[Patch V5] i2c: imx: implement bus recovery
Gao Pandy
gaopan at freescale.com
Fri Sep 18 00:40:16 PDT 2015
Ping...
From: Gao Pan <mailto:b54642 at freescale.com> Sent: Friday, September 11, 2015 6:43 PM
> To: wsa at the-dreams.de; u.kleine-koenig at pengutronix.de;
> shawnguo at kernel.org; kernel at pengutronix.de
> Cc: linux-i2c at vger.kernel.org; Li Frank-B20596; Duan Fugang-B38611; Gao
> Pan-B54642; linux-arm-kernel at lists.infradead.org
> Subject: [Patch V5] i2c: imx: implement bus recovery
>
> Implement bus recovery methods for i2c-imx so we can recover from
> situations where SCL/SDA are stuck low.
>
> Once i2c bus SCL/SDA are stuck low during transfer, config the i2c
> pinctrl to gpio mode by calling pinctrl sleep set function, and then use
> GPIO to emulate the i2c protocol to send nine dummy clock to recover i2c
> device. After recovery, set i2c pinctrl to default group setting.
>
> Signed-off-by: Fugang Duan <B38611 at freescale.com>
> Signed-off-by: Gao Pan <b54642 at freescale.com>
> ---
> V2:
> As Uwe Kleine-König's suggestion, the version do below changes:
> -replace of_get_named_gpio() with devm_gpiod_get_optional() -move
> gpio_direction_input() and gpio_direction_output() call to the
> prepare callback
> -use 0 and 1 as return value for the get_scl and get_sda callbacks
>
> V3:
> -replace "...-gpio" with "...-gpios" in i2c binding doc -document the
> requirement of using sleep state to configure
> the pins as gpio in i2c binding doc
> -remove i2c_recover_bus() in i2c_imx_trx_complete() -use GPIOD_OUT_HIGH
> as the parameter of devm_gpiod_get_optional to
> config the gpios as output high
> -add error disposal as devm_gpiod_get_optional meets error
>
> V4:
> -remove include <linux/of_gpio.h>
> -call i2c_recover_bus under the condition of the existing of
> both sda and scl. Drop the sda and scl check in i2c_imx_get_scl,
> i2c_imx_get_sda, i2c_imx_set_scl, i2c_imx_prepare_recovery and
> i2c_imx_prepare_recovery
> -use GPIOD_OUT_IN as the parameter of devm_gpiod_get_optional -remove
> documenting the requirement of using sleep state to configure
> the pins as gpio in i2c binding doc
>
> V5:
> -introduce a dedicated gpio state for bus recovery.
> -assign adapter.bus_recovery_info after the two gpios were aquired
> successfully.
>
> Documentation/devicetree/bindings/i2c/i2c-imx.txt | 9 ++
> drivers/i2c/busses/i2c-imx.c | 121
> ++++++++++++++++++++--
> 2 files changed, 123 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-imx.txt
> b/Documentation/devicetree/bindings/i2c/i2c-imx.txt
> index ce4311d..eab5836 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-imx.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-imx.txt
> @@ -14,6 +14,10 @@ Optional properties:
> The absence of the propoerty indicates the default frequency 100 kHz.
> - dmas: A list of two dma specifiers, one for each entry in dma-names.
> - dma-names: should contain "tx" and "rx".
