usb: gadget: udc: lpc32xx: add support for stotg04 phy

The STOTG04 phy is used as a drop-in replacement of the ISP1301 but some
bits doesn't have exactly the same meaning and this can lead to issues.
Detect the phy dynamically and avoid writing to reserved bits.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/udc/lpc32xx_udc.c

@@ -115,6 +115,11 @@ struct lpc32xx_ep {
 	bool			wedge;
 };
 
+enum atx_type {
+	ISP1301,
+	STOTG04,
+};
+
 /*
  * Common UDC structure
  */
@@ -149,6 +154,7 @@ struct lpc32xx_udc {
 	u8			last_vbus;
 	int			pullup;
 	int			poweron;
+	enum atx_type		atx;
 
 	/* Work queues related to I2C support */
 	struct work_struct	pullup_job;
@@ -550,6 +556,15 @@ static inline void remove_debug_file(struct lpc32xx_udc *udc) {}
 /* Primary initialization sequence for the ISP1301 transceiver */
 static void isp1301_udc_configure(struct lpc32xx_udc *udc)
 {
+	u8 value;
+	s32 vendor, product;
+
+	vendor = i2c_smbus_read_word_data(udc->isp1301_i2c_client, 0x00);
+	product = i2c_smbus_read_word_data(udc->isp1301_i2c_client, 0x02);
+
+	if (vendor == 0x0483 && product == 0xa0c4)
+		udc->atx = STOTG04;
+
 	/* LPC32XX only supports DAT_SE0 USB mode */
 	/* This sequence is important */
 
@@ -569,8 +584,12 @@ static void isp1301_udc_configure(struct lpc32xx_udc *udc)
 	 */
 	i2c_smbus_write_byte_data(udc->isp1301_i2c_client,
 		(ISP1301_I2C_MODE_CONTROL_2 | ISP1301_I2C_REG_CLEAR_ADDR), ~0);
+
+	value = MC2_BI_DI;
+	if (udc->atx != STOTG04)
+		value |= MC2_SPD_SUSP_CTRL;
 	i2c_smbus_write_byte_data(udc->isp1301_i2c_client,
-		ISP1301_I2C_MODE_CONTROL_2, (MC2_BI_DI | MC2_SPD_SUSP_CTRL));
+		ISP1301_I2C_MODE_CONTROL_2, value);
 
 	/* Driver VBUS_DRV high or low depending on board setup */
 	if (udc->board->vbus_drv_pol != 0)
@@ -610,12 +629,11 @@ static void isp1301_udc_configure(struct lpc32xx_udc *udc)
 	i2c_smbus_write_byte_data(udc->isp1301_i2c_client,
 		ISP1301_I2C_INTERRUPT_RISING, INT_SESS_VLD | INT_VBUS_VLD);
 
-	dev_info(udc->dev, "ISP1301 Vendor ID  : 0x%04x\n",
-		 i2c_smbus_read_word_data(udc->isp1301_i2c_client, 0x00));
-	dev_info(udc->dev, "ISP1301 Product ID : 0x%04x\n",
-		 i2c_smbus_read_word_data(udc->isp1301_i2c_client, 0x02));
+	dev_info(udc->dev, "ISP1301 Vendor ID  : 0x%04x\n", vendor);
+	dev_info(udc->dev, "ISP1301 Product ID : 0x%04x\n", product);
 	dev_info(udc->dev, "ISP1301 Version ID : 0x%04x\n",
 		 i2c_smbus_read_word_data(udc->isp1301_i2c_client, 0x14));
+
 }
 
 /* Enables or disables the USB device pullup via the ISP1301 transceiver */
@@ -658,6 +676,10 @@ static void isp1301_pullup_enable(struct lpc32xx_udc *udc, int en_pullup,
 /* Powers up or down the ISP1301 transceiver */
 static void isp1301_set_powerstate(struct lpc32xx_udc *udc, int enable)
 {
+	/* There is no "global power down" register for stotg04 */
+	if (udc->atx == STOTG04)
+		return;
+
 	if (enable != 0)
 		/* Power up ISP1301 - this ISP1301 will automatically wakeup
 		   when VBUS is detected */