[PATCH v7 2/7] i2c: mediatek: Reset the handshake signal between i2c and dma
From: Kewei Xu <hidden>
Date: 2021-09-17 10:14:31
Also in:
linux-arm-kernel, linux-i2c, linux-mediatek, lkml
Subsystem:
i2c subsystem, i2c subsystem host drivers, mediatek i2c controller driver, the rest · Maintainers:
Wolfram Sang, Andi Shyti, Qii Wang, Linus Torvalds
Due to changes in the hardware design of the handshaking signal between i2c and dma, it is necessary to reset the handshaking signal before each transfer to ensure that the multi-msgs can be transferred correctly. Signed-off-by: Kewei Xu <redacted> Reviewed-by: Qii Wang <qii.wang@mediatek.com> --- drivers/i2c/busses/i2c-mt65xx.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)
diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index 32518081b5a4..08ce8a417bed 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c@@ -15,6 +15,7 @@ #include <linux/init.h> #include <linux/interrupt.h> #include <linux/io.h> +#include <linux/iopoll.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/module.h>
@@ -47,6 +48,9 @@ #define I2C_RD_TRANAC_VALUE 0x0001 #define I2C_SCL_MIS_COMP_VALUE 0x0000 #define I2C_CHN_CLR_FLAG 0x0000 +#define I2C_CLR_DEBUGCTR 0x0000 +#define I2C_RELIABILITY 0x0010 +#define I2C_DMAACK_ENABLE 0x0008 #define I2C_DMA_CON_TX 0x0000 #define I2C_DMA_CON_RX 0x0001
@@ -842,6 +846,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs, u16 restart_flag = 0; u16 dma_sync = 0; u32 reg_4g_mode; + u32 reg_dma_reset; u8 *dma_rd_buf = NULL; u8 *dma_wr_buf = NULL; dma_addr_t rpaddr = 0;
@@ -855,6 +860,27 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs, reinit_completion(&i2c->msg_complete); + if (i2c->dev_comp->apdma_sync && i2c->op != I2C_MASTER_WRRD && num > 1) { + mtk_i2c_writew(i2c, I2C_CLR_DEBUGCTR, OFFSET_DEBUGCTRL); + writel(I2C_DMA_HANDSHAKE_RST | I2C_DMA_WARM_RST, + i2c->pdmabase + OFFSET_RST); + + ret = readw_poll_timeout(i2c->pdmabase + OFFSET_RST, + reg_dma_reset, + !(reg_dma_reset & I2C_DMA_WARM_RST), + 0, 100); + if (ret) { + dev_err(i2c->dev, "DMA warm reset timeout\n"); + return -ETIMEDOUT; + } + + writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST); + mtk_i2c_writew(i2c, I2C_HANDSHAKE_RST, OFFSET_SOFTRESET); + mtk_i2c_writew(i2c, I2C_CHN_CLR_FLAG, OFFSET_SOFTRESET); + mtk_i2c_writew(i2c, I2C_RELIABILITY | I2C_DMAACK_ENABLE, + OFFSET_DEBUGCTRL); + } + control_reg = mtk_i2c_readw(i2c, OFFSET_CONTROL) & ~(I2C_CONTROL_DIR_CHANGE | I2C_CONTROL_RS); if ((i2c->speed_hz > I2C_MAX_FAST_MODE_PLUS_FREQ) || (left_num >= 1))
--
2.25.1