> +- scl-gpios: specify the gpio related to SCL pin
> +- sda-gpios: specify the gpio related to SDA pin
> +- pinctrl: add extra pinctrl to configure i2c pins to gpio function for
> +i2c
> + bus recovery, call it "gpio" state
>
> Examples:
>
> @@ -37,4 +41,9 @@ i2c0: i2c at 40066000 { /* i2c0 on vf610 */
> dmas = <&edma0 0 50>,
> <&edma0 0 51>;
> dma-names = "rx","tx";
> + pinctrl-names = "default", "gpio";
> + pinctrl-0 = <&pinctrl_i2c1>;
> + pinctrl-1 = <&pinctrl_i2c1_gpio>;
> + scl-gpios = <&gpio5 26 GPIO_ACTIVE_HIGH>;
> + sda-gpios = <&gpio5 27 GPIO_ACTIVE_HIGH>;
> };
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index d7c823b..90c0e0f 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -40,6 +40,7 @@
> #include <linux/dmapool.h>
> #include <linux/err.h>
> #include <linux/errno.h>
> +#include <linux/gpio.h>
> #include <linux/i2c.h>
> #include <linux/init.h>
> #include <linux/interrupt.h>
> @@ -64,6 +65,8 @@
> /* Default value */
> #define IMX_I2C_BIT_RATE 100000 /* 100kHz */
>
> +#define I2C_PINCTRL_STATE_GPIO "gpio"
> +
> /*
> * Enable DMA if transfer byte size is bigger than this threshold.
> * As the hardware request, it must bigger than 4 bytes.\ @@ -178,6
> +181,11 @@ enum imx_i2c_type {
> VF610_I2C,
> };
>
> +struct imx_i2c_pinctrl {
> + struct gpio_desc *sda;
> + struct gpio_desc *scl;
> +};
> +
> struct imx_i2c_hwdata {
> enum imx_i2c_type devtype;
> unsigned regshift;
> @@ -209,8 +217,13 @@ struct imx_i2c_struct {
> unsigned int ifdr; /* IMX_I2C_IFDR */
> unsigned int cur_clk;
> unsigned int bitrate;
> + struct imx_i2c_pinctrl pins;
> const struct imx_i2c_hwdata *hwdata;
>
> + struct pinctrl *pinctrl;
> + struct pinctrl_state *pinctrl_pins_default;
> + struct pinctrl_state *pinctrl_pins_gpio;
> +
> struct imx_i2c_dma *dma;
> };
>
> @@ -439,7 +452,10 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct
> *i2c_imx, int for_busy)
> if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500)))
> {
> dev_dbg(&i2c_imx->adapter.dev,
> "<%s> I2C bus is busy\n", __func__);
> - return -ETIMEDOUT;
> + if (i2c_imx->adapter.bus_recovery_info)
> + return i2c_recover_bus(&i2c_imx->adapter);
> + else
> + return -ETIMEDOUT;
> }
> schedule();
> }
> @@ -963,6 +979,62 @@ out:
> return (result < 0) ? result : num;
> }
>
> +static int i2c_imx_get_scl(struct i2c_adapter *adap) {
> + struct imx_i2c_struct *i2c_imx;
> +
> + i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
> +
> + return gpiod_get_value(i2c_imx->pins.scl);
> +}
> +
> +static int i2c_imx_get_sda(struct i2c_adapter *adap) {
> + struct imx_i2c_struct *i2c_imx;
> +
> + i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
> +
> + return gpiod_get_value(i2c_imx->pins.sda);
> +}
> +
> +static void i2c_imx_set_scl(struct i2c_adapter *adap, int val) {
> + struct imx_i2c_struct *i2c_imx;
> +
> + i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
> +
> + gpiod_set_value(i2c_imx->pins.scl, val); }
> +
> +static void i2c_imx_prepare_recovery(struct i2c_adapter *adap) {
> + struct imx_i2c_struct *i2c_imx;
> +
> + i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
> +
> + pinctrl_select_state(i2c_imx->pinctrl, i2c_imx->pinctrl_pins_gpio);
