[PATCH 4/6] i2c: fsl_i2c: fix m68k transferts

Angelo Dureghello
2023-04-04T23:00:27Z

This driver is actually used for powerpc and m68k/ColdFire.

On ColdFire SoC's, interrupt flag get not set if IIEN flag (mbcr bit6,
interrupt enabled) is not set appropriately before each transfert.
As a result, the transfert hangs forever waiting for IIEN.
This patch set IIEN before each transfert, while considering this fix
as not harming powerpc arch.

Signed-off-by: Angelo Dureghello <angelo@kernel-space.org>
---
arch/m68k/include/asm/fsl_i2c.h | 10 ++++++++++
drivers/i2c/fsl_i2c.c | 16 +++++++++-------
2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/arch/m68k/include/asm/fsl_i2c.h b/arch/m68k/include/asm/fsl_i2c.h
index 9c54fdea77..dc6b37a575 100644
--- a/arch/m68k/include/asm/fsl_i2c.h
+++ b/arch/m68k/include/asm/fsl_i2c.h
@@ -57,4 +57,14 @@ typedef struct fsl_i2c_base {
#define I2C_DR_RES ~(I2C_DR)
} fsl_i2c_t;

+#if CONFIG_IS_ENABLED(DM_I2C)
+struct fsl_i2c_dev {
+ struct fsl_i2c_base __iomem *base; /* register base */
+ u32 i2c_clk;
+ u32 index;
+ u8 slaveadd;
+ uint speed;
+};
+#endif
+
#endif /* _ASM_I2C_H_ */
diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c
index d312f35f04..d9d8ee81d2 100644
--- a/drivers/i2c/fsl_i2c.c
+++ b/drivers/i2c/fsl_i2c.c
@@ -278,7 +278,8 @@ static void __i2c_init(const struct fsl_i2c_base *base, int speed, int
set_i2c_bus_speed(base, i2c_clk, speed);
writeb(slaveadd << 1, &base->adr);/* write slave address */
writeb(0x0, &base->sr); /* clear status register */
- writeb(I2C_CR_MEN, &base->cr); /* start I2C controller */
+ /* start I2C controller */
+ writeb(I2C_CR_MEN | I2C_CR_MIEN, &base->cr);

timeval = get_ticks();
while (readb(&base->sr) & I2C_SR_MBB) {
@@ -346,7 +347,7 @@ static int i2c_wait(const struct fsl_i2c_base *base, int write)
static int i2c_write_addr(const struct fsl_i2c_base *base, u8 dev,
u8 dir, int rsta)
{
- writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX
+ writeb(I2C_CR_MEN | I2C_CR_MIEN | I2C_CR_MSTA | I2C_CR_MTX
| (rsta ? I2C_CR_RSTA : 0),
&base->cr);

@@ -378,7 +379,8 @@ static int __i2c_read_data(const struct fsl_i2c_base *base, u8 *data,
{
int i;

- writeb(I2C_CR_MEN | I2C_CR_MSTA | ((length == 1) ? I2C_CR_TXAK : 0),
+ writeb(I2C_CR_MEN | I2C_CR_MIEN |
+ I2C_CR_MSTA | ((length == 1) ? I2C_CR_TXAK : 0),
&base->cr);

/* dummy read */
@@ -390,13 +392,13 @@ static int __i2c_read_data(const struct fsl_i2c_base *base, u8 *data,

/* Generate ack on last next to last byte */
if (i == length - 2)
- writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_TXAK,
- &base->cr);
+ writeb(I2C_CR_MEN | I2C_CR_MIEN | I2C_CR_MSTA |
+ I2C_CR_TXAK, &base->cr);

/* Do not generate stop on last byte */
if (i == length - 1)
- writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX,
- &base->cr);
+ writeb(I2C_CR_MEN | I2C_CR_MIEN | I2C_CR_MSTA |
+ I2C_CR_MTX, &base->cr);

data[i] = readb(&base->dr);
}
--
2.40.0