i2c: at91: implement i2c bus recovery (d3d3fdcc) · Commits · 戴 / test

drivers/i2c/busses/i2c-at91-master.c

+78 −0

Original line number	Diff line number	Diff line
		@@ -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;

drivers/i2c/busses/i2c-at91.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -151,6 +151,10 @@ struct at91_twi_dev {
		u32 fifo_size;
		struct at91_twi_dma dma;
		bool slave_detected;
		struct i2c_bus_recovery_info rinfo;
		struct pinctrl *pinctrl;
		struct pinctrl_state *pinctrl_pins_default;
		struct pinctrl_state *pinctrl_pins_gpio;
		#ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL
		unsigned smr;
		struct i2c_client *slave;

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