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i2c: designware_i2c: Tidy up use of NULL priv

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At present we still have pre-driver-model code in this driver and it makes
things a bit confusing. In particular calc_bus_speed() is called with priv
as NULL if not using driver model.

This results in spk_cnt and comp_param1 being read from an invalid address
if not using driver model. For comp_param1 this may not cause problems if
reading from addresses close to 0 happens to be allowed, as high speed is
only supported by DM code. But spk_cnt is subsequently used to calculate
the bus periods and so this may cause problems (e.g. on spear600 board
which has not been migrated yet).

Add a new parameter regs parameter to calc_bus_speed() and add more
comments to this function and to _dw_i2c_set_bus_speed(), which calls it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Simon Glass 2020-04-22 10:13:53 -06:00 committed by Heiko Schocher
parent ab80137cc4
commit bcf08503f5
1 changed files with 23 additions and 11 deletions
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34
drivers/i2c/designware_i2c.c
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@ -199,18 +199,24 @@ static int dw_i2c_calc_timing(struct dw_i2c *priv, enum i2c_speed_mode mode,
return 0;
}
static int calc_bus_speed(struct dw_i2c *priv, int speed, ulong bus_clk,
struct dw_i2c_speed_config *config)
/**
* calc_bus_speed() - Calculate the config to use for a particular i2c speed
*
* @priv: Private information for the driver (NULL if not using driver model)
* @i2c_base: Registers for the I2C controller
* @speed: Required i2c speed in Hz
* @bus_clk: Input clock to the I2C controller in Hz (e.g. IC_CLK)
* @config: Returns the config to use for this speed
* @return 0 if OK, -ve on error
*/
static int calc_bus_speed(struct dw_i2c *priv, struct i2c_regs *regs, int speed,
ulong bus_clk, struct dw_i2c_speed_config *config)
{
const struct dw_scl_sda_cfg *scl_sda_cfg = NULL;
struct i2c_regs *regs = priv->regs;
enum i2c_speed_mode i2c_spd;
u32 comp_param1;
int spk_cnt;
int ret;
comp_param1 = readl(&regs->comp_param1);
if (priv)
scl_sda_cfg = priv->scl_sda_cfg;
/* Allow high speed if there is no config, or the config allows it */
@ -225,6 +231,9 @@ static int calc_bus_speed(struct dw_i2c *priv, int speed, ulong bus_clk,
/* Check is high speed possible and fall back to fast mode if not */
if (i2c_spd == IC_SPEED_MODE_HIGH) {
u32 comp_param1;
comp_param1 = readl(&regs->comp_param1);
if ((comp_param1 & DW_IC_COMP_PARAM_1_SPEED_MODE_MASK)
!= DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH)
i2c_spd = IC_SPEED_MODE_FAST;
@ -260,11 +269,14 @@ static int calc_bus_speed(struct dw_i2c *priv, int speed, ulong bus_clk,
return 0;
}
/*
* _dw_i2c_set_bus_speed - Set the i2c speed
* @speed: required i2c speed
/**
* _dw_i2c_set_bus_speed() - Set the i2c speed
*
* Set the i2c speed.
* @priv: Private information for the driver (NULL if not using driver model)
* @i2c_base: Registers for the I2C controller
* @speed: Required i2c speed in Hz
* @bus_clk: Input clock to the I2C controller in Hz (e.g. IC_CLK)
* @return 0 if OK, -ve on error
*/
static int _dw_i2c_set_bus_speed(struct dw_i2c *priv, struct i2c_regs *i2c_base,
unsigned int speed, unsigned int bus_clk)
@ -274,7 +286,7 @@ static int _dw_i2c_set_bus_speed(struct dw_i2c *priv, struct i2c_regs *i2c_base,
unsigned int ena;
int ret;
ret = calc_bus_speed(priv, speed, bus_clk, &config);
ret = calc_bus_speed(priv, i2c_base, speed, bus_clk, &config);
if (ret)
return ret;