sdio: add sdio_f0_readb() and sdio_f0_writeb()
Add sdio_f0_readb() and sdio_f0_writeb() functions to reading and
writing function 0 registers. Writes outside the vendor specific CCCR
registers (0xF0 - 0xFF) are not permitted.
Signed-off-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index 34b085d..625b92c 100644
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -482,3 +482,67 @@
}
EXPORT_SYMBOL_GPL(sdio_writel);
+/**
+ * sdio_f0_readb - read a single byte from SDIO function 0
+ * @func: an SDIO function of the card
+ * @addr: address to read
+ * @err_ret: optional status value from transfer
+ *
+ * Reads a single byte from the address space of SDIO function 0.
+ * If there is a problem reading the address, 0xff is returned
+ * and @err_ret will contain the error code.
+ */
+unsigned char sdio_f0_readb(struct sdio_func *func, unsigned int addr,
+ int *err_ret)
+{
+ int ret;
+ unsigned char val;
+
+ BUG_ON(!func);
+
+ if (err_ret)
+ *err_ret = 0;
+
+ ret = mmc_io_rw_direct(func->card, 0, 0, addr, 0, &val);
+ if (ret) {
+ if (err_ret)
+ *err_ret = ret;
+ return 0xFF;
+ }
+
+ return val;
+}
+EXPORT_SYMBOL_GPL(sdio_f0_readb);
+
+/**
+ * sdio_f0_writeb - write a single byte to SDIO function 0
+ * @func: an SDIO function of the card
+ * @b: byte to write
+ * @addr: address to write to
+ * @err_ret: optional status value from transfer
+ *
+ * Writes a single byte to the address space of SDIO function 0.
+ * @err_ret will contain the status of the actual transfer.
+ *
+ * Only writes to the vendor specific CCCR registers (0xF0 -
+ * 0xFF) are permiited; @err_ret will be set to -EINVAL for *
+ * writes outside this range.
+ */
+void sdio_f0_writeb(struct sdio_func *func, unsigned char b, unsigned int addr,
+ int *err_ret)
+{
+ int ret;
+
+ BUG_ON(!func);
+
+ if (addr < 0xF0 || addr > 0xFF) {
+ if (err_ret)
+ *err_ret = -EINVAL;
+ return;
+ }
+
+ ret = mmc_io_rw_direct(func->card, 1, 0, addr, b, NULL);
+ if (err_ret)
+ *err_ret = ret;
+}
+EXPORT_SYMBOL_GPL(sdio_f0_writeb);