Add bridged amplifiers to cs42l43

Merge series from Charles Keepax <ckeepax@opensource.cirrus.com>:

In some cs42l43 systems a couple of cs35l56 amplifiers are attached
to the cs42l43's SPI and I2S. On Windows the cs42l43 is controlled
by a SDCA class driver and these two amplifiers are controlled by
firmware running on the cs42l43. However, under Linux the decision
was made to interact with the cs42l43 directly, affording the user
greater control over the audio system. However, this has resulted
in an issue where these two bridged cs35l56 amplifiers are not
populated in ACPI and must be added manually. There is at least an
SDCA extension unit DT entry we can key off.

The process of adding this is handled using a software node, firstly the
ability to add native chip selects to software nodes must be added.
Secondly, an additional flag for naming the SPI devices is added this
allows the machine driver to key to the correct amplifier. Then finally,
the cs42l43 SPI driver adds the two amplifiers directly onto its SPI
bus.

An additional series will follow soon to add the audio machine driver
parts (in the sof-sdw driver), however that is fairly orthogonal to
this part of the process, getting the actual amplifiers registered.

1 files changed, 18 insertions, 0 deletions

diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
index bd8aa83b47e5..75a988c0bd79 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.c
+++ b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -25,6 +25,8 @@
 #define PCS_POWER_STATE_DOWN	0x6
 #define PCS_POWER_STATE_UP	0x4
 
+#define RFE_RD_FIFO_TH_3_DWORDS	0x3
+
 static void pci11x1x_strap_get_status(struct lan743x_adapter *adapter)
 {
 	u32 chip_rev;
@@ -3272,6 +3274,21 @@ static void lan743x_full_cleanup(struct lan743x_adapter *adapter)
 	lan743x_pci_cleanup(adapter);
 }
 
+static void pci11x1x_set_rfe_rd_fifo_threshold(struct lan743x_adapter *adapter)
+{
+	u16 rev = adapter->csr.id_rev & ID_REV_CHIP_REV_MASK_;
+
+	if (rev == ID_REV_CHIP_REV_PCI11X1X_B0_) {
+		u32 misc_ctl;
+
+		misc_ctl = lan743x_csr_read(adapter, MISC_CTL_0);
+		misc_ctl &= ~MISC_CTL_0_RFE_READ_FIFO_MASK_;
+		misc_ctl |= FIELD_PREP(MISC_CTL_0_RFE_READ_FIFO_MASK_,
+				       RFE_RD_FIFO_TH_3_DWORDS);
+		lan743x_csr_write(adapter, MISC_CTL_0, misc_ctl);
+	}
+}
+
 static int lan743x_hardware_init(struct lan743x_adapter *adapter,
 				 struct pci_dev *pdev)
 {
@@ -3287,6 +3304,7 @@ static int lan743x_hardware_init(struct lan743x_adapter *adapter,
 		pci11x1x_strap_get_status(adapter);
 		spin_lock_init(&adapter->eth_syslock_spinlock);
 		mutex_init(&adapter->sgmii_rw_lock);
+		pci11x1x_set_rfe_rd_fifo_threshold(adapter);
 	} else {
 		adapter->max_tx_channels = LAN743X_MAX_TX_CHANNELS;
 		adapter->used_tx_channels = LAN743X_USED_TX_CHANNELS;