[PATCH 1/1] mfd: intel-lpss: Fix Intel Cannon Lake LPSS I2C input clock

[Kai-Heng Feng]

From: Jarkko Nikula <jarkko.nikula at linux.intel.com>

BugLink: https://bugs.launchpad.net/bugs/1789790

Intel Cannon Lake PCH has much higher 216 MHz input clock to LPSS I2C
than Sunrisepoint which uses 120 MHz. Preliminary information was that
both share the same clock rate but actual silicon implements elevated
rate for better support for 3.4 MHz high-speed I2C.

This incorrect input clock rate results too high I2C bus clock in case
ACPI doesn't provide tuned I2C timing parameters since I2C host
controller driver calculates them from input clock rate.

Fix this by using the correct rate. We still share the same 230 ns SDA
hold time value than Sunrisepoint.

Cc: stable at vger.kernel.org
Fixes: b418bbff36dd ("mfd: intel-lpss: Add Intel Cannonlake PCI IDs")
Reported-by: Jian-Hong Pan <jian-hong at endlessm.com>
Reported-by: Chris Chiu <chiu at endlessm.com>
Reported-by: Daniel Drake <drake at endlessm.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula at linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg at linux.intel.com>
Tested-by: Jian-Hong Pan <jian-hong at endlessm.com>
Signed-off-by: Lee Jones <lee.jones at linaro.org>
(cherry picked from commit 4e93a658576ab115977225c9d0992b97ff19ba8c)
Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
---
 drivers/mfd/intel-lpss-pci.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/mfd/intel-lpss-pci.c b/drivers/mfd/intel-lpss-pci.c
index d1c46de89eb4..d9ae983095c5 100644
--- a/drivers/mfd/intel-lpss-pci.c
+++ b/drivers/mfd/intel-lpss-pci.c
@@ -124,6 +124,11 @@ static const struct intel_lpss_platform_info apl_i2c_info = {
 	.properties = apl_i2c_properties,
 };
 
+static const struct intel_lpss_platform_info cnl_i2c_info = {
+	.clk_rate = 216000000,
+	.properties = spt_i2c_properties,
+};
+
 static const struct pci_device_id intel_lpss_pci_ids[] = {
 	/* BXT A-Step */
 	{ PCI_VDEVICE(INTEL, 0x0aac), (kernel_ulong_t)&bxt_i2c_info },
@@ -207,13 +212,13 @@ static const struct pci_device_id intel_lpss_pci_ids[] = {
 	{ PCI_VDEVICE(INTEL, 0x9daa), (kernel_ulong_t)&spt_info },
 	{ PCI_VDEVICE(INTEL, 0x9dab), (kernel_ulong_t)&spt_info },
 	{ PCI_VDEVICE(INTEL, 0x9dfb), (kernel_ulong_t)&spt_info },
-	{ PCI_VDEVICE(INTEL, 0x9dc5), (kernel_ulong_t)&spt_i2c_info },
-	{ PCI_VDEVICE(INTEL, 0x9dc6), (kernel_ulong_t)&spt_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9dc5), (kernel_ulong_t)&cnl_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9dc6), (kernel_ulong_t)&cnl_i2c_info },
 	{ PCI_VDEVICE(INTEL, 0x9dc7), (kernel_ulong_t)&spt_uart_info },
-	{ PCI_VDEVICE(INTEL, 0x9de8), (kernel_ulong_t)&spt_i2c_info },
-	{ PCI_VDEVICE(INTEL, 0x9de9), (kernel_ulong_t)&spt_i2c_info },
-	{ PCI_VDEVICE(INTEL, 0x9dea), (kernel_ulong_t)&spt_i2c_info },
-	{ PCI_VDEVICE(INTEL, 0x9deb), (kernel_ulong_t)&spt_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9de8), (kernel_ulong_t)&cnl_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9de9), (kernel_ulong_t)&cnl_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9dea), (kernel_ulong_t)&cnl_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9deb), (kernel_ulong_t)&cnl_i2c_info },
 	/* SPT-H */
 	{ PCI_VDEVICE(INTEL, 0xa127), (kernel_ulong_t)&spt_uart_info },
 	{ PCI_VDEVICE(INTEL, 0xa128), (kernel_ulong_t)&spt_uart_info },
@@ -240,10 +245,10 @@ static const struct pci_device_id intel_lpss_pci_ids[] = {
 	{ PCI_VDEVICE(INTEL, 0xa32b), (kernel_ulong_t)&spt_info },
 	{ PCI_VDEVICE(INTEL, 0xa37b), (kernel_ulong_t)&spt_info },
 	{ PCI_VDEVICE(INTEL, 0xa347), (kernel_ulong_t)&spt_uart_info },
-	{ PCI_VDEVICE(INTEL, 0xa368), (kernel_ulong_t)&spt_i2c_info },
-	{ PCI_VDEVICE(INTEL, 0xa369), (kernel_ulong_t)&spt_i2c_info },
-	{ PCI_VDEVICE(INTEL, 0xa36a), (kernel_ulong_t)&spt_i2c_info },
-	{ PCI_VDEVICE(INTEL, 0xa36b), (kernel_ulong_t)&spt_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0xa368), (kernel_ulong_t)&cnl_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0xa369), (kernel_ulong_t)&cnl_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0xa36a), (kernel_ulong_t)&cnl_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0xa36b), (kernel_ulong_t)&cnl_i2c_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(pci, intel_lpss_pci_ids);
-- 
2.17.1