net: Microchip encx24j600 driver

This ethernet driver supports the Micorchip enc424j600/626j600 Ethernet
controller over a SPI bus interface. This driver makes use of the regmap API to
optimize access to registers by caching registers where possible.

Datasheet:
http://ww1.microchip.com/downloads/en/DeviceDoc/39935b.pdf

Signed-off-by: Jon Ringle <jringle@gridpoint.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 513 insertions, 0 deletions

diff --git a/drivers/net/ethernet/microchip/encx24j600-regmap.c b/drivers/net/ethernet/microchip/encx24j600-regmap.c
new file mode 100644
index 0000000..f3bb905
--- /dev/null
+++ b/drivers/net/ethernet/microchip/encx24j600-regmap.c
@@ -0,0 +1,513 @@
+/**
+ * Register map access API - ENCX24J600 support
+ *
+ * Copyright 2015 Gridpoint
+ *
+ * Author: Jon Ringle <jringle@gridpoint.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.
+ */
+
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include "encx24j600_hw.h"
+
+static inline bool is_bits_set(int value, int mask)
+{
+	return (value & mask) == mask;
+}
+
+static int encx24j600_switch_bank(struct encx24j600_context *ctx,
+					 int bank)
+{
+	int ret = 0;
+
+	int bank_opcode = BANK_SELECT(bank);
+	ret = spi_write(ctx->spi, &bank_opcode, 1);
+	if (ret == 0)
+		ctx->bank = bank;
+
+	return ret;
+}
+
+static int encx24j600_cmdn(struct encx24j600_context *ctx, u8 opcode,
+			    const void *buf, size_t len)
+{
+	struct spi_message m;
+	struct spi_transfer t[2] = { { .tx_buf = &opcode, .len = 1, },
+				     { .tx_buf = buf, .len = len }, };
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+
+	return spi_sync(ctx->spi, &m);
+}
+
+static void regmap_lock_mutex(void *context)
+{
+	struct encx24j600_context *ctx = context;
+	mutex_lock(&ctx->mutex);
+}
+
+static void regmap_unlock_mutex(void *context)
+{
+	struct encx24j600_context *ctx = context;
+	mutex_unlock(&ctx->mutex);
+}
+
+static int regmap_encx24j600_sfr_read(void *context, u8 reg, u8 *val,
+				      size_t len)
+{
+	struct encx24j600_context *ctx = context;
+	u8 banked_reg = reg & ADDR_MASK;
+	u8 bank = ((reg & BANK_MASK) >> BANK_SHIFT);
+	u8 cmd = RCRU;
+	int ret = 0;
+	int i = 0;
+	u8 tx_buf[2];
+
+	if (reg < 0x80) {
+		cmd = RCRCODE | banked_reg;
+		if ((banked_reg < 0x16) && (ctx->bank != bank))
+			ret = encx24j600_switch_bank(ctx, bank);
+		if (unlikely(ret))
+			return ret;
+	} else {
+		/* Translate registers that are more effecient using
+		 * 3-byte SPI commands
+		 */
+		switch (reg) {
+		case EGPRDPT:
+			cmd = RGPRDPT; break;
+		case EGPWRPT:
+			cmd = RGPWRPT; break;
+		case ERXRDPT:
+			cmd = RRXRDPT; break;
+		case ERXWRPT:
+			cmd = RRXWRPT; break;
+		case EUDARDPT:
+			cmd = RUDARDPT; break;
+		case EUDAWRPT:
+			cmd = RUDAWRPT; break;
+		case EGPDATA:
+		case ERXDATA:
+		case EUDADATA:
+		default:
+			return -EINVAL;
+		}
+	}
+
+	tx_buf[i++] = cmd;
+	if (cmd == RCRU)
+		tx_buf[i++] = reg;
+
+	ret = spi_write_then_read(ctx->spi, tx_buf, i, val, len);
+
+	return ret;
+}
+
+static int regmap_encx24j600_sfr_update(struct encx24j600_context *ctx,
+					u8 reg, u8 *val, size_t len,
+					u8 unbanked_cmd, u8 banked_code)
+{
+	u8 banked_reg = reg & ADDR_MASK;
