[PATCH v2 2/2] phy: meson: add USB2 PHY support for Meson GXL and GXM
Martin Blumenstingl
martin.blumenstingl at googlemail.com
Sat Apr 1 02:37:46 PDT 2017
Hi Kishon,
On Wed, Mar 29, 2017 at 12:56 PM, Kishon Vijay Abraham I <kishon at ti.com> wrote:
> Hi,
>
> On Wednesday 29 March 2017 03:03 AM, Martin Blumenstingl wrote:
>> Hi Kishon,
>>
>> On Sat, Mar 18, 2017 at 2:00 PM, Martin Blumenstingl
>> <martin.blumenstingl at googlemail.com> wrote:
>>> This adds a new driver for the USB2 PHYs found on Meson GXL and GXM SoCs
>>> (both SoCs are using the same USB PHY register layout).
>>>
>>> The USB2 PHY is a simple PHY which only has a few registers to configure
>>> the mode (host/device) and a reset register (to enable/disable the PHY).
>>>
>>> Unfortunately there are no datasheets available for this PHY. The driver
>>> was written by reading the code from Amlogic's GPL kernel sources and
>>> by analyzing the registers on an actual GXL and GXM device running the
>>> kernel that was shipped on the boards I have.
>> gentle ping - did you have time to review this patch in v2 yet?
>
> Have a few comments, see below..
thanks for taking the time to review this!
>>
>>> Signed-off-by: Martin Blumenstingl <martin.blumenstingl at googlemail.com>
>>> ---
>>> drivers/phy/Kconfig | 14 ++
>>> drivers/phy/Makefile | 1 +
>>> drivers/phy/phy-meson-gxl-usb2.c | 273 +++++++++++++++++++++++++++++++++++++++
>>> 3 files changed, 288 insertions(+)
>>> create mode 100644 drivers/phy/phy-meson-gxl-usb2.c
>>>
>>> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
>>> index dc5277ad1b5a..2573e139fd17 100644
>>> --- a/drivers/phy/Kconfig
>>> +++ b/drivers/phy/Kconfig
>>> @@ -510,6 +510,19 @@ config PHY_MESON8B_USB2
>>> and GXBB SoCs.
>>> If unsure, say N.
>>>
>>> +config PHY_MESON_GXL_USB
>>> + tristate "Meson GXL and GXM USB2 PHY drivers"
>>> + default ARCH_MESON
>>> + depends on OF && (ARCH_MESON || COMPILE_TEST)
>>> + depends on USB_SUPPORT
>>> + select USB_COMMON
>>> + select GENERIC_PHY
>>> + select REGMAP_MMIO
>>> + help
>>> + Enable this to support the Meson USB2 PHYs found in Meson
>>> + GXL and GXM SoCs.
>>> + If unsure, say N.
>>> +
>>> config PHY_NSP_USB3
>>> tristate "Broadcom NorthStar plus USB3 PHY driver"
>>> depends on OF && (ARCH_BCM_NSP || COMPILE_TEST)
>>> @@ -518,4 +531,5 @@ config PHY_NSP_USB3
>>> help
>>> Enable this to support the Broadcom Northstar plus USB3 PHY.
>>> If unsure, say N.
>>> +
>
> spurious space..
you're right, this shouldn't be here. I'll fix this in the next version
>>> endmenu
>>> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
>>> index e7b0feb1e125..e680b856e38e 100644
>>> --- a/drivers/phy/Makefile
>>> +++ b/drivers/phy/Makefile
>>> @@ -62,4 +62,5 @@ obj-$(CONFIG_PHY_CYGNUS_PCIE) += phy-bcm-cygnus-pcie.o
>>> obj-$(CONFIG_ARCH_TEGRA) += tegra/
>>> obj-$(CONFIG_PHY_NS2_PCIE) += phy-bcm-ns2-pcie.o
>>> obj-$(CONFIG_PHY_MESON8B_USB2) += phy-meson8b-usb2.o
>>> +obj-$(CONFIG_PHY_MESON_GXL_USB) += phy-meson-gxl-usb2.o
>>> obj-$(CONFIG_PHY_NSP_USB3) += phy-bcm-nsp-usb3.o
>>> diff --git a/drivers/phy/phy-meson-gxl-usb2.c b/drivers/phy/phy-meson-gxl-usb2.c
>>> new file mode 100644
>>> index 000000000000..4bf646a52c45
>>> --- /dev/null
>>> +++ b/drivers/phy/phy-meson-gxl-usb2.c
>>> @@ -0,0 +1,273 @@
>>> +/*
>>> + * Meson GXL and GXM USB2 PHY driver
>>> + *
>>> + * Copyright (C) 2017 Martin Blumenstingl <martin.blumenstingl at googlemail.com>
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License version 2 as
>>> + * published by the Free Software Foundation.
