Skip to content

Commit

Permalink
i2c: mediatek: Add arb clock in i2c driver
Browse files Browse the repository at this point in the history
When two i2c controllers are internally connected to the same
GPIO pins, the arb clock is needed to ensure that the waveforms
do not interfere with each other. And we also need to enable
the interrupt to find arb lost, old i2c controllers also have
the bit.

Signed-off-by: Qii Wang <qii.wang@mediatek.com>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
  • Loading branch information
Qii Wang authored and Wolfram Sang committed Apr 15, 2019
1 parent a343815 commit cad6dc5
Showing 1 changed file with 22 additions and 3 deletions.
25 changes: 22 additions & 3 deletions drivers/i2c/busses/i2c-mt65xx.c
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@
#include <linux/slab.h>

#define I2C_RS_TRANSFER (1 << 4)
#define I2C_ARB_LOST (1 << 3)
#define I2C_HS_NACKERR (1 << 2)
#define I2C_ACKERR (1 << 1)
#define I2C_TRANSAC_COMP (1 << 0)
Expand Down Expand Up @@ -181,6 +182,7 @@ struct mtk_i2c {
struct clk *clk_main; /* main clock for i2c bus */
struct clk *clk_dma; /* DMA clock for i2c via DMA */
struct clk *clk_pmic; /* PMIC clock for i2c from PMIC */
struct clk *clk_arb; /* Arbitrator clock for i2c */
bool have_pmic; /* can use i2c pins from PMIC */
bool use_push_pull; /* IO config push-pull mode */

Expand Down Expand Up @@ -299,8 +301,18 @@ static int mtk_i2c_clock_enable(struct mtk_i2c *i2c)
if (ret)
goto err_pmic;
}

if (i2c->clk_arb) {
ret = clk_prepare_enable(i2c->clk_arb);
if (ret)
goto err_arb;
}

return 0;

err_arb:
if (i2c->have_pmic)
clk_disable_unprepare(i2c->clk_pmic);
err_pmic:
clk_disable_unprepare(i2c->clk_main);
err_main:
Expand All @@ -311,6 +323,9 @@ static int mtk_i2c_clock_enable(struct mtk_i2c *i2c)

static void mtk_i2c_clock_disable(struct mtk_i2c *i2c)
{
if (i2c->clk_arb)
clk_disable_unprepare(i2c->clk_arb);

if (i2c->have_pmic)
clk_disable_unprepare(i2c->clk_pmic);

Expand Down Expand Up @@ -519,13 +534,13 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,

/* Clear interrupt status */
mtk_i2c_writew(i2c, restart_flag | I2C_HS_NACKERR | I2C_ACKERR |
I2C_TRANSAC_COMP, OFFSET_INTR_STAT);
I2C_ARB_LOST | I2C_TRANSAC_COMP, OFFSET_INTR_STAT);

mtk_i2c_writew(i2c, I2C_FIFO_ADDR_CLR, OFFSET_FIFO_ADDR_CLR);

/* Enable interrupt */
mtk_i2c_writew(i2c, restart_flag | I2C_HS_NACKERR | I2C_ACKERR |
I2C_TRANSAC_COMP, OFFSET_INTR_MASK);
I2C_ARB_LOST | I2C_TRANSAC_COMP, OFFSET_INTR_MASK);

/* Set transfer and transaction len */
if (i2c->op == I2C_MASTER_WRRD) {
Expand Down Expand Up @@ -659,7 +674,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,

/* Clear interrupt mask */
mtk_i2c_writew(i2c, ~(restart_flag | I2C_HS_NACKERR | I2C_ACKERR |
I2C_TRANSAC_COMP), OFFSET_INTR_MASK);
I2C_ARB_LOST | I2C_TRANSAC_COMP), OFFSET_INTR_MASK);

if (i2c->op == I2C_MASTER_WR) {
dma_unmap_single(i2c->dev, wpaddr,
Expand Down Expand Up @@ -884,6 +899,10 @@ static int mtk_i2c_probe(struct platform_device *pdev)
return PTR_ERR(i2c->clk_dma);
}

i2c->clk_arb = devm_clk_get(&pdev->dev, "arb");
if (IS_ERR(i2c->clk_arb))
i2c->clk_arb = NULL;

clk = i2c->clk_main;
if (i2c->have_pmic) {
i2c->clk_pmic = devm_clk_get(&pdev->dev, "pmic");
Expand Down

0 comments on commit cad6dc5

Please sign in to comment.