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authorPrzemyslaw Gaj <pgaj@cadence.com>2019-11-18 16:01:14 +0100
committerBoris Brezillon <boris.brezillon@collabora.com>2019-12-09 16:07:21 +0100
commitdbd6654329fcb0f5fc11d07997ddb61683c085f2 (patch)
tree53a2aaac4ac046ed269e115decc16c011af68d3f /drivers/i3c
parente42617b825f8073569da76dc4510bfa019b1c35a (diff)
downloadlinux-dbd6654329fcb0f5fc11d07997ddb61683c085f2.tar.bz2
i3c: master: cdns: add data hold delay support
This patch adds support for THD_DEL (Data Hold Delay) to Cadence I3C master constoller driver. As per MIPI I3C Specification 1.0, Table 75 (page 142) defines non-zero minimal tHD_PP timing on master output (Fig 65). This setting allows to meet this timing on master's soc outputs, regardless of PCB balancing. Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Diffstat (limited to 'drivers/i3c')
-rw-r--r--drivers/i3c/master/i3c-master-cdns.c49
1 files changed, 44 insertions, 5 deletions
diff --git a/drivers/i3c/master/i3c-master-cdns.c b/drivers/i3c/master/i3c-master-cdns.c
index 10db0bf0655a..eed2e4fa299c 100644
--- a/drivers/i3c/master/i3c-master-cdns.c
+++ b/drivers/i3c/master/i3c-master-cdns.c
@@ -22,6 +22,7 @@
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
+#include <linux/of_device.h>
#define DEV_ID 0x0
#define DEV_ID_I3C_MASTER 0x5034
@@ -60,6 +61,7 @@
#define CTRL_HALT_EN BIT(30)
#define CTRL_MCS BIT(29)
#define CTRL_MCS_EN BIT(28)
+#define CTRL_THD_DELAY(x) (((x) << 24) & GENMASK(25, 24))
#define CTRL_HJ_DISEC BIT(8)
#define CTRL_MST_ACK BIT(7)
#define CTRL_HJ_ACK BIT(6)
@@ -70,6 +72,7 @@
#define CTRL_MIXED_FAST_BUS_MODE 2
#define CTRL_MIXED_SLOW_BUS_MODE 3
#define CTRL_BUS_MODE_MASK GENMASK(1, 0)
+#define THD_DELAY_MAX 3
#define PRESCL_CTRL0 0x14
#define PRESCL_CTRL0_I2C(x) ((x) << 16)
@@ -388,6 +391,10 @@ struct cdns_i3c_xfer {
struct cdns_i3c_cmd cmds[0];
};
+struct cdns_i3c_data {
+ u8 thd_delay_ns;
+};
+
struct cdns_i3c_master {
struct work_struct hj_work;
struct i3c_master_controller base;
@@ -408,6 +415,7 @@ struct cdns_i3c_master {
struct clk *pclk;
struct cdns_i3c_master_caps caps;
unsigned long i3c_scl_lim;
+ const struct cdns_i3c_data *devdata;
};
static inline struct cdns_i3c_master *
@@ -1181,6 +1189,20 @@ static int cdns_i3c_master_do_daa(struct i3c_master_controller *m)
return 0;
}
+static u8 cdns_i3c_master_calculate_thd_delay(struct cdns_i3c_master *master)
+{
+ unsigned long sysclk_rate = clk_get_rate(master->sysclk);
+ u8 thd_delay = DIV_ROUND_UP(master->devdata->thd_delay_ns,
+ (NSEC_PER_SEC / sysclk_rate));
+
+ /* Every value greater than 3 is not valid. */
+ if (thd_delay > THD_DELAY_MAX)
+ thd_delay = THD_DELAY_MAX;
+
+ /* CTLR_THD_DEL value is encoded. */
+ return (THD_DELAY_MAX - thd_delay);
+}
+
static int cdns_i3c_master_bus_init(struct i3c_master_controller *m)
{
struct cdns_i3c_master *master = to_cdns_i3c_master(m);
@@ -1264,6 +1286,15 @@ static int cdns_i3c_master_bus_init(struct i3c_master_controller *m)
* We will issue ENTDAA afterwards from the threaded IRQ handler.
*/
ctrl |= CTRL_HJ_ACK | CTRL_HJ_DISEC | CTRL_HALT_EN | CTRL_MCS_EN;
+
+ /*
+ * Configure data hold delay based on device-specific data.
+ *
+ * MIPI I3C Specification 1.0 defines non-zero minimal tHD_PP timing on
+ * master output. This setting allows to meet this timing on master's
+ * SoC outputs, regardless of PCB balancing.
+ */
+ ctrl |= CTRL_THD_DELAY(cdns_i3c_master_calculate_thd_delay(master));
writel(ctrl, master->regs + CTRL);
cdns_i3c_master_enable(master);
@@ -1521,6 +1552,15 @@ static void cdns_i3c_master_hj(struct work_struct *work)
i3c_master_do_daa(&master->base);
}
+static struct cdns_i3c_data cdns_i3c_devdata = {
+ .thd_delay_ns = 10,
+};
+
+static const struct of_device_id cdns_i3c_master_of_ids[] = {
+ { .compatible = "cdns,i3c-master", .data = &cdns_i3c_devdata },
+ { /* sentinel */ },
+};
+
static int cdns_i3c_master_probe(struct platform_device *pdev)
{
struct cdns_i3c_master *master;
@@ -1532,6 +1572,10 @@ static int cdns_i3c_master_probe(struct platform_device *pdev)
if (!master)
return -ENOMEM;
+ master->devdata = of_device_get_match_data(&pdev->dev);
+ if (!master->devdata)
+ return -EINVAL;
+
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
master->regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(master->regs))
@@ -1631,11 +1675,6 @@ static int cdns_i3c_master_remove(struct platform_device *pdev)
return 0;
}
-static const struct of_device_id cdns_i3c_master_of_ids[] = {
- { .compatible = "cdns,i3c-master" },
- { /* sentinel */ },
-};
-
static struct platform_driver cdns_i3c_master = {
.probe = cdns_i3c_master_probe,
.remove = cdns_i3c_master_remove,