I2C: mediatek: Add driver for MediaTek MT8173 I2C controller

Add mediatek MT8173 I2C controller driver. Compare to I2C controller
of earlier mediatek SoC, MT8173 fix write-then-read limitation, and
also increase message size to 64kb.

Signed-off-by: Xudong Chen <xudong.chen@mediatek.com>
Signed-off-by: Liguo Zhang <liguo.zhang@mediatek.com>
Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index b1d2d7c..9920eef 100644 (file)
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -33,10 +33,13 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 
+#define I2C_RS_TRANSFER                        (1 << 4)
 #define I2C_HS_NACKERR                 (1 << 2)
 #define I2C_ACKERR                     (1 << 1)
 #define I2C_TRANSAC_COMP               (1 << 0)
 #define I2C_TRANSAC_START              (1 << 0)
+#define I2C_RS_MUL_CNFG                        (1 << 15)
+#define I2C_RS_MUL_TRIG                        (1 << 14)
 #define I2C_DCM_DISABLE                        0x0000
 #define I2C_IO_CONFIG_OPEN_DRAIN       0x0003
 #define I2C_IO_CONFIG_PUSH_PULL                0x0000
@@ -126,6 +129,7 @@ struct mtk_i2c_compatible {
        const struct i2c_adapter_quirks *quirks;
        unsigned char pmic_i2c: 1;
        unsigned char dcm: 1;
+       unsigned char auto_restart: 1;
 };
 
 struct mtk_i2c {
@@ -159,21 +163,39 @@ static const struct i2c_adapter_quirks mt6577_i2c_quirks = {
        .max_comb_2nd_msg_len = 31,
 };
 
+static const struct i2c_adapter_quirks mt8173_i2c_quirks = {
+       .max_num_msgs = 65535,
+       .max_write_len = 65535,
+       .max_read_len = 65535,
+       .max_comb_1st_msg_len = 65535,
+       .max_comb_2nd_msg_len = 65535,
+};
+
 static const struct mtk_i2c_compatible mt6577_compat = {
        .quirks = &mt6577_i2c_quirks,
        .pmic_i2c = 0,
        .dcm = 1,
+       .auto_restart = 0,
 };
 
 static const struct mtk_i2c_compatible mt6589_compat = {
        .quirks = &mt6577_i2c_quirks,
        .pmic_i2c = 1,
        .dcm = 0,
+       .auto_restart = 0,
+};
+
+static const struct mtk_i2c_compatible mt8173_compat = {
+       .quirks = &mt8173_i2c_quirks,
+       .pmic_i2c = 0,
+       .dcm = 1,
+       .auto_restart = 1,
 };
 
 static const struct of_device_id mtk_i2c_of_match[] = {
        { .compatible = "mediatek,mt6577-i2c", .data = &mt6577_compat },
        { .compatible = "mediatek,mt6589-i2c", .data = &mt6589_compat },
+       { .compatible = "mediatek,mt8173-i2c", .data = &mt8173_compat },
        {}
 };
 MODULE_DEVICE_TABLE(of, mtk_i2c_of_match);
@@ -332,21 +354,27 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk,
        return 0;
 }
 
-static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs)
+static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
+                              int num, int left_num)
 {
        u16 addr_reg;
+       u16 start_reg;
        u16 control_reg;
+       u16 restart_flag = 0;
        dma_addr_t rpaddr = 0;
        dma_addr_t wpaddr = 0;
        int ret;
 
        i2c->irq_stat = 0;
 
+       if (i2c->dev_comp->auto_restart)
+               restart_flag = I2C_RS_TRANSFER;
+
        reinit_completion(&i2c->msg_complete);
 
        control_reg = readw(i2c->base + OFFSET_CONTROL) &
                        ~(I2C_CONTROL_DIR_CHANGE | I2C_CONTROL_RS);
-       if (i2c->speed_hz > 400000)
+       if ((i2c->speed_hz > 400000) || (left_num >= 1))
                control_reg |= I2C_CONTROL_RS;
 
        if (i2c->op == I2C_MASTER_WRRD)
@@ -367,13 +395,13 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs)
        writew(addr_reg, i2c->base + OFFSET_SLAVE_ADDR);
 
        /* Clear interrupt status */
-       writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP,
-              i2c->base + OFFSET_INTR_STAT);
+       writew(restart_flag | I2C_HS_NACKERR | I2C_ACKERR |
+              I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_STAT);
        writew(I2C_FIFO_ADDR_CLR, i2c->base + OFFSET_FIFO_ADDR_CLR);
 
