Tegra: I2C: Add T114 clock support to tegra_i2c driver
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@nvidia.com>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
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_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 @@
* 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 @@
* @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 @@
return -1;
}
+ i2c_bus->is_scs = is_scs;
+
i2c_bus->is_dvc = is_dvc;
if (is_dvc) {
i2c_bus->control =
@@ -403,18 +428,25 @@
const void *blob = gd->fdt_blob;
int count;
+ /* 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;
+
- /* First get the normal i2c ports */
+ /* 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;
}