>>> + *
>>> + * You should have received a copy of the GNU General Public License
>>> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
>>> + */
>>> +
>>> +#include <linux/delay.h>
>>> +#include <linux/io.h>
>>> +#include <linux/module.h>
>>> +#include <linux/of_device.h>
>>> +#include <linux/regmap.h>
>>> +#include <linux/phy/phy.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/usb/of.h>
>>> +
>>> +/* bits [31:27] are read-only */
>>> +#define U2P_R0 0x0
>>> + #define U2P_R0_BYPASS_SEL BIT(0)
>>> + #define U2P_R0_BYPASS_DM_EN BIT(1)
>>> + #define U2P_R0_BYPASS_DP_EN BIT(2)
>>> + #define U2P_R0_TXBITSTUFF_ENH BIT(3)
>>> + #define U2P_R0_TXBITSTUFF_EN BIT(4)
>>> + #define U2P_R0_DM_PULLDOWN BIT(5)
>>> + #define U2P_R0_DP_PULLDOWN BIT(6)
>>> + #define U2P_R0_DP_VBUS_VLD_EXT_SEL BIT(7)
>>> + #define U2P_R0_DP_VBUS_VLD_EXT BIT(8)
>>> + #define U2P_R0_ADP_PRB_EN BIT(9)
>>> + #define U2P_R0_ADP_DISCHARGE BIT(10)
>>> + #define U2P_R0_ADP_CHARGE BIT(11)
>>> + #define U2P_R0_DRV_VBUS BIT(12)
>>> + #define U2P_R0_ID_PULLUP BIT(13)
>>> + #define U2P_R0_LOOPBACK_EN_B BIT(14)
>>> + #define U2P_R0_OTG_DISABLE BIT(15)
>>> + #define U2P_R0_COMMON_ONN BIT(16)
>>> + #define U2P_R0_FSEL_MASK GENMASK(19, 17)
>>> + #define U2P_R0_REF_CLK_SEL_MASK GENMASK(21, 20)
>>> + #define U2P_R0_POWER_ON_RESET BIT(22)
>>> + #define U2P_R0_V_ATE_TEST_EN_B_MASK GENMASK(24, 23)
>>> + #define U2P_R0_ID_SET_ID_DQ BIT(25)
>>> + #define U2P_R0_ATE_RESET BIT(26)
>>> + #define U2P_R0_FSV_MINUS BIT(27)
>>> + #define U2P_R0_FSV_PLUS BIT(28)
>>> + #define U2P_R0_BYPASS_DM_DATA BIT(29)
>>> + #define U2P_R0_BYPASS_DP_DATA BIT(30)
>>> +
>>> +#define U2P_R1 0x4
>>> + #define U2P_R1_BURN_IN_TEST BIT(0)
>>> + #define U2P_R1_ACA_ENABLE BIT(1)
>>> + #define U2P_R1_DCD_ENABLE BIT(2)
>>> + #define U2P_R1_VDAT_SRC_EN_B BIT(3)
>>> + #define U2P_R1_VDAT_DET_EN_B BIT(4)
>>> + #define U2P_R1_CHARGES_SEL BIT(5)
>>> + #define U2P_R1_TX_PREEMP_PULSE_TUNE BIT(6)
>>> + #define U2P_R1_TX_PREEMP_AMP_TUNE_MASK GENMASK(8, 7)
>>> + #define U2P_R1_TX_RES_TUNE_MASK GENMASK(10, 9)
>>> + #define U2P_R1_TX_RISE_TUNE_MASK GENMASK(12, 11)
>>> + #define U2P_R1_TX_VREF_TUNE_MASK GENMASK(16, 13)
>>> + #define U2P_R1_TX_FSLS_TUNE_MASK GENMASK(20, 17)
>>> + #define U2P_R1_TX_HSXV_TUNE_MASK GENMASK(22, 21)
>>> + #define U2P_R1_OTG_TUNE_MASK GENMASK(25, 23)
>>> + #define U2P_R1_SQRX_TUNE_MASK GENMASK(28, 26)
>>> + #define U2P_R1_COMP_DIS_TUNE_MASK GENMASK(31, 29)
>>> +
>>> +/* bits [31:14] are read-only */
>>> +#define U2P_R2 0x8
>>> + #define U2P_R2_DATA_IN_MASK GENMASK(3, 0)
>>> + #define U2P_R2_DATA_IN_EN_MASK GENMASK(7, 4)
>>> + #define U2P_R2_ADDR_MASK GENMASK(11, 8)
>>> + #define U2P_R2_DATA_OUT_SEL BIT(12)
>>> + #define U2P_R2_CLK BIT(13)
>>> + #define U2P_R2_DATA_OUT_MASK GENMASK(17, 14)
>>> + #define U2P_R2_ACA_PIN_RANGE_C BIT(18)
>>> + #define U2P_R2_ACA_PIN_RANGE_B BIT(19)
>>> + #define U2P_R2_ACA_PIN_RANGE_A BIT(20)
>>> + #define U2P_R2_ACA_PIN_GND BIT(21)
>>> + #define U2P_R2_ACA_PIN_FLOAT BIT(22)
>>> + #define U2P_R2_CHARGE_DETECT BIT(23)
>>> + #define U2P_R2_DEVICE_SESSION_VALID BIT(24)
>>> + #define U2P_R2_ADP_PROBE BIT(25)
>>> + #define U2P_R2_ADP_SENSE BIT(26)
>>> + #define U2P_R2_SESSION_END BIT(27)
>>> + #define U2P_R2_VBUS_VALID BIT(28)
>>> + #define U2P_R2_B_VALID BIT(29)
>>> + #define U2P_R2_A_VALID BIT(30)
>>> + #define U2P_R2_ID_DIG BIT(31)
>>> +
>>> +#define U2P_R3 0xc
>>> +
>>> +#define RESET_COMPLETE_TIME 500
>>> +
>>> +struct phy_meson_gxl_usb2_priv {
>>> + struct regmap *regmap;
>>> + enum phy_mode mode;
>>> + int is_enabled;
>>> +};
>>> +
>>> +static const struct regmap_config phy_meson_gxl_usb2_regmap_conf = {
>>> + .reg_bits = 8,
>>> + .val_bits = 32,
>>> + .reg_stride = 4,
>>> + .max_register = U2P_R3,
>>> +};
>>> +
>>> +static int phy_meson_gxl_usb2_reset(struct phy *phy)
>>> +{
>>> + struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);
