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Commit 4ecfb9d3 authored by Wolfram Sang's avatar Wolfram Sang Committed by Wolfram Sang
Browse files

i2c: sh_mobile: add new frequency calculation for later SoC 



The formula to generate the desired bus speeds has changed a little over
time. Implement the new formula and allow drivers to opt-in by changing
to this new config set. Ensure in probe that we don't divide by zero.
The returned values on a R-Car H2 (r8a7790/Lager board) match the
suggested values in the datasheet.

Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent c3449f73

drivers/i2c/busses/i2c-sh_mobile.c

+18 −1
Original line number Original line Diff line number Diff line
@@ -299,6 +299,18 @@ static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd) 
	return sh_mobile_i2c_check_timing(pd);

	return sh_mobile_i2c_check_timing(pd);

}

}





static int sh_mobile_i2c_v2_init(struct sh_mobile_i2c_data *pd)

{

	unsigned long clks_per_cycle;



	/* L = 5, H = 4, L + H = 9 */

	clks_per_cycle = clk_get_rate(pd->clk) / pd->bus_speed;

	pd->iccl = DIV_ROUND_UP(clks_per_cycle * 5 / 9 - 1, pd->clks_per_count);

	pd->icch = DIV_ROUND_UP(clks_per_cycle * 4 / 9 - 5, pd->clks_per_count);



	return sh_mobile_i2c_check_timing(pd);

}



static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,

static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,

			    enum sh_mobile_i2c_op op, unsigned char data)

			    enum sh_mobile_i2c_op op, unsigned char data)

{

{
@@ -785,6 +797,11 @@ static const struct sh_mobile_dt_config fast_clock_dt_config = { 
	.setup = sh_mobile_i2c_init,

	.setup = sh_mobile_i2c_init,

};

};





static const struct sh_mobile_dt_config v2_freq_calc_dt_config = {

	.clks_per_count = 2,

	.setup = sh_mobile_i2c_v2_init,

};



static const struct sh_mobile_dt_config r8a7740_dt_config = {

static const struct sh_mobile_dt_config r8a7740_dt_config = {

	.clks_per_count = 1,

	.clks_per_count = 1,

	.setup = sh_mobile_i2c_r8a7740_workaround,

	.setup = sh_mobile_i2c_r8a7740_workaround,
@@ -875,7 +892,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev) 
		return PTR_ERR(pd->reg);

		return PTR_ERR(pd->reg);





	ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed);

	ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed);

	pd->bus_speed = ret ? STANDARD_MODE : bus_speed;

	pd->bus_speed = (ret || !bus_speed) ? STANDARD_MODE : bus_speed;

	pd->clks_per_count = 1;

	pd->clks_per_count = 1;





	/* Newer variants come with two new bits in ICIC */

	/* Newer variants come with two new bits in ICIC */