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[PATCH v2 14/16] mfd: intel-lpss: Pass SDA hold time to I2C host controller driver

From Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Newsgroups linux.kernel
Subject [PATCH v2 14/16] mfd: intel-lpss: Pass SDA hold time to I2C host controller driver
Date 2015-11-30 16:20 +0100
Message-ID <qAypd-5id-51@gated-at.bofh.it> (permalink)
References <qAypb-5id-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: Mika Westerberg <mika.westerberg@linux.intel.com>

Intel Skylake the LPSS I2C pad circuit has internal delays that require
programming non-zero SDA hold time for the I2C host controller. If this is
not done communication to slave devices may fail with arbitration lost
errors like the one seen below taken from Lenovo Yoga 900:

  i2c_hid i2c-SYNA2B29:00: Fetching the HID descriptor
  i2c_hid i2c-SYNA2B29:00: __i2c_hid_command: cmd=20 00
  i2c_designware i2c_designware.1: i2c_dw_handle_tx_abort: lost arbitration

To fix this we follow what the Windows driver is doing and pass the default
SDA hold time of 230 ns to all Intel Skylake host controllers. This still
allows the platform to override these values by passing special ACPI
methods SSCN and FMCN.

Reported-by: Kevin Fenzi <kevin@scrye.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/mfd/intel-lpss-acpi.c | 19 +++++++++++++++++--
 drivers/mfd/intel-lpss-pci.c  | 31 +++++++++++++++++++++++--------
 2 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/drivers/mfd/intel-lpss-acpi.c b/drivers/mfd/intel-lpss-acpi.c
index b6fd904..06f00d6 100644
--- a/drivers/mfd/intel-lpss-acpi.c
+++ b/drivers/mfd/intel-lpss-acpi.c
@@ -18,6 +18,7 @@
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
 #include <linux/platform_device.h>
+#include <linux/property.h>
 
 #include "intel-lpss.h"
 
@@ -25,6 +26,20 @@ static const struct intel_lpss_platform_info spt_info = {
 	.clk_rate = 120000000,
 };
 
+static struct property_entry spt_i2c_properties[] = {
+	PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 230),
+	{ },
+};
+
+static struct property_set spt_i2c_pset = {
+	.properties = spt_i2c_properties,
+};
+
+static const struct intel_lpss_platform_info spt_i2c_info = {
+	.clk_rate = 120000000,
+	.pset = &spt_i2c_pset,
+};
+
 static const struct intel_lpss_platform_info bxt_info = {
 	.clk_rate = 100000000,
 };
@@ -35,8 +50,8 @@ static const struct intel_lpss_platform_info bxt_i2c_info = {
 
 static const struct acpi_device_id intel_lpss_acpi_ids[] = {
 	/* SPT */
-	{ "INT3446", (kernel_ulong_t)&spt_info },
-	{ "INT3447", (kernel_ulong_t)&spt_info },
+	{ "INT3446", (kernel_ulong_t)&spt_i2c_info },
+	{ "INT3447", (kernel_ulong_t)&spt_i2c_info },
 	/* BXT */
 	{ "80860AAC", (kernel_ulong_t)&bxt_i2c_info },
 	{ "80860ABC", (kernel_ulong_t)&bxt_info },
diff --git a/drivers/mfd/intel-lpss-pci.c b/drivers/mfd/intel-lpss-pci.c
index 5bfdfcc..a677480 100644
--- a/drivers/mfd/intel-lpss-pci.c
+++ b/drivers/mfd/intel-lpss-pci.c
@@ -17,6 +17,7 @@
 #include <linux/pci.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
+#include <linux/property.h>
 
 #include "intel-lpss.h"
 
@@ -65,6 +66,20 @@ static const struct intel_lpss_platform_info spt_info = {
 	.clk_rate = 120000000,
 };
 
