ks8851: Low level functions for read/write to companion eeprom

Low-level functions provide 16bits words read and write capability
to ks8851 companion eeprom.

Signed-off-by: Sebastien Jan <s-jan@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 241 insertions, 1 deletions

diff --git a/drivers/net/ks8851.c b/drivers/net/ks8851.c
index 623171f37d99..3dba57b72ef8 100644
--- a/drivers/net/ks8851.c
+++ b/drivers/net/ks8851.c
@@ -1034,6 +1034,234 @@ static const struct net_device_ops ks8851_netdev_ops = {
         .ndo_validate_addr      = eth_validate_addr,
 };
 
+/* Companion eeprom access */
+
+enum {  /* EEPROM programming states */
+        EEPROM_CONTROL,
+        EEPROM_ADDRESS,
+        EEPROM_DATA,
+        EEPROM_COMPLETE
+};
+
+/**
+ * ks8851_eeprom_read - read a 16bits word in ks8851 companion EEPROM
+ * @dev: The network device the PHY is on.
+ * @addr: EEPROM address to read
+ *
+ * eeprom_size: used to define the data coding length. Can be changed
+ * through debug-fs.
+ *
+ * Programs a read on the EEPROM using ks8851 EEPROM SW access feature.
+ * Warning: The READ feature is not supported on ks8851 revision 0.
+ *
+ * Rough programming model:
+ *  - on period start: set clock high and read value on bus
+ *  - on period / 2: set clock low and program value on bus
+ *  - start on period / 2
+ */
+unsigned int ks8851_eeprom_read(struct net_device *dev, unsigned int addr)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        int eepcr;
+        int ctrl = EEPROM_OP_READ;
+        int state = EEPROM_CONTROL;
+        int bit_count = EEPROM_OP_LEN - 1;
+        unsigned int data = 0;
+        int dummy;
+        unsigned int addr_len;
+
+        addr_len = (ks->eeprom_size == 128) ? 6 : 8;
+
+        /* start transaction: chip select high, authorize write */
+        mutex_lock(&ks->lock);
+        eepcr = EEPCR_EESA | EEPCR_EESRWA;
+        ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+        eepcr |= EEPCR_EECS;
+        ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+        mutex_unlock(&ks->lock);
+
+        while (state != EEPROM_COMPLETE) {
+                /* falling clock period starts... */
+                /* set EED_IO pin for control and address */
+                eepcr &= ~EEPCR_EEDO;
+                switch (state) {
+                case EEPROM_CONTROL:
+                        eepcr |= ((ctrl >> bit_count) & 1) << 2;
+                        if (bit_count-- <= 0) {
+                                bit_count = addr_len - 1;
+                                state = EEPROM_ADDRESS;
+                        }
+                        break;
+                case EEPROM_ADDRESS:
+                        eepcr |= ((addr >> bit_count) & 1) << 2;
+                        bit_count--;
+                        break;
+                case EEPROM_DATA:
+                        /* Change to receive mode */
+                        eepcr &= ~EEPCR_EESRWA;
+                        break;
+                }
+
+                /* lower clock  */
+                eepcr &= ~EEPCR_EESCK;
+
+                mutex_lock(&ks->lock);
+                ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+                mutex_unlock(&ks->lock);
+
+                /* waitread period / 2 */
+                udelay(EEPROM_SK_PERIOD / 2);
+
+                /* rising clock period starts... */
+
+                /* raise clock */
+                mutex_lock(&ks->lock);
+                eepcr |= EEPCR_EESCK;
+                ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+                mutex_unlock(&ks->lock);
+
+                /* Manage read */
+                switch (state) {
+                case EEPROM_ADDRESS:
+                        if (bit_count < 0) {
+                                bit_count = EEPROM_DATA_LEN - 1;
+                                state = EEPROM_DATA;
+                        }
+                        break;
+                case EEPROM_DATA:
+                        mutex_lock(&ks->lock);
+                        dummy = ks8851_rdreg16(ks, KS_EEPCR);
+                        mutex_unlock(&ks->lock);
+                        data |= ((dummy >> EEPCR_EESB_OFFSET) & 1) << bit_count;
+                        if (bit_count-- <= 0)
+                                state = EEPROM_COMPLETE;
+                        break;
+                }
+
+                /* wait period / 2 */
+                udelay(EEPROM_SK_PERIOD / 2);
+        }
+
+        /* close transaction */
+        mutex_lock(&ks->lock);
+        eepcr &= ~EEPCR_EECS;
+        ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+        eepcr = 0;
+        ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+        mutex_unlock(&ks->lock);
+
+        return data;
+}
+
+/**
+ * ks8851_eeprom_write - write a 16bits word in ks8851 companion EEPROM
+ * @dev: The network device the PHY is on.
+ * @op: operand (can be WRITE, EWEN, EWDS)
+ * @addr: EEPROM address to write
+ * @data: data to write
+ *
+ * eeprom_size: used to define the data coding length. Can be changed
+ * through debug-fs.
+ *
+ * Programs a write on the EEPROM using ks8851 EEPROM SW access feature.
+ *
+ * Note that a write enable is required before writing data.
+ *
+ * Rough programming model:
+ *  - on period start: set clock high
+ *  - on period / 2: set clock low and program value on bus
+ *  - start on period / 2
+ */
+void ks8851_eeprom_write(struct net_device *dev, unsigned int op,
+                                        unsigned int addr, unsigned int data)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        int eepcr;
+        int state = EEPROM_CONTROL;
+        int bit_count = EEPROM_OP_LEN - 1;
+        unsigned int addr_len;
+
+        addr_len = (ks->eeprom_size == 128) ? 6 : 8;
+
+        switch (op) {
+        case EEPROM_OP_EWEN:
+                addr = 0x30;
+        break;
+        case EEPROM_OP_EWDS:
+                addr = 0;
+                break;
+        }
+
+        /* start transaction: chip select high, authorize write */
+        mutex_lock(&ks->lock);
+        eepcr = EEPCR_EESA | EEPCR_EESRWA;
+        ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+        eepcr |= EEPCR_EECS;
+        ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+        mutex_unlock(&ks->lock);
+
+        while (state != EEPROM_COMPLETE) {
+                /* falling clock period starts... */
+                /* set EED_IO pin for control and address */
+                eepcr &= ~EEPCR_EEDO;
+                switch (state) {
+                case EEPROM_CONTROL:
+                        eepcr |= ((op >> bit_count) & 1) << 2;
+                        if (bit_count-- <= 0) {
+                                bit_count = addr_len - 1;
+                                state = EEPROM_ADDRESS;
+                        }
+                        break;
+                case EEPROM_ADDRESS:
+                        eepcr |= ((addr >> bit_count) & 1) << 2;
+                        if (bit_count-- <= 0) {
+                                if (op == EEPROM_OP_WRITE) {
+                                        bit_count = EEPROM_DATA_LEN - 1;
+                                        state = EEPROM_DATA;
+                                } else {
+                                        state = EEPROM_COMPLETE;
+                                }
+                        }
+                        break;
+                case EEPROM_DATA:
+                        eepcr |= ((data >> bit_count) & 1) << 2;
+                        if (bit_count-- <= 0)
+                                state = EEPROM_COMPLETE;
+                        break;
+                }
+
+                /* lower clock  */
+                eepcr &= ~EEPCR_EESCK;
+
+                mutex_lock(&ks->lock);
+                ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+                mutex_unlock(&ks->lock);
+
+                /* wait period / 2 */
+                udelay(EEPROM_SK_PERIOD / 2);
+
+                /* rising clock period starts... */
+
+                /* raise clock */
+                eepcr |= EEPCR_EESCK;
+                mutex_lock(&ks->lock);
+                ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+                mutex_unlock(&ks->lock);
+
+                /* wait period / 2 */
+                udelay(EEPROM_SK_PERIOD / 2);
+        }
+
+        /* close transaction */
+        mutex_lock(&ks->lock);
+        eepcr &= ~EEPCR_EECS;
+        ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+        eepcr = 0;
+        ks8851_wrreg16(ks, KS_EEPCR, eepcr);
+        mutex_unlock(&ks->lock);
+
+}
+
 /* ethtool support */
 
 static void ks8851_get_drvinfo(struct net_device *dev,
diff --git a/drivers/net/ks8851.h b/drivers/net/ks8851.h
index f52c312cc356..537fb06e5932 100644
--- a/drivers/net/ks8851.h
+++ b/drivers/net/ks8851.h
@@ -25,12 +25,24 @@
 #define OBCR_ODS_16mA                           (1 << 6)
 
 #define KS_EEPCR                                0x22
+#define EEPCR_EESRWA                            (1 << 5)
 #define EEPCR_EESA                              (1 << 4)
-#define EEPCR_EESB                              (1 << 3)
+#define EEPCR_EESB_OFFSET                       3
+#define EEPCR_EESB                              (1 << EEPCR_EESB_OFFSET)
 #define EEPCR_EEDO                              (1 << 2)
 #define EEPCR_EESCK                             (1 << 1)
 #define EEPCR_EECS                              (1 << 0)
 
+#define EEPROM_OP_LEN                           3       /* bits:*/
+#define EEPROM_OP_READ                          0x06
+#define EEPROM_OP_EWEN                          0x04
+#define EEPROM_OP_WRITE                         0x05
+#define EEPROM_OP_EWDS                          0x14
+
+#define EEPROM_DATA_LEN                         16      /* 16 bits EEPROM */
+#define EEPROM_WRITE_TIME                       4       /* wrt ack time in ms */
+#define EEPROM_SK_PERIOD                        400     /* in us */
+
 #define KS_MBIR                                 0x24
 #define MBIR_TXMBF                              (1 << 12)
 #define MBIR_TXMBFA                             (1 << 11)