        /* Enable interrupt */
-       writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP,
-              i2c->base + OFFSET_INTR_MASK);
+       writew(restart_flag | I2C_HS_NACKERR | I2C_ACKERR |
+              I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_MASK);
 
        /* Set transfer and transaction len */
        if (i2c->op == I2C_MASTER_WRRD) {
@@ -382,7 +410,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs)
                writew(I2C_WRRD_TRANAC_VALUE, i2c->base + OFFSET_TRANSAC_LEN);
        } else {
                writew(msgs->len, i2c->base + OFFSET_TRANSFER_LEN);
-               writew(I2C_RD_TRANAC_VALUE, i2c->base + OFFSET_TRANSAC_LEN);
+               writew(num, i2c->base + OFFSET_TRANSAC_LEN);
        }
 
        /* Prepare buffer data to start transfer */
@@ -426,13 +454,21 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs)
        }
 
        writel(I2C_DMA_START_EN, i2c->pdmabase + OFFSET_EN);
-       writew(I2C_TRANSAC_START, i2c->base + OFFSET_START);
+
+       if (!i2c->dev_comp->auto_restart) {
+               start_reg = I2C_TRANSAC_START;
+       } else {
+               start_reg = I2C_TRANSAC_START | I2C_RS_MUL_TRIG;
+               if (left_num >= 1)
+                       start_reg |= I2C_RS_MUL_CNFG;
+       }
+       writew(start_reg, i2c->base + OFFSET_START);
 
        ret = wait_for_completion_timeout(&i2c->msg_complete,
                                          i2c->adap.timeout);
 
        /* Clear interrupt mask */
-       writew(~(I2C_HS_NACKERR | I2C_ACKERR |
+       writew(~(restart_flag | I2C_HS_NACKERR | I2C_ACKERR |
               I2C_TRANSAC_COMP), i2c->base + OFFSET_INTR_MASK);
 
        if (i2c->op == I2C_MASTER_WR) {
@@ -476,28 +512,33 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap,
        if (ret)
                return ret;
 
-       if (!msgs->buf) {
-               dev_dbg(i2c->dev, "data buffer is NULL.\n");
-               ret = -EINVAL;
-               goto err_exit;
-       }
-
-       if (msgs->flags & I2C_M_RD)
-               i2c->op = I2C_MASTER_RD;
-       else
-               i2c->op = I2C_MASTER_WR;
+       while (left_num--) {
+               if (!msgs->buf) {
+                       dev_dbg(i2c->dev, "data buffer is NULL.\n");
+                       ret = -EINVAL;
+                       goto err_exit;
+               }
 
-       if (num > 1) {
-               /* combined two messages into one transaction */
-               i2c->op = I2C_MASTER_WRRD;
-               left_num--;
-       }
+               if (msgs->flags & I2C_M_RD)
+                       i2c->op = I2C_MASTER_RD;
+               else
+                       i2c->op = I2C_MASTER_WR;
+
+               if (!i2c->dev_comp->auto_restart) {
+                       if (num > 1) {
+                               /* combined two messages into one transaction */
+                               i2c->op = I2C_MASTER_WRRD;
+                               left_num--;
+                       }
+               }
 
-       /* always use DMA mode. */
-       ret = mtk_i2c_do_transfer(i2c, msgs);
-       if (ret < 0)
-               goto err_exit;
+               /* always use DMA mode. */
+               ret = mtk_i2c_do_transfer(i2c, msgs, num, left_num);
+               if (ret < 0)
+                       goto err_exit;
 
+               msgs++;
+       }
        /* the return value is number of executed messages */
        ret = num;
 
@@ -509,9 +550,13 @@ err_exit:
 static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id)
 {
        struct mtk_i2c *i2c = dev_id;
+       u16 restart_flag = 0;
+
+       if (i2c->dev_comp->auto_restart)
+               restart_flag = I2C_RS_TRANSFER;
 
        i2c->irq_stat = readw(i2c->base + OFFSET_INTR_STAT);
-       writew(I2C_HS_NACKERR | I2C_ACKERR
+       writew(restart_flag | I2C_HS_NACKERR | I2C_ACKERR
                | I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_STAT);
 
        complete(&i2c->msg_complete);