+static struct property_entry spt_i2c_properties[] = {
+	PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 230),
+	{ },
+};
+
+static struct property_set spt_i2c_pset = {
+	.properties = spt_i2c_properties,
+};
+
+static const struct intel_lpss_platform_info spt_i2c_info = {
+	.clk_rate = 120000000,
+	.pset = &spt_i2c_pset,
+};
+
 static const struct intel_lpss_platform_info spt_uart_info = {
 	.clk_rate = 120000000,
 	.clk_con_id = "baudclk",
@@ -121,20 +136,20 @@ static const struct pci_device_id intel_lpss_pci_ids[] = {
 	{ PCI_VDEVICE(INTEL, 0x9d28), (kernel_ulong_t)&spt_uart_info },
 	{ PCI_VDEVICE(INTEL, 0x9d29), (kernel_ulong_t)&spt_info },
 	{ PCI_VDEVICE(INTEL, 0x9d2a), (kernel_ulong_t)&spt_info },
-	{ PCI_VDEVICE(INTEL, 0x9d60), (kernel_ulong_t)&spt_info },
-	{ PCI_VDEVICE(INTEL, 0x9d61), (kernel_ulong_t)&spt_info },
-	{ PCI_VDEVICE(INTEL, 0x9d62), (kernel_ulong_t)&spt_info },
-	{ PCI_VDEVICE(INTEL, 0x9d63), (kernel_ulong_t)&spt_info },
-	{ PCI_VDEVICE(INTEL, 0x9d64), (kernel_ulong_t)&spt_info },
-	{ PCI_VDEVICE(INTEL, 0x9d65), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0x9d60), (kernel_ulong_t)&spt_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9d61), (kernel_ulong_t)&spt_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9d62), (kernel_ulong_t)&spt_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9d63), (kernel_ulong_t)&spt_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9d64), (kernel_ulong_t)&spt_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0x9d65), (kernel_ulong_t)&spt_i2c_info },
 	{ PCI_VDEVICE(INTEL, 0x9d66), (kernel_ulong_t)&spt_uart_info },
 	/* SPT-H */
 	{ PCI_VDEVICE(INTEL, 0xa127), (kernel_ulong_t)&spt_uart_info },
 	{ PCI_VDEVICE(INTEL, 0xa128), (kernel_ulong_t)&spt_uart_info },
 	{ PCI_VDEVICE(INTEL, 0xa129), (kernel_ulong_t)&spt_info },
 	{ PCI_VDEVICE(INTEL, 0xa12a), (kernel_ulong_t)&spt_info },
-	{ PCI_VDEVICE(INTEL, 0xa160), (kernel_ulong_t)&spt_info },
-	{ PCI_VDEVICE(INTEL, 0xa161), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0xa160), (kernel_ulong_t)&spt_i2c_info },
+	{ PCI_VDEVICE(INTEL, 0xa161), (kernel_ulong_t)&spt_i2c_info },
 	{ PCI_VDEVICE(INTEL, 0xa166), (kernel_ulong_t)&spt_uart_info },
 	{ }
 };
-- 
2.6.2

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Thread

[PATCH v2 00/16] intel-lpss: support non-ACPI platforms Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-11-30 16:20 +0100
  [PATCH v2 11/16] driver core: Do not overwrite secondary fwnode with NULL if it is set Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-11-30 16:20 +0100
  [PATCH v2 03/16] device property: refactor built-in properties support Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-11-30 16:20 +0100
  [PATCH v2 12/16] mfd: core: propagate device properties to sub devices drivers Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-11-30 16:20 +0100
  [PATCH v2 01/16] device property: always check for fwnode type Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-11-30 16:20 +0100
  [PATCH v2 16/16] i2c: designware: Convert to use unified device property API Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-11-30 16:20 +0100
    Re: [PATCH v2 16/16] i2c: designware: Convert to use unified device  property API Wolfram Sang <wsa@the-dreams.de> - 2015-11-30 21:00 +0100
      Re: [PATCH v2 16/16] i2c: designware: Convert to use unified device  property API Mika Westerberg <mika.westerberg@linux.intel.com> - 2015-12-01 10:10 +0100
      Re: [PATCH v2 16/16] i2c: designware: Convert to use unified device  property API Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-12-01 11:40 +0100
        Re: [PATCH v2 16/16] i2c: designware: Convert to use unified device property API "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-02 02:00 +0100
          Re: [PATCH v2 16/16] i2c: designware: Convert to use unified device  property API Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-12-02 10:30 +0100
            Re: [PATCH v2 16/16] i2c: designware: Convert to use unified device  property API Mika Westerberg <mika.westerberg@linux.intel.com> - 2015-12-02 10:40 +0100
              Re: [PATCH v2 16/16] i2c: designware: Convert to use unified device  property API Wolfram Sang <wsa@the-dreams.de> - 2015-12-02 11:00 +0100
  [PATCH v2 14/16] mfd: intel-lpss: Pass SDA hold time to I2C host controller driver Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-11-30 16:20 +0100
  [PATCH v2 15/16] mfd: intel-lpss: Pass HSUART configuration via properties Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-11-30 16:20 +0100
  [PATCH v2 13/16] mfd: intel-lpss: Add support for passing device properties Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-11-30 16:20 +0100
  Re: [PATCH v2 00/16] intel-lpss: support non-ACPI platforms "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-12-07 02:20 +0100

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