[U-Boot] [PATCH v3 1/3] Tegra: I2C: Add T114 clock support to tegra_i2c driver
Tom Warren
twarren.nvidia at gmail.com
Fri Feb 8 18:25:30 CET 2013
T114 has a slightly different I2C clock, with a new (extra) divisor
in standard/fast mode and HS mode. Tested on my Dalmore, and the I2C
clock is 100KHz +/- 3Hz on my Saleae Logic analyzer.
Added a new entry in compat_names for T114 I2C since it differs
from the previous Tegra SoCs. A flag is set when T114 I2C HW is
found so new features like the extra clock divisor can be used.
Signed-off-by: Tom Warren <twarren at nvidia.com>
Acked-by: Laxman Dewangan <ldewangan at nvidia.com>
---
v2: new
V3:
- Added tegra114-i2c name to compat_names/compat_id table(s)
- Add search for T114 I2C node in i2c_init_board
- Added is_scs flag to i2c_bus struct (single clock source HW)
- Use is_scs flag to trigger new clock source rate calculation
arch/arm/include/asm/arch-tegra/tegra_i2c.h | 6 ++++
drivers/i2c/tegra_i2c.c | 42 +++++++++++++++++++++++---
include/fdtdec.h | 1 +
lib/fdtdec.c | 1 +
4 files changed, 45 insertions(+), 5 deletions(-)
diff --git a/arch/arm/include/asm/arch-tegra/tegra_i2c.h b/arch/arm/include/asm/arch-tegra/tegra_i2c.h
index 2650744..853e59b 100644
--- a/arch/arm/include/asm/arch-tegra/tegra_i2c.h
+++ b/arch/arm/include/asm/arch-tegra/tegra_i2c.h
@@ -105,6 +105,7 @@ struct i2c_ctlr {
u32 sl_delay_count; /* 3C: I2C_I2C_SL_DELAY_COUNT */
u32 reserved_2[4]; /* 40: */
struct i2c_control control; /* 50 ~ 68 */
+ u32 clk_div; /* 6C: I2C_I2C_CLOCK_DIVISOR */
};
/* bit fields definitions for IO Packet Header 1 format */
@@ -154,6 +155,11 @@ struct i2c_ctlr {
#define I2C_INT_ARBITRATION_LOST_SHIFT 2
#define I2C_INT_ARBITRATION_LOST_MASK (1 << I2C_INT_ARBITRATION_LOST_SHIFT)
+/* I2C_CLK_DIVISOR_REGISTER */
+#define CLK_DIV_STD_FAST_MODE 0x19
+#define CLK_DIV_HS_MODE 1
+#define CLK_MULT_STD_FAST_MODE 8
+
/**
* Returns the bus number of the DVC controller
*
diff --git a/drivers/i2c/tegra_i2c.c b/drivers/i2c/tegra_i2c.c
index efc77fa..ca71cd3 100644
--- a/drivers/i2c/tegra_i2c.c
+++ b/drivers/i2c/tegra_i2c.c
@@ -46,6 +46,7 @@ struct i2c_bus {
struct i2c_control *control;
struct i2c_ctlr *regs;
int is_dvc; /* DVC type, rather than I2C */
+ int is_scs; /* single clock source (T114+) */
int inited; /* bus is inited */
};
@@ -88,7 +89,28 @@ static void i2c_init_controller(struct i2c_bus *i2c_bus)
* 16 to get the right frequency.
*/
clock_start_periph_pll(i2c_bus->periph_id, CLOCK_ID_PERIPH,
- i2c_bus->speed * 2 * 8);
+ i2c_bus->speed * 2 * 8);
+
+ if (i2c_bus->is_scs) {
+ /*
+ * T114 I2C went to a single clock source for standard/fast and
+ * HS clock speeds. The new clock rate setting calculation is:
+ * SCL = CLK_SOURCE.I2C /
+ * (CLK_MULT_STD_FAST_MODE * (I2C_CLK_DIV_STD_FAST_MODE+1) *
+ * I2C FREQUENCY DIVISOR) as per the T114 TRM (sec 30.3.1).
+ *
+ * NOTE: We do this here, after the initial clock/pll start,
+ * because if we read the clk_div reg before the controller
+ * is running, we hang, and we need it for the new calc.
