i2c: st: Implement bus clear (40027b2f) · Commits · 戴 / test

drivers/i2c/busses/i2c-st.c

+44 −1

Original line number	Diff line number	Diff line
		@@ -337,10 +337,42 @@ static void st_i2c_hw_config(struct st_i2c_dev *i2c_dev)
		writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH_DATAOUT);
		}

		static int st_i2c_recover_bus(struct i2c_adapter *i2c_adap)
		{
		struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
		u32 ctl;

		dev_dbg(i2c_dev->dev, "Trying to recover bus\n");

		/*
		* SSP IP is dual role SPI/I2C to generate 9 clock pulses
		* we switch to SPI node, 9 bit words and write a 0. This
		* has been validate with a oscilloscope and is easier
		* than switching to GPIO mode.
		*/

		/* Disable interrupts */
		writel_relaxed(0, i2c_dev->base + SSC_IEN);

		st_i2c_hw_config(i2c_dev);

		ctl = SSC_CTL_EN \| SSC_CTL_MS \| SSC_CTL_EN_RX_FIFO \| SSC_CTL_EN_TX_FIFO;
		st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl);

		st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_I2CM);
		usleep_range(8000, 10000);

		writel_relaxed(0, i2c_dev->base + SSC_TBUF);
		usleep_range(2000, 4000);
		st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_I2CM);

		return 0;
		}

		static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev)
		{
		u32 sta;
		int i;
		int i, ret;

		for (i = 0; i < 10; i++) {
		sta = readl_relaxed(i2c_dev->base + SSC_STA);
		@@ -352,6 +384,12 @@ static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev)

		dev_err(i2c_dev->dev, "bus not free (status = 0x%08x)\n", sta);

		ret = i2c_recover_bus(&i2c_dev->adap);
		if (ret) {
		dev_err(i2c_dev->dev, "Failed to recover the bus (%d)\n", ret);
		return ret;
		}

		return -EBUSY;
		}

		@@ -743,6 +781,10 @@ static struct i2c_algorithm st_i2c_algo = {
		.functionality = st_i2c_func,
		};

		static struct i2c_bus_recovery_info st_i2c_recovery_info = {
		.recover_bus = st_i2c_recover_bus,
		};

		static int st_i2c_of_get_deglitch(struct device_node *np,
		struct st_i2c_dev *i2c_dev)
		{
		@@ -825,6 +867,7 @@ static int st_i2c_probe(struct platform_device *pdev)
		adap->timeout = 2 * HZ;
		adap->retries = 0;
		adap->algo = &st_i2c_algo;
		adap->bus_recovery_info = &st_i2c_recovery_info;
		adap->dev.parent = &pdev->dev;
		adap->dev.of_node = pdev->dev.of_node;

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