Commit 1ab92956 authored by David Wu's avatar David Wu Committed by Wolfram Sang
Browse files

i2c: rk3x: switch to i2c generic dt parsing 



Switch to the new generic functions: i2c_parse_fw_timings().

Signed-off-by: default avatarDavid Wu <david.wu@rock-chips.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent b69e5c67

drivers/i2c/busses/i2c-rk3x.c

+24 −63
Original line number Diff line number Diff line
@@ -101,10 +101,7 @@ struct rk3x_i2c { 
	struct notifier_block clk_rate_nb;



	/* Settings */

	unsigned int scl_frequency;

	unsigned int scl_rise_ns;

	unsigned int scl_fall_ns;

	unsigned int sda_fall_ns;

	struct i2c_timings t;



	/* Synchronization & notification */

	spinlock_t lock;
@@ -437,10 +434,7 @@ out: 
 * Calculate divider values for desired SCL frequency

 *

 * @clk_rate: I2C input clock rate

 * @scl_rate: Desired SCL rate

 * @scl_rise_ns: How many ns it takes for SCL to rise.

 * @scl_fall_ns: How many ns it takes for SCL to fall.

 * @sda_fall_ns: How many ns it takes for SDA to fall.

 * @t: Known I2C timing information.

 * @div_low: Divider output for low

 * @div_high: Divider output for high

 *
@@ -448,11 +442,10 @@ out: 
 * 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_calc_divs(unsigned long clk_rate,

			      struct i2c_timings *t,

			      unsigned long *div_low,

			      unsigned long *div_high)

{

	unsigned long spec_min_low_ns, spec_min_high_ns;

	unsigned long spec_setup_start, spec_max_data_hold_ns;
@@ -472,12 +465,12 @@ static int rk3x_i2c_calc_divs(unsigned long clk_rate, unsigned long scl_rate, 
	int ret = 0;



	/* Only support standard-mode and fast-mode */

	if (WARN_ON(scl_rate > 400000))

		scl_rate = 400000;

	if (WARN_ON(t->bus_freq_hz > 400000))

		t->bus_freq_hz = 400000;



	/* prevent scl_rate_khz from becoming 0 */

	if (WARN_ON(scl_rate < 1000))

		scl_rate = 1000;

	if (WARN_ON(t->bus_freq_hz < 1000))

		t->bus_freq_hz = 1000;



	/*

	 * min_low_ns:  The minimum number of ns we need to hold low to
@@ -491,7 +484,7 @@ static int rk3x_i2c_calc_divs(unsigned long clk_rate, unsigned long scl_rate, 
	 *	 This is because the i2c host on Rockchip holds the data line

	 *	 for half the low time.

	 */

	if (scl_rate <= 100000) {

	if (t->bus_freq_hz <= 100000) {

		/* Standard-mode */

		spec_min_low_ns = 4700;

		spec_setup_start = 4700;
@@ -506,7 +499,7 @@ static int rk3x_i2c_calc_divs(unsigned long clk_rate, unsigned long scl_rate, 
		spec_max_data_hold_ns = 900;

		data_hold_buffer_ns = 50;

	}

	min_high_ns = scl_rise_ns + spec_min_high_ns;

	min_high_ns = t->scl_rise_ns + spec_min_high_ns;



	/*

	 * Timings for repeated start:
@@ -517,18 +510,18 @@ static int rk3x_i2c_calc_divs(unsigned long clk_rate, unsigned long scl_rate, 
	 * we meet tSU;STA and tHD;STA times.

