovery(struct i2c_adapter *adap) {
> + struct lpi2c_imx_struct *lpi2c_imx;
> +
> + lpi2c_imx = container_of(adap, struct lpi2c_imx_struct, adapter);
> +
> + pinctrl_select_state(lpi2c_imx->pinctrl,
> +lpi2c_imx->pinctrl_pins_default); }
> +
> +/*
> + * 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
> + * 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;
> +
> + lpi2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
> + if (!lpi2c_imx->pinctrl || IS_ERR(lpi2c_imx->pinctrl)) {
> + dev_info(&pdev->dev, "can't get pinctrl, bus recovery not
> supported\n");
> + return PTR_ERR(lpi2c_imx->pinctrl);
> + }
> +
> + lpi2c_imx->pinctrl_pins_default = pinctrl_lookup_state(lpi2c_imx->pinctrl,
> + PINCTRL_STATE_DEFAULT);
> + lpi2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(lpi2c_imx->pinctrl,
> + "gpio");
> + rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN);
> + rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl",
> +GPIOD_OUT_HIGH_OPEN_DRAIN);
> +
> + if (PTR_ERR(rinfo->sda_gpiod) == -EPROBE_DEFER ||
> + PTR_ERR(rinfo->scl_gpiod) == -EPROBE_DEFER) {
> + return -EPROBE_DEFER;
> + } else if (IS_ERR(rinfo->sda_gpiod) ||
> + IS_ERR(rinfo->scl_gpiod) ||
> + IS_ERR(lpi2c_imx->pinctrl_pins_default) ||
> + IS_ERR(lpi2c_imx->pinctrl_pins_gpio)) {
> + dev_dbg(&pdev->dev, "recovery information incomplete\n");
> + return 0;
> + }
> +
> + dev_info(&pdev->dev, "using scl%s for recovery\n",
> + rinfo->sda_gpiod ? ",sda" : "");
> +
> + rinfo->prepare_recovery = lpi2c_imx_prepare_recovery;
> + rinfo->unprepare_recovery = lpi2c_imx_unprepare_recovery;
> + rinfo->recover_bus = i2c_generic_scl_recovery;
> + 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 | @@ -632,6 +709,12
> @@ 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;
> +
> ret = i2c_add_adapter(&lpi2c_imx->adapter);
> if (ret)
> goto rpm_disable;
> --
> 2.25.1
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