usb: misc: onboard_usb_dev: Fix usb5744 initialization sequence

Introduce i2c APIs to read/write for proper configuration register
programming. It ensures that read-modify-write sequence is performed
and reserved bit in Runtime Flags 2 register are not touched.

Also legacy smbus block write inserted an extra count value into the
i2c data stream which breaks the register write on the usb5744.

Switching to new read/write i2c APIs fixes both issues.

Fixes: 6782311d04df ("usb: misc: onboard_usb_dev: add Microchip usb5744 SMBus programming support")
Cc: stable <stable@kernel.org>
Signed-off-by: Jonathan Stroud <jonathan.stroud@amd.com>
Co-developed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Link: https://lore.kernel.org/r/1747398760-284021-1-git-send-email-radhey.shyam.pandey@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/misc/onboard_usb_dev.c b/drivers/usb/misc/onboard_usb_dev.c
index 40bc98019e0b933fc3a1447a00696ab12f79185f..1048e3912068ced166c76838cf7306d86e192fe4 100644 (file)
--- a/drivers/usb/misc/onboard_usb_dev.c
+++ b/drivers/usb/misc/onboard_usb_dev.c
@@ -36,9 +36,10 @@
 #define USB5744_CMD_CREG_ACCESS                        0x99
 #define USB5744_CMD_CREG_ACCESS_LSB            0x37
 #define USB5744_CREG_MEM_ADDR                  0x00
+#define USB5744_CREG_MEM_RD_ADDR               0x04
 #define USB5744_CREG_WRITE                     0x00
-#define USB5744_CREG_RUNTIMEFLAGS2             0x41
-#define USB5744_CREG_RUNTIMEFLAGS2_LSB         0x1D
+#define USB5744_CREG_READ                      0x01
+#define USB5744_CREG_RUNTIMEFLAGS2             0x411D
 #define USB5744_CREG_BYPASS_UDC_SUSPEND                BIT(3)
 
 static void onboard_dev_attach_usb_driver(struct work_struct *work);
@@ -309,11 +310,88 @@ static void onboard_dev_attach_usb_driver(struct work_struct *work)
                pr_err("Failed to attach USB driver: %pe\n", ERR_PTR(err));
 }
 
+static int onboard_dev_5744_i2c_read_byte(struct i2c_client *client, u16 addr, u8 *data)
+{
+       struct i2c_msg msg[2];
+       u8 rd_buf[3];
+       int ret;
+
+       u8 wr_buf[7] = {0, USB5744_CREG_MEM_ADDR, 4,
+                       USB5744_CREG_READ, 1,
+                       addr >> 8 & 0xff,
+                       addr & 0xff};
+       msg[0].addr = client->addr;
+       msg[0].flags = 0;
+       msg[0].len = sizeof(wr_buf);
+       msg[0].buf = wr_buf;
+
+       ret = i2c_transfer(client->adapter, msg, 1);
+       if (ret < 0)
+               return ret;
+
+       wr_buf[0] = USB5744_CMD_CREG_ACCESS;
+       wr_buf[1] = USB5744_CMD_CREG_ACCESS_LSB;
+       wr_buf[2] = 0;
+       msg[0].len = 3;
+
+       ret = i2c_transfer(client->adapter, msg, 1);
+       if (ret < 0)
+               return ret;
+
+       wr_buf[0] = 0;
+       wr_buf[1] = USB5744_CREG_MEM_RD_ADDR;
+       msg[0].len = 2;
+
+       msg[1].addr = client->addr;
+       msg[1].flags = I2C_M_RD;
+       msg[1].len = 2;
+       msg[1].buf = rd_buf;
+
+       ret = i2c_transfer(client->adapter, msg, 2);
+       if (ret < 0)
+               return ret;
+       *data = rd_buf[1];
+
+       return 0;
+}
+
+static int onboard_dev_5744_i2c_write_byte(struct i2c_client *client, u16 addr, u8 data)
+{
+       struct i2c_msg msg[2];
+       int ret;
+
+       u8 wr_buf[8] = {0, USB5744_CREG_MEM_ADDR, 5,
+                       USB5744_CREG_WRITE, 1,
+                       addr >> 8 & 0xff,
+                       addr & 0xff,
+                       data};
+       msg[0].addr = client->addr;
+       msg[0].flags = 0;
+       msg[0].len = sizeof(wr_buf);
+       msg[0].buf = wr_buf;
+
+       ret = i2c_transfer(client->adapter, msg, 1);
+       if (ret < 0)
+               return ret;
+
+       msg[0].len = 3;
+       wr_buf[0] = USB5744_CMD_CREG_ACCESS;
+       wr_buf[1] = USB5744_CMD_CREG_ACCESS_LSB;
+       wr_buf[2] = 0;
+
+       ret = i2c_transfer(client->adapter, msg, 1);
+       if (ret < 0)
+               return ret;
+
+       return 0;
+}
+
 static int onboard_dev_5744_i2c_init(struct i2c_client *client)
 {
 #if IS_ENABLED(CONFIG_USB_ONBOARD_DEV_USB5744)
        struct device *dev = &client->dev;
        int ret;
+       u8 reg;
 
        /*
         * Set BYPASS_UDC_SUSPEND bit to ensure MCU is always enabled
@@ -321,20 +399,16 @@ static int onboard_dev_5744_i2c_init(struct i2c_client *client)
         * The command writes 5 bytes to memory and single data byte in
         * configuration register.
         */
-       char wr_buf[7] = {USB5744_CREG_MEM_ADDR, 5,
-                         USB5744_CREG_WRITE, 1,
-                         USB5744_CREG_RUNTIMEFLAGS2,
-                         USB5744_CREG_RUNTIMEFLAGS2_LSB,
-                         USB5744_CREG_BYPASS_UDC_SUSPEND};
-
-       ret = i2c_smbus_write_block_data(client, 0, sizeof(wr_buf), wr_buf);
+       ret = onboard_dev_5744_i2c_read_byte(client,
+                                            USB5744_CREG_RUNTIMEFLAGS2, &reg);
        if (ret)
-               return dev_err_probe(dev, ret, "BYPASS_UDC_SUSPEND bit configuration failed\n");
+               return dev_err_probe(dev, ret, "CREG_RUNTIMEFLAGS2 read failed\n");
 
-       ret = i2c_smbus_write_word_data(client, USB5744_CMD_CREG_ACCESS,
-                                       USB5744_CMD_CREG_ACCESS_LSB);
+       reg |= USB5744_CREG_BYPASS_UDC_SUSPEND;
+       ret = onboard_dev_5744_i2c_write_byte(client,
+                                             USB5744_CREG_RUNTIMEFLAGS2, reg);
        if (ret)
-               return dev_err_probe(dev, ret, "Configuration Register Access Command failed\n");
+               return dev_err_probe(dev, ret, "BYPASS_UDC_SUSPEND bit configuration failed\n");
 
        /* Send SMBus command to boot hub. */
        ret = i2c_smbus_write_word_data(client, USB5744_CMD_ATTACH,