	 */

	min_high_ns = max(min_high_ns,

		DIV_ROUND_UP((scl_rise_ns + spec_setup_start) * 1000, 875));

		DIV_ROUND_UP((t->scl_rise_ns + spec_setup_start) * 1000, 875));

	min_high_ns = max(min_high_ns,

		DIV_ROUND_UP((scl_rise_ns + spec_setup_start +

			      sda_fall_ns + spec_min_high_ns), 2));

		DIV_ROUND_UP((t->scl_rise_ns + spec_setup_start +

			      t->sda_fall_ns + spec_min_high_ns), 2));



	min_low_ns = scl_fall_ns + spec_min_low_ns;

	min_low_ns = t->scl_fall_ns + spec_min_low_ns;

	max_low_ns = spec_max_data_hold_ns * 2 - data_hold_buffer_ns;

	min_total_ns = min_low_ns + min_high_ns;



	/* Adjust to avoid overflow */

	clk_rate_khz = DIV_ROUND_UP(clk_rate, 1000);

	scl_rate_khz = scl_rate / 1000;

	scl_rate_khz = t->bus_freq_hz / 1000;



	/*

	 * We need the total div to be >= this number
@@ -616,14 +609,13 @@ 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)

{

	struct i2c_timings *t = &i2c->t;

	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,

				 i2c->scl_fall_ns, i2c->sda_fall_ns,

				 &div_low, &div_high);

	WARN_ONCE(ret != 0, "Could not reach SCL freq %u", i2c->scl_frequency);

	ret = rk3x_i2c_calc_divs(clk_rate, t, &div_low, &div_high);

	WARN_ONCE(ret != 0, "Could not reach SCL freq %u", t->bus_freq_hz);



	clk_enable(i2c->clk);

	i2c_writel(i2c, (div_high << 16) | (div_low & 0xffff), REG_CLKDIV);
@@ -634,7 +626,7 @@ static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate) 
	dev_dbg(i2c->dev,

		"CLK %lukhz, Req %uns, Act low %lluns high %lluns\n",

		clk_rate / 1000,

		1000000000 / i2c->scl_frequency,

		1000000000 / t->bus_freq_hz,

		t_low_ns, t_high_ns);

}
@@ -664,9 +656,7 @@ static int rk3x_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long 


	switch (event) {

	case PRE_RATE_CHANGE:

		if (rk3x_i2c_calc_divs(ndata->new_rate, i2c->scl_frequency,

				       i2c->scl_rise_ns, i2c->scl_fall_ns,

				       i2c->sda_fall_ns,

		if (rk3x_i2c_calc_divs(ndata->new_rate, &i2c->t,

				       &div_low, &div_high) != 0)

			return NOTIFY_STOP;
@@ -879,37 +869,8 @@ static int rk3x_i2c_probe(struct platform_device *pdev) 
	match = of_match_node(rk3x_i2c_match, np);

	i2c->soc_data = (struct rk3x_i2c_soc_data *)match->data;



	if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",

				 &i2c->scl_frequency)) {

		dev_info(&pdev->dev, "using default SCL frequency: %d\n",

			 DEFAULT_SCL_RATE);

		i2c->scl_frequency = DEFAULT_SCL_RATE;

	}



	if (i2c->scl_frequency == 0 || i2c->scl_frequency > 400 * 1000) {

		dev_warn(&pdev->dev, "invalid SCL frequency specified.\n");

		dev_warn(&pdev->dev, "using default SCL frequency: %d\n",

			 DEFAULT_SCL_RATE);

		i2c->scl_frequency = DEFAULT_SCL_RATE;

	}



	/*

	 * Read rise and fall time from device tree. If not available use

	 * the default maximum timing from the specification.

	 */

	if (of_property_read_u32(pdev->dev.of_node, "i2c-scl-rising-time-ns",

				 &i2c->scl_rise_ns)) {

		if (i2c->scl_frequency <= 100000)

			i2c->scl_rise_ns = 1000;

		else

			i2c->scl_rise_ns = 300;

	}

	if (of_property_read_u32(pdev->dev.of_node, "i2c-scl-falling-time-ns",

				 &i2c->scl_fall_ns))

		i2c->scl_fall_ns = 300;

	if (of_property_read_u32(pdev->dev.of_node, "i2c-sda-falling-time-ns",

				 &i2c->sda_fall_ns))

		i2c->sda_fall_ns = i2c->scl_fall_ns;

	/* use common interface to get I2C timing properties */

	i2c_parse_fw_timings(&pdev->dev, &i2c->t, true);



	strlcpy(i2c->adap.name, "rk3x-i2c", sizeof(i2c->adap.name));

	i2c->adap.owner = THIS_MODULE;

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