Commit a76e7c68 authored by Thomas Kavanagh's avatar Thomas Kavanagh Committed by Wolfram Sang
Browse files

i2c: algo: pca: Fix chip reset function for PCA9665 



The parameter passed to pca9665_reset is adap->data (which is bus driver
specific), not i2c_algp_pca_data *adap. pca9665_reset expects it to be
i2c_algp_pca_data *adap. All other wrappers from the algo call back to
the bus driver, which knows to handle its custom data. Only pca9665_reset
resides inside the algorithm code and does not know how to handle a custom
data structure. This can result in a kernel crash.

Fix by re-factoring pca_reset() from a macro to a function handling chip
specific code, and only call adap->reset_chip() if the chip is not PCA9665.

Signed-off-by: default avatarThomas Kavanagh <tkavanagh@juniper.net>
Signed-off-by: default avatarGuenter Roeck <groeck@juniper.net>
Signed-off-by: default avatarWolfram Sang <w.sang@pengutronix.de>
parent 0c25aefa

drivers/i2c/algos/i2c-algo-pca.c

+14 −13
Original line number Diff line number Diff line
@@ -46,14 +46,19 @@ static int i2c_debug; 
#define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)

#define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)

#define pca_wait(adap) adap->wait_for_completion(adap->data)

#define pca_reset(adap) adap->reset_chip(adap->data)



static void pca9665_reset(void *pd)

static void pca_reset(struct i2c_algo_pca_data *adap)

{

	struct i2c_algo_pca_data *adap = pd;

	if (adap->chip == I2C_PCA_CHIP_9665) {

		/* Ignore the reset function from the module,

		 * we can use the parallel bus reset.

		 */

		pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);

		pca_outw(adap, I2C_PCA_IND, 0xA5);

		pca_outw(adap, I2C_PCA_IND, 0x5A);

	} else {

		adap->reset_chip(adap->data);

	}

}



/*
@@ -378,11 +383,12 @@ static unsigned int pca_probe_chip(struct i2c_adapter *adap) 
	pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);

	if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) {

		printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name);

		return I2C_PCA_CHIP_9665;

		pca_data->chip = I2C_PCA_CHIP_9665;

	} else {

		printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);

		return I2C_PCA_CHIP_9564;

		pca_data->chip = I2C_PCA_CHIP_9564;

	}

	return pca_data->chip;

}



static int pca_init(struct i2c_adapter *adap)
@@ -456,11 +462,6 @@ static int pca_init(struct i2c_adapter *adap) 
		 */

		int raise_fall_time;



		/* Ignore the reset function from the module,

		 * we can use the parallel bus reset

		 */

		pca_data->reset_chip = pca9665_reset;



		if (pca_data->i2c_clock > 1265800) {

			printk(KERN_WARNING "%s: I2C clock speed too high."

				" Using 1265.8kHz.\n", adap->name);

include/linux/i2c-algo-pca.h

+1 −0
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ struct i2c_algo_pca_data { 
	 * 330000, 288000, 217000, 146000, 88000, 59000, 44000, 36000

	 * For PCA9665, use the frequency you want here. */

	unsigned int			i2c_clock;

	unsigned int			chip;

};



int i2c_pca_add_bus(struct i2c_adapter *);

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