>>> +
>>> + if (priv->is_enabled) {
>>> + /* reset the PHY and wait until settings are stabilized */
>>> + regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_POWER_ON_RESET,
>>> + U2P_R0_POWER_ON_RESET);
>>> + udelay(RESET_COMPLETE_TIME);
>>> + regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_POWER_ON_RESET,
>>> + 0);
>>> + udelay(RESET_COMPLETE_TIME);
>>> + }
>
> Instead of having big if condition blocks, it could be
> if (!priv->is_enabled)
> return 0
>
> the configuration when priv->is_enabled is true should go here.
makes sense (and the code easier to read) in this case - I'll fix it
in the next version
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int phy_meson_gxl_usb2_set_mode(struct phy *phy, enum phy_mode mode)
>>> +{
>>> + struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);
>>> +
>>> + switch (mode) {
>>> + case PHY_MODE_USB_HOST:
>>> + case PHY_MODE_USB_OTG:
>>> + regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_DM_PULLDOWN,
>>> + U2P_R0_DM_PULLDOWN);
>>> + regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_DP_PULLDOWN,
>>> + U2P_R0_DP_PULLDOWN);
>>> + regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_ID_PULLUP, 0);
>>> + break;
>>> +
>>> + case PHY_MODE_USB_DEVICE:
>>> + regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_DM_PULLDOWN,
>>> + 0);
>>> + regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_DP_PULLDOWN,
>>> + 0);
>>> + regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_ID_PULLUP,
>>> + U2P_R0_ID_PULLUP);
>>> + break;
>>> +
>>> + default:
>>> + return -EINVAL;
>>> + }
>>> +
>>> + phy_meson_gxl_usb2_reset(phy);
>>> +
>>> + priv->mode = mode;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int phy_meson_gxl_usb2_power_off(struct phy *phy)
>>> +{
>>> + struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);
>>> +
>>> + priv->is_enabled = 0;
>>> +
>>> + /* power off the PHY by putting it into reset mode */
>>> + regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_POWER_ON_RESET,
>>> + U2P_R0_POWER_ON_RESET);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int phy_meson_gxl_usb2_power_on(struct phy *phy)
>>> +{
>>> + struct phy_meson_gxl_usb2_priv *priv = phy_get_drvdata(phy);
>>> + int ret;
>>> +
>>> + priv->is_enabled = 1;
>>> +
>>> + /* power on the PHY by taking it out of reset mode */
>>> + regmap_update_bits(priv->regmap, U2P_R0, U2P_R0_POWER_ON_RESET, 0);
>>> +
>>> + ret = phy_meson_gxl_usb2_set_mode(phy, priv->mode);
>
> Since this is already part of phy_ops, the consumer of this phy will take care
> of setting the mode right?
many USB PHYs are configured through of_usb_get_dr_mode_by_phy()
(which fetches the USB controller DT node and looks up the dr_mode
property). this means that the driver will even work for controller
which did not call phy_set_mode() (currently dwc2 and dwc3 are an
example where phy_set_mode() is not called, and this driver is
probably going to be used by both). are you fine with keeping this or
should we instead investigate why dwc2 and dwc3 are not calling
phy_set_mode yet?
>>> + if (ret) {
>>> + phy_meson_gxl_usb2_power_off(phy);
>
> This would mess up the reference count in phy_core, since this function is also
> part of the phy_ops. The consumer should be responsible for powering off the phy.
actually it shouldn't. it would cause issues if I used
phy_power_off(phy) here, but I'm using the driver-internal callback
here.
if phy_meson_gxl_usb2_power_on() fails then phy_power_on() (from
phy-core) prints a warnings and does not increment the internal
ref-counter (++phy->power_count).
so in my opinion there shouldn't be a problem
could you please have a look at my replies for issue #3 and #4 (both
affecting phy_meson_gxl_usb2_power_on) and let me know what you think?
Regards,
Martin
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