Commit 221a5344 authored by Parthiban Veerasooran's avatar Parthiban Veerasooran Committed by Paolo Abeni
Browse files

net: phy: microchip_t1s: replace read-modify-write code with phy_modify_mmd 



Replace read-modify-write code in the lan867x_config_init function to
avoid handling data type mismatch and to simplify the code.

Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarParthiban Veerasooran <Parthiban.Veerasooran@microchip.com>
Reviewed-by: default avatarRamón Nordin Rodriguez <ramon.nordin.rodriguez@ferroamp.se>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent ca33db4a

drivers/net/phy/microchip_t1s.c

+13 −28
Original line number Diff line number Diff line
@@ -31,19 +31,19 @@ 
 * W   0x1F 0x0099 0x7F80 ------

 */



static const int lan867x_fixup_registers[12] = {

static const u32 lan867x_fixup_registers[12] = {

	0x00D0, 0x00D1, 0x0084, 0x0085,

	0x008A, 0x0087, 0x0088, 0x008B,

	0x0080, 0x00F1, 0x0096, 0x0099,

};



static const int lan867x_fixup_values[12] = {

static const u16 lan867x_fixup_values[12] = {

	0x0002, 0x0000, 0x3380, 0x0006,

	0xC000, 0x801C, 0x033F, 0x0404,

	0x0600, 0x2400, 0x2000, 0x7F80,

};



static const int lan867x_fixup_masks[12] = {

static const u16 lan867x_fixup_masks[12] = {

	0x0E03, 0x0300, 0xFFC0, 0x000F,

	0xF800, 0x801C, 0x1FFF, 0xFFFF,

	0x0600, 0x7F00, 0x2000, 0xFFFF,
@@ -51,35 +51,20 @@ static const int lan867x_fixup_masks[12] = { 


static int lan867x_config_init(struct phy_device *phydev)

{

	/* HW quirk: Microchip states in the application note (AN1699) for the phy

	 * that a set of read-modify-write (rmw) operations has to be performed

	 * on a set of seemingly magic registers.

	 * The result of these operations is just described as 'optimal performance'

	 * Microchip gives no explanation as to what these mmd regs do,

	 * in fact they are marked as reserved in the datasheet.

	 * It is unclear if phy_modify_mmd would be safe to use or if a write

	 * really has to happen to each register.

	 * In order to exactly conform to what is stated in the AN phy_write_mmd is

	 * used, which might then write the same value back as read + modified.

	 */



	int reg_value;

	int err;

	int reg;



	/* Read-Modified Write Pseudocode (from AN1699)

	 * current_val = read_register(mmd, addr) // Read current register value

	 * new_val = current_val AND (NOT mask) // Clear bit fields to be written

	 * new_val = new_val OR value // Set bits

	 * write_register(mmd, addr, new_val) // Write back updated register value

	/* Reference to AN1699

	 * https://ww1.microchip.com/downloads/aemDocuments/documents/AIS/ProductDocuments/SupportingCollateral/AN-LAN8670-1-2-config-60001699.pdf

	 * AN1699 says Read, Modify, Write, but the Write is not required if the

	 * register already has the required value. So it is safe to use

	 * phy_modify_mmd here.

	 */

	for (int i = 0; i < ARRAY_SIZE(lan867x_fixup_registers); i++) {

		reg = lan867x_fixup_registers[i];

		reg_value = phy_read_mmd(phydev, MDIO_MMD_VEND2, reg);

		reg_value &= ~lan867x_fixup_masks[i];

		reg_value |= lan867x_fixup_values[i];

		err = phy_write_mmd(phydev, MDIO_MMD_VEND2, reg, reg_value);

		if (err != 0)

		err = phy_modify_mmd(phydev, MDIO_MMD_VEND2,

				     lan867x_fixup_registers[i],

				     lan867x_fixup_masks[i],

				     lan867x_fixup_values[i]);

		if (err)

			return err;

	}