+	u8 bank = ((reg & BANK_MASK) >> BANK_SHIFT);
+	u8 cmd = unbanked_cmd;
+	struct spi_message m;
+	struct spi_transfer t[3] = { { .tx_buf = &cmd, .len = sizeof(cmd), },
+				     { .tx_buf = &reg, .len = sizeof(reg), },
+				     { .tx_buf = val, .len = len }, };
+
+	if (reg < 0x80) {
+		int ret = 0;
+		cmd = banked_code | banked_reg;
+		if ((banked_reg < 0x16) && (ctx->bank != bank))
+			ret = encx24j600_switch_bank(ctx, bank);
+		if (unlikely(ret))
+			return ret;
+	} else {
+		/* Translate registers that are more effecient using
+		 * 3-byte SPI commands
+		 */
+		switch (reg) {
+		case EGPRDPT:
+			cmd = WGPRDPT; break;
+		case EGPWRPT:
+			cmd = WGPWRPT; break;
+		case ERXRDPT:
+			cmd = WRXRDPT; break;
+		case ERXWRPT:
+			cmd = WRXWRPT; break;
+		case EUDARDPT:
+			cmd = WUDARDPT; break;
+		case EUDAWRPT:
+			cmd = WUDAWRPT; break;
+		case EGPDATA:
+		case ERXDATA:
+		case EUDADATA:
+		default:
+			return -EINVAL;
+		}
+	}
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+
+	if (cmd == unbanked_cmd) {
+		t[1].tx_buf = &reg;
+		spi_message_add_tail(&t[1], &m);
+	}
+
+	spi_message_add_tail(&t[2], &m);
+	return spi_sync(ctx->spi, &m);
+}
+
+static int regmap_encx24j600_sfr_write(void *context, u8 reg, u8 *val,
+				       size_t len)
+{
+	struct encx24j600_context *ctx = context;
+	return regmap_encx24j600_sfr_update(ctx, reg, val, len, WCRU, WCRCODE);
+}
+
+static int regmap_encx24j600_sfr_set_bits(struct encx24j600_context *ctx,
+					  u8 reg, u8 val)
+{
+	return regmap_encx24j600_sfr_update(ctx, reg, &val, 1, BFSU, BFSCODE);
+}
+
+static int regmap_encx24j600_sfr_clr_bits(struct encx24j600_context *ctx,
+					  u8 reg, u8 val)
+{
+	return regmap_encx24j600_sfr_update(ctx, reg, &val, 1, BFCU, BFCCODE);
+}
+
+static int regmap_encx24j600_reg_update_bits(void *context, unsigned int reg,
+					     unsigned int mask,
+					     unsigned int val)
+{
+	struct encx24j600_context *ctx = context;
+
+	int ret = 0;
+	unsigned int set_mask = mask & val;
+	unsigned int clr_mask = mask & ~val;
+
+	if ((reg >= 0x40 && reg < 0x6c) || reg >= 0x80)
+		return -EINVAL;
+
+	if (set_mask & 0xff)
+		ret = regmap_encx24j600_sfr_set_bits(ctx, reg, set_mask);
+
+	set_mask = (set_mask & 0xff00) >> 8;
+
+	if ((set_mask & 0xff) && (ret == 0))
+		ret = regmap_encx24j600_sfr_set_bits(ctx, reg + 1, set_mask);
+
+	if ((clr_mask & 0xff) && (ret == 0))
+		ret = regmap_encx24j600_sfr_clr_bits(ctx, reg, clr_mask);
+
+	clr_mask = (clr_mask & 0xff00) >> 8;
+
+	if ((clr_mask & 0xff) && (ret == 0))
+		ret = regmap_encx24j600_sfr_clr_bits(ctx, reg + 1, clr_mask);
+
+	return ret;
+}
+
+int regmap_encx24j600_spi_write(void *context, u8 reg, const u8 *data,
+				size_t count)
+{
+	struct encx24j600_context *ctx = context;
+
+	if (reg < 0xc0)
+		return encx24j600_cmdn(ctx, reg, data, count);
+	else
+		/* SPI 1-byte command. Ignore data */
+		return spi_write(ctx->spi, &reg, 1);
+}
+EXPORT_SYMBOL_GPL(regmap_encx24j600_spi_write);
+
+int regmap_encx24j600_spi_read(void *context, u8 reg, u8 *data, size_t count)
+{
+	struct encx24j600_context *ctx = context;
+
+	if (reg == RBSEL && count > 1)
+		count = 1;
+
+	return spi_write_then_read(ctx->spi, &reg, sizeof(reg), data, count);
