Re: [PATCH v1 1/3] i2c: rk3x: add calc_divs ops for new version

From: Jianqun Xu
Date: Mon Dec 14 2015 - 19:33:00 EST

Hi David:

It's better to add a cover-letter, and add changes note for new version,
such as:

changes since v0:
- split patch to two patches or more, one patch for one new feature (Heiko)

and NOT to have two same signed-off-by

在 11/12/2015 22:33, David Wu 写道:
The calc_divs of new version is different form the old.
The time of tHD;sda, tHD;sda, tSU;sta, tHD;sta and tSU;sto
could be configured by RKI2C_CON register.
So it need a new way to calc_divs for new i2c controller.

Signed-off-by: David Wu <wdc@xxxxxxxxxxxxxx>
Signed-off-by: David Wu <david.wu@xxxxxxxxxxxxxx>
---

drivers/i2c/busses/i2c-rk3x.c | 54 ++++++++++++++++++++++++++++++++++---------
1 file changed, 43 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index c1935eb..0ff299f 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -58,6 +58,12 @@ enum {
#define REG_CON_LASTACK BIT(5) /* 1: send NACK after last received byte */
#define REG_CON_ACTACK BIT(6) /* 1: stop if NACK is received */

+#define VERSION_MASK 0xffff0000
+#define VERSION_SHIFT 16
+
+#define RK3X_I2C_V0 0x0
+#define RK3X_I2C_V1 0x1
+
/* REG_MRXADDR bits */
#define REG_MRXADDR_VALID(x) BIT(24 + (x)) /* [x*8+7:x*8] of MRX[R]ADDR valid */

@@ -90,10 +96,22 @@ struct rk3x_i2c_soc_data {
int grf_offset;
};

+struct rk3x_i2c_ops {
+ int (*calc_divs)(unsigned long,
+ unsigned long,
+ unsigned long,
+ unsigned long,
+ unsigned long,
+ unsigned long *,
+ unsigned long *,
+ unsigned int *);
+};
+
struct rk3x_i2c {
struct i2c_adapter adap;
struct device *dev;
struct rk3x_i2c_soc_data *soc_data;
+ struct rk3x_i2c_ops ops;

/* Hardware resources */
void __iomem *regs;
@@ -116,6 +134,7 @@ struct rk3x_i2c {
u8 addr;
unsigned int mode;
bool is_last_msg;
+ unsigned int time_con;

/* I2C state machine */
enum rk3x_i2c_state state;
@@ -151,7 +170,8 @@ static void rk3x_i2c_start(struct rk3x_i2c *i2c)
i2c_writel(i2c, REG_INT_START, REG_IEN);

/* enable adapter with correct mode, send START condition */
- val = REG_CON_EN | REG_CON_MOD(i2c->mode) | REG_CON_START;
+ val = i2c->time_con | REG_CON_EN | REG_CON_MOD(i2c->mode)
+ | REG_CON_START;

/* if we want to react to NACK, set ACTACK bit */
if (!(i2c->msg->flags & I2C_M_IGNORE_NAK))
@@ -443,16 +463,19 @@ out:
* @sda_fall_ns: How many ns it takes for SDA to fall.
* @div_low: Divider output for low
* @div_high: Divider output for high
+ * @con: version0 is not used
*
* Returns: 0 on success, -EINVAL if the goal SCL rate is too slow. In that case
* a best-effort divider value is returned in divs. If the target rate is
* too high, we silently use the highest possible rate.
*/
-static int rk3x_i2c_calc_divs(unsigned long clk_rate, unsigned long scl_rate,
- unsigned long scl_rise_ns,
- unsigned long scl_fall_ns,
- unsigned long sda_fall_ns,
- unsigned long *div_low, unsigned long *div_high)
+static int rk3x_i2c_v0_calc_divs(unsigned long clk_rate, unsigned long scl_rate,
+ unsigned long scl_rise_ns,
+ unsigned long scl_fall_ns,
+ unsigned long sda_fall_ns,
+ unsigned long *div_low,
+ unsigned long *div_high,
+ unsigned int *con)
{
unsigned long spec_min_low_ns, spec_min_high_ns;
unsigned long spec_setup_start, spec_max_data_hold_ns;
@@ -616,17 +639,19 @@ static int rk3x_i2c_calc_divs(unsigned long clk_rate, unsigned long scl_rate,

static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate)
{
+ unsigned int con = 0;
unsigned long div_low, div_high;
u64 t_low_ns, t_high_ns;
int ret;

- ret = rk3x_i2c_calc_divs(clk_rate, i2c->scl_frequency, i2c->scl_rise_ns,
+ ret = i2c->ops.calc_divs(clk_rate, i2c->scl_frequency, i2c->scl_rise_ns,
i2c->scl_fall_ns, i2c->sda_fall_ns,
- &div_low, &div_high);
+ &div_low, &div_high, &con);
WARN_ONCE(ret != 0, "Could not reach SCL freq %u", i2c->scl_frequency);

clk_enable(i2c->clk);
i2c_writel(i2c, (div_high << 16) | (div_low & 0xffff), REG_CLKDIV);
+ i2c->time_con = con;
clk_disable(i2c->clk);

t_low_ns = div_u64(((u64)div_low + 1) * 8 * 1000000000, clk_rate);
@@ -661,13 +686,14 @@ static int rk3x_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long
struct clk_notifier_data *ndata = data;
struct rk3x_i2c *i2c = container_of(nb, struct rk3x_i2c, clk_rate_nb);
unsigned long div_low, div_high;
+ unsigned int con = 0;

switch (event) {
case PRE_RATE_CHANGE:
- if (rk3x_i2c_calc_divs(ndata->new_rate, i2c->scl_frequency,
+ if (i2c->ops.calc_divs(ndata->new_rate, i2c->scl_frequency,
i2c->scl_rise_ns, i2c->scl_fall_ns,
i2c->sda_fall_ns,
- &div_low, &div_high) != 0)
+ &div_low, &div_high, &con) != 0)
return NOTIFY_STOP;

/* scale up */
@@ -816,7 +842,8 @@ static int rk3x_i2c_xfer(struct i2c_adapter *adap,

/* Force a STOP condition without interrupt */
i2c_writel(i2c, 0, REG_IEN);
- i2c_writel(i2c, REG_CON_EN | REG_CON_STOP, REG_CON);
+ i2c_writel(i2c, i2c->time_con | REG_CON_EN |
+ REG_CON_STOP, REG_CON);

i2c->state = STATE_IDLE;

@@ -871,6 +898,7 @@ static int rk3x_i2c_probe(struct platform_device *pdev)
u32 value;
int irq;
unsigned long clk_rate;
+ unsigned int version;

i2c = devm_kzalloc(&pdev->dev, sizeof(struct rk3x_i2c), GFP_KERNEL);
if (!i2c)
@@ -983,6 +1011,10 @@ static int rk3x_i2c_probe(struct platform_device *pdev)

platform_set_drvdata(pdev, i2c);

+ version = (readl(i2c->regs + REG_CON) & VERSION_MASK) >> VERSION_SHIFT;
+ if (version == RK3X_I2C_V0)
+ i2c->ops.calc_divs = rk3x_i2c_v0_calc_divs;
+
ret = clk_prepare(i2c->clk);
if (ret < 0) {
dev_err(&pdev->dev, "Could not prepare clock\n");


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