> + gpiod_direction_input(i2c_imx->pins.sda);
> + gpiod_direction_output(i2c_imx->pins.scl, 1); }
> +
> +static void i2c_imx_unprepare_recovery(struct i2c_adapter *adap) {
> + struct imx_i2c_struct *i2c_imx;
> +
> + i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
> +
> + pinctrl_select_state(i2c_imx->pinctrl, i2c_imx-
> >pinctrl_pins_default);
> +}
> +
> +static struct i2c_bus_recovery_info i2c_imx_bus_recovery_info = {
> + .get_scl = i2c_imx_get_scl,
> + .get_sda = i2c_imx_get_sda,
> + .set_scl = i2c_imx_set_scl,
> + .prepare_recovery = i2c_imx_prepare_recovery,
> + .unprepare_recovery = i2c_imx_unprepare_recovery,
> + .recover_bus = i2c_generic_scl_recovery, };
> +
> static u32 i2c_imx_func(struct i2c_adapter *adapter) {
> return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL @@ -1011,12 +1083,12 @@
> static int i2c_imx_probe(struct platform_device *pdev)
>
> /* Setup i2c_imx driver structure */
> strlcpy(i2c_imx->adapter.name, pdev->name, sizeof(i2c_imx-
> >adapter.name));
> - i2c_imx->adapter.owner = THIS_MODULE;
> - i2c_imx->adapter.algo = &i2c_imx_algo;
> - i2c_imx->adapter.dev.parent = &pdev->dev;
> - i2c_imx->adapter.nr = pdev->id;
> - i2c_imx->adapter.dev.of_node = pdev->dev.of_node;
> - i2c_imx->base = base;
> + i2c_imx->adapter.owner = THIS_MODULE;
> + i2c_imx->adapter.algo = &i2c_imx_algo;
> + i2c_imx->adapter.dev.parent = &pdev->dev;
> + i2c_imx->adapter.nr = pdev->id;
> + i2c_imx->adapter.dev.of_node = pdev->dev.of_node;
> + i2c_imx->base = base;
>
> /* Get I2C clock */
> i2c_imx->clk = devm_clk_get(&pdev->dev, NULL); @@ -1031,6 +1103,23
> @@ static int i2c_imx_probe(struct platform_device *pdev)
> return ret;
> }
>
> + i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
> + if (IS_ERR(i2c_imx->pinctrl)) {
> + ret = PTR_ERR(i2c_imx->pinctrl);
> + goto clk_disable;
> + }
> +
> + i2c_imx->pinctrl_pins_default = pinctrl_lookup_state(i2c_imx-
> >pinctrl,
> + PINCTRL_STATE_DEFAULT);
> + if (IS_ERR(i2c_imx->pinctrl_pins_default))
> + dev_warn(&pdev->dev, "could not get default state\n");
> + else {
> + i2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(i2c_imx-
> >pinctrl,
> + I2C_PINCTRL_STATE_GPIO);
> + if (IS_ERR(i2c_imx->pinctrl_pins_gpio))
> + dev_warn(&pdev->dev, "could not get gpio state\n");
> + }
> +
> /* Request IRQ */
> ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, 0,
> pdev->name, i2c_imx);
> @@ -1057,6 +1146,24 @@ static int i2c_imx_probe(struct platform_device
> *pdev)
> if (ret < 0)
> goto rpm_disable;
>
> + /* Init recover pins */
> + i2c_imx->pins.sda =
> + devm_gpiod_get_optional(&pdev->dev, "sda-gpios", GPIOD_IN);
> + i2c_imx->pins.scl =
> + devm_gpiod_get_optional(&pdev->dev, "scl-gpios", GPIOD_IN);
> +
> + if (IS_ERR(i2c_imx->pins.sda)) {
> + ret = PTR_ERR(i2c_imx->pins.sda);
> + goto clk_disable;
> + }
> +
> + if (IS_ERR(i2c_imx->pins.scl)) {
> + ret = PTR_ERR(i2c_imx->pins.scl);
> + goto clk_disable;
> + }
> +
> + i2c_imx->adapter.bus_recovery_info = &i2c_imx_bus_recovery_info;
> +
> /* Set up clock divider */
> i2c_imx->bitrate = IMX_I2C_BIT_RATE;
> ret = of_property_read_u32(pdev->dev.of_node,
> --
> 1.9.1
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