Re: [PATCH v2 8/9] phy: add Broadcom Kona USB2 PHY driver

[Matt Porter <matt.porter@linaro.org>]

On Mon, Nov 04, 2013 at 11:57:10AM +0530, Kishon Vijay Abraham I wrote:
> Hi,
> 
> On Saturday 02 November 2013 01:15 AM, Matt Porter wrote:
> >Add a driver for the internal Broadcom Kona USB 2.0 PHY found
> >on the BCM281xx family of SoCs.
> >
> >Signed-off-by: Matt Porter <matt.porter@linaro.org>
> >---
> >  drivers/phy/Kconfig             |   6 ++
> >  drivers/phy/Makefile            |   2 +
> >  drivers/phy/phy-bcm-kona-usb2.c | 161 ++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 169 insertions(+)
> >  create mode 100644 drivers/phy/phy-bcm-kona-usb2.c
> >
> >diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> >index 349bef2..cedada5 100644
> >--- a/drivers/phy/Kconfig
> >+++ b/drivers/phy/Kconfig
> >@@ -15,4 +15,10 @@ config GENERIC_PHY
> >  	  phy users can obtain reference to the PHY. All the users of this
> >  	  framework should select this config.
> >
> >+config BCM_KONA_USB2_PHY
> >+	tristate "Broadcom Kona USB2 PHY Driver"
> >+	depends on GENERIC_PHY
> >+	help
> >+	  Enable this to support the Broadcom Kona USB 2.0 PHY.
> >+
> >  endmenu
> >diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
> >index 9e9560f..ce83a14 100644
> >--- a/drivers/phy/Makefile
> >+++ b/drivers/phy/Makefile
> >@@ -3,3 +3,5 @@
> >  #
> >
> >  obj-$(CONFIG_GENERIC_PHY)	+= phy-core.o
> >+
> >+obj-$(CONFIG_BCM_KONA_USB2_PHY)	+= phy-bcm-kona-usb2.o
> >diff --git a/drivers/phy/phy-bcm-kona-usb2.c b/drivers/phy/phy-bcm-kona-usb2.c
> >new file mode 100644
> >index 0000000..1beea7f
> >--- /dev/null
> >+++ b/drivers/phy/phy-bcm-kona-usb2.c
> >@@ -0,0 +1,161 @@
> >+/*
> >+ * phy-bcm-kona-usb2.c - Broadcom Kona USB2 Phy Driver
> >+ *
> >+ * Copyright (C) 2013 Linaro Limited
> >+ * Matt Porter <matt.porter@linaro.org>
> >+ *
> >+ * This software is licensed under the terms of the GNU General Public
> >+ * License version 2, as published by the Free Software Foundation, and
> >+ * may be copied, distributed, and modified under those terms.
> >+ *
> >+ * This program is distributed in the hope that it will be useful,
> >+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> >+ * GNU General Public License for more details.
> >+ */
> >+
> >+#include <linux/module.h>
> >+#include <linux/of.h>
> >+#include <linux/delay.h>
> >+#include <linux/platform_device.h>
> >+#include <linux/err.h>
> >+#include <linux/io.h>
> >+#include <linux/clk.h>
> >+#include <linux/phy/phy.h>
> >+
> >+#define OTGCTL_OTGSTAT2		(1 << 31)
> >+#define OTGCTL_OTGSTAT1		(1 << 30)
> >+#define OTGCTL_PRST_N_SW	(1 << 11)
> >+#define OTGCTL_HRESET_N		(1 << 10)
> >+#define OTGCTL_UTMI_LINE_STATE1	(1 << 9)
> >+#define OTGCTL_UTMI_LINE_STATE0	(1 << 8)
> >+
> >+#define P1CTL_SOFT_RESET	(1 << 1)
> >+#define P1CTL_NON_DRIVING	(1 << 0)
> >+
> >+struct bcm_kona_usb_phy_regs {
> >+	u32 ctrl;
> >+	u32 cfg;
> >+	u32 p1ctl;
> >+	u32 status;
> >+	u32 bc_cfg;
> >+	u32 tp_in;
> >+	u32 tp_out;
> >+	u32 phy_ctrl;
> >+	u32 usbreg;
> >+	u32 usbproben;
> >+};
> 
> I would prefer to have constant macros for register offset unless
> you have a good reason to do otherwise.

I'll switch to constant macros in v3. It's just my personal preference
for style.

> >+
> >+struct bcm_kona_usb {
> >+	struct bcm_kona_usb_phy_regs *regs;
> >+};
> >+
> >+static void bcm_kona_usb_phy_power(struct bcm_kona_usb *phy, int on)
> >+{
> >+	u32 val;
> >+
> >+	val = readl(&phy->regs->ctrl);
> >+	if (on) {
> >+		/* Configure and power PHY */
> >+		val &= ~(OTGCTL_OTGSTAT2 | OTGCTL_OTGSTAT1 |
> >+			 OTGCTL_UTMI_LINE_STATE1 | OTGCTL_UTMI_LINE_STATE0);
> >+		val |= OTGCTL_PRST_N_SW | OTGCTL_HRESET_N;
> >+		writel(val, &phy->regs->ctrl);
> >+
> >+		/* Soft reset PHY */
> >+		val = readl(&phy->regs->p1ctl);
> >+		val &= ~P1CTL_NON_DRIVING;
> >+		val |= P1CTL_SOFT_RESET;
> >+		writel(val, &phy->regs->p1ctl);
> >+		writel(val & ~P1CTL_SOFT_RESET, &phy->regs->p1ctl);
> >+		/* Reset needs to be asserted for 2ms */
> >+		mdelay(2);
> >+		writel(val | P1CTL_SOFT_RESET, &phy->regs->p1ctl);
> 
> Is soft reset needed for every power-on? Shouldn't soft reset be
> present in phy_init?

Not needed for every power-on. Yes, I've addressed that now for v3,
thanks.

-Matt