+}
+EXPORT_SYMBOL_GPL(regmap_encx24j600_spi_read);
+
+static int regmap_encx24j600_write(void *context, const void *data,
+				   size_t len)
+{
+	u8 *dout = (u8 *)data;
+	u8 reg = dout[0];
+	++dout;
+	--len;
+
+	if (reg > 0xa0)
+		return regmap_encx24j600_spi_write(context, reg, dout, len);
+
+	if (len > 2)
+		return -EINVAL;
+
+	return regmap_encx24j600_sfr_write(context, reg, dout, len);
+}
+
+static int regmap_encx24j600_read(void *context,
+				  const void *reg_buf, size_t reg_size,
+				  void *val, size_t val_size)
+{
+	u8 reg = *(const u8 *)reg_buf;
+
+	if (reg_size != 1) {
+		pr_err("%s: reg=%02x reg_size=%zu\n", __func__, reg, reg_size);
+		return -EINVAL;
+	}
+
+	if (reg > 0xa0)
+		return regmap_encx24j600_spi_read(context, reg, val, val_size);
+
+	if (val_size > 2) {
+		pr_err("%s: reg=%02x val_size=%zu\n", __func__, reg, val_size);
+		return -EINVAL;
+	}
+
+	return regmap_encx24j600_sfr_read(context, reg, val, val_size);
+}
+
+static bool encx24j600_regmap_readable(struct device *dev, unsigned int reg)
+{
+	if ((reg < 0x36) ||
+	    ((reg >= 0x40) && (reg < 0x4c)) ||
+	    ((reg >= 0x52) && (reg < 0x56)) ||
+	    ((reg >= 0x60) && (reg < 0x66)) ||
+	    ((reg >= 0x68) && (reg < 0x80)) ||
+	    ((reg >= 0x86) && (reg < 0x92)) ||
+	    (reg == 0xc8))
+		return true;
+	else
+		return false;
+}
+
+static bool encx24j600_regmap_writeable(struct device *dev, unsigned int reg)
+{
+	if ((reg < 0x12) ||
+	    ((reg >= 0x14) && (reg < 0x1a)) ||
+	    ((reg >= 0x1c) && (reg < 0x36)) ||
+	    ((reg >= 0x40) && (reg < 0x4c)) ||
+	    ((reg >= 0x52) && (reg < 0x56)) ||
+	    ((reg >= 0x60) && (reg < 0x68)) ||
+	    ((reg >= 0x6c) && (reg < 0x80)) ||
+	    ((reg >= 0x86) && (reg < 0x92)) ||
+	    ((reg >= 0xc0) && (reg < 0xc8)) ||
+	    ((reg >= 0xca) && (reg < 0xf0)))
+		return true;
+	else
+		return false;
+}
+
+static bool encx24j600_regmap_volatile(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case ERXHEAD:
+	case EDMACS:
+	case ETXSTAT:
+	case ETXWIRE:
+	case ECON1:	/* Can be modified via single byte cmds */
+	case ECON2:	/* Can be modified via single byte cmds */
+	case ESTAT:
+	case EIR:	/* Can be modified via single byte cmds */
+	case MIRD:
+	case MISTAT:
+		return true;
+	default:
+		break;
+	}
+
+	return false;
+}
+
+static bool encx24j600_regmap_precious(struct device *dev, unsigned int reg)
+{
+	/* single byte cmds are precious */
+	if (((reg >= 0xc0) && (reg < 0xc8)) ||
+	    ((reg >= 0xca) && (reg < 0xf0)))
+		return true;
+	else
+		return false;
+}
+
+static int regmap_encx24j600_phy_reg_read(void *context, unsigned int reg,
+					  unsigned int *val)
+{
+	struct encx24j600_context *ctx = context;
+	int ret;
+	unsigned int mistat;
+
+	reg = MIREGADR_VAL | (reg & PHREG_MASK);
+	ret = regmap_write(ctx->regmap, MIREGADR, reg);
+	if (unlikely(ret))
+		goto err_out;
+
+	ret = regmap_write(ctx->regmap, MICMD, MIIRD);
+	if (unlikely(ret))
+		goto err_out;
+
+	usleep_range(26, 100);
+	while ((ret = regmap_read(ctx->regmap, MISTAT, &mistat) != 0) &&
+	       (mistat & BUSY))
+		cpu_relax();
+
+	if (unlikely(ret))
+		goto err_out;
+
+	ret = regmap_write(ctx->regmap, MICMD, 0);
