From 894acb2f823b13afacfe40b02efbd9146af58586 Mon Sep 17 00:00:00 2001
From: David Box <david.e.box@linux.intel.com>
Date: Thu, 15 Jan 2015 01:12:17 -0800
Subject: i2c: designware: Add Intel Baytrail PMIC I2C bus support

This patch implements an I2C bus sharing mechanism between the host and platform
hardware on select Intel BayTrail SoC platforms using the X-Powers AXP288 PMIC.

On these platforms access to the PMIC must be shared with platform hardware. The
hardware unit assumes full control of the I2C bus and the host must request
access through a special semaphore. Hardware control of the bus also makes it
necessary to disable runtime pm to avoid interfering with hardware transactions.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
 drivers/i2c/busses/i2c-designware-platdrv.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

(limited to 'drivers/i2c/busses/i2c-designware-platdrv.c')

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 2b463c313e4e..c270f5f9a8f9 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -195,6 +195,10 @@ static int dw_i2c_probe(struct platform_device *pdev)
 			clk_freq = pdata->i2c_scl_freq;
 	}
 
+	r = i2c_dw_eval_lock_support(dev);
+	if (r)
+		return r;
+
 	dev->functionality =
 		I2C_FUNC_I2C |
 		I2C_FUNC_10BIT_ADDR |
@@ -257,10 +261,14 @@ static int dw_i2c_probe(struct platform_device *pdev)
 		return r;
 	}
 
-	pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
-	pm_runtime_use_autosuspend(&pdev->dev);
-	pm_runtime_set_active(&pdev->dev);
-	pm_runtime_enable(&pdev->dev);
+	if (dev->pm_runtime_disabled) {
+		pm_runtime_forbid(&pdev->dev);
+	} else {
+		pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
+		pm_runtime_use_autosuspend(&pdev->dev);
+		pm_runtime_set_active(&pdev->dev);
+		pm_runtime_enable(&pdev->dev);
+	}
 
 	return 0;
 }
@@ -310,7 +318,9 @@ static int dw_i2c_resume(struct device *dev)
 	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
 
 	clk_prepare_enable(i_dev->clk);
-	i2c_dw_init(i_dev);
+
+	if (!i_dev->pm_runtime_disabled)
+		i2c_dw_init(i_dev);
 
 	return 0;
 }
-- 
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