Change in flashrom[master]: lspcon: restart MPU on programmer shutdown

[Edward O'Callaghan (Code Review)]

Edward O'Callaghan has submitted this change. ( https://review.coreboot.org/c/flashrom/+/55403 )

Change subject: lspcon: restart MPU on programmer shutdown
......................................................................

lspcon: restart MPU on programmer shutdown

Programmer initialization stops the on-chip MPU, and it was never
restarted. Leaving it stopped seems to prevent some display detection
from working, so implement restarting the MPU on programmer shutdown.

BUG=b:190359231
TEST=display hotplug works reliably after device communication

Change-Id: I66cd68f8f6905a2bfaf5b085bf08dcb218f42855
Reviewed-on: https://review.coreboot.org/c/flashrom/+/55403
Tested-by: build bot (Jenkins) 
Reviewed-by: Angel Pons 
Reviewed-by: Edward O'Callaghan 
Reviewed-by: Sam McNally 
---
M lspcon_i2c_spi.c
1 file changed, 9 insertions(+), 6 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Angel Pons: Looks good to me, approved
  Edward O'Callaghan: Looks good to me, approved
  Sam McNally: Looks good to me, approved

diff --git a/lspcon_i2c_spi.c b/lspcon_i2c_spi.c
index 9f3bb9a..b590f1d 100644
--- a/lspcon_i2c_spi.c
+++ b/lspcon_i2c_spi.c
@@ -318,11 +318,13 @@
    return ret;
 }

-static int lspcon_i2c_spi_reset_mpu_stop(int fd)
+static int lspcon_i2c_spi_set_mpu_active(int fd, int running)
 {
    int ret = 0;
-	ret |= lspcon_i2c_spi_write_register(fd, MPU, 0xc0); // cmd mode
-	ret |= lspcon_i2c_spi_write_register(fd, MPU, 0x40); // stop mcu
+	// Cmd mode
+	ret |= lspcon_i2c_spi_write_register(fd, MPU, 0xc0);
+	// Stop or release MPU
+	ret |= lspcon_i2c_spi_write_register(fd, MPU, running ? 0 : 0x40);

return ret;
 }
@@ -418,15 +420,16 @@
    .write_aai = lspcon_i2c_spi_write_aai,
 };

-/* TODO: MPU still stopped at this point, probably need to reset it. */
 static int lspcon_i2c_spi_shutdown(void *data)
 {
    int ret = 0;
         struct lspcon_i2c_spi_data *lspcon_data =
    	(struct lspcon_i2c_spi_data *)data;
    int fd = lspcon_data->fd;
+
    ret |= lspcon_i2c_spi_enable_write_protection(fd);
    ret |= lspcon_i2c_spi_toggle_register_protection(fd, 0);
+	ret |= lspcon_i2c_spi_set_mpu_active(fd, 1);
    i2c_close(fd);
    free(data);

@@ -439,9 +442,9 @@
    if (fd < 0)
    	return fd;

-	int ret = lspcon_i2c_spi_reset_mpu_stop(fd);
+	int ret = lspcon_i2c_spi_set_mpu_active(fd, 0);
    if (ret) {
-		msg_perr("%s: call to reset_mpu_stop failed.\n", __func__);
+		msg_perr("%s: call to set_mpu_active failed.\n", __func__);
    	i2c_close(fd);
    	return ret;
    }