usb: atmel_usba_udc: Add at91sam9g45 and at91sam9x5 errata handling

at91sam9g45 and at91sam9x5 SoCs have an hardware bug forcing us to
generate a pulse on the BIAS signal on "USB end of reset” and
“USB end of resume" events.

Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Reported-by: Patrice VILCHEZ <patrice.vilchez@atmel.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

2 files changed, 29 insertions, 1 deletions

diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
index 36fd34b77387..55c8dde67f83 100644
--- a/drivers/usb/gadget/udc/atmel_usba_udc.c
+++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
@@ -331,6 +331,17 @@ static void toggle_bias(struct usba_udc *udc, int is_on)
                 udc->errata->toggle_bias(udc, is_on);
 }
 
+static void generate_bias_pulse(struct usba_udc *udc)
+{
+        if (!udc->bias_pulse_needed)
+                return;
+
+        if (udc->errata && udc->errata->pulse_bias)
+                udc->errata->pulse_bias(udc);
+
+        udc->bias_pulse_needed = false;
+}
+
 static void next_fifo_transaction(struct usba_ep *ep, struct usba_request *req)
 {
         unsigned int transaction_len;
@@ -1607,6 +1618,7 @@ static irqreturn_t usba_udc_irq(int irq, void *devid)
         if (status & USBA_DET_SUSPEND) {
                 toggle_bias(udc, 0);
                 usba_writel(udc, INT_CLR, USBA_DET_SUSPEND);
+                udc->bias_pulse_needed = true;
                 DBG(DBG_BUS, "Suspend detected\n");
                 if (udc->gadget.speed != USB_SPEED_UNKNOWN
                                 && udc->driver && udc->driver->suspend) {
@@ -1624,6 +1636,7 @@ static irqreturn_t usba_udc_irq(int irq, void *devid)
 
         if (status & USBA_END_OF_RESUME) {
                 usba_writel(udc, INT_CLR, USBA_END_OF_RESUME);
+                generate_bias_pulse(udc);
                 DBG(DBG_BUS, "Resume detected\n");
                 if (udc->gadget.speed != USB_SPEED_UNKNOWN
                                 && udc->driver && udc->driver->resume) {
@@ -1659,6 +1672,7 @@ static irqreturn_t usba_udc_irq(int irq, void *devid)
                 struct usba_ep *ep0;
 
                 usba_writel(udc, INT_CLR, USBA_END_OF_RESET);
+                generate_bias_pulse(udc);
                 reset_all_endpoints(udc);
 
                 if (udc->gadget.speed != USB_SPEED_UNKNOWN && udc->driver) {
@@ -1818,13 +1832,25 @@ static void at91sam9rl_toggle_bias(struct usba_udc *udc, int is_on)
                 at91_pmc_write(AT91_CKGR_UCKR, uckr & ~(AT91_PMC_BIASEN));
 }
 
+static void at91sam9g45_pulse_bias(struct usba_udc *udc)
+{
+        unsigned int uckr = at91_pmc_read(AT91_CKGR_UCKR);
+
+        at91_pmc_write(AT91_CKGR_UCKR, uckr & ~(AT91_PMC_BIASEN));
+        at91_pmc_write(AT91_CKGR_UCKR, uckr | AT91_PMC_BIASEN);
+}
+
 static const struct usba_udc_errata at91sam9rl_errata = {
         .toggle_bias = at91sam9rl_toggle_bias,
 };
 
+static const struct usba_udc_errata at91sam9g45_errata = {
+        .pulse_bias = at91sam9g45_pulse_bias,
+};
+
 static const struct of_device_id atmel_udc_dt_ids[] = {
         { .compatible = "atmel,at91sam9rl-udc", .data = &at91sam9rl_errata },
-        { .compatible = "atmel,at91sam9g45-udc" },
+        { .compatible = "atmel,at91sam9g45-udc", .data = &at91sam9g45_errata },
         { .compatible = "atmel,sama5d3-udc" },
         { /* sentinel */ }
 };
diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.h b/drivers/usb/gadget/udc/atmel_usba_udc.h
index 456899e9ee62..72b3537f56ce 100644
--- a/drivers/usb/gadget/udc/atmel_usba_udc.h
+++ b/drivers/usb/gadget/udc/atmel_usba_udc.h
@@ -306,6 +306,7 @@ struct usba_request {
 
 struct usba_udc_errata {
         void (*toggle_bias)(struct usba_udc *udc, int is_on);
+        void (*pulse_bias)(struct usba_udc *udc);
 };
 
 struct usba_udc {
@@ -326,6 +327,7 @@ struct usba_udc {
         struct clk *pclk;
         struct clk *hclk;
         struct usba_ep *usba_ep;
+        bool bias_pulse_needed;
 
         u16 devstatus;