diff options
Diffstat (limited to 'src/soc/nvidia/tegra/i2c.c')
| -rw-r--r-- | src/soc/nvidia/tegra/i2c.c | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/src/soc/nvidia/tegra/i2c.c b/src/soc/nvidia/tegra/i2c.c index 9a4d71bc3cf0..6c269cfaed07 100644 --- a/src/soc/nvidia/tegra/i2c.c +++ b/src/soc/nvidia/tegra/i2c.c @@ -23,9 +23,36 @@ #include <stdlib.h> #include <string.h> #include <soc/addressmap.h> - #include "i2c.h" +static void do_bus_clear(int bus) +{ + struct tegra_i2c_bus_info *info = &tegra_i2c_info[bus]; + struct tegra_i2c_regs * const regs = info->base; + uint32_t bc; + + // BUS CLEAR regs (from TRM): + // 1. Reset the I2C controller (already done) + // 2. Set the # of clock pulses required (using default of 9) + // 3. Select STOP condition (using default of 1 = STOP) + // 4. Set TERMINATE condition (1 = THRESHOLD) + bc = read32(®s->bus_clear_config); + bc |= I2C_BUS_CLEAR_CONFIG_BC_TERMINATE_THRESHOLD; + write32(bc, ®s->bus_clear_config); + // 4.1 Set MSTR_CONFIG_LOAD and wait for clear + write32(I2C_CONFIG_LOAD_MSTR_CONFIG_LOAD_ENABLE, ®s->config_load); + do { + printk(BIOS_DEBUG, "%s: wait for MSTR_CONFIG_LOAD to clear\n", + __func__); + } while (read32(®s->config_load) & I2C_CONFIG_LOAD_MSTR_CONFIG_LOAD_ENABLE); + // 5. Set ENABLE to start the bus clear op + write32(bc | I2C_BUS_CLEAR_CONFIG_BC_ENABLE, ®s->bus_clear_config); + do { + printk(BIOS_DEBUG, "%s: wait for bus clear completion\n", + __func__); + } while (read32(®s->bus_clear_config) & I2C_BUS_CLEAR_CONFIG_BC_ENABLE); +} + static int tegra_i2c_send_recv(int bus, int read, uint32_t *headers, int header_words, uint8_t *data, int data_len) @@ -91,6 +118,11 @@ static int tegra_i2c_send_recv(int bus, int read, "%s: Lost arbitration.\n", __func__); info->reset_func(info->reset_bit); + + /* Use Tegra bus clear registers to unlock SDA */ + do_bus_clear(bus); + + /* Return w/error, let caller decide what to do */ return -1; } } |