platform/chrome: cros_ec_lpc: Add support for mec1322 EC

This adds support for the ChromeOS LPC Microchip Embedded Controller
(mec1322) variant.

mec1322 accesses I/O region [800h, 9ffh] through embedded memory
interface (EMI) rather than LPC.

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Benson Leung <bleung@chromium.org>

2 files changed, 104 insertions, 0 deletions

diff --git a/include/linux/mfd/cros_ec_lpc_mec.h b/include/linux/mfd/cros_ec_lpc_mec.h
new file mode 100644
index 000000000000..176496ddc66c
--- /dev/null
+++ b/include/linux/mfd/cros_ec_lpc_mec.h
@@ -0,0 +1,90 @@
+/*
+ * cros_ec_lpc_mec - LPC variant I/O for Microchip EC
+ *
+ * Copyright (C) 2016 Google, Inc
+ *
+ * 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.
+ *
+ * This driver uses the Chrome OS EC byte-level message-based protocol for
+ * communicating the keyboard state (which keys are pressed) from a keyboard EC
+ * to the AP over some bus (such as i2c, lpc, spi).  The EC does debouncing,
+ * but everything else (including deghosting) is done here.  The main
+ * motivation for this is to keep the EC firmware as simple as possible, since
+ * it cannot be easily upgraded and EC flash/IRAM space is relatively
+ * expensive.
+ */
+
+#ifndef __LINUX_MFD_CROS_EC_MEC_H
+#define __LINUX_MFD_CROS_EC_MEC_H
+
+#include <linux/mfd/cros_ec_commands.h>
+
+enum cros_ec_lpc_mec_emi_access_mode {
+	/* 8-bit access */
+	ACCESS_TYPE_BYTE = 0x0,
+	/* 16-bit access */
+	ACCESS_TYPE_WORD = 0x1,
+	/* 32-bit access */
+	ACCESS_TYPE_LONG = 0x2,
+	/*
+	 * 32-bit access, read or write of MEC_EMI_EC_DATA_B3 causes the
+	 * EC data register to be incremented.
+	 */
+	ACCESS_TYPE_LONG_AUTO_INCREMENT = 0x3,
+};
+
+enum cros_ec_lpc_mec_io_type {
+	MEC_IO_READ,
+	MEC_IO_WRITE,
+};
+
+/* Access IO ranges 0x800 thru 0x9ff using EMI interface instead of LPC */
+#define MEC_EMI_RANGE_START EC_HOST_CMD_REGION0
+#define MEC_EMI_RANGE_END   (EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SIZE)
+
+/* EMI registers are relative to base */
+#define MEC_EMI_BASE 0x800
+#define MEC_EMI_HOST_TO_EC (MEC_EMI_BASE + 0)
+#define MEC_EMI_EC_TO_HOST (MEC_EMI_BASE + 1)
+#define MEC_EMI_EC_ADDRESS_B0 (MEC_EMI_BASE + 2)
+#define MEC_EMI_EC_ADDRESS_B1 (MEC_EMI_BASE + 3)
+#define MEC_EMI_EC_DATA_B0 (MEC_EMI_BASE + 4)
+#define MEC_EMI_EC_DATA_B1 (MEC_EMI_BASE + 5)
+#define MEC_EMI_EC_DATA_B2 (MEC_EMI_BASE + 6)
+#define MEC_EMI_EC_DATA_B3 (MEC_EMI_BASE + 7)
+
+/*
+ * cros_ec_lpc_mec_init
+ *
+ * Initialize MEC I/O.
+ */
+void cros_ec_lpc_mec_init(void);
+
+/*
+ * cros_ec_lpc_mec_destroy
+ *
+ * Cleanup MEC I/O.
+ */
+void cros_ec_lpc_mec_destroy(void);
+
+/**
+ * cros_ec_lpc_io_bytes_mec - Read / write bytes to MEC EMI port
+ *
+ * @io_type: MEC_IO_READ or MEC_IO_WRITE, depending on request
+ * @offset:  Base read / write address
+ * @length:  Number of bytes to read / write
+ * @buf:     Destination / source buffer
+ *
+ * @return 8-bit checksum of all bytes read / written
+ */
+u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
+			    unsigned int offset, unsigned int length, u8 *buf);
+
+#endif /* __LINUX_MFD_CROS_EC_MEC_H */
diff --git a/include/linux/mfd/cros_ec_lpc_reg.h b/include/linux/mfd/cros_ec_lpc_reg.h
index 4089bd5c8313..5560bef63c2b 100644
--- a/include/linux/mfd/cros_ec_lpc_reg.h
+++ b/include/linux/mfd/cros_ec_lpc_reg.h
@@ -44,4 +44,18 @@ u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest);
  */
 u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg);
 
+/**
+ * cros_ec_lpc_reg_init
+ *
+ * Initialize register I/O.
+ */
+void cros_ec_lpc_reg_init(void);
+
+/**
+ * cros_ec_lpc_reg_destroy
+ *
+ * Cleanup reg I/O.
+ */
+void cros_ec_lpc_reg_destroy(void);
+
 #endif /* __LINUX_MFD_CROS_EC_REG_H */