From ab1e9de84aff0ca897dee5e4d6692ff46788697b Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 14 Jun 2022 10:46:10 +0200 Subject: [PATCH 1/3] dt-bindings: dp83867: add binding for io_impedance_ctrl nvmem cell We have a board where measurements indicate that the current three options - leaving IO_IMPEDANCE_CTRL at the reset value (which is factory calibrated to a value corresponding to approximately 50 ohms) or using one of the two boolean properties to set it to the min/max value - are too coarse. There is no fixed mapping from register values to values in the range 35-70 ohms; it varies from chip to chip, and even that target range is approximate. So add a DT binding for an nvmem cell which can be populated during production with a value suitable for each specific board. Reviewed-by: Rob Herring Reviewed-by: Andrew Lunn Signed-off-by: Rasmus Villemoes Signed-off-by: Jakub Kicinski --- .../devicetree/bindings/net/ti,dp83867.yaml | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/Documentation/devicetree/bindings/net/ti,dp83867.yaml b/Documentation/devicetree/bindings/net/ti,dp83867.yaml index 047d757e8d82..76ff08a477ba 100644 --- a/Documentation/devicetree/bindings/net/ti,dp83867.yaml +++ b/Documentation/devicetree/bindings/net/ti,dp83867.yaml @@ -31,6 +31,16 @@ properties: reg: maxItems: 1 + nvmem-cells: + maxItems: 1 + description: + Nvmem data cell containing the value to write to the + IO_IMPEDANCE_CTRL field of the IO_MUX_CFG register. + + nvmem-cell-names: + items: + - const: io_impedance_ctrl + ti,min-output-impedance: type: boolean description: | @@ -42,9 +52,11 @@ properties: description: | MAC Interface Impedance control to set the programmable output impedance to a maximum value (70 ohms). - Note: ti,min-output-impedance and ti,max-output-impedance are mutually - exclusive. When both properties are present ti,max-output-impedance - takes precedence. + Note: Specifying an io_impedance_ctrl nvmem cell or one of the + ti,min-output-impedance, ti,max-output-impedance properties + are mutually exclusive. If more than one is present, an nvmem + cell takes precedence over ti,max-output-impedance, which in + turn takes precedence over ti,min-output-impedance. tx-fifo-depth: $ref: /schemas/types.yaml#/definitions/uint32 From a793679827a87b01f9d973ea30b923cd5a3ff2c5 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 14 Jun 2022 10:46:11 +0200 Subject: [PATCH 2/3] linux/phy.h: add phydev_err_probe() wrapper for dev_err_probe() The dev_err_probe() function is quite useful to avoid boilerplate related to -EPROBE_DEFER handling. Add a phydev_err_probe() helper to simplify making use of that from phy drivers which otherwise use the phydev_* helpers. Signed-off-by: Rasmus Villemoes Signed-off-by: Jakub Kicinski --- include/linux/phy.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/phy.h b/include/linux/phy.h index 508f1149665b..bed9a347481b 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -1539,6 +1539,9 @@ static inline void phy_device_reset(struct phy_device *phydev, int value) #define phydev_err(_phydev, format, args...) \ dev_err(&_phydev->mdio.dev, format, ##args) +#define phydev_err_probe(_phydev, err, format, args...) \ + dev_err_probe(&_phydev->mdio.dev, err, format, ##args) + #define phydev_info(_phydev, format, args...) \ dev_info(&_phydev->mdio.dev, format, ##args) From 5c2d0a6a0701ba86a4bb0bf1876266c751e328bd Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 14 Jun 2022 10:46:12 +0200 Subject: [PATCH 3/3] net: phy: dp83867: implement support for io_impedance_ctrl nvmem cell We have a board where measurements indicate that the current three options - leaving IO_IMPEDANCE_CTRL at the (factory calibrated) reset value or using one of the two boolean properties to set it to the min/max value - are too coarse. Implement support for the newly added binding allowing device tree to specify an nvmem cell containing an appropriate value for this specific board. Signed-off-by: Rasmus Villemoes Signed-off-by: Jakub Kicinski --- drivers/net/phy/dp83867.c | 55 ++++++++++++++++++++++++++++++++++----- 1 file changed, 49 insertions(+), 6 deletions(-) diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c index 13dafe7a29bd..1e38039c5c56 100644 --- a/drivers/net/phy/dp83867.c +++ b/drivers/net/phy/dp83867.c @@ -14,6 +14,7 @@ #include #include #include +#include #include @@ -522,6 +523,51 @@ static int dp83867_verify_rgmii_cfg(struct phy_device *phydev) } #if IS_ENABLED(CONFIG_OF_MDIO) +static int dp83867_of_init_io_impedance(struct phy_device *phydev) +{ + struct dp83867_private *dp83867 = phydev->priv; + struct device *dev = &phydev->mdio.dev; + struct device_node *of_node = dev->of_node; + struct nvmem_cell *cell; + u8 *buf, val; + int ret; + + cell = of_nvmem_cell_get(of_node, "io_impedance_ctrl"); + if (IS_ERR(cell)) { + ret = PTR_ERR(cell); + if (ret != -ENOENT) + return phydev_err_probe(phydev, ret, + "failed to get nvmem cell io_impedance_ctrl\n"); + + /* If no nvmem cell, check for the boolean properties. */ + if (of_property_read_bool(of_node, "ti,max-output-impedance")) + dp83867->io_impedance = DP83867_IO_MUX_CFG_IO_IMPEDANCE_MAX; + else if (of_property_read_bool(of_node, "ti,min-output-impedance")) + dp83867->io_impedance = DP83867_IO_MUX_CFG_IO_IMPEDANCE_MIN; + else + dp83867->io_impedance = -1; /* leave at default */ + + return 0; + } + + buf = nvmem_cell_read(cell, NULL); + nvmem_cell_put(cell); + + if (IS_ERR(buf)) + return PTR_ERR(buf); + + val = *buf; + kfree(buf); + + if ((val & DP83867_IO_MUX_CFG_IO_IMPEDANCE_MASK) != val) { + phydev_err(phydev, "nvmem cell 'io_impedance_ctrl' contents out of range\n"); + return -ERANGE; + } + dp83867->io_impedance = val; + + return 0; +} + static int dp83867_of_init(struct phy_device *phydev) { struct dp83867_private *dp83867 = phydev->priv; @@ -549,12 +595,9 @@ static int dp83867_of_init(struct phy_device *phydev) } } - if (of_property_read_bool(of_node, "ti,max-output-impedance")) - dp83867->io_impedance = DP83867_IO_MUX_CFG_IO_IMPEDANCE_MAX; - else if (of_property_read_bool(of_node, "ti,min-output-impedance")) - dp83867->io_impedance = DP83867_IO_MUX_CFG_IO_IMPEDANCE_MIN; - else - dp83867->io_impedance = -1; /* leave at default */ + ret = dp83867_of_init_io_impedance(phydev); + if (ret) + return ret; dp83867->rxctrl_strap_quirk = of_property_read_bool(of_node, "ti,dp83867-rxctrl-strap-quirk");