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i2c: designware: Add Intel Baytrail PMIC I2C bus support

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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>
This commit is contained in:
David Box
2015-01-15 01:12:17 -08:00
committed by Wolfram Sang
parent c0601d285e
commit 894acb2f82
5 changed files with 193 additions and 5 deletions
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20
drivers/i2c/busses/i2c-designware-platdrv.c
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@@ -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;
}