+	if (unlikely(ret))
+		goto err_out;
+
+	ret = regmap_read(ctx->regmap, MIRD, val);
+
+err_out:
+	if (ret)
+		pr_err("%s: error %d reading reg %02x\n", __func__, ret,
+		       reg & PHREG_MASK);
+
+	return ret;
+}
+
+static int regmap_encx24j600_phy_reg_write(void *context, unsigned int reg,
+					   unsigned int val)
+{
+	struct encx24j600_context *ctx = context;
+	int ret;
+	unsigned int mistat;
+
+	reg = MIREGADR_VAL | (reg & PHREG_MASK);
+	ret = regmap_write(ctx->regmap, MIREGADR, reg);
+	if (unlikely(ret))
+		goto err_out;
+
+	ret = regmap_write(ctx->regmap, MIWR, val);
+	if (unlikely(ret))
+		goto err_out;
+
+	usleep_range(26, 100);
+	while ((ret = regmap_read(ctx->regmap, MISTAT, &mistat) != 0) &&
+	       (mistat & BUSY))
+		cpu_relax();
+
+err_out:
+	if (ret)
+		pr_err("%s: error %d writing reg %02x=%04x\n", __func__, ret,
+		       reg & PHREG_MASK, val);
+
+	return ret;
+}
+
+static bool encx24j600_phymap_readable(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case PHCON1:
+	case PHSTAT1:
+	case PHANA:
+	case PHANLPA:
+	case PHANE:
+	case PHCON2:
+	case PHSTAT2:
+	case PHSTAT3:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool encx24j600_phymap_writeable(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case PHCON1:
+	case PHCON2:
+	case PHANA:
+		return true;
+	case PHSTAT1:
+	case PHSTAT2:
+	case PHSTAT3:
+	case PHANLPA:
+	case PHANE:
+	default:
+		return false;
+	}
+}
+
+static bool encx24j600_phymap_volatile(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case PHSTAT1:
+	case PHSTAT2:
+	case PHSTAT3:
+	case PHANLPA:
+	case PHANE:
+	case PHCON2:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static struct regmap_config regcfg = {
+	.name = "reg",
+	.reg_bits = 8,
+	.val_bits = 16,
+	.max_register = 0xee,
+	.reg_stride = 2,
+	.cache_type = REGCACHE_RBTREE,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+	.readable_reg = encx24j600_regmap_readable,
+	.writeable_reg = encx24j600_regmap_writeable,
+	.volatile_reg = encx24j600_regmap_volatile,
+	.precious_reg = encx24j600_regmap_precious,
+	.lock = regmap_lock_mutex,
+	.unlock = regmap_unlock_mutex,
+};
+
+static struct regmap_bus regmap_encx24j600 = {
+	.write = regmap_encx24j600_write,
+	.read = regmap_encx24j600_read,
+	.reg_update_bits = regmap_encx24j600_reg_update_bits,
+};
+
+static struct regmap_config phycfg = {
+	.name = "phy",
+	.reg_bits = 8,
+	.val_bits = 16,
+	.max_register = 0x1f,
+	.cache_type = REGCACHE_RBTREE,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+	.readable_reg = encx24j600_phymap_readable,
+	.writeable_reg = encx24j600_phymap_writeable,
+	.volatile_reg = encx24j600_phymap_volatile,
+};
+static struct regmap_bus phymap_encx24j600 = {
+	.reg_write = regmap_encx24j600_phy_reg_write,
+	.reg_read = regmap_encx24j600_phy_reg_read,
+};
+
+void devm_regmap_init_encx24j600(struct device *dev,
+				 struct encx24j600_context *ctx)
+{
+	mutex_init(&ctx->mutex);
+	regcfg.lock_arg = ctx;
+	ctx->regmap = devm_regmap_init(dev, &regmap_encx24j600, ctx, &regcfg);
+	ctx->phymap = devm_regmap_init(dev, &phymap_encx24j600, ctx, &phycfg);
+}
+EXPORT_SYMBOL_GPL(devm_regmap_init_encx24j600);
+
+MODULE_LICENSE("GPL");