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authorHans de Goede <hdegoede@redhat.com>2017-08-29 14:08:35 +0200
committerWolfram Sang <wsa@the-dreams.de>2017-08-31 20:27:39 +0200
commit231d069fcde22bd0582c2c9564f1b334d280c7d7 (patch)
tree8f14e8489cf675c64a2f193ebaea0392b1e3d9c1
parentba201c4f5ebe13d7819081756378777d8153f23e (diff)
i2c: designware: Round down ACPI provided clk to nearest supported clk
The Lenovo Miix2 8 DSDT contains an i2c clk / bus speed of 1700000 Hz for one if its devices, which is not supported. This is the second DSDT to show up with an unsupported clk in a short time, remove the hardcoded fix for DSDTs with a 1 MiHz clock and simply always round down the clk to the nearest supported value. Reported-by: russianneuromancer@ya.ru Fixes: 682c6c2188 ("i2c: designware: Some broken DSTDs use 1MiHz ...") Signed-off-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
-rw-r--r--drivers/i2c/busses/i2c-designware-platdrv.c16
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 57248bccadbc..2b98a173136f 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -256,7 +256,8 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
struct dw_i2c_dev *dev;
u32 acpi_speed, ht = 0;
struct resource *mem;
- int irq, ret;
+ int i, irq, ret;
+ const int supported_speeds[] = { 0, 100000, 400000, 1000000, 3400000 };
irq = platform_get_irq(pdev, 0);
if (irq < 0)
@@ -297,9 +298,16 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
}
acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
- /* Some broken DSTDs use 1MiHz instead of 1MHz */
- if (acpi_speed == 1048576)
- acpi_speed = 1000000;
+ /*
+ * Some DSTDs use a non standard speed, round down to the lowest
+ * standard speed.
+ */
+ for (i = 1; i < ARRAY_SIZE(supported_speeds); i++) {
+ if (acpi_speed < supported_speeds[i])
+ break;
+ }
+ acpi_speed = supported_speeds[i - 1];
+
/*
* Find bus speed from the "clock-frequency" device property, ACPI
* or by using fast mode if neither is set.