diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-at91-master.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-at91-master.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c index 7a862e00b475..0aba51a7df32 100644 --- a/drivers/i2c/busses/i2c-at91-master.c +++ b/drivers/i2c/busses/i2c-at91-master.c @@ -18,11 +18,13 @@ #include <linux/dma-mapping.h> #include <linux/dmaengine.h> #include <linux/err.h> +#include <linux/gpio/consumer.h> #include <linux/i2c.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/of.h> #include <linux/of_device.h> +#include <linux/pinctrl/consumer.h> #include <linux/platform_device.h> #include <linux/platform_data/dma-atmel.h> #include <linux/pm_runtime.h> @@ -478,6 +480,7 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) unsigned long time_left; bool has_unre_flag = dev->pdata->has_unre_flag; bool has_alt_cmd = dev->pdata->has_alt_cmd; + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; /* * WARNING: the TXCOMP bit in the Status Register is NOT a clear on @@ -637,6 +640,13 @@ error: at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_THRCLR | AT91_TWI_LOCKCLR); } + + if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) { + dev_dbg(dev->dev, + "SDA is down; clear bus using gpio\n"); + i2c_recover_bus(&dev->adapter); + } + return ret; } @@ -806,6 +816,70 @@ error: return ret; } +static void at91_prepare_twi_recovery(struct i2c_adapter *adap) +{ + struct at91_twi_dev *dev = i2c_get_adapdata(adap); + + pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio); +} + +static void at91_unprepare_twi_recovery(struct i2c_adapter *adap) +{ + struct at91_twi_dev *dev = i2c_get_adapdata(adap); + + pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default); +} + +static int at91_init_twi_recovery_info(struct platform_device *pdev, + struct at91_twi_dev *dev) +{ + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; + + dev->pinctrl = devm_pinctrl_get(&pdev->dev); + if (!dev->pinctrl || IS_ERR(dev->pinctrl)) { + dev_info(dev->dev, "can't get pinctrl, bus recovery not supported\n"); + return PTR_ERR(dev->pinctrl); + } + + dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl, + PINCTRL_STATE_DEFAULT); + dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl, + "gpio"); + rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN); + if (PTR_ERR(rinfo->sda_gpiod) == -EPROBE_DEFER) + return -EPROBE_DEFER; + + rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl", + GPIOD_OUT_HIGH_OPEN_DRAIN); + if (PTR_ERR(rinfo->scl_gpiod) == -EPROBE_DEFER) + return -EPROBE_DEFER; + + if (IS_ERR(rinfo->sda_gpiod) || + IS_ERR(rinfo->scl_gpiod) || + IS_ERR(dev->pinctrl_pins_default) || + IS_ERR(dev->pinctrl_pins_gpio)) { + dev_info(&pdev->dev, "recovery information incomplete\n"); + if (!IS_ERR(rinfo->sda_gpiod)) { + gpiod_put(rinfo->sda_gpiod); + rinfo->sda_gpiod = NULL; + } + if (!IS_ERR(rinfo->scl_gpiod)) { + gpiod_put(rinfo->scl_gpiod); + rinfo->scl_gpiod = NULL; + } + return -EINVAL; + } + + dev_info(&pdev->dev, "using scl, sda for recovery\n"); + + rinfo->prepare_recovery = at91_prepare_twi_recovery; + rinfo->unprepare_recovery = at91_unprepare_twi_recovery; + rinfo->recover_bus = i2c_generic_scl_recovery; + dev->adapter.bus_recovery_info = rinfo; + + return 0; +} + int at91_twi_probe_master(struct platform_device *pdev, u32 phy_addr, struct at91_twi_dev *dev) { @@ -838,6 +912,10 @@ int at91_twi_probe_master(struct platform_device *pdev, "i2c-analog-filter"); at91_calc_twi_clock(dev); + rc = at91_init_twi_recovery_info(pdev, dev); + if (rc == -EPROBE_DEFER) + return rc; + dev->adapter.algo = &at91_twi_algorithm; dev->adapter.quirks = &at91_twi_quirks; |