+ */
+ int clk_div_stdfst_mode = readl(&i2c_bus->regs->clk_div) >> 16;
+ debug("%s: CLK_DIV_STD_FAST_MODE setting = %d\n", __func__,
+ clk_div_stdfst_mode);
+
+ clock_start_periph_pll(i2c_bus->periph_id, CLOCK_ID_PERIPH,
+ CLK_MULT_STD_FAST_MODE * (clk_div_stdfst_mode + 1) *
+ i2c_bus->speed * 2);
+ }
/* Reset I2C controller. */
i2c_reset_controller(i2c_bus);
@@ -352,10 +374,11 @@ static int i2c_get_config(const void *blob, int node, struct i2c_bus *i2c_bus)
* @param node_list list of nodes to process (any <=0 are ignored)
* @param count number of nodes to process
* @param is_dvc 1 if these are DVC ports, 0 if standard I2C
+ * @param is_scs 1 if this HW uses a single clock source (T114+)
* @return 0 if ok, -1 on error
*/
static int process_nodes(const void *blob, int node_list[], int count,
- int is_dvc)
+ int is_dvc, int is_scs)
{
struct i2c_bus *i2c_bus;
int i;
@@ -375,6 +398,8 @@ static int process_nodes(const void *blob, int node_list[], int count,
return -1;
}
+ i2c_bus->is_scs = is_scs;
+
i2c_bus->is_dvc = is_dvc;
if (is_dvc) {
i2c_bus->control =
@@ -403,18 +428,25 @@ void i2c_init_board(void)
const void *blob = gd->fdt_blob;
int count;
- /* First get the normal i2c ports */
+ /* First check for newer (T114+) I2C ports */
+ count = fdtdec_find_aliases_for_id(blob, "i2c",
+ COMPAT_NVIDIA_TEGRA114_I2C, node_list,
+ TEGRA_I2C_NUM_CONTROLLERS);
+ if (process_nodes(blob, node_list, count, 0, 1))
+ return;
+
+ /* Now get the older (T20/T30) normal I2C ports */
count = fdtdec_find_aliases_for_id(blob, "i2c",
COMPAT_NVIDIA_TEGRA20_I2C, node_list,
TEGRA_I2C_NUM_CONTROLLERS);
- if (process_nodes(blob, node_list, count, 0))
+ if (process_nodes(blob, node_list, count, 0, 0))
return;
/* Now look for dvc ports */
count = fdtdec_add_aliases_for_id(blob, "i2c",
COMPAT_NVIDIA_TEGRA20_DVC, node_list,
TEGRA_I2C_NUM_CONTROLLERS);
- if (process_nodes(blob, node_list, count, 1))
+ if (process_nodes(blob, node_list, count, 1, 0))
return;
}
diff --git a/include/fdtdec.h b/include/fdtdec.h
index f77d195..5abf9e7 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -62,6 +62,7 @@ struct fdt_memory {
enum fdt_compat_id {
COMPAT_UNKNOWN,
COMPAT_NVIDIA_TEGRA20_USB, /* Tegra20 USB port */
+ COMPAT_NVIDIA_TEGRA114_I2C, /* Tegra114 I2C w/single clock source */
COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra20 i2c */
COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra20 dvc (really just i2c) */
COMPAT_NVIDIA_TEGRA20_EMC, /* Tegra20 memory controller */
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 16921e1..2681d74 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -37,6 +37,7 @@ DECLARE_GLOBAL_DATA_PTR;
static const char * const compat_names[COMPAT_COUNT] = {
COMPAT(UNKNOWN, "<none>"),
COMPAT(NVIDIA_TEGRA20_USB, "nvidia,tegra20-ehci"),
+ COMPAT(NVIDIA_TEGRA114_I2C, "nvidia,tegra114-i2c"),
COMPAT(NVIDIA_TEGRA20_I2C, "nvidia,tegra20-i2c"),
COMPAT(NVIDIA_TEGRA20_DVC, "nvidia,tegra20-i2c-dvc"),
COMPAT(NVIDIA_TEGRA20_EMC, "nvidia,tegra20-emc"),
--
1.7.0.4
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