diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2017-08-29 15:08:35 +0300 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2017-08-31 21:27:39 +0300 |
| commit | 231d069fcde22bd0582c2c9564f1b334d280c7d7 (patch) | |
| tree | 8f14e8489cf675c64a2f193ebaea0392b1e3d9c1 /drivers/i2c | |
| parent | ba201c4f5ebe13d7819081756378777d8153f23e (diff) | |
| download | linux-231d069fcde22bd0582c2c9564f1b334d280c7d7.tar.xz | |
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>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-platdrv.c | 16 |
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. |