mtd: spi-nor: Send write disable cmd after every write enable

Write enable(06h) command will be sent to a flash device to
set the write enable latch bit before every program, erase,
write command. After that write disable command (04h) needs
to be sent to clear the write enable latch.

This write_disable() is missing at the majority of the places
in the driver, add it to clear write enable latch.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Link: https://gist.github.com/PrasanthBabuMantena/c12f39744de188a9d08cd5ca51dc2a7b
Tested-by: Prasanth Babu Mantena <p-mantena@ti.com>

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index c03136c1c20ecd9e7218b186ce9bf6c30e2aefb8..655bf3aaf81ff21a558dee2e9fe2932e42ea37ac 100644 (file)
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -944,6 +944,7 @@ static int spi_nor_erase_chip_wait_till_ready(struct spi_nor *nor, unsigned long
 static int clean_bar(struct spi_nor *nor)
 {
        u8 cmd, bank_sel = 0;
+       int ret;
 
        if (nor->bank_curr == 0)
                return 0;
@@ -951,7 +952,11 @@ static int clean_bar(struct spi_nor *nor)
        nor->bank_curr = 0;
        write_enable(nor);
 
-       return nor->write_reg(nor, cmd, &bank_sel, 1);
+       ret = nor->write_reg(nor, cmd, &bank_sel, 1);
+       if (ret)
+               return ret;
+
+       return write_disable(nor);
 }
 
 static int write_bar(struct spi_nor *nor, u32 offset)
@@ -1272,6 +1277,10 @@ static int write_sr_and_check(struct spi_nor *nor, u8 status_new, u8 mask)
        if (ret)
                return ret;
 
+       ret = write_disable(nor);
+       if (ret)
+               return ret;
+
        ret = read_sr(nor);
        if (ret < 0)
                return ret;
@@ -1809,13 +1818,18 @@ static int sst26_lock_ctl(struct spi_nor *nor, loff_t ofs, uint64_t len, enum lo
        if (ctl == SST26_CTL_CHECK)
                return 0;
 
+       /* Write latch enable before write operation */
+       ret = write_enable(nor);
+       if (ret)
+               return ret;
+
        ret = nor->write_reg(nor, SPINOR_OP_WRITE_BPR, bpr_buff, bpr_size);
        if (ret < 0) {
                dev_err(nor->dev, "fail to write block-protection register\n");
                return ret;
        }
 
-       return 0;
+       return write_disable(nor);
 }
 
 static int sst26_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
@@ -2217,7 +2231,7 @@ static int write_sr_cr(struct spi_nor *nor, u8 *sr_cr)
                return ret;
        }
 
-       return 0;
+       return write_disable(nor);
 }
 
 /**
@@ -4305,6 +4319,9 @@ static int spi_nor_init(struct spi_nor *nor)
                                write_disable(nor);
                        }
                }
+               err = write_disable(nor);
+               if (err)
+                       return err;
        }
 
        if (nor->quad_enable) {