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authorMaxim Polyakov <max.senia.poliak@gmail.com>2020-06-20 17:26:21 +0300
committerNico Huber <nico.h@gmx.de>2020-10-11 11:12:53 +0000
commitaa99830c067036015b6ce45c01063b4482bf05b9 (patch)
treea006f690674c98df1808a3e08e23520d359d17bb /src/ec/kontron
parent0af1926353d48242f03d6c80c6b2c8f646a3c145 (diff)
downloadcoreboot-aa99830c067036015b6ce45c01063b4482bf05b9.tar.xz
ec/kontron/kempld: add option to configure I2C frequency
Allows to change the I2C bus frequency by overriding i2c_frequency option from the board devicetree. Thus, the I2C controller can use Fast-mode (Fm), with a bit rate up to 400 kbit/s and Fast-mode Plus (Fm+), with a bit rate up to 1 Mbit/s [1]. Tested on Kontron mAL10 COMe module with T10-TNI carrierboard [2]. [1] I2C-bus specification and user manual, doc #UM10204, Rev. 6, 4 April 2014. [2] https://review.coreboot.org/c/coreboot/+/39133 Change-Id: If0eb477af10d00eb4f17f9c01209f170b746ad3d Signed-off-by: Maxim Polyakov <max.senia.poliak@gmail.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/44476 Reviewed-by: Angel Pons <th3fanbus@gmail.com> Reviewed-by: Nico Huber <nico.h@gmx.de> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'src/ec/kontron')
-rw-r--r--src/ec/kontron/kempld/chip.h8
-rw-r--r--src/ec/kontron/kempld/kempld_i2c.c23
2 files changed, 25 insertions, 6 deletions
diff --git a/src/ec/kontron/kempld/chip.h b/src/ec/kontron/kempld/chip.h
index 8ca8d246e9..30f40fe097 100644
--- a/src/ec/kontron/kempld/chip.h
+++ b/src/ec/kontron/kempld/chip.h
@@ -12,6 +12,13 @@ enum kempld_uart_io {
KEMPLD_UART_2E8 = 3,
};
+enum kempld_i2c_frequency {
+ KEMPLD_I2C_FREQ_STANDARD_MODE_100KHZ = 100,
+ KEMPLD_I2C_FREQ_FAST_MODE_400KHZ = 400,
+ KEMPLD_I2C_FREQ_FAST_PLUS_MODE_1MHZ = 1000,
+ KEMPLD_I2C_FREQ_MAX = 2700,
+};
+
struct kempld_uart {
enum kempld_uart_io io;
unsigned int irq;
@@ -19,6 +26,7 @@ struct kempld_uart {
struct ec_kontron_kempld_config {
struct kempld_uart uart[KEMPLD_NUM_UARTS];
+ unsigned short i2c_frequency;
};
#endif /* EC_KONTRON_KEMPLD_CHIP_H */
diff --git a/src/ec/kontron/kempld/kempld_i2c.c b/src/ec/kontron/kempld/kempld_i2c.c
index 296cf76ddd..8abbb4b856 100644
--- a/src/ec/kontron/kempld/kempld_i2c.c
+++ b/src/ec/kontron/kempld/kempld_i2c.c
@@ -13,6 +13,7 @@
#include <timer.h>
#include <delay.h>
+#include "chip.h"
#include "kempld.h"
#include "kempld_internal.h"
@@ -40,9 +41,6 @@
#define I2C_CMD_READ_NACK 0x29
#define I2C_CMD_IACK 0x01
-#define KEMPLD_I2C_FREQ_MAX 2700 /* 2.7 mHz */
-#define KEMPLD_I2C_FREQ_STD 100 /* 100 kHz */
-
#define EIO 5
#define ENXIO 6
#define EAGAIN 11
@@ -230,7 +228,8 @@ static struct device_operations kempld_i2c_dev_ops = {
void kempld_i2c_device_init(struct device *const dev)
{
- u16 prescale_corr;
+ const struct ec_kontron_kempld_config *const config = dev->chip_info;
+ u16 prescale_corr, frequency;
long prescale;
u8 ctrl;
u8 stat;
@@ -244,11 +243,23 @@ void kempld_i2c_device_init(struct device *const dev)
ctrl &= ~(I2C_CTRL_EN | I2C_CTRL_IEN);
kempld_write8(KEMPLD_I2C_CTRL, ctrl);
+ frequency = KEMPLD_I2C_FREQ_STANDARD_MODE_100KHZ;
+ if (config && config->i2c_frequency) {
+ if (config->i2c_frequency <= KEMPLD_I2C_FREQ_MAX) {
+ frequency = config->i2c_frequency;
+ } else {
+ printk(BIOS_NOTICE,
+ "kempld_i2c: %d kHz is too high!\n",
+ config->i2c_frequency);
+ }
+ }
+ printk(BIOS_INFO, "kempld_i2c: Use frequency %d\n", frequency);
+
const u8 spec_major = KEMPLD_SPEC_GET_MAJOR(kempld_read8(KEMPLD_SPEC));
if (spec_major == 1)
- prescale = KEMPLD_CLK / (KEMPLD_I2C_FREQ_STD * 5) - 1000;
+ prescale = KEMPLD_CLK / (frequency * 5) - 1000;
else
- prescale = KEMPLD_CLK / (KEMPLD_I2C_FREQ_STD * 4) - 3000;
+ prescale = KEMPLD_CLK / (frequency * 4) - 3000;
if (prescale < 0)
prescale = 0;