Merge "i2c-msm-v2: add wait time to let recovery complete" (e6a6e38e) · Commits · e / devices / android_kernel_sony_msm8994

drivers/i2c/busses/i2c-msm-v2.c

+26 −6

Original line number	Diff line number	Diff line
		@@ -2045,9 +2045,14 @@ static bool i2c_msm_qup_slv_holds_bus(struct i2c_msm_ctrl *ctrl)
		{
		u32 status = readl_relaxed(ctrl->rsrcs.base + QUP_I2C_STATUS);

		return !(status & QUP_I2C_SDA) &&
		bool slv_holds_bus = !(status & QUP_I2C_SDA) &&
		(status & QUP_BUS_ACTIVE) &&
		!(status & QUP_BUS_MASTER);
		if (slv_holds_bus)
		dev_info(ctrl->dev,
		"bus lines held low by a slave detected\n");

		return slv_holds_bus;
		}

		/*
		@@ -2470,6 +2475,7 @@ static int i2c_msm_qup_init(struct i2c_msm_ctrl *ctrl)
		static bool i2c_msm_qup_do_bus_clear(struct i2c_msm_ctrl *ctrl)
		{
		int ret;
		ulong min_sleep_usec;
		dev_info(ctrl->dev, "Executing bus recovery procedure (9 clk pulse)\n");

		/* call i2c_msm_qup_init() to set core in idle state */
		@@ -2477,15 +2483,29 @@ static bool i2c_msm_qup_do_bus_clear(struct i2c_msm_ctrl *ctrl)
		if (ret)
		return ret;

		/* call i2c_msm_qup_xfer_init_run_state() to set clock dividers */
		i2c_msm_qup_xfer_init_run_state(ctrl);

		/* must be in run state for bus clear */
		ret = i2c_msm_qup_state_set(ctrl, QUP_STATE_RUN);
		if (ret)
		return ret;

		/*
		* call i2c_msm_qup_xfer_init_run_state() to set clock dividers.
		* the dividers are necessary for bus clear.
		*/
		i2c_msm_qup_xfer_init_run_state(ctrl);

		writel_relaxed(0x1, ctrl->rsrcs.base + QUP_I2C_MASTER_BUS_CLR);

		/*
		* wait for recovery (9 clock pulse cycles) to complete.
		* min_time = 9 clock *10 (1000% margin)
		* max_time = 10* min_time
		*/
		min_sleep_usec =
		max_t(ulong, (9 * 10 * USEC_PER_SEC) / ctrl->rsrcs.clk_freq_out, 100);

		usleep_range(min_sleep_usec, min_sleep_usec * 10);

		return 0;
		}