linux-kernel - [PATCH v2 2/5] gpio: pca953x: add register definitions for pcal6524 and fix address calculation

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Date:   Wed,  4 Apr 2018 21:00:21 +0200
From:   "H. Nikolaus Schaller" <hns@...delico.com>
To:     galak@...eaurora.org, andy.shevchenko@...il.com,
        Rob Herring <robh+dt@...nel.org>,
        Pawel Moll <pawel.moll@....com>,
        Mark Rutland <mark.rutland@....com>,
        Ian Campbell <ijc+devicetree@...lion.org.uk>,
        Linus Walleij <linus.walleij@...aro.org>,
        Alexandre Courbot <gnurou@...il.com>
Cc:     devicetree@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org, letux-kernel@...nphoenux.org,
        kernel@...a-handheld.com,
        "H. Nikolaus Schaller" <hns@...delico.com>
Subject: [PATCH v2 2/5] gpio: pca953x: add register definitions for pcal6524 and fix address calculation

PCAL chips ("L" seems to stand for "latched") have additional
registers starting at address 0x40 to control the latches,
interrupt mask, pull-up and pull down etc.

The constants are so far defined in a way that they fit for
the pcal9555a when shifted by the number of banks, i.e. multiplied
by 2.

Now the pcal6524 has 3 banks which means the relative offset
must be multiplied by 4 which gives a wrong result if not done
carefully, since the base offset is already included in the offset.

For the basic registers shared with all pca93xx/tca64xx chips
there is no such offset.

Therefore, we add code to adjust the register number for exended
registers in this case.

And we add additional register offset constants (not yet used by
the driver code) which are specific to the pcal6524.

Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
---
 drivers/gpio/gpio-pca953x.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 4a075619b93e..c70acba710c7 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -41,9 +41,19 @@
 #define PCA957X_MSK		6
 #define PCA957X_INTS		7
 
-#define PCAL953X_IN_LATCH	34
-#define PCAL953X_INT_MASK	37
-#define PCAL953X_INT_STAT	38
+#define PCAL953X_OUT_STRENGTH	0x20
+#define PCAL953X_IN_LATCH	0x22
+#define PCAL953X_PULL_EN	0x23
+#define PCAL953X_PULL_SEL	0x24
+#define PCAL953X_INT_MASK	0x25
+#define PCAL953X_INT_STAT	0x26
+#define PCAL953X_OUT_CONF	0x27
+
+#define PCAL6524_INT_EDGE	0x28
+#define PCAL6524_INT_CLR	0x2a
+#define PCAL6524_IN_STATUS	0x2b
+#define PCAL6524_OUT_INDCONF	0x2c
+#define PCAL6524_DEBOUNCE	0x2d
 
 #define PCA_GPIO_MASK		0x00FF
 #define PCA_INT			0x0100
@@ -208,6 +218,10 @@ static int pca953x_write_regs_24(struct pca953x_chip *chip, int reg, u8 *val)
 {
 	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
 
+	/* adjust register address for pcal6524 */
+	if (reg >= PCAL953X_OUT_STRENGTH)
+		reg -= PCAL953X_OUT_STRENGTH >> 1;
+
 	return i2c_smbus_write_i2c_block_data(chip->client,
 					      (reg << bank_shift) | REG_ADDR_AI,
 					      NBANK(chip), val);
@@ -250,6 +264,10 @@ static int pca953x_read_regs_24(struct pca953x_chip *chip, int reg, u8 *val)
 {
 	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
 
+	/* adjust register address for pcal6524 */
+	if (reg >= PCAL953X_OUT_STRENGTH)
+		reg -= PCAL953X_OUT_STRENGTH >> 1;
+
 	return i2c_smbus_read_i2c_block_data(chip->client,
 					     (reg << bank_shift) | REG_ADDR_AI,
 					     NBANK(chip), val);
-- 
2.12.2