Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

[linux-block.git] / drivers / rtc / rtc-abx80x.c

diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
index 2e0e6432901b844aeb301375d4252c7d8c5e4f66..f34a2e59cac765380d50a93f7892690cd72afa41 100644 (file)
--- a/drivers/rtc/rtc-abx80x.c
+++ b/drivers/rtc/rtc-abx80x.c
@@ -11,6 +11,7 @@
  */
 
 #include <linux/bcd.h>
+#include <linux/bitfield.h>
 #include <linux/i2c.h>
 #include <linux/kstrtox.h>
 #include <linux/module.h>
@@ -88,6 +89,16 @@
 #define ABX8XX_TRICKLE_STANDARD_DIODE  0x8
 #define ABX8XX_TRICKLE_SCHOTTKY_DIODE  0x4
 
+#define ABX8XX_REG_EXTRAM      0x3f
+#define ABX8XX_EXTRAM_XADS     GENMASK(1, 0)
+
+#define ABX8XX_SRAM_BASE       0x40
+#define ABX8XX_SRAM_WIN_SIZE   0x40
+#define ABX8XX_RAM_SIZE                256
+
+#define NVMEM_ADDR_LOWER       GENMASK(5, 0)
+#define NVMEM_ADDR_UPPER       GENMASK(7, 6)
+
 static u8 trickle_resistors[] = {0, 3, 6, 11};
 
 enum abx80x_chip {AB0801, AB0803, AB0804, AB0805,
@@ -674,6 +685,68 @@ static int abx80x_setup_watchdog(struct abx80x_priv *priv)
 }
 #endif
 
+static int abx80x_nvmem_xfer(struct abx80x_priv *priv, unsigned int offset,
+                            void *val, size_t bytes, bool write)
+{
+       int ret;
+
+       while (bytes) {
+               u8 extram, reg, len, lower, upper;
+
+               lower = FIELD_GET(NVMEM_ADDR_LOWER, offset);
+               upper = FIELD_GET(NVMEM_ADDR_UPPER, offset);
+               extram = FIELD_PREP(ABX8XX_EXTRAM_XADS, upper);
+               reg = ABX8XX_SRAM_BASE + lower;
+               len = min(lower + bytes, (size_t)ABX8XX_SRAM_WIN_SIZE) - lower;
+               len = min_t(u8, len, I2C_SMBUS_BLOCK_MAX);
+
+               ret = i2c_smbus_write_byte_data(priv->client, ABX8XX_REG_EXTRAM,
+                                               extram);
+               if (ret)
+                       return ret;
+
+               if (write)
+                       ret = i2c_smbus_write_i2c_block_data(priv->client, reg,
+                                                            len, val);
+               else
+                       ret = i2c_smbus_read_i2c_block_data(priv->client, reg,
+                                                           len, val);
+               if (ret)
+                       return ret;
+
+               offset += len;
+               val += len;
+               bytes -= len;
+       }
+
+       return 0;
+}
+
+static int abx80x_nvmem_read(void *priv, unsigned int offset, void *val,
+                            size_t bytes)
+{
+       return abx80x_nvmem_xfer(priv, offset, val, bytes, false);
+}
+
+static int abx80x_nvmem_write(void *priv, unsigned int offset, void *val,
+                             size_t bytes)
+{
+       return abx80x_nvmem_xfer(priv, offset, val, bytes, true);
+}
+
+static int abx80x_setup_nvmem(struct abx80x_priv *priv)
+{
+       struct nvmem_config config = {
+               .type = NVMEM_TYPE_BATTERY_BACKED,
+               .reg_read = abx80x_nvmem_read,
+               .reg_write = abx80x_nvmem_write,
+               .size = ABX8XX_RAM_SIZE,
+               .priv = priv,
+       };
+
+       return devm_rtc_nvmem_register(priv->rtc, &config);
+}
+
 static const struct i2c_device_id abx80x_id[] = {
        { "abx80x", ABX80X },
        { "ab0801", AB0801 },
@@ -840,6 +913,10 @@ static int abx80x_probe(struct i2c_client *client)
                        return err;
        }
 
+       err = abx80x_setup_nvmem(priv);
+       if (err)
+               return err;
+
        if (client->irq > 0) {
                dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
                err = devm_request_threaded_irq(&client->dev, client->irq, NULL,