linux-kernel - [PATCH v6 2/5] i2c: npcm: Remove own slave addresses 2:10

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Message-Id: <20220525032341.3182-3-warp5tw@gmail.com>
Date:   Wed, 25 May 2022 11:23:38 +0800
From:   Tyrone Ting <warp5tw@...il.com>
To:     avifishman70@...il.com, tmaimon77@...il.com, tali.perry1@...il.com,
        venture@...gle.com, yuenn@...gle.com, benjaminfair@...gle.com,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        wsa@...nel.org, andriy.shevchenko@...ux.intel.com,
        jarkko.nikula@...ux.intel.com, semen.protsenko@...aro.org,
        jie.deng@...el.com, jsd@...ihalf.com, sven@...npeter.dev,
        lukas.bulwahn@...il.com, olof@...om.net, arnd@...db.de,
        warp5tw@...il.com, tali.perry@...oton.com, Avi.Fishman@...oton.com,
        tomer.maimon@...oton.com, KWLIU@...oton.com, JJLIU0@...oton.com,
        kfting@...oton.com
Cc:     openbmc@...ts.ozlabs.org, linux-i2c@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v6 2/5] i2c: npcm: Remove own slave addresses 2:10

From: Tali Perry <tali.perry1@...il.com>

NPCM can support up to 10 own slave addresses. In practice, only one
address is actually being used. In order to access addresses 2 and above,
need to switch register banks. The switch needs spinlock.
To avoid using spinlock for this useless feature removed support of SA >=
2. Also fix returned slave event enum.

Remove some comment since the bank selection is not required. The bank
selection is not required since the supported slave addresses are reduced.

Fixes: 56a1485b102e ("i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver")
Signed-off-by: Tali Perry <tali.perry1@...il.com>
Signed-off-by: Tyrone Ting <kfting@...oton.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 41 +++++++++++++-------------------
 1 file changed, 16 insertions(+), 25 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 5960ccde6574..b5cc83e51029 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -123,11 +123,11 @@ enum i2c_addr {
  * Since the addr regs are sprinkled all over the address space,
  * use this array to get the address or each register.
  */
-#define I2C_NUM_OWN_ADDR 10
+#define I2C_NUM_OWN_ADDR 2
+#define I2C_NUM_OWN_ADDR_SUPPORTED 2
+
 static const int npcm_i2caddr[I2C_NUM_OWN_ADDR] = {
-	NPCM_I2CADDR1, NPCM_I2CADDR2, NPCM_I2CADDR3, NPCM_I2CADDR4,
-	NPCM_I2CADDR5, NPCM_I2CADDR6, NPCM_I2CADDR7, NPCM_I2CADDR8,
-	NPCM_I2CADDR9, NPCM_I2CADDR10,
+	NPCM_I2CADDR1, NPCM_I2CADDR2,
 };
 #endif
 
@@ -392,14 +392,10 @@ static void npcm_i2c_disable(struct npcm_i2c *bus)
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 	int i;
 
-	/* select bank 0 for I2C addresses */
-	npcm_i2c_select_bank(bus, I2C_BANK_0);
-
 	/* Slave addresses removal */
-	for (i = I2C_SLAVE_ADDR1; i < I2C_NUM_OWN_ADDR; i++)
+	for (i = I2C_SLAVE_ADDR1; i < I2C_NUM_OWN_ADDR_SUPPORTED; i++)
 		iowrite8(0, bus->reg + npcm_i2caddr[i]);
 
-	npcm_i2c_select_bank(bus, I2C_BANK_1);
 #endif
 	/* Disable module */
 	i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2);
@@ -604,8 +600,7 @@ static int npcm_i2c_slave_enable(struct npcm_i2c *bus, enum i2c_addr addr_type,
 			i2cctl1 &= ~NPCM_I2CCTL1_GCMEN;
 		iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1);
 		return 0;
-	}
-	if (addr_type == I2C_ARP_ADDR) {
+	} else if (addr_type == I2C_ARP_ADDR) {
 		i2cctl3 = ioread8(bus->reg + NPCM_I2CCTL3);
 		if (enable)
 			i2cctl3 |= I2CCTL3_ARPMEN;
@@ -614,16 +609,16 @@ static int npcm_i2c_slave_enable(struct npcm_i2c *bus, enum i2c_addr addr_type,
 		iowrite8(i2cctl3, bus->reg + NPCM_I2CCTL3);
 		return 0;
 	}
+	if (addr_type > I2C_SLAVE_ADDR2 && addr_type <= I2C_SLAVE_ADDR10)
+		dev_err(bus->dev, "try to enable more than 2 SA not supported\n");
+
 	if (addr_type >= I2C_ARP_ADDR)
 		return -EFAULT;
-	/* select bank 0 for address 3 to 10 */
-	if (addr_type > I2C_SLAVE_ADDR2)
-		npcm_i2c_select_bank(bus, I2C_BANK_0);
+
 	/* Set and enable the address */
 	iowrite8(sa_reg, bus->reg + npcm_i2caddr[addr_type]);
 	npcm_i2c_slave_int_enable(bus, enable);
-	if (addr_type > I2C_SLAVE_ADDR2)
-		npcm_i2c_select_bank(bus, I2C_BANK_1);
+
 	return 0;
 }
 #endif
@@ -846,15 +841,11 @@ static u8 npcm_i2c_get_slave_addr(struct npcm_i2c *bus, enum i2c_addr addr_type)
 {
 	u8 slave_add;
 
-	/* select bank 0 for address 3 to 10 */
-	if (addr_type > I2C_SLAVE_ADDR2)
-		npcm_i2c_select_bank(bus, I2C_BANK_0);
+	if (addr_type > I2C_SLAVE_ADDR2 && addr_type <= I2C_SLAVE_ADDR10)
+		dev_err(bus->dev, "get slave: try to use more than 2 SA not supported\n");
 
 	slave_add = ioread8(bus->reg + npcm_i2caddr[(int)addr_type]);
 
-	if (addr_type > I2C_SLAVE_ADDR2)
-		npcm_i2c_select_bank(bus, I2C_BANK_1);
-
 	return slave_add;
 }
 
@@ -864,12 +855,12 @@ static int npcm_i2c_remove_slave_addr(struct npcm_i2c *bus, u8 slave_add)
 
 	/* Set the enable bit */
 	slave_add |= 0x80;
-	npcm_i2c_select_bank(bus, I2C_BANK_0);
-	for (i = I2C_SLAVE_ADDR1; i < I2C_NUM_OWN_ADDR; i++) {
+
+	for (i = I2C_SLAVE_ADDR1; i < I2C_NUM_OWN_ADDR_SUPPORTED; i++) {
 		if (ioread8(bus->reg + npcm_i2caddr[i]) == slave_add)
 			iowrite8(0, bus->reg + npcm_i2caddr[i]);
 	}
-	npcm_i2c_select_bank(bus, I2C_BANK_1);
+
 	return 0;
 }
